Emergency (****); * (*): *-* This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Copyright © 2015 Shahid Beheshti University of Medical Sciences. All rights reserved. Downloaded from: www.jemerg.com 16 Emergency (2015); 3 (1): 16-21 ORIGINAL RESEARCH The Most Important Causes of Death in Iranian Population; a Retrospective Cohort Study Soheil Saadat1, Mahmoud Yousefifard2, Hadi Asady3, Ali Moghadas Jafari4, Mohammad Fayaz5, Mostafa Hosseini5* 1. Sina Trauma and Surgery Research Center, Sina Hospital, Tehran University of Medical Sciences, Tehran, Iran. 2. Department of Physiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran. 3. Department of Occupational Health Engineering, Faculty of Public Health, Tehran University of Medical Sciences, Tehran, Iran. 4. Department of Emergency Medicine, School of Medicine, Bushehr University of Medical Sciences, Bushehr, Iran. 5. Department of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran. *Corresponding Author: Mostafa Hosseini; Department of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, Poursina Avenue, Tehran, Iran. Tel/Fax: +982188989125; Email: mhossein110@yahoo.com Received: September 2014; Accepted: October 2014 Abstract Introduction: Health care providers and health policy managers need updated and valid information regarding causes of death (COD) for development the health care facilities, directing primary prevention, assigning funds, and promoting public health. The major causes of death and its burden have not been yet appropriately identified in Iran. Although several studies had been carried out in this area, most of them were local or performed in the past years and need to be update. Thus, the present study aimed to address the major causes of death and its burden in Iran. Methods: The present cross-sectional study was performed on graduate students and their families from February to March 2014. Through a two-stage random sampling procedure, data on 11315 subjects were obtained. The corresponding age of death, gender, and calendar year of death were inquired. All causes of death were cate- gorized in nine groups including major cardiovascular disease, cancers, motor vehicle accidents, unintentional in- juries, intentional injuries, stroke, lower respiratory infections, diabetes, and other reasons. Years of life lost (YLL) and person years of life lost were computed as the burden of diseases. Results: Totally, 11315 (50.4% male) sub- jects were studied. The results regarding death of relatives revealed that 360 deaths occurred (66.9% male). COD in 95 cases (26.4%) was cardiovascular diseases, 64 (17.8%) motor vehicle accidents, 41 (11.4%) cancers, 23 (6.4%) unintentional injuries, 22 (6.1%) intentional injuries, 10 (2.8%) stroke, 8 (2.2%) lower respi ratory infec- tions, 6 (1.8%) diabetes, and 91 (25.3%) other reasons. The average YLL due to all COD was 34.4±18.5. YLL for motor vehicle accidents and injuries (unintentional and intentional) were higher than cardiovascular diseases (p<0.001). In addition, person years of life lost for motor vehicle accidents were 2613.1 years. Cardiovascular dis- eases (2159.4 years), cancers (1321.0 years), and unintentional injuries (990.4 years) were in the next ranks. Con- clusion: Based on the findings, it seems that cardiovascular diseases, motor vehicle accidents, cancers, intentional and unintentional injuries are the major causes of death in Iranian population. Most of years of life lost were due to motor vehicle accidents, cardiovascular diseases and cancers, intentional and unintentional injuries, respec- tively. Key words: Cause of death; mortality; life expectancy; cardiovascular diseases; traffic accidents Cite This Article as: Saadat S, Yousefifard M, Asady H, Moghadas Jafari A, Fayaz M, Hosseini M. The most important causes of death in Iranian population; a retrospective cohort study. Emergency. 2015;3(1):16-21. Introduction: ealth care providers and health policy managers need updated and valid information regarding causes of death (COD) for development the health care facilities, directing primary prevention, as- signing funds, and promoting public health (1). How- ever, due to a high prevalence of deaths and its variation in different geographical regions (2), it is not easy to identify the COD precisely. Based on World Health Or- ganization (WHO), Non-Communicable Diseases (NCDs) will be accountable for 70% of all deaths in 2030. Cardi- ovascular diseases (CVDs), cancers, diabetes and chronic lung diseases are the first four causes of death in world- wide (3). The recent WHO report showed that ischemic H mailto:mhossein110@yahoo.com This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Copyright © 2015 Shahid Beheshti University of Medical Sciences. All rights reserved. Downloaded from: www.jemerg.com 17 Emergency (2015); 3 (1): 16-21 heart disease (11.2%), brain stroke (10.6%), lower res- piratory tract infections (6.7%), obstructive pulmonary disease (5.8%), diarrhea (4.7%), and HIV/AIDS (3.01%) are the most important causes of mortality globally. Also, this report revealed that bronchus and lung cancer (2.7%), diabetes (2.6%), and traffic accidents (2.2%) have the ranks of seventh to ninth, respectively (4). How- ever, the COD in many countries is different from WHO reports. For example, trauma and poisoning in Iran are in the second rank and traffic accident is in the third (1). There are many reasons for such variations and one of the most important of these diversities is the dissimilar- ity among risk factors of death in different countries. For instance, in Sub-Saharan Africa malnourishment, domes- tic air pollutants arising from fuels, and suboptimal breastfeeding are the health problems (5) while, in de- veloped countries obesity, high blood cholesterol, and inappropriate dietary habits are the main health prob- lems (6). Therefore, regional and national identification of COD has a high priority. As a result, WHO has devel- oped some facilities in recent years to evaluate the COD in national, regional, and global scales (7). Years of life lost (YLL) is used to determine the burden of fetal diseases and the effect of it on quality of life. YLL along with years lived with disability (YLD) are sug- gested by WHO and World Bank to display the burden of diseases and health priorities (8). These tools let health policy-makers to determine the priorities to control of diseases and evaluate the effectiveness of preventive programs. The major causes of death and its burden have not been yet appropriately identified in Iran. Although several studies had been carried out in this area, most of them were local or performed in the past years and need to be update. Thus, the present study aimed to address the major causes of death and its burden in Iran. Methods: Study design and setting The present cross-sectional study was performed on graduate students and their families with the goal of finding the main causes of mortality among them from February to March 2014. The target population was all the men and women graduate students of Tehran Uni- versity of Medical Sciences, Tehran, Iran and their fami- lies. This university as the largest university in the coun- try has accepted students from all the country. Thus, de- termining the cause of mortality among these students and their families is a good representative of COD from whole country. The present study was approved by Eth- ical Committee of Tehran University of Medical Sciences. Participants All graduate students of Tehran University of Medical Sciences who were studying during 2014 were taken to this study. The lack of consent was considered as the ex- clusion criteria. Two hundred graduate students were enrolled into this study through a two-stage random sampling procedure. In first step, one of the ten faculties was randomly se- lected and then from the list of students, 200 ones were selected using computer-generated random numbers. In this study, the data on parents, spouse and her/his fam- ily, children, brothers and sisters, uncles, aunts and their children were asked from each student. Based on our pi- lot study, it was estimated that by interview with each student, the information of about 50 persons of his/her relatives could be obtained. Consequently, by studying 200 students it was expected to provide the information of about 10000 individuals. Finally, data on 11315 sub- jects were obtained. To decrease the potential recall bias, the information of close relatives was only asked. Data collection In this study, studied subjects were asked to state any death happened to their relatives. The corresponding age of death, gender, and calendar year of death were in- quired. In a pilot study, the validity of questionnaire was verified by expert panel, the reliability of it confirmed through a test-retest from 15 students, and the agree- ment on answers found to be 93.3%. Statistical analysis All causes of death were categorized in nine groups in- cluding major cardiovascular disease, cancers, motor ve- hicle accidents, unintentional injuries, intentional inju- ries, stroke, lower respiratory infections, diabetes, and other reasons. Multinomial logistic regression was used to assess significant differences among the frequency of death in various causes of death. To calculate the YLL for each person, age of death was subtracted from his/her life expectancy derived from the life table of Iranian pop- ulation. Also, for computing person years of life lost, the number of death was multiplied to average YLL for each COD. One-way analysis of variance was performed to compare mean YLL and person years of life lost among CODs. p<0.05 was considered as significant. Results: In the present study by interviewing 200 graduate stu- dents, the data on 11315 subjects were collected of whom 5700 (50.4%) were male and 5615 (49.6%) fe- male. The findings on death of relatives revealed that to- tally 360 deaths occurred because of various reasons, that 241 (66.9%) were male and 119 (33.1%) female. 110 specific causes of death were classified into nine groups as shown in Table 1. COD in 95 cases (26.4%) was cardiovascular diseases, 64 (17.8%) motor vehicle acci- dents, 41 (11.4%) cancers, 23 (6.4%) unintentional inju- ries, 22 (6.1%) intentional injuries, 10 (2.8%) stroke, 8 (2.2%) lower respiratory infections, 6 (1.8%) diabetes, and 91 (25.3%) other reasons. As Table 1 and Figure 1 show, cardiovascular diseases has the first rank (p<0.001). Figure 2 displays the percentage of death in each age group according to COD. Motor vehicle accidents are the This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Copyright © 2015 Shahid Beheshti University of Medical Sciences. All rights reserved. Downloaded from: www.jemerg.com Saadat et al 18 major cause of death in ages younger than 45 years. While in older than 45 years, cardiovascular diseases are the main cause of death. Multinomial logistic regression showed that in adults (aged 25-74 years), cardiovascular deaths were significantly higher than deaths due to mo- tor vehicle accidents (p<0.001). The average YLL and its 95% confidence interval are shown in table 2 for male and female of different CODs. The sverage YLL due to all COD was 34.4±18.5. The YLL had significant difference among various CODs (df: 8, 344; F=9.9; p<0.0001). Bonferroni post hoc analysis showed that YLL for motor vehicle accidents and injuries (unintentional and intentional) were higher than cardio- vascular diseases (p<0.001). Total person years of life lost were 12394.8 years. Per- son years of life lost for motor vehicle accidents were 2613.1 years. Cardiovascular disease (2159.4 years), cancers (1321.0 years), and unintentional injuries (990.4 years) were also in the next ranks. However, in- tentional injuries (931.7 years), lower respiratory tract infections (312.0 years), stroke (283.3 years), and diabe- tes (150.2 years) had the least person years of life lost. Discussion: The present study showed that cardiovascular disease, motor vehicle accidents, cancers, intentional and unin- tentional injuries are the major causes of death in Ira- nian population. Also, the motor vehicle accidents deaths had the highest person years of life lost followed by car- diovascular disease, cancers, intentional and uninten- tional injuries, respectively. Like other countries, cardiovascular diseases, motor ve- hicle accidents, cancers, intentional and unintentional injuries, lower respiratory tract infections, and stroke are the most important causes of mortality in Iran. Based on WHO reports, cardiovascular diseases were ac- counted as the major COD and led to 11 million deaths in 2011. In East Asia the burden of cardiovascular diseases has the second rank, too (4). Similarly, in this study car- diovascular diseases have the first rank of COD and the second highest burden of death by YLLs. This issue arises from changing in Iranian lifestyle, which leads to in- crease the risk factors of cardiovascular diseases. Smoking, hypertension, alcohol consumption, weight gain, high blood cholesterol, lower consumption of fruits, and sodium rich foods are the most important risk fac- tors of cardiovascular diseases which have a high preva- lence in Iranian population (9-13). The primary level of prevention is the most critical strategy for controlling these risk factors. Additionally, primary care could pro- vide an easy access to new treatment and medical inter- ventions to control some of these risk factors like hyper- tension and high blood pressure. Applying such proceed- ings could remarkably reduce the deaths arisen from cardiovascular diseases (14); consequently, these poli- cies have decreased the burden of cardiovascular dis- eases in developing countries. Figure 1: The most common causes of death in the stud- ied population 0.0 10.0 20.0 30.0 Other Diabetes Lower respiratory infections Stroke Intentional injuries Unintentional injuries Cancers Motor vehicle accidents Major cardiovascular diseases Percent of death Men Women 0 10 20 30 40 50 60 <15 15-24 25-34 35-44 45-54 55-64 65-74 75-84 >84 P e r c e n t o f d e a th s i n a g e g r o u p Age (years) Major cardiovascular diseases Motor vehicle accidents Cancers Unintentional injuries Intentional injuries Stroke Lower respiratory infections Diabetes Figure 2: Age-specific causes of death in the studied population This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Copyright © 2015 Shahid Beheshti University of Medical Sciences. All rights reserved. Downloaded from: www.jemerg.com 19 Emergency (2015); 3 (1): 16-21 Motor vehicles accidents have the second rank of COD in this study line with Frouzanfar et al. They demonstrated that the death rate due to motor vehicle accidents is higher than twice of the global average. Since most of the motor vehicle accidents deaths (81.25%) happen under the age of 45, the rank of its burden is the highest (1, 15). The preventive measures are suggested to improve the road safety, quality and safety of vehicles, and establish strict rules for violators. On the other hand, more coor- dination among different units such as police stations, fire stations, and emergency departments could improve the service delivery to victims. This management leads to reduce the arrival time to the scene and provide criti- cal interventions faster. Cancers are the third cause of mortality and the burden of diseases. In the study of Frouzanfar et al cancers has the second rank of COD (1). Smoking has a key role in developing cancers as the major risk factor. In addition, household air pollution from solid fuels, urban air pollu- tion caused by fossil fuels, exposure to occupational pol- lutants, drug usage, and inappropriate diet are other risk factors of cancers (16-18). Today, such factors have been dramatically increased in urban areas. Therefore, pre- ventive policies should be taken to decrease these risks. Moreover, cancer-screening programs could help in early diagnosis, which leads to better treatment re- sponse. Stomach, lung, and breast cancers are the lead- ings in Iran (19). As a result, increasing the free access to diagnostic tools such as mammography is one of the best screening and preventive interventions, economically. In addition, smoking and inappropriate diet are two critical risk factors that their combination exacerbates the dis- ease status. Unfortunately, the prevalence of these two risk factors is high in the country. Thus, it is suggested to implement educational programs to improve the nutri- tional status and smoking cessation. Table 1: Cumulative incidence of death in the studied population Cause of death Frequency Cumulative incidence of death (%) In dead cases (n=360) In samples (n=11315) Male Fe- male To- tal Male Female Total Male Female Total Cardiovascular diseases 65 30 95 18.1 8.3 26.4 0.57 0.27 0.84 Motor vehicle accidents 52 12 64 14.4 3.3 17.7 0.46 0.11 0.57 Cancers 25 16 41 6.9 4.4 11.4 0.22 0.14 0.36 Unintentional injuries 14 9 23 3.9 2.5 6.4 0.12 0.08 0.20 Intentional injuries 20 2 22 5.6 0.6 6.1 0.18 0.02 0.19 Stroke 8 2 10 2.2 0.6 2.8 0.07 0.02 0.09 Lower respiratory infec- tions 5 3 8 1.4 0.8 2.2 0.04 0.03 0.07 Diabetes 4 2 6 1.1 0.6 1.7 0.04 0.02 0.05 Other 48 43 91 13.3 11.9 25.2 0.42 0.38 0.80 Total 241 119 360 66.9 39.8 100 2.13 1.05 3.18 Figure 3: Gender- specific person years of life lost strat- ified by cause of death 0 1000 2000 3000 4000 Other Diabetes Stroke Lower respiratory infection Intentional injuries Unintentional injuries Cancer Major cardiovascular diseases Motor vehicle accidents Person years of life lost Men Women This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Copyright © 2015 Shahid Beheshti University of Medical Sciences. All rights reserved. Downloaded from: www.jemerg.com Saadat et al 20 In the present study lower respiratory infections as the only communicable diseases were the main CODs in Iran. However, its rate is lower than other diseases. Since 1990 the prevalence of communicable diseases like diar- rhea, lower respiratory infections, and tetanus has de- creased (4). Although Iran is a low and middle income country, in recent years effective changes has been made in health promotion which cause to shift disease pattern in the society from communicable diseases to non-com- municable diseases, similar to developed countries (15). The present study had some limitations one of the most important of which is the lack of calculating the lived years with disability. If evaluation of this factor was pos- sible, calculating the disability-adjusted life year (DALY) would be conceivable, which is critical in finding the bur- den of diseases. Another limitation was recall bias; alt- hough complete removing of recall bias in observational studies is not possible, in the present study it decreased noticeably by confining the information of close rela- tives. Conclusion: Based on the findings, it seems that cardiovascular dis- eases, motor vehicle accidents, cancers, intentional and unintentional injuries are the major causes of death in Iranian population. Most of years of life lost were due to motor vehicle accidents, cardiovascular diseases and cancers, intentional and unintentional injuries, respec- tively. Acknowledgments: The authors would like to thank all the graduate students who cooperated in this study. The present study is the result of a research project enacted by the Sina Trauma and Surgery Research Center, Sina Hospital, Tehran Uni- versity of Medical Sciences, Tehran, Iran (Grant No: 20932). The authors also would like to thank Mrs. Mar- ziyeh Mirzahoseini Nejad and Mr. Milad Derakhshan for their invaluable helps. Conflict of interest: None Funding support: None Authors’ contributions: All authors passed four criteria for authorship contribu- tion based on recommendations of the International Committee of Medical Journal Editors. References: 1. Forouzanfar MH, Sepanlou SG, Shahraz S, et al. Evaluating causes of death and morbidity in Iran, global burden of diseases, injuries, and risk factors study 2010. Arch Iran Med. 2014;17(5):304-20. Table 2: Mean years of life lost (95 % confidence interval) according to gender Cause Men Women Total Cardiovascular diseases 22.9 (19.3-26.5) 22.4 (17.4-27.4) 22.7 (19.8-25.6) Motor vehicle accidents 40.3 (36.8-43.8) 43.1 (34.7-51.5) 40.8 (37.6-44.0) Cancers 30.1 (24.8-36.0) 35.5 (29.5-41.5) 32.2 (27.9-36.5) Unintentional injuries 34.6 (24.9-44.2) 56.3 (47.0-65.6) 43.1 (35.0-51.2) Intentional injuries 42.7 (39.9-45.4) 39.2 (4.3-82.7) 42.4 (38.5-46.2) Stroke 31.2 (14.5-47.4) 16.9 (7.2-26.6) 28.3 (15.0-41.2) Lower respiratory infection 32.5 (8.3-56.8) 49.8 (33.6-66.1) 39.0 (22.4-55.6) Diabetes 19.1 (15.0-23.2) 36.9 (28.5-45.2) 25.0 (16.9-33.1) Other 40.6 (34.3-46.9) 39.8 (32.5-47.0) 40.2 (35.5-44.9) Total 33.5 (31.3-35.8) 36.3 (35.6-40.0) 34.4 (32.5-36.4) This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Copyright © 2015 Shahid Beheshti University of Medical Sciences. All rights reserved. Downloaded from: www.jemerg.com 21 Emergency (2015); 3 (1): 16-21 2. Welch HG, Sharp SM, Gottlieb DJ, Skinner JS, Wennberg JE. Geographic variation in diagnosis frequency and risk of death among Medicare beneficiaries. JAMA. 2011;305(11):1113-8. 3. Hunter DJ, Reddy KS. Noncommunicable diseases. N Engl J Med. 2013;369(14):1336-43. 4. Organization WH. The top 10 causes of death: The 10 leading causes of death in the world, 2000 and 2011. Retrieved July; 2013. 5. Roth GA, Murray CJ. The Global Burden of Disease Study 2010 Does Not Show a Rise in the Age-Standardized Mortality Rate for Cardiovascular Disease in Sub-Saharan Africa. Prog Cardiovasc Dis. 2013;56(3):278-80. 6. Lim SS, Vos T, Flaxman AD, et al. A comparative risk assessment of burden of disease and injury attributable to 67 risk factors and risk factor clusters in 21 regions, 1990–2010: a systematic analysis for the Global Burden of Disease Study 2010. Lancet. 2013;380(9859):2224-60. 7. Mathers CD, Boerma T, Fat DM. Global and regional causes of death. Br Med Bull. 2009;92(1):7-32. 8. Gaunt E, Harvala H, McIntyre C, Templeton K, Simmonds P. Disease burden of the most commonly detected respiratory viruses in hospitalized patients calculated using the disability adjusted life year (DALY) model. J Clin Virol. 2011;52(3):215- 21. 9. Hosseini M, Yousefifard M, Taslimi S, et al. Trend of blood cholesterol level in iran: results of four national surveys during 1991-2008. Acta Med Iran. 2013;51(9):642-51.. 10. Hosseini M, Taslimi S, Yousefifard M, et al. Serum Cholesterol Level Nomograms for Iranian Population; Suggestion for National Cut-Offs. Iran J public health. 2013;42(2):164-71. 11. Hosseini M, Navidi I, Hesamifard B, et al. Weight, Height and Body Mass Index Nomograms; Early Adiposity Rebound in a sample of children in tehran, iran. Int J Prev Med. 2013;4(12): 1414-20. 12. Heydari G, Heidari F, Yousefifard M, Hosseini M. Smoking and Diet in Healthy Adults: A Cross-Sectional Study in Tehran, Iran, 2010. Iran J Public health. 2014;43(4):485-91. 13. Hosseini-Esfahani F, Khameneh AMN, Mirmiran P, Ghanbarian A, Azizi F. Trends in risk factors for cardiovascular disease among Iranian adolescents: the tehran lipid and glucose study, 1999–2008. J Epidemiol. 2011;21(5):319-28. 14. He J, Gu D, Wu X, et al. Major causes of death among men and women in China. N Engl J Med. 2005;353(11):1124-34. 15. Naghavi M, Shahraz S, Sepanlou S, et al. Health Transition in Iran toward Chronic Diseases Based on Results of Global Burden of Disease 2010. Arch Iran Med. 2014;17(5):321-35. 16. Hosseini M, Naghan PA, Karimi S, et al. Environmental risk factors for lung cancer in Iran: a case–control study. Int J Epidemiol. 2009;38(4):989-96. 17. Masjedi MR, Naghan PA, Taslimi S, et al. Opium could be considered an independent risk factor for lung cancer: a case- control study. Respiration. 2012;85(2):112-8. 18. Mordukhovich I, Reiter PL, Backes DM, et al. A review of African American-white differences in risk factors for cancer: prostate cancer. Cancer Causes Control. 2011;22(3):341-57. 19. Forouzanfar MH, Foreman KJ, Delossantos AM, et al. Breast and cervical cancer in 187 countries between 1980 and 2010: a systematic analysis. Lancet. 2011;378(9801):1461-84.