










































This is an open access article under the terms of a license that permits non-commercial use, provided the original work is properly cited.  
© 2022 The Authors. Société Internationale d'Urologie Journal, published by the Société Internationale d'Urologie, Canada.

Key Words Competing Interests Article Information

Prostate cancer, commercial airline pilots, 
incidence, mortality

None declared. Received on September 1, 2021 
Accepted on January 23, 2022 
This article has been peer reviewed.

Soc Int Urol J. 2022;3(3):145–162

DOI: 10.48083/PDKF1241

145SIUJ.ORG SIUJ  •  Volume 3, Number 3  •  May 2022

REVIEW

Incidence and Mortality of Prostate Cancer in 
Commercial Airline Cockpit Crew: Systematic  
Review and Meta-Analysis

Hadia Khanani,1 George McClintock,1 Hilary Fernando,1 Gillian Heller,2 Rebecca Asher,2  
Cindy Garcia,1 David P. Smith,3 Ian Getley,4 Nariman Ahmadi,1 Norbert Doeuk,1  
Scott Leslie,1 Niruban Thanigasalam,1 Henry H. Woo1

1 Department of Uro-Oncology, Chris O’Brien Lifehouse, Camperdown, Australia 2 National Health and Medical Research Council Clinical Trials Centre, University of 
Sydney, Sydney, Australia 3 Daffodil Centre, The University of Sydney, a joint venture with Cancer Council New South Wales, Sydney, Australia  School of Public Health 
and Preventative Medicine, Monash University, Melbourne, Australia  Menzies Health Institute Queensland, Griffith University, Australia 4 PCAire Inc, Australia 
5 College of Health and Medicine, Australian National University, Wahroonga, Australia.  SAN Prostate Centre of Excellence, Sydney Adventist Hospital,  
Wahroonga, Australia 

Abstract

Commercial airline cockpit crew (CCC) are potentially exposed to occupational risk factors that may have detrimental 
health effects. However, available literature on prostate cancer (PCa) as a health outcome is conflicted. Therefore, this 
review of cohort studies aims to evaluate the incidence of and mortality from PCa in CCC based on studies published 
to date. PubMed, Medline, EMBASE and SCOPUS were searched from 1946 to April 2021. Cohort studies reporting 
standardized incidence ratios (SIR) and/or standardized mortality ratios (SMR) of PCa in CCC were included. 
Military, cabin crew and service personnel data were excluded. Independent data extraction was conducted, and study 
quality assessed. Standardized ratios were pooled using a fixed effects model and expressed with 95% confidence 
intervals. 75 studies were assessed for eligibility from which 6 involving 129 374 licensed CCC were included in the 
final analysis: Two reported incidence only, 1 incidence and mortality and 3 reported mortalities only. The pooled 
SIR for PCa in CCC was 1.41 (95% CI 1.17 to 1.71) with moderate heterogeneity (I2 = 53%) however, the pooled SMR 
was not statistically significant (1.08; 95% CI 0.94 to 1.24) also with moderate heterogeneity (I2 = 70%). The available 
evidence shows that CCC are at a higher risk of developing PCa but there is no evidence to suggest a similarly higher 
risk of death from the disease. The effect of early detection through PSA testing in this cohort is unclear. Occupational 
exposure to radiation and sleep disturbance may play a role, but clear evidence of additional risk is lacking. Our 
review indicates that most evidence is dated and to confidently assess contemporary health outcomes of CCC, further 
research is required.

Introduction
Commercial airline cockpit crew (CCC) usually includes captains (pilot in command), co-pilots (first officer) and 
flight engineers with variations in number depending on type of aircraft and route[1]. This is an occupational 
cohort who undergo strict medical surveillance and are often regarded as healthier than the general population[2]. 
Although a healthy worker effect exists among pilots[3,4], their unique work environment exposes them to several 
risk factors including exposure to electromagnetic fields, ionizing radiation of cosmic origin, disruptions of circadian 
rhythm, and noise pollution[5], ultimately raising their risk of poorer outcomes in several physical and mental health 
parameters[6–8,9].

http://SIUJ.org
https://orcid.org/0000-0003-2101-8261
https://orcid.org/0000-0002-6992-8013
https://orcid.org/0000-0003-3647-8658
https://orcid.org/0000-0003-1270-1499
https://orcid.org/0000-0003-2502-4693
https://orcid.org/0000-0002-5787-2964
https://orcid.org/0000-0002-1474-3214
https://orcid.org/0000-0001-5864-1044
https://orcid.org/0000-0001-8727-5952
https://orcid.org/0000-0003-4322-2984
https://orcid.org/0000-0001-9848-969X
https://orcid.org/0000-0002-6438-8732
https://orcid.org/0000-0003-4099-0339
mailto:henry.woo%40lh.org.au?subject=SIUJ


In 1990, T he Internat iona l Com mission on 
Radiological Protection recommended that natural 
background radiation exposure be included as an occu-
pational hazard for aircrew[10], and since then, various 
reports[5,9,11–21] have described the incidence and 
mortality risks of cancer in pilot cohorts. In summary, 
decreased mortality from cardiovascular and respiratory 
diseases was reported in some cohorts[5,11,13,14] as well 
as all cancer deaths[13,15,16,18,20,21] when compared 
with mortality in the general population. Malignant 
melanoma has been consistently associated with high 
incidence[12,13,22–26] and mortality ratios[5,13,14].

Prostate cancer ranks second in incidence after 
lung cancer and fifth in mortality rates in males glob-
ally[27]. To our knowledge, no studies have exclusively 
investigated PCa in CCC. However, data on prostate 
cancer risks have been reported in studies document-
ing outcomes from multiple disease types that report 
conflicting results associated with incidence and mortal-
ity rates of PCa. From these, 6 studies have reported 
increased incidence[12,13,25–29], 2 reported no signif-
icant association[23,26] and one[30] reported a lower 
incidence of PCa compared with background popu-
lation rates. Similar contradictory evidence is avail-
able in mortality studies, with data reporting lower[9], 
unchanged[14,16,17,21,31,32], and higher[5,13,33] 
mortality rates of PCa in CCC relative to population 
statistics.

Several commentaries[7], meta-analyses[34,35], 
and reviews[36] have reported cancer risks in f light 
personnel, with data for cockpit crew, f light atten-
dants, and military personnel generally analyzed sepa-
rately. These studies report for all cancer types, except 
one study[37] that focused exclusively on PCa in pilots. 
Raslau et al. in the review and meta-analysis reported a 
higher incidence of PCa (RR 1.20; 95% CI 1.08 to 1.33) 
in pilots compared with the general population, but 
mortality was not significantly elevated (RR 1.20; 95% 
CI 0.91 to 1.60). After initial retraction[38], the revised 
version[37] was criticised[39] for omission of eligible 
studies[5,9,12,21] and re-inclusion of military data[40].

Given the inconclusive nature of literature in this area 
and the previously retracted and criticised review, a new 
analysis is required. This study, therefore, in addition 

to correcting past errors, aimed to provide a systematic 
review and meta-analysis of data exclusively focusing on 
PCa in CCC.

Materials and Methods
This systemat ic rev iew a nd meta-a na lysis was 
undertaken in accordance with the Preferred Reporting 
Items for Systematic Reviews and Meta-Analyses 
(PR ISMA) statement recommendations[41]. Two 
independent investigators (H.F. and H.K.) conducted the 
literature search, study selection, and data extraction, 
and resolved any discrepancies through discussion.

Selection criteria
Studies that fit the following criteria were included 
in the meta-analysis: (1) published studies only, (2) 
original population data, (3) cohort study design, (4) 
investigating CCC only, (5) PCa as either one of the 
outcomes or the only outcome reported, (6) reporting 
in terms of standardized incidence ratios (SIR) or 
standardized mortality ratios (SMR) and their 95% 
confidence intervals (CI) only or studies containing 
sufficient data for calculation of these parameters, (7) 
reporting 2 or more cases of prostate cancer in either 
incidence or mortality occurrences and (8) written in 
any language. All studies that investigated military, 
cabin crew, f light attendants and other personnel 
not designated as an occupation undertaken inside 
the cockpit were excluded. Latest studies that were 
investigative extensions of previous data cohorts were 
selected to avoid data duplication.

Literature search and data sources
Eligible cohort studies in any language published 
on PubMed, Medline, EMBASE and SCOPUS from 
inception up to April 2021 were searched using the 
search strategies outlined in Appendix 1. Commercial 
aircraft pilot, navigator, and flight engineer data were 
included as CCC, and military and helicopter pilots, 
flight/cabin attendant and service personnel data were 
excluded. Flight attendant cohorts that reported cancer 
incidence[24,42] and mortality[43,44] collectively 
analyzed 5 times as many females as males; most of 
the population were younger than 50 years, and they 
had a much shorter work period than pilots. They 
were therefore excluded. Military and helicopter pilots 
fly different routes and at different altitudes[29] from 
commercial cockpit crew and so were also excluded 
from the analysis.

The titles and abstracts of all identified articles were 
reviewed by 2 investigators independently, and disagree-
ments and ambiguities resolved by discussion. The refer-
ence lists of identified studies and previous systematic 
reviews were manually examined for additional stud-

Abbreviations 
CCC commercial airline cockpit crew
PCa prostate cancer
PSA prostate specific antigen
SIR standardized incidence ratio
SMR standardized mortality ratio

146 SIUJ  •  Volume 3, Number 3  •  May 2022 SIUJ.ORG

REVIEW

http://SIUJ.org


ies of interest. Reports in which the data were dupli-
cated were identified, and only the most recent cohorts 
were included. The abbreviation “CCC” and the words 
“pilots” and “cockpit crew” are used interchangeably 
throughout the paper.

Data extraction and quality assessment
A standardized data extraction form was used by 2 
independent researchers. The following relevant infor-
mation was extracted from each study: author, year of 
publication, study outcome (incidence, mortality, or 
both), title of paper, country, population size of cohort, 
duration of study, mean age at conclusion, Newcastle–
Ottawa Scale (NOS)[45] score, risk factors assessed 
(years of employment, cumulative radiation dose in 
µSv or mSv, cumulative block hours and high altitude 
long-haul or short-haul flights), observed and expected 
number of PCa cases, SIR or SMR, and 95% confidence 
intervals.

The quality of the papers included in the review was 
assessed using the Newcastle–Ottawa Scale (NOS) 
developed by Wells et al.[45]. The NOS is tailored to the 
design type and allows assessment the validity of results 
in the presence of selection, reporting, and confound-
ing biases. It uses 3 domains for assessment: selection, 
comparability, and outcome. Stars were added in each 
domain, with the totals signifying “good,” “fair,” or 
“poor” quality. Details of each item can be found on the 
website (www.ohri.ca/programs/clinical_epidemiology/
oxford.asp).

Data synthesis and statistical analysis
The outcomes of interest were standardized incidence 
rat ios (SIR) a nd sta nda rdized mor ta lit y rat ios 
(SMR). For each study, the observed and expected 
numbers were extracted. This allowed the calculation 
of the standardized ratios (SR) and corresponding 
confidence intervals to be consistent across studies. 
The SR was calculated as observed/expected and 
then log-transformed. The standard error of the 
log(SR) was calculated using 1/sqrt(observed) and 
confidence intervals constructed on the log-scale and 
exponentiated. This ensured that all estimates would be 
positive.

A fixed effects meta-analysis was used to calculate the 
pooled standardized ratios across studies. The I2 statistic 
was calculated to investigate the extent of heterogeneity 
across studies. Heterogeneity was considered low for 
I2 values between 25% and 50%, moderate for 50% to 
75%, and high for >75%. R software (version 4.0.2) was 
used for computation of the estimates and construction 
of forest plots packages, with packages meta[46] and 
metaphor[47]. Publication bias could not be assessed as 
the study included fewer than 10 studies[48].

Results
Literature search and study selection
Figure 1 shows the literature search and study selection 
process. We identified 3100 records by key word search, 
and hand searching elicited 17 further studies. After 
screening, 75 remaining full-text articles were assessed 
for eligibility of which 6 were included in the review:  
2 studies reported incidence only, 3 reported mortality 
only, and 1 reported both for PCa. From the large number 
of studies excluded, 30 were tabulated with reasons 
for ex clusion and selected data characteristics (0- and 
Supplementary Table S1B).

Methodological evaluation of studies: 
identification of systematic bias
The NOS components and total scores are shown against 
each study in Table 1. The 1996 study by Band et al.[13] 
was assessed for incidence and mortality outcomes 
separately. The median total score was 6, and only 2 
studies scored a total of 7, indicating an overall good 
quality of studies and no manuscripts with a high risk of 
bias. Total scores and thus quality of the studies tended 
to be less prone to bias if they were published more 
recently.

Incidence of prostate cancer among CCC: 
meta-analysis results
Table 2 and Figure 2 summarize the results of the meta-
analysis of 3 studies reporting incidence of PCa. The 
pooled analysis resulted in a pSIR of 1.41 (95% CI 1.17 
to 1.71) suggesting that observed rates were significantly 
higher than expected. The pooled results were of 
moderate heterogeneity (I2= 53%). An exploration of 
sources and subsequently a pooled analysis of sub-
groups and risk factors was not possible because of 
heterogeneity and lack of sufficient and consistent data in 
individual cohorts. Studies by Band et al.[12,13] did not 
include a risk factor analysis, leaving only one[25] from 
the included incidence studies attempting to analyze 
cosmic radiation and circadian disruptions as risk 
factors of PCa by calculating relative risk estimates. They 
did so by approximating radiation exposure with block 
hours on short-haul flights and hormone disturbances 
with block hours on long-haul flights.

Mortality of prostate cancer among CCC: 
meta-analysis results
The summary of results of the meta-analysis of the  
4 mortality studies are shown in Table 3 and Figure 3. 
The analysis resulted a pSMR of 1.08 (95% CI 0.94 to 
1.24), suggesting that observed mortality rates were not 
significantly different to the rate expected in the general 
population with moderate heterogeneity (I2=70%). 
The 1990[12] study by Band et al. was excluded from 
the mortality analysis because only 1 death from PCa 

147SIUJ.ORG SIUJ  •  Volume 3, Number 3  •  May 2022

Incidence and Mortality of Prostate Cancer in Commercial Airline Cockpit Crew: Systematic Review and Meta-Analysis

http://www.ohri.ca/programs/clinical_epidemiology/oxford.asp
http://www.ohri.ca/programs/clinical_epidemiology/oxford.asp
http://SIUJ.org


was observed. From the included studies, only 2[5,21]  
reported a risk factor analysis (discussed below); 
however, it is noteworthy that Yong et al.[21] reported 
standardized rate ratios of duration of employment and 
cumulative cosmic radiation dose with mortality, but no 
data on PCa were available. Lack of risk factor analysis 
from other included studies prevented a multivariable 
analysis with mortality data as well.

Discussion
This systematic review and meta-analysis summarizes 
available literature pertaining to incidence and mortality 
rates of PCa in CCC. These results may support the 
hypothesis that prostate cancer risks in CCC ref lect 

a combination of screening, sociodemographic, and 
environmental factors that increase the risk of diagnosis 
but have no effect on the risk of death from prostate 
cancer. However, because of substantial heterogeneity 
among studies and an overall small sample size, we 
believe these results should be interpreted with caution.

The most plausible drivers of the observed increased 
incidence of PCa in CCC appear to be occupational 
risk factors discussed in detail below. However, it is also 
worth noting that over the last 2 decades the rise of pros-
tate specific antigen (PSA) testing in many developed 
countries has led to dramatic increases in the incidence 
rates of PCa via diagnosis of sub-clinical disease[49]. 
Although in most developed countries, PSA testing is 

FIGURE 1. 

Flow diagram of literature search and study selection for meta-analysis of prostate cancer in commercial airline 
cockpit crew/pilots.

Records identi�ed through 
search of MEDLINE, PubMed, 

EMBASE and SCOPUS
(n = 3100)

 

In
cl

ud
ed

S
cr

ee
ni

ng
Id

en
ti

�c
at

io
n

El
ig

ib
il

it
y

Additional records identi�ed 
through manual search

(n = 17)

Records after duplicates removed
(n = 2852)

Records screened
(n = 2852)

Records excluded 
(n = 2777)

Full-text articles assessed 
for eligibility

(n =75)

Studies included in meta-analysis
(n= 6)

Incidence and mortality of 
prostate cancer

(n = 1)

Mortality of prostate cancer
(n = 3)

Incidence of prostate cancer
(n = 2)

Full-text articles excluded, 
with reasons:air force data / 

military data / cabin crew data / 
no data on outcome of interest / 

no data on prostate cancer / 
duplicated data cohorts

(n = 69)

148 SIUJ  •  Volume 3, Number 3  •  May 2022 SIUJ.ORG

REVIEW

http://SIUJ.org


not mandated as part of the medical certification process 
for CCC[50–52], CCC are more likely to be tested for 
PSA upon inquiry of reported lower urinary tract symp-
toms as they undergo more regularly scheduled and 
concentrated medical surveillance[2] than males in the 
general population. The results of this meta-analysis 
are likely also affected by increased use of PSA testing 
in CCC, which results in the detection of more localised 
PCa compared to the general population. CCC typi-
cally have higher incomes and PSA testing with subse-
quent follow-up of abnormal results is performed more 
frequently in men with higher incomes[53].

Despite increased incidence, mortality from PCa was 
unchanged as compared with the general population. 
Higher socioeconomic status and better baseline health 
could be factors in this observation, especially given the 
general long life expectancy of men diagnosed with PCa. 
The data related to the impact of PSA testing and early 
diagnosis of PCa is controversial, with current literature 
suggesting it does not affect overall mortality[54], which 
would be consistent with these results.

Exposure to ionizing radiation of cosmic origin
PCa is not frequently included in the list of neoplasms 

attributable to ionizing radiation[55], largely due to the 
lack of sensitivity of the prostate to ionizing radiation, 
but also due to the latency period of radiation induced 
solid tumours being decades[56] and PCa being among 
the slower growing solid tumours. Supporting this 
theory, studies investigating radiologists and other 
medical radiation workers have shown no increase in 
incidence[57] or mortality[58] rates of PCa. In contrast 
to this, studies after the 1986 Chernobyl incident show 
an increase in the incidence of PCa in regions surround-
ing the area of the accident[56,59]. The large release of 
radioactive material from the incident[60] makes it less 
relevant to pilots; however, findings of radiation induced 
incidence rates of PCa in pilots show similarly conflict-
ing results.

The study of Nordic pilots[25] quantified cumula-
tive radiation exposure by converting aircraft specific 
block hours to effective doses. Block hours are indus-
try-standard measure of aircraft use and are defined as 
the time elapsed between closure of aircraft doors before 
departure and opening of these doors at the arrival 
gate following landing of the aircraft. The same study 
used the number of block hours on long-haul aircrafts 
to estimate circadian hormonal disruption among 
pilots as well. A statistically significant increase of PCa 
was observed in exposure category ≥ 20 mSv, RR 9.13; 
95% CI 1.11 to 74.9 in men age < 60 years as compared 
with older ages in the same category of exposure (RR 
1.08; 95% CI 0.55 to 2.12). Similarly, Gudmundsdóttir 
et al.[26] reported a statistically significant risk ratio of 
2.57 (95% CI 1.18 to 5.56) in Icelandic pilots exposed to > 

25mSv of ionizing radiation of cosmic origin compared 
with pilots who were not. These values could possibly be 
related to greater levels of UV radiation at the poles than 
at the equator. The association between prostate cancer 
and radiation exposure remains uncertain. According to 
available literature it seems unlikely that development of 
prostate cancer at an early age would be associated with 
ionizing radiation as no studies have been able to estab-
lish a causal link between the two[25]. Adding to this 
evidence is the 20-year-old Norwegian study[23] that 
reported an inconsistent trend in SIR values as ioniz-
ing radiation exposure increased from 0mSv to >20mSv 
with a statistically non-significant elevated SIR of 1.8 
(95% CI 0.7 to 4.0) for pilots exposed to >20mSv of ioniz-
ing radiation.

Overall mortality data show moderate but higher 
heterogeneity than incidence data, but information on 
measurement of risk factors is less conflicted, with the 
majority of studies showing no significant difference, 
although with heterogeneity in measurement meth-
odology. A mortality analysis of PCa cases exposed to 
>25 mSv cumulative effective dose of cosmic radiation 
reported in a German publication[32] reported low and 
non-significant mortality and risk ratios (SMR 0.92; 
95% CI 0.00 to 37.69, RR 0.94; 95% CI, 0.18 to 4.79).  
A large European cohort study (ESCAPE)[61] attempted 
a risk factor analysis of cosmic radiation and mortal-
ity rates in pilots. PCa was placed in the category of 
non-radiation related neoplasms[62,63] but SMRs of 
PCa with increasing doses of radiation were not reported 
individually. Mortality studies that quantify years of 
employment[16,31] or number of block hours since 
attaining a license[15] as proxies for radiation expo-
sure have reported no statistically significant mortal-
ity ratios of PCa. An extension[5] of the ESCAPE[61] 
study cohort with addition of pilots from Greece and 
United Kingdom, analyzed years of employment as 
proxy for cumulative radiation exposure. This large 
study, included in this review, also reported no consis-
tent change in SMRs in proportion to increasing years 
of employment. It is important to keep in mind that this 
study was an extension of previously reported cohorts 
hence similar results were to be expected. Further 
research into occupations frequently exposed to radi-
ation is warranted for clarification of the relationship 
between radiation and prostate cancer.

Exposure to electromagnetic fields  
and disruption of circadian rhythm
Although not fully understood, the incidence of PCa has 
been suspected to be linked with exposure to magnetic 
fields, which, it has been suggested, may lead to alteration 
in pineal function, subsequently causing reduction in 
levels of the pineal hormone, melatonin[33]. Melatonin 
is associated with the sleep–wake cycle and maintenance 

149SIUJ.ORG SIUJ  •  Volume 3, Number 3  •  May 2022

Incidence and Mortality of Prostate Cancer in Commercial Airline Cockpit Crew: Systematic Review and Meta-Analysis

http://SIUJ.org


TABLE 1. 

Characteristics of six studies included in the meta-analysis of prostate cancer among pilots 

Study author (Year)
Sample 

size
Study period Country/ region Observed Expected SIR (95% CI)

Mean age at 
conclusion

Risk factors 
considered

Quality score categories
Total quality score*

Selection Comparability Outcome

Band et al. (1990) 891 1950–1988 Canada 6 3.9 1.54 (0.69–3.43) 49.9 Not available      
6 

Fair

Band et al. (1996) 2680 1950–1992 Canada 34 18.2 1.87 (1.34–2.62) 50.5 Not available     
6 

Fair

Pukkala et al. (2003) 10 051

1946–1997 
(Denmark from 1946,  
Finland up to 1996,  
Iceland from 1937,  

Norway 1946–1994,  
Sweden 1957–1994)

Nordic countries 64 52.9 1.21 (0.93–1.54) Not available
Cumulative block 
hours, Cumulative 

radiation dose
    

7 
Good

Band et al. (1996) 2680 1950–1992 Canada 7 4.62 1.52 (0.72–3.19) 50.5 Not available     
6 

Fair

Cashman et al. (2007) 72 972 1980–2002 United States 4 10.9 0.37 (0.10–0.94) 43.09 Not available     
6 

Fair

Yong et al. (2014) 5964 1953–2008
United States  

(PanAm)
77 Not available 0.90 (0.71–1.12) Not available

Duration of 
employment, 
Cumulative  

radiation dose
    

6 
Good

Hammer et al. (2014) 36 816

1957–1999 
(Denmark 1960–1996,  

Finland 1971–1997, 
Germany, Greece,  

Iceland 1960–1997, 
Italy 1965–1996, 

Norway 1962–1994, 
Sweden  1957–1994, 

United Kingdom 
1989–1999)

Europe /  
United States†

114 119.99 1.23 (1.03–1.47) 53.3
Duration of 

employment as proxy 
for radiation exposure

   
7 

Good

*Assessed by the Newcastle-Ottawa Scale45  
†United States was part of the cohort but data on pilots was not available or analysed (cabin crew data analysed only)

150 SIUJ  •  Volume 3, Number 3  •  May 2022 SIUJ.ORG

REVIEW

http://SIUJ.org


TABLE 1. 

Characteristics of six studies included in the meta-analysis of prostate cancer among pilots 

Study author (Year)
Sample 

size
Study period Country/ region Observed Expected SIR (95% CI)

Mean age at 
conclusion

Risk factors 
considered

Quality score categories
Total quality score*

Selection Comparability Outcome

Band et al. (1990) 891 1950–1988 Canada 6 3.9 1.54 (0.69–3.43) 49.9 Not available      
6 

Fair

Band et al. (1996) 2680 1950–1992 Canada 34 18.2 1.87 (1.34–2.62) 50.5 Not available     
6 

Fair

Pukkala et al. (2003) 10 051

1946–1997 
(Denmark from 1946,  
Finland up to 1996,  
Iceland from 1937,  

Norway 1946–1994,  
Sweden 1957–1994)

Nordic countries 64 52.9 1.21 (0.93–1.54) Not available
Cumulative block 
hours, Cumulative 

radiation dose
    

7 
Good

Band et al. (1996) 2680 1950–1992 Canada 7 4.62 1.52 (0.72–3.19) 50.5 Not available     
6 

Fair

Cashman et al. (2007) 72 972 1980–2002 United States 4 10.9 0.37 (0.10–0.94) 43.09 Not available     
6 

Fair

Yong et al. (2014) 5964 1953–2008
United States  

(PanAm)
77 Not available 0.90 (0.71–1.12) Not available

Duration of 
employment, 
Cumulative  

radiation dose
    

6 
Good

Hammer et al. (2014) 36 816

1957–1999 
(Denmark 1960–1996,  

Finland 1971–1997, 
Germany, Greece,  

Iceland 1960–1997, 
Italy 1965–1996, 

Norway 1962–1994, 
Sweden  1957–1994, 

United Kingdom 
1989–1999)

Europe /  
United States†

114 119.99 1.23 (1.03–1.47) 53.3
Duration of 

employment as proxy 
for radiation exposure

   
7 

Good

*Assessed by the Newcastle-Ottawa Scale45  
†United States was part of the cohort but data on pilots was not available or analysed (cabin crew data analysed only)

151SIUJ.ORG SIUJ  •  Volume 3, Number 3  •  May 2022

Incidence and Mortality of Prostate Cancer in Commercial Airline Cockpit Crew: Systematic Review and Meta-Analysis

http://SIUJ.org


of circadian rhythm, and it may have a protective effect 
against prostate cancer[64]. Magnetic field exposure 
in commercial aircraft has been measured in a prior 
study[65] and was concluded to be substantially higher 
than that of a home or a typical office environment. 
Most studies used block hours as approximate values 
for amount of magnetic field exposure and hormonal 
disruption[21,25]. The Nordic study[25] reported 
increased risk associated with a greater number of long-
haul hours in men > 60 years of age as the strongest 
flying-related variable studied in the context of prostate 
cancer. The possibility that circadian disruptions have 
a role in causing hormone-related neoplasms cannot 
therefore be entirely excluded. However, a precise 
association or disassociation between jet lag and 
development of hormone-related cancers could not be 
established. Gudmundsdóttir et al.[26] observed similar 
results of higher incidence rates of PCa in pilots with 
>10 000 cumulative air hours (RR 2.61; 95% CI 1.22 
to 5.60). In contrast, however, an incidence study[29] 
not included in the meta-analysis (Supplementary 
Table S1A and Supplementary Table S1B) reported 
no significant increase in the incidence of PCa in 
relation to block hours (SIR 1.28; 95% CI 0.73 to 2.08 
for >10 000 block hours). Similarly, the Norwegian pilot 
cohort[23] reported a statistically non-significant SIR of 
1.1 (95% CI 0.6 to 1.9) among pilots who flew >10 000 

block hours. The same year, in their study on Icelandic 
pilots, Raffnson et al.[28] attempted to evaluate the 
possible association between cancer risk and circadian 
rhythm disturbance but reported only incidence rates of 
malignant melanoma and all-cancer risk. An extension 
of this cohort[26] could not differentiate between pilots 
who had flown to North America and those who had 
flown within Europe, as all Icelandic pilots had flown 
both ways and so were unable to report cases of PCa in 
pilots on long-haul versus short-haul flights.

Although long-haul flights suppress melatonin and, 
as hypothesized, might be expected to be associated with 
higher incidence rates of PCa, a study of British Airways 
pilots[14] (excluded from the review because of inclusion 
of helicopter crew data) reported a statistically non-sig-
nificant relative risk of PCa (RR 2.47; 95% CI 0.83 to 
7.65) for short-haul compared with long-haul flights. In 
an attempt to resolve ambiguities in this area, a recent 
review[66] reported that neither short sleep (RR 0.99; 
95% CI 0.91 to 1.07) nor long sleep (RR 0.88; 95% CI 0.75 
to 1.04) was associated with PCa in the general popula-
tion, and long sleep may have a protective effect on PCa; 
however, specific pilot cohorts were not investigated. 
Available evidence has again proven to be inconsistent in 
arriving at a conclusion on the association of circadian 
abnormalities and PCa necessitating deeper investiga-
tion into the subject.

FIGURE 2. 

Study Year SIR 95% CI Weight

Band et al. 1990

0.5 1 2 3.5

1.54 (0.69–3.43) 5.8%

Band et al. 1996 1.87 (1.34–2.62) 32.7%

Pukkala et al. 2003 1.21 (0.95–1.55) 61.5%

1.41 (1.17–1.71) 100%

TABLE 2. 

Included incidence studies with observed and expected number of prostate cancer cases, individual and calculated 
SIR, weightage, and calculated heterogeneity. SIR, standardised incidence ratio 

Study author (Year) Observed Expected SIR (95% CI)            Weight, %

Band et al. (1990) 6 3.9 1.5400 (0.6919–3.4279) 5.8

Band et al. (1996) 34 18.16 1.8700 (1.3362–2.6171) 32.7

Pukkala et al (2003) 64 52.9 1.2100 (0.9471–1.5459) 61.5

Overall I2 = 53%   1.4146 [1.1673–1.7144] 100.0

152 SIUJ  •  Volume 3, Number 3  •  May 2022 SIUJ.ORG

REVIEW

http://SIUJ.org


Other considerations
The pilot population investigated to date has reported 
a mean age at conclusion of 41.7 to 50.5 years in 
incidence and 43.1 to 53.3 years in mortality studies. It 
is important to note that the Japanese study[11] recorded 
a mean age of 45.9±13.6 years at conclusion of follow-up, 
indicating PCa cases contributing to the reported all-
cancer mortality could possibly be non-existent because 
of the very low incidence of prostate cancer in younger 
men[67]. As older age is a well-established risk factor for 
PCa, it can be deduced that studies on CCC reflecting 
the mean age group mentioned above may be reporting 
an underestimation of true risk of the disease.

The strengths of this review lie in its exhaustive 
search and strict selection criteria for accurate represen-
tation of disease outcome and the inclusion of only CCC. 
Including data related to military pilots and cabin crew 
can often be misleading, especially when risk factors 
such as ionizing radiation exposure and circadian 
rhythm are being explored concomitantly, because of 
the differences in aircraft and route selection and flight 
altitudes between the 2 categories of pilot[29]. Although 
a sub-group analysis was not performed because of 
heterogenous exposure assessments in different stud-
ies, a streamlined sample approach aims to increase the 
credibility of this review.

An important limitation of our review was the inabil-
ity of search terms to produce important studies that 
were instead discovered by manual searching of refer-
ences by both researchers. The large North American 
study[9] eligible for the meta-analysis, as well as some 
that were later excluded, were not initially identified 
via the online database search. It is noteworthy that the 
recent review by Raslau et al.[37] did not include this 
study, perhaps due to the same reason.

Quality assessment of each study was conducted by 
both researchers independently, using the NOS[45] that 
has proven to be useful in multiple similar systematic 
reviews[68,69]. The quality of 2 out of 3 incidence studies 
was “fair,” only one was “good” and none were “poor.” 
It was noted that studies with lower population samples 
were of ‘fair’ quality and also reported higher incidence 
rates than the ‘good’ quality study. This phenomenon of 
likelihood of publishing studies with lower sample sizes 
and positive associations has been previously described 
by researchers[70]. Additionally, studies with fair quality 
were also older (published in the 1990s) than the ‘good’ 
quality study (published in 2003)[25].

In comparison to incidence cohorts, half of the 
mortality studies were of “fair” quality, and the other 
half were of “good” quality (none were of “poor” quality). 
It is noteworthy that the study with the largest sample 

TABLE 3.  

Included mortality studies with observed and expected number of deaths due to prostate cancer, individual and 
calculated SMR, weightage and calculated heterogeneity. SMR, standardised mortality ratio 

   Study author (Year) Observed Expected            SMR (95% CI)            Weight, %

Band et al. (1996) 7 4.62 1.5200 (0.7246–3.1884] 3.4

Cashman et al. (2007) 4 10.9 0.3700 [0.1389–0.9858] 1.9

Hammer et al.(2014) 114 119.99 1.2300 [1.0285–1.4710] 57.7

Yong et al. (2014) 77 not available 0.9000 [0.7198–1.1252] 37.0

     Overall I2 = 70%   1.0783 [0.9413–1.2353] 100

FIGURE 3. 

Study Year SMR 95% CI Weight

Band et al. 1996

0.50.1 1 2 3.5

1.52 (0.72–3.19) 3.4%

Cashman et al. 2007 0.37 (0.14–0.99) 1.9%

Hammer et al. 2014 1.23 (1.03–1.47) 57.7%

Yong et al. 2014 0.90 (0.72–1.13) 37.0%

1.08 (0.94–1.24) 100%

153SIUJ.ORG SIUJ  •  Volume 3, Number 3  •  May 2022

Incidence and Mortality of Prostate Cancer in Commercial Airline Cockpit Crew: Systematic Review and Meta-Analysis

http://SIUJ.org


of pilots (n = 72 972)[9] scored a total of 6 on the NOS 
and was of “fair” quality. It also reported a markedly 
decreased mortality rate of PCa among pilots, the lowest 
among all mortality studies, as well as in comparison to 
the pooled SMR (1.08; 95% CI 0.94 to 1.24). Although 
risk of potential bias is known to decrease with a higher 
sample size, this study is not only an exception but is also 
outnumbered by other included studies in this review 
that support results of low or unchanged mortality rates 
among pilots in comparison to the general population. 
The 1996 publication by Band et al.[13] favours the 
theory of increased risk of bias associated with a smaller 
sample size and positive associations as it reported the 
highest mortality rate among all studies.

We a re awa re of t he latest 2017 st udy by  
Gudmundsdóttir et al.[26]. However, after consider-
ation by the authors, it was concluded that this study 
should be excluded for a number of reasons. Firstly, 
the 2003 study by Pukkala et al. was a multinational 
cohort[25], inclusion of which would allow examina-
tion of a larger sample size, whereas the 2017[26] study 
by Gudmundsdóttir et al. investigated only Icelandic 
pilots. Secondly, the latter study added only 47 new 
pilots to the initial Icelandic sample in the Pukkala et al. 
study, resulting in 83.6% data duplication (n = 239[25] 
and n = 286[26]). Furthermore, it cannot be confirmed 
that differences in observed cases of PCa from the 2003 
study were in fact, observed cases in the added number 

of pilots. To demonstrate that results remain unchanged 
even with inclusion of this study, an analysis was 
performed with adjustment of sample sizes between the 
2 studies to prevent data duplication (Supplementary 
Figure S1A). Supplementary Figure S1B shows pooled 
SIR results (meta-SIR 1.39; 95% CI 1.16 to 1.67 with 
I2 = 35.9%). It is evident that results remain largely 
unchanged.

Conclusions
This systematic review of all available evidence suggests 
that compared with the general population, commercial 
airline cockpit crew have an increased risk of developing 
PCa; however, there was no evidence of elevated risk 
of death from this disease. Caution is suggested in 
interpretation of results, as most evidence is dated, 
results are inconclusive, and because of significant data 
duplication, the sample size for assessment of outcomes 
is ultimately small. The risk of developing PCa as a 
result of exposure to ionizing radiation and circadian 
disruptions needs to be investigated further for accurate 
estimates of the associated burden of disease. This 
work supports previous calls for national registries for 
commercial airline cockpit crew to track incidence and 
mortality rates of PCa and for better understanding of 
health outcomes in this population.

154 SIUJ  •  Volume 3, Number 3  •  May 2022 SIUJ.ORG

REVIEW

http://SIUJ.org


References

1. Yan S, Chang J-C. Airline cockpit crew scheduling. Eur J Oper 
Res.2002;136(3):501–511.

2. dos Santos Silva I, De Stavola B, Pizzi C, Evans AD, Evans SA. Cancer 
incidence in professional flight crew and air traffic control officers: 
disentangling the effect of occupational versus lifestyle exposures. 
Int J Cancer.2013;132(2):374–384. doi: 10.1002/ijc.27612. Epub 2012 
May 22.

3. Li G, Baker SP, Grabowski JG, Qiang Y, McCarthy ML, Rebok GW. 
Age, flight experience, and risk of crash involvement in a cohort of 
professional pilots. Am J Epidemiol.2003;157(10):874–880. doi: 
10.1093/aje/kwg071.

4. Howe GR, Chiarelli AM, Lindsay JP. Components and modifiers 
of the healthy worker effect: evidence from three occupational 
cohor ts and implications for industrial compensation. Am J 
Epidemiol.1988;128(6):1364–1375. doi: 10.1093/oxfordjournals.aje.
a115089

5. Hammer GP, Auvinen A, De Stavola BL, Grajewski B, Gundestrup 
M, Haldorsen T, et al. Mortality from cancer and other causes in 
commercial airline crews: a joint analysis of cohorts from 10 countries. 
Occup Environ Med.2014;71(5):313–322. doi: 10.1136/oemed-2013-
101395. Epub 2014 Jan 3.

6. Miura K, Olsen CM, Rea S, Marsden J, Green AC. Do airline 
pilots and cabin crew have raised risks of melanoma and other 
skin cancers? Systematic review and meta-analysis. Br J 
Dermatol.2019;181(1):55 – 64. doi: 10.1111/bjd.17586. Epub 2019  
Mar 18.

7. Lynge E. Commentar y: cancer in the air. Int J Epidemiol.2001;    
30(4):830–832. doi: 10.1093/ije/30.4.830.

8. Wu AC, Donnelly-McLay D, Weisskopf MG, McNeely E, Betancourt 
TS, Allen JG. Airplane pilot mental health and suicidal thoughts: a 
cross-sectional descriptive study via anonymous web-based survey. 
Environ Health.2016;15(1):121. doi.org/10.1186/s12940-016-0200-6

9. International Commission of Radiation Protection. Recommendations 
of the ICRP. In: Press P, ed. New York.1991.

10. Kaji M, Tango T, Asukata I, Tajima N, Yamamoto K, Yamamoto Y, et al. 
Mortality experience of cockpit crewmembers from Japan Airlines. 
Aviat Space Environ Med.1993;64(8):748–750.

11. Band PR, Spinelli JJ, Ng V T Y, Math M, Moody J, Gallagher RP. 
Mortality and cancer incidence in a cohort of commercial airline pilots. 
Aviat Space Environ Med.1990;61(4):299–302.

12. Band PR, Le ND, Fang R, Deschamps M, Goldman AJ, Gallagher RP, 
et al. Cohort study of Air Canada pilots: mortality, cancer incidence, 
and leukemia risk. Am J Epidemiol.1996;143(2):137–143. doi: 10.1093/
oxfordjournals.aje.a008722

13. Irvine D, Davies DM. British Airways flightdeck mortality study, 
1950–1992. Aviat Space Environ Med.1999;70(6):548–555.

14. Zeeb H, Blettner M, Hammer GP, Langner I. Cohort mortality study of  
German cockpit crew, 1960–1997. Epidemiology.2002;13(6):693–699. 
doi: 10.1097/01.EDE.0000029605.69271.8E.

15. Zeeb H, Hammer GP, Langner I, Schafft T, Bennack S, Blettner M. 
Cancer mortality among German aircrew: second follow-up. Radiat 
Environ Biophys.2010;49(2):187–194. doi: 10.1007/s00411-009-0248-6. 
Epub 2009 Oct 16.

16. Blettner M, Zeeb H, Auvinen A, Ballard TJ, Caldora M, Eliasch H, et al. 
Mortality from cancer and other causes among male airline cockpit 
crew in Europe. Int J Cancer.2003;106(6):946–952.  doi: 10.1002/
ijc.11328.

17. Paridou A, Velonakis E, Langner I, Zeeb H, Blettner M, Tzonou A. 
Mortality among pilots and cabin crew in Greece, 1960–1997. Int J 
Epidemiol.2003;32(2):244–247. doi: 10.1093/ije/dyg056.

18. Cashman JP, Nicholas JS, D. L, Mohr LC, Woolson RS, G. G, et al. 
Mortality Among Airline Pilots in the United States. International 
Journal of Applied Aviation Studies.2007;7(2):202–211.

19. Linnersjo A, Brodin LA, Andersson C, Alfredsson L, Hammar N. 
Low mortality and myocardial infarction incidence among flying 
personnel during working career and beyond. Scand J Work Environ 
Health.2011;37(3):219–226. doi: 10.5271/sjweh.3134. Epub 2010 Nov 22.

20. De Stavola BL, Pizzi C, Clemens F, Evans SA, Evans AD, Dos Santos Silva 
I. Cause-specific mortality in professional flight crew and air traffic 
control officers: findings from two UK population-based cohorts of over 
20,000 subjects. Intl Arch Occup Environ Health.2012;85(3):283–293. 
doi: 10.1007/s00420-011-0660-5. Epub 2011 Jun 15.

21. Yong LC, Pinkerton LE, Yiin JH, Anderson JL, Deddens JA. Mortality 
among a cohort of U.S. commercial airline cockpit crew. Am J Ind 
Med.2014;57(8):906–914. doi: 10.1002/ajim.22318 Published online 
2014 Apr 3.

22. Perez-Gomez B, Pollán M, Gustavsson P, Plato N, Aragonés N, López-
Abente G. Cutaneous melanoma: hints from occupational risks by 
anatomic site in Swedish men. Occup Environ Med.2004;61(2):117–126.  
doi: 10.1136/oem.2002.006320

23. Haldorsen T, Reitan JB, Tveten U. Cancer incidence among Norwegian 
airline pilots. Scand J Work Environ Health.2000;26(2):106–111.  doi: 
10.5271/sjweh.519.

24. Linnersjö A, Hammar N, Dammström BG, Johansson M, Eliasch H. 
Cancer incidence in airline cabin crew: experience from Sweden. 
Occup Environ Med.2003;60(11):810–814. doi: 10.1136/oem.60.11.810.

25. Pukkala E, Aspholm R, Auvinen A, Eliasch H, Gundestrup M, Haldorsen 
T, et al. Cancer incidence among 10,211 airline pilots: a Nordic study. 
Aviat Space Environ Med.2003;74(7):699–706. PMID: 12862322

26. Gudmundsdottir EM, Hrafnkelsson J, Rafnsson V. Incidence of cancer 
among licenced commercial pilots flying North Atlantic routes. Environ 
Health.2017;16(1):86. doi: 10.1186/s12940-017-0295-4.

155SIUJ.ORG SIUJ  •  Volume 3, Number 3  •  May 2022

Incidence and Mortality of Prostate Cancer in Commercial Airline Cockpit Crew: Systematic Review and Meta-Analysis

http://SIUJ.org


27. Bray F, Ferlay J, Soerjomataram I, Siegel RL, Torre L A, Jemal A. 
Global cancer statistics 2018: GLOBOCAN estimates of incidence 
and mortality worldwide for 36 cancers in 185 countries. CA Cancer  
J Clin.2018;68(6):394– 424. doi: 10.3322/caac.21492. Epub 2018  
Sep 12.

28. Rafnsson V, Hrafnkelsson J, Tulinius H. Incidence of cancer among 
commercial airline pilots. Occup Environ Med.2000;57(3):175–179. 
doi: 10.1136/oem.57.3.175

29. Hammar N, Linnersjö A, Alfredsson L, Dammström BG, Johansson M, 
Eliasch H. Cancer incidence in airline and military pilots in Sweden 
1961–1996. Aviat Space Environ Med.2002;73(1):2–7. PMID: 11817615

30. Gundestrup M, Storm HH. Radiation-induced acute myeloid leukaemia 
and other cancers in commercial jet cockpit crew: a population-based 
cohort study. Lancet.1999;354(9195):2029 –2031. doi: 10.1016/
S0140-6736(99)05093-X.

31. Ballard TJ, Lagorio S, De Santis M, De Angelis G, Santaquilani 
M, Caldora M, et al. A retrospective cohort mortality study of 
Italian commercial airline cockpit crew and cabin attendants, 
19 65 – 9 6. Int J Occup Environ Health.20 02;8 (2):87– 9 6. doi: 
10.1179/107735202800338957.

32. Hammer GP, Blettner M, Langner I, Zeeb H. Cosmic radiation and 
mortality from cancer among male German airline pilots: extended 
cohort follow-up. Eur J Epidemiol.2012;27(6):419–429. doi: 10.1007/
s10654-012-9698-2. Epub 2012 Jun 8.

33. Nicholas JS, Lackland DT, Dosemeci M, Mohr Jr LC, Dunbar JB, 
Grosche B, et al. Mor talit y among US commercial pilots and 
navigators. J Occup Environ Med.1998;4 0 (11):980 – 985. doi: 
10.1097/00043764-199811000-00008.

34. Buja A, Lange JH, Perissinotto E, Rausa G, Grigoletto F, Canova 
C, et al. Cancer incidence among male militar y and civil pilots 
and flight attendants: an analysis on published data. Toxicol Ind 
Health.2005;21(10):273–282. doi: 10.1191/0748233705th238oa.

35. Ballard T, Lagorio S, De Angelis G, Verdecchia A. Cancer incidence and 
mortality among flight personnel: a meta-analysis. Aviat Space Environ 
Med.2000;71(3):216–224. PMID: 10716165

36. Blettner M, Grosche B, Zeeb H. Occupational cancer risk in pilots and 
flight attendants: current epidemiological knowledge. Radiat Environ 
Biophys.1998;37(2):75–80. doi: 10.1007/s004110050097.

37. Raslau D, Abu Dabrh AM, Summerfield DT, Wang Z, Steinkraus 
LW, Murad MH. Prostate cancer in pilots. Aerosp Med Hum 
Perform.2016;87(6):565–570. doi: 10.3357/AMHP.4453.2016.

38. Bonato F. Retraction. Aerosp Med Hum Perform.2015;86(5):491. PMID: 
25945673

39. Rafnsson V. Letter to the Editor re: Prostate cancer in pilots: Letter. 
Aerosp Med Hum Perform.2017;88(6):600. PMID: 28539153

40. Rogers D, Boyd DD, Fox EE, Cooper S, Goldhagen M, Shen Y, et al. 
Prostate cancer incidence in U.S. Air Force aviators compared with 
non-aviators. Aviat Space Environ Med.2011;82(11):1067–1070. doi: 
10.3357/asem.3090.2011.

41. Moher D, Liberati A, Tetzlaff J, Altman DG. Preferred reporting items 
for systematic reviews and meta-analyses: the PRISMA statement. 
Ann Intern Med.2009;151(4):264–269, W64. doi: 10.7326/0003-4819-
151-4-200908180-00135. Epub 2009 Jul 20.

42. Pukkala E, Helminen M, Haldorsen T, Hammar N, Kojo K, Linnersjö 
A, et al. Cancer incidence among Nordic airline cabin crew. Int J 
Cancer.2012;131(12):2886–2897. doi: 10.1002/ijc.27551. Epub 2012 
Apr 16.

43. Zeeb H, Blettner M, Langner I, Hammer GP, Ballard TJ, Santaquilani 
M, et al. Mortality from cancer and other causes among airline cabin 
attendants in Europe: a collaborative cohort study in eight countries. 
Am J Epidemiol.2003;158(1):35–46. doi: 10.1093/aje/kwg107

44. Blettner M, Zeeb H, Langner I, Hammer GP, Schafft T. Mortality from 
cancer and other causes among airline cabin attendants in Germany, 
1960–1997. Am J Epidemiol.2002;156(6):556–565. doi: 10.1093/aje/
kwf083

45. Wells G, Shea B, O’Connell J. The Newcastle-Ottawa Scale (NOS) for 
assessing the quality of nonrandomised studies in meta-analyses. 
Ottawa Health Research Institute Web site. 2014;7.

46. Balduzzi S, Rücker G, Schwarzer G. How to perform a meta-analysis with 
R: a practical tutorial. Evid Based Ment Health.2019;22(4):153–160. 
doi: 10.1136/ebmental-2019-300117. Epub 2019 Sep 28.

47. Viechtbauer W. Conducting meta-analyses in R with The Metafor 
Package. Journal of Statistical Software.2010;36. doi.org/10.18637/
jss.v036.i03

48. Dalton JE, Bolen SD, Mascha EJ. Publication bias: the elephant 
in the review. Anesth Analg.2016;123(4):812–813. doi: 10.1213/
ANE.0000000000001596

49. R a w l a P. E p i d e mio l o g y  o f P r o s t a t e C a n c e r.  Wo rl d J 
Oncol.2019;10(2):63–89. doi: 10.14740/wjon1191. Epub 2019 Apr 20.

50. Federal Aviation Administration. Guide for aviation medical examiners-
application process for medical certification. United States Department 
of Transportation. 2016. Available at: https://www.faa.gov/about/
office_org/headquarters_offices/avs/offices/aam/ame/guide/
app_process/exam_tech/. Accessed April 8, 2022.

51. United Kingdom Civil Aviation Authority. Medical examination 
information. United Kingdom. 2015. ht tps://w w w.caa.co.uk /
Commercial-industry/Pilot-licences/Medical/Medical-examination-
information/. Accessed April 8, 2022.

156 SIUJ  •  Volume 3, Number 3  •  May 2022 SIUJ.ORG

REVIEW

https://www.faa.gov/about/office_org/headquarters_offices/avs/offices/aam/ame/guide/app_process/exam_tech/. Accessed April 8, 2022
https://www.faa.gov/about/office_org/headquarters_offices/avs/offices/aam/ame/guide/app_process/exam_tech/. Accessed April 8, 2022
https://www.faa.gov/about/office_org/headquarters_offices/avs/offices/aam/ame/guide/app_process/exam_tech/. Accessed April 8, 2022
https://www.caa.co.uk/Commercial-industry/Pilot-licences/Medical/Medical-examination-information/
https://www.caa.co.uk/Commercial-industry/Pilot-licences/Medical/Medical-examination-information/
https://www.caa.co.uk/Commercial-industry/Pilot-licences/Medical/Medical-examination-information/
http://SIUJ.org


52. Australian Government Civil Aviation and Safety Authority. Designated 
aviation medical examiner’s handbook. 4.4 Special reports and periodic 
tests required for medical certification. 2018. https://www.casa.gov.
au/information-dame-dao-co-and-medical-specialists/publication/
designated-aviation-medical-examiners-handbook. Accessed April 
8, 2022.

53. Nair-Shalliker V, Bang A, Weber M, Goldsbury DE, Caruana M, Emery 
J, et al. Factors associated with prostate specific antigen testing in 
Australians: analysis of the New South Wales 45 and Up Study. Sci 
Rep.2018;8(1):4261. doi: 10.1038/s41598-018-22589-y

54. Ilic D, Djulbegovic M, Jung JH, Hwang EC, Zhou Q, Cleves A, et al. 
Prostate cancer screening with prostate-specific antigen (PSA) test: 
a systematic review and meta-analysis. BMJ.2018;362:k3519. doi: 
10.1136/bmj.k3519.

55. Parkin DM, Darby SC. 12. Cancers in 2010 attributable to ionising 
radiation exposure in the UK. Br J Cancer.2011;105(Suppl 2):S57–S65. 
doi: 10.1038/bjc.2011.485

56. Leung KM, Shabat G, Lu P, Fields AC, Lukashenko A, Davids JS, et al. 
Trends in solid tumor incidence in Ukraine 30 years after Chernobyl. J 
Glob Oncol.2019;5:1–10. doi: 10.1200/JGO.19.00099

57. Sigurdson AJ, Doody MM, Rao RS, Freedman DM, Alexander BH, 
Hauptmann M, et al. Cancer incidence in the US radiologic technologists 
health study, 1983–1998. Cancer.2003;97(12):3080 –3089. doi: 
10.1002/cncr.11444

58. Berrington de González A, Ntowe E, Kitahara CM, Gilbert E, Miller 
DL, Kleinerman RA, et al. Long-term mor tality in 43 763 U.S. 
radiologists compared with 64 990 U.S. psychiatrists. Radiology. 
2016;281(3):847–857. doi: 10.1148/radiol.2016152472. Epub 2016  
Jul 19.

59. Vosianov AF, Romanenko AM, Zabarko LB, Szende B, Wang CY, 
Landas S, et al. Prostatic intraepithelial neoplasia and apoptosis 
in benign prostatic hyperplasia before and after the Chernobyl 
accident in Ukraine. Pathol Oncol Res.1999;5(1):28–31. doi: 10.1053/
paor.1999.0028

60. Ten years after Chernobyl: what do we really know? Based on the 
proceedings of the IAEA/ WHO/EC international conference, Vienna, 
April 1996 (INIS-X A--001). International Atomic Energy Agency 
(IAEA):1–24.

61. Langner I, Blettner M, Gundestrup M, Storm H, Aspholm R, Auvinen 
A, et al. Cosmic radiation and cancer mortality among airline pilots: 
results from a European cohort study (ESCAPE). Radiat Environ 
Biophys.2004;42(4):247–256. doi: 10.1007/s00411-003-0214-7. Epub 
2003 Nov 28.

62. Boice JD, Land CE, Preston DL. Ionizing Radiation. In: Schottenfeld 
D, Fraumeni JF, Eds. Cancer Epidemiology and Prevention. Oxford 
University Press: New York;1996:319–341.

63. UNSCEAR. Sources and effects of ionizing radiation. Report to the 
General Assembly, with Scientific Annexes. New York: United Nations 
2000.

64. Stevens RG, Davis S. The melatonin hypothesis: electric power and 
breast cancer. Environ Health Perspect.1996;104(Suppl 1):135–140. 
doi: 10.1289/ehp.96104s1135

65. Nicholas JS, Butler GC, L ackland DT, Hood WC Jr, Hoel 
DG, Mohr LC Jr. Flight deck magnetic fields in commercial 
a i r c r a f t .  A m  J  I n d  M e d . 2 0 0 0 ; 3 8 ( 5 ) : 5 4 8 – 5 5 4 .  d o i : 
10.1002/1097-0274(200011)38:5<548::aid-ajim7>3.0.co;2-h.

66. Liu R, Wu S, Zhang B, Guo M, Zhang Y. The association between sleep 
duration and prostate cancer: A systematic review and meta-analysis. 
Medicine.2020;99(28):e21180-e. doi: 10.1097/MD.0000000000021180

67. Bell KJL, Del Mar C, Wright G, Dickinson J, Glasziou P. Prevalence of 
incidental prostate cancer: a systematic review of autopsy studies. 
Int J Cancer.2015;137(7):1749–1757. doi: 10.1002/ijc.29538. Epub 
2015 Apr 21.

68. Geng Q, Zhang QE, Wang F, Zheng W, Ng CH, Ungvari GS, et al. 
Comparison of comorbid depression bet ween irritable bowel 
syndrome and inflammatory bowel disease: a meta-analysis of 
comparative studies. J Affect Disord.2018;237:37–46. doi: 10.1016/j.
jad.2018.04.111. Epub 2018 May 4.

69. He X, Yang K, Wang H, Chen X, Wu H, Yao L, et al. Expression and 
clinical significance of survivin in ovarian cancer: a meta-analysis. 
PLoS One.2018;13(5):e0194463-e. Published online 2018 May 24. doi: 
10.1371/journal.pone.0194463

70. Rivera-Izquierdo M, Martínez-Ruiz V, Castillo-Ruiz EM, Manzaneda-
Navío M, Pérez-Gómez B, Jiménez-Moleón JJ. Shift work and prostate 
cancer: an updated systematic review and meta-analysis. Int J Environ 
Res Public Health.2020;17(4):1345. Published online 2020 Feb 19. doi: 
10.3390/ijerph17041345

157SIUJ.ORG SIUJ  •  Volume 3, Number 3  •  May 2022

Incidence and Mortality of Prostate Cancer in Commercial Airline Cockpit Crew: Systematic Review and Meta-Analysis

https://www.casa.gov.au/information-dame-dao-co-and-medical-specialists/publication/designated-aviation-medical-examiners-handbook
https://www.casa.gov.au/information-dame-dao-co-and-medical-specialists/publication/designated-aviation-medical-examiners-handbook
https://www.casa.gov.au/information-dame-dao-co-and-medical-specialists/publication/designated-aviation-medical-examiners-handbook
http://SIUJ.org


SUPPLEMENTARY TABLE S1A.  

Incidence studies excluded during eligibility assessment for the final meta-analysis, with characteristics and  
reasons for exclusion 

Study Sample size Study duration Observed Expected Standardized ratio
Mean age at 
conclusion

Country/ region Reason(s) for exclusion

Prostate cancer Incidence data:  Standardized Incidence Ratio (SIR)

1 Haldorsen et al. (2000) 3701 1946–1994 25 25 1.00 (0.68–1.48) Not reported Norway Duplicated data cohort in Pukkala et al. (2003)

2 Gudmundsdottir et al. (2017) 286 1955–2015 15 11.8 1.27 (0.71– 2.10) Not reported Iceland Duplicated data cohort in Pukkala et al. (2003) 

3 Rafnsson et al. (2000) 265 1955–1997 4 2.84 1.41 (0.53– 3.76) Not reported Iceland Duplicated data cohort in Pukkala et al. (2003)

4 Hammar et al. (2002) 1490 1961–1997 18 14.5 1.24 (0.78–1.97) Not reported Sweden Duplicated data cohort in Pukkala et al. (2003)

5 Dos Santos De Silva et al. (2013) 15 867 1989–1999 Not reported Not reported 1.10 (0.96–1.26) Not reported United Kingdom Duplicated data cohort in Hammer et al. (2014)

6 Gundestrup et al. (1999) 3790 1921–1995
3 (jet)

3 (non-jet) 
3.97 (jet)

3.59 (non-jet)
0.8 (0.2–2.2) for both 41.65 years Denmark Duplicated data cohort in Pukkala et al. (2002)

7 Milanov et al. (1999) 34 1964–1994 Not reported Not reported Not reported Not reported Republic of Bulgaria
No statistical data on prostate cancer 

reported

8 Nicholas et al. (2001) 6533 1970–1998 65 Not reported 0.7 (0.59–0.84) Not reported United States, Canada

Investigated cancer incidence by 
questionnaire (self-reported disease 

outcomes)–different methodology could give 
inconsistent results

9 Pukkala et al. (2002) 10 032

1946–1997
(Denmark from 1946, Finland up to 1996,  
Norway 1946–1994, Sweden 1957–1994  

Iceland 1955–1997

64 52.9 1.21 (0.93–1.54) Not reported Nordic countries Duplicate data cohort in Pukkala et al. (2003)

10 Pukkala et al. (2012) 1559
1947–1997

(Finland 1947–1993, Iceland 1947–1997,  
Norway 1950–1994, Sweden 1957–1994)

24 21.7 1.11 (0.71–1.65) Not reported
Finland, Iceland, 
Norway, Sweden

Cabin crew data

11 Rogers et al. (2011) 106 418 1987–2008 Not reported Not reported Not reported
Mean age at 

diagnosis ~ 50 
years

United States
Exclusively Air force / military data, 

comparative study, calculates hazard ratio

158 SIUJ  •  Volume 3, Number 3  •  May 2022 SIUJ.ORG

REVIEW

http://SIUJ.org


SUPPLEMENTARY TABLE S1A.  

Incidence studies excluded during eligibility assessment for the final meta-analysis, with characteristics and  
reasons for exclusion 

Study Sample size Study duration Observed Expected Standardized ratio
Mean age at 
conclusion

Country/ region Reason(s) for exclusion

Prostate cancer Incidence data:  Standardized Incidence Ratio (SIR)

1 Haldorsen et al. (2000) 3701 1946–1994 25 25 1.00 (0.68–1.48) Not reported Norway Duplicated data cohort in Pukkala et al. (2003)

2 Gudmundsdottir et al. (2017) 286 1955–2015 15 11.8 1.27 (0.71– 2.10) Not reported Iceland Duplicated data cohort in Pukkala et al. (2003) 

3 Rafnsson et al. (2000) 265 1955–1997 4 2.84 1.41 (0.53– 3.76) Not reported Iceland Duplicated data cohort in Pukkala et al. (2003)

4 Hammar et al. (2002) 1490 1961–1997 18 14.5 1.24 (0.78–1.97) Not reported Sweden Duplicated data cohort in Pukkala et al. (2003)

5 Dos Santos De Silva et al. (2013) 15 867 1989–1999 Not reported Not reported 1.10 (0.96–1.26) Not reported United Kingdom Duplicated data cohort in Hammer et al. (2014)

6 Gundestrup et al. (1999) 3790 1921–1995
3 (jet)

3 (non-jet) 
3.97 (jet)

3.59 (non-jet)
0.8 (0.2–2.2) for both 41.65 years Denmark Duplicated data cohort in Pukkala et al. (2002)

7 Milanov et al. (1999) 34 1964–1994 Not reported Not reported Not reported Not reported Republic of Bulgaria
No statistical data on prostate cancer 

reported

8 Nicholas et al. (2001) 6533 1970–1998 65 Not reported 0.7 (0.59–0.84) Not reported United States, Canada

Investigated cancer incidence by 
questionnaire (self-reported disease 

outcomes)–different methodology could give 
inconsistent results

9 Pukkala et al. (2002) 10 032

1946–1997
(Denmark from 1946, Finland up to 1996,  
Norway 1946–1994, Sweden 1957–1994  

Iceland 1955–1997

64 52.9 1.21 (0.93–1.54) Not reported Nordic countries Duplicate data cohort in Pukkala et al. (2003)

10 Pukkala et al. (2012) 1559
1947–1997

(Finland 1947–1993, Iceland 1947–1997,  
Norway 1950–1994, Sweden 1957–1994)

24 21.7 1.11 (0.71–1.65) Not reported
Finland, Iceland, 
Norway, Sweden

Cabin crew data

11 Rogers et al. (2011) 106 418 1987–2008 Not reported Not reported Not reported
Mean age at 

diagnosis ~ 50 
years

United States
Exclusively Air force / military data, 

comparative study, calculates hazard ratio

159SIUJ.ORG SIUJ  •  Volume 3, Number 3  •  May 2022

Incidence and Mortality of Prostate Cancer in Commercial Airline Cockpit Crew: Systematic Review and Meta-Analysis

http://SIUJ.org


SUPPLEMENTARY TABLE S1B. 

Mortality studies excluded during eligibility assessment for the final meta-analysis,  
with characteristics and reasons for exclusion 

Study Sample size Study duration Observed Expected Standardized ratio
Mean age at 
conclusion

Country/ region Reason(s) for exclusion

1 Salisbury et al. (1991) 402 1950–1984 Not reported Not reported Not reported Not reported Canada
Discusses proportional mortality rates, unable 

to pool in to standardized mortality data

2 Irvine & Davies (1992) 411 1966–1989 Not reported Not reported Not reported Not reported United Kingdom
Helicopter pilots included and discusses 

proportional mortality rates, unable to pool in 
to standardized mortality data

3 Kaji et al. (1993) 2327 1952–1988 Not reported Not reported Not reported 45.9 ± 13.6 years Japan No statistical data on prostate cancer

4 Nicholas et al. (1998) 1538 1984–1991 38 27.56 1.38 (1.00–1.90) Not reported USA
Discusses proportional mortality rates, unable 

to pool in to standardized mortality data

5 Haldorsen et al. (2002) 3707 1946–1994 Not reported Not reported Not reported Not reported Norway
Helicopter pilots included, duplicated data 

cohort in Hammer et al. (2014) and no 
statistical data on prostate cancer. 

6 Irvine & Davies (1999) 6209 1950–1992 15 13.48 111.3 (62.3–183.5) Not reported United Kingdom Includes helicopter pilot data as well

7 Ballard et al. (2002) 3022 1965–1996 4 3.76 1.06 (0.40–2.82) Not reported Italy Duplicated data cohort in Hammer et al. (2014)

8 Zeeb et al. (2002) (cockpit crew) 6061 1953–1997 8.7 6.9 1.26 (0.53–2.59) Not reported Germany Duplicated data cohort in Blettner et al. (2003)

9
Zeeb et al. (2003) (cabin crew/

att -endants)
11 079

1946–1997  
(Denmark 1947–1996) (Finland 1947–1992)  
(Germany 1953–1997) (Greece 1946–1997) 

(Iceland 1955–1997)  (Italy 1965–1995) 
(Norway 1950–1994) (Sweden 1957–1994)

5.2 4.8 1.09 (0.35–2.68) Not reported Europe
Cabin crew data, no mention of separate  

data for pilots/cockpit crew

10 Zeeb et al. (2010) (cockpit crew) 6017 1953–2003 11 Not reported 0.96 (0.42–1.91) Not reported Germany
Extended (+6 years) follow up after 2003 

study – no new cohort members added hence 
duplicated data cohort in Blettner et al. (2003)

11 Blettner et al. (2003) 27 797

1921–1997  
(Denmark 1946–1996) (Finland 1921–1997)  
(Germany 1953–1997) (Greece 1946–1997)  

(Iceland 1935–1997) (Italy 1965–1995) 
(Norway1946–1994) (Sweden 1957–1994)   

(United Kingdom 1950–1997)

54 60.1 0.94 (0.72–1.23) Not reported Europe Duplicated data cohort in Hammer et al. (2014)

12 Hammer et al. (2012) 6006 1960–2004 11.9* 12.4 0.96 (0.36–2.53) 51.5 years Germany Duplicated data cohort in Hammer et al. (2014)

13 Dreger et al. (2020) 6006 1960–2014 24 27.5 0.93 (0.54–1.51) 59.8 years Germany

Only German data and extended follow-up  
(to 2014) of the same cohort from Hammer  

et al. 2014. Cumulative SMR of all countries 
only in 2014 study

14 Langner et al. (2004) 19 184 (ESCAPE) 1921–1997 Not reported Not reported Not reported Not reported Europe
Duplicated data cohort in Hammer et al. (2014) 

and no statistical data on prostate cancer

15 Stavola et al. (2012) 15 881 1989–1999 Not reported Not reported Not reported Not reported United Kingdom
Duplicated data cohort in Dos Santos de Silva 
et al. (2013) and no statistical data on prostate 

cancer

16 Krstev et al. (1998) 60 878 1984–1993 Not reported Not reported Not reported Not reported United States
Discusses mortality odds ratio—unable to 

pool in to standardized mortality data,  
case–control study

17 Linnersjö et al. (2011) 1478 1957–1994 Not reported Not reported Not reported Not reported Sweden No statistical data on prostate cancer

18 Blettner et al. (2002) 4185 1953–1997 Not reported Not reported Not reported Not reported Germany Cabin crew / attendant data

19 Paridou et al. (2003) 2678 1960–1997 Not reported Not reported Not reported Not reported Greece No statistical data on prostate cancer

160 SIUJ  •  Volume 3, Number 3  •  May 2022 SIUJ.ORG

REVIEW

http://SIUJ.org


SUPPLEMENTARY TABLE S1B. 

Mortality studies excluded during eligibility assessment for the final meta-analysis,  
with characteristics and reasons for exclusion 

Study Sample size Study duration Observed Expected Standardized ratio
Mean age at 
conclusion

Country/ region Reason(s) for exclusion

1 Salisbury et al. (1991) 402 1950–1984 Not reported Not reported Not reported Not reported Canada
Discusses proportional mortality rates, unable 

to pool in to standardized mortality data

2 Irvine & Davies (1992) 411 1966–1989 Not reported Not reported Not reported Not reported United Kingdom
Helicopter pilots included and discusses 

proportional mortality rates, unable to pool in 
to standardized mortality data

3 Kaji et al. (1993) 2327 1952–1988 Not reported Not reported Not reported 45.9 ± 13.6 years Japan No statistical data on prostate cancer

4 Nicholas et al. (1998) 1538 1984–1991 38 27.56 1.38 (1.00–1.90) Not reported USA
Discusses proportional mortality rates, unable 

to pool in to standardized mortality data

5 Haldorsen et al. (2002) 3707 1946–1994 Not reported Not reported Not reported Not reported Norway
Helicopter pilots included, duplicated data 

cohort in Hammer et al. (2014) and no 
statistical data on prostate cancer. 

6 Irvine & Davies (1999) 6209 1950–1992 15 13.48 111.3 (62.3–183.5) Not reported United Kingdom Includes helicopter pilot data as well

7 Ballard et al. (2002) 3022 1965–1996 4 3.76 1.06 (0.40–2.82) Not reported Italy Duplicated data cohort in Hammer et al. (2014)

8 Zeeb et al. (2002) (cockpit crew) 6061 1953–1997 8.7 6.9 1.26 (0.53–2.59) Not reported Germany Duplicated data cohort in Blettner et al. (2003)

9
Zeeb et al. (2003) (cabin crew/

att -endants)
11 079

1946–1997  
(Denmark 1947–1996) (Finland 1947–1992)  
(Germany 1953–1997) (Greece 1946–1997) 

(Iceland 1955–1997)  (Italy 1965–1995) 
(Norway 1950–1994) (Sweden 1957–1994)

5.2 4.8 1.09 (0.35–2.68) Not reported Europe
Cabin crew data, no mention of separate  

data for pilots/cockpit crew

10 Zeeb et al. (2010) (cockpit crew) 6017 1953–2003 11 Not reported 0.96 (0.42–1.91) Not reported Germany
Extended (+6 years) follow up after 2003 

study – no new cohort members added hence 
duplicated data cohort in Blettner et al. (2003)

11 Blettner et al. (2003) 27 797

1921–1997  
(Denmark 1946–1996) (Finland 1921–1997)  
(Germany 1953–1997) (Greece 1946–1997)  

(Iceland 1935–1997) (Italy 1965–1995) 
(Norway1946–1994) (Sweden 1957–1994)   

(United Kingdom 1950–1997)

54 60.1 0.94 (0.72–1.23) Not reported Europe Duplicated data cohort in Hammer et al. (2014)

12 Hammer et al. (2012) 6006 1960–2004 11.9* 12.4 0.96 (0.36–2.53) 51.5 years Germany Duplicated data cohort in Hammer et al. (2014)

13 Dreger et al. (2020) 6006 1960–2014 24 27.5 0.93 (0.54–1.51) 59.8 years Germany

Only German data and extended follow-up  
(to 2014) of the same cohort from Hammer  

et al. 2014. Cumulative SMR of all countries 
only in 2014 study

14 Langner et al. (2004) 19 184 (ESCAPE) 1921–1997 Not reported Not reported Not reported Not reported Europe
Duplicated data cohort in Hammer et al. (2014) 

and no statistical data on prostate cancer

15 Stavola et al. (2012) 15 881 1989–1999 Not reported Not reported Not reported Not reported United Kingdom
Duplicated data cohort in Dos Santos de Silva 
et al. (2013) and no statistical data on prostate 

cancer

16 Krstev et al. (1998) 60 878 1984–1993 Not reported Not reported Not reported Not reported United States
Discusses mortality odds ratio—unable to 

pool in to standardized mortality data,  
case–control study

17 Linnersjö et al. (2011) 1478 1957–1994 Not reported Not reported Not reported Not reported Sweden No statistical data on prostate cancer

18 Blettner et al. (2002) 4185 1953–1997 Not reported Not reported Not reported Not reported Germany Cabin crew / attendant data

19 Paridou et al. (2003) 2678 1960–1997 Not reported Not reported Not reported Not reported Greece No statistical data on prostate cancer

161SIUJ.ORG SIUJ  •  Volume 3, Number 3  •  May 2022

Incidence and Mortality of Prostate Cancer in Commercial Airline Cockpit Crew: Systematic Review and Meta-Analysis

http://SIUJ.org


SUPPLEMENTARY FIGURE S1B. 

Pooled SIR results with inclusion of latest study 

Study Year OR 95% CI Weight

Band et al. 1990

0.5 1 2 3.5

1.54 (0.69–3.43) 5.4%

Band et al. 1996 1.87 (1.34–2.62) 30.4%

Pukkala et al. 2003 1.21 (0.95–1.55) 56.5%

GGudmundsdóttir  et al. 2017 1.12 (0.58–2.17) 7.8%

I2 = 35.9% 1.39 (1.16–1.67) 100%

SUPPLEMENTARY FIGURE S1A. 

Adjustmentof sample size between 2 studies 

Study Original totals
Number 

overlapping
Number 

deducted

Pukkala et al.

Total 10032 239 120

Observed 64 0.77

Expected 52.9 0.63

Gudmundsdóttir  et al. 

Total 286 239 119 

Observed 15 6.24

Expected 11.8 4.91

162 SIUJ  •  Volume 3, Number 3  •  May 2022 SIUJ.ORG

REVIEW

http://SIUJ.org

