Stesura Seveso Archivio Italiano di Urologia e Andrologia 2024; 96(1):12022 1 ORIGINAL PAPER INTRODUCTION Urolithiasis is the presence of stones inside the urinary tract. It is one of the most prevalent urological diseases, preceded only by urinary tract infections and prostate diseases (1). Urolithiasis is a multifaceted condition and doesn’t have a specific etiology. Risk factors for the development of kidney stones (KSs) are divided into intrinsic and extrinsic factors. Intrinsic factors are age, gender, ethnicity, and genetics. Extrinsic factors are climatic and environmental conditions, dietary habits, and occupation (2-4). The prevalence of KSs increases with age in both men and women. Men are more susceptible to developing KSs than females, while in children, both sexes have the same probability of KS formation (2, 5). The prevalence of this condition differs across various geographical areas, with an estimated prevalence ranging from 1% to 5% in Asia, 5% to 9% in Europe, and a significantly higher at 13% in North America. Additionally, it is important to highlight that the likeli- hood of recurrence for this condition is on the rise, exceeding 50% within a 5- to 10-year timeframe (6). Occupations that involve dehydration, prolonged expo- sure to the sun and high temperatures, perspiration, pro- longed sitting, and infrequent urination increase the like- lihood of KS formation (7-11). The economic burden of KSs is substantial. The USA spent 1.83 billion dollars and 2.1 billion dollars in the years 1995 and 2000, respec- tively. The estimated cost of stone-related problems could reach 4.1 billion dollars by the year 2030 (12). Qatar is a Middle Eastern country that is characterized by its dry and subtropical desert climate. It is situated with- in the Afro-Asian-Stone Belt region, and the workforce composition is marked by the presence of diverse nation- alities (13, 14). This study aims to investigate the role of occupation in urolithiasis in the Qatar population. Additionally, it seeks to examine the correlation of occupation and several intrinsic factors with KS characteristics. Background: Urolithiasis is one of the most prevalent urological diseases and is associat- ed with a substantial economic burden. Its prevalence varies according to geographical location. Qatar is a Middle Eastern country located in the Afro-Asian Stone Belt. It has a dry and hot climate, which may predispose individuals working in these environments to form kidney stones (KSs). Methods: A population sample of 4204 patients was categorized into five occupational classes. The frequencies and correlations of these occupations with KS formation were calculated. Results: Among the total cases, 2000 presented with KSs, with the majority being of Asian descent (49%), followed by individu- als of Middle Eastern descent (35.1%). Technicians accounted for 35.15% of KS cases followed by clerks (29.2%) and execu- tives (14.6%). Among KS cases, 44% had a single stone, 30% had multiple stones, and 26% had two stones. In comparing both KS and non-KS groups, age, gender, occupation, and race were significantly associated with KS formation (p-value < 0.05), while BMI did not show any significant correlation (p-value > 0.05). Asian males aged 31-40, working as techni- cians, were significantly more prone to urolithiasis. In compar- ing age, BMI, and gender with stone characteristics, only age was found significantly associated with stone size (p-value < 0.05). Occupation showed an impact on all studied stone char- acteristics. Clerks and technicians presented more frequently with stones within the 11-15 mm range, while executives more frequently presented with smaller stones (p-value < 0.001). Stone density was more frequently < 500 HU in workers, tech- nicians and housewives and > 500 HU in executives and clerks (p-value < 0.001). Conclusions: Our findings revealed an elevated risk of urolithia- sis among certain occupational groups, particularly technicians, who frequently work outdoors in high-temperature environ- ments. Alternatively, the sedentary nature of clerical and execu- tive positions can also contribute to the risk of urolithiasis. KEY WORDS: Urolithiasis; Occupational risk; Environmental factors; Geographic prevalence; Qatar. Submitted 24 October 2023; Accepted 9 January 2024 Occupational hazard in urolithiasis patients in Qatar: A single-center cross-sectional study Kamran Hassan Bhatti 1, Rawa Bapir 2-4, Nadeem Sohail 1, Faaz Salah Gomha 1, Ahmed H.A. Shaat 1, Aftab Ahmed Channa 5, Khalid Mohammed Abdelrahman 1, Bryar Othman Muhammed 6, Nali H. Hama 2, 7, Fahmi H. Kakamad 2, 3, 7, Berun A. Abdalla 2, 3, Jihad Ibrahim Hama 8, Hiwa O. Abdullah 2, 3 1 Urology Department, Hamad Medical Corporation, Alkhor, Qatar; 2 Smart Health Tower, Madam Mitterrand Street, Sulaimani, Kurdistan, Iraq; 3 Kscien Organization for Scientific Research (Middle East Office), Hamid Str, Azadi Mall, Sulaimani, Kurdistan, Iraq; 4 Department of Urology, Surgical Teaching Hospital, Sulaimani, Kurdistan, Iraq; 5 Urology Unit, Islam Medical College, Sialkot, Pakistan; 6 Smart Health Tower (Raparin Branch), Karux Street, Rania, Sulaimani, Kurdistan, Iraq; 7 College of Medicine, University of Sulaimani, Madam Mitterrand Street, Sulaimani, Kurdistan, Iraq; 8 Research Center, University of Halabja, Halabja, Kurdistan, Iraq. DOI: 10.4081/aiua.2024.12022 Summary Archivio Italiano di Urologia e Andrologia 2024; 96(1):12022 K. Hassan Bhatti, R. Bapir, N. Sohail, et al. 2 METHODS Study design This was a retrospective cross-sectional study of 4204 patients who visited Al-Khor Hospital over the past eight years. Specific information such as age, gender, BMI, occu- pation, race, smoking status, comorbidities, medical histo- ry, having KS or not, stone characteristics (in patients with KS), and any previous history of renal surgery (in cases with KS) were collected. The review of the data presented no risks to the subjects involved, as it entailed a compre- hensive review of historical medical records without the implementation of any new or invasive measures. Study population and setting The study sample comprised medical records of 4204 patients, sourced from pre-existing data within the reg- istry of Al-Khor Hospital, encompassing individuals who have either presented with renal or ureteric stones or vis- ited the hospital for general check-ups over the preceding 8 years. The study population encompassed a diverse spectrum of occupational categories, including clerks, executives, technicians, workers, and housewives. Within this classification, technicians were engineers and skilled laborers who were engaged in tasks related to machinery and technology. Workers represented a broader category encompassing individuals involved in manual labor or strenuous physical activities, spanning various industries including construction, agriculture, and manufacturing. Clerks denoted employees fulfilling various roles within an office setting, while executives were supervisors pri- marily engaged in meetings and responsible for decision- making processes. The frequencies of these occupations were calculated in both groups of patients with or with- out KSs and compared against each other. Inclusion and exclusion criteria The study included adult patients who were admitted to Al-Khor Hospital with renal or ureteric colic or visited it for routine check-ups between January 1, 2014, and December 31, 2022. Individuals within the pediatric age group were excluded from this study. Statistical analysis The acquired data were inputted into the Statistical Package for the Social Sciences (SPSS, v.25; IBM Corp.), with optimization of variables for subsequent analysis. Descriptive statistics were then generated, followed by correlation testing, where the Chi-squared (𝝌²) test was employed to identify associations among diverse parame- ters. The significance level was predetermined at p ≤ 0.05. RESULTS Among the total number of individuals included, 2000 presented with KS, with the majority being of Asian descent (49%), followed by individuals of Middle Eastern descent (35.1%). In both KS and non-KS cases, a higher proportion of subjects were male (84.1% and 80.6%, respectively), with male-to-female ratios of 5.3:1 and 4.1:1, respectively. The mean age of KS cases was 36.9 ± 9.1, concentrated in their thirties to forties, while non-KS cases were commonly distributed over thirty years with a mean age of 41.6 ± 13.4. The BMI of KS cases was 28.9 ± 3.6, compared to 29 ± 3.71 in non-KS cases. Table 1. The baseline characteristics of the patients. Patients with KS (No., %) Patients with no KS (No., %) Overall (No., %) Race Asian (979, 49.0%) Asian (1081, 49.1%) Asian (2060, 49.0%) Middle Eastern (701, 35.1%) Middle Eastern (843, 38.2%) Middle Eastern (1544, 36.7%) Unknown (184, 9.0%) Unknown (0, 0.0%) Unknown (184, 4.4%) African (132, 6.6%) African (245, 11.1%) African (377, 8.9%) American (3, 0.2%) American (12, 0.5%) American (15, 0.4%) European (1, 0.1%) European (23, 1.0%) European (24, 0.6%) Sex Male (1682, 84.1%) Male (1776, 80.6%) Male (3458, 82.3%) Female (318, 15.9%) Female (428, 19.4%) Female (746, 17.7%) Age (yrs.) 18-23 (0, 0.0%) 18-23 (155, 7.0%) 18-23 (155, 3.7%) 24-30 (488, 24.4%) 24-30 (347, 15.7%) 24-30 (835, 19.9%) 31-40 (851, 42.55%) 31-40 (621, 28.2%) 31-40 (1472, 35.0%) 41-50 (330, 16.5%) 41-50 (557, 25.3%) 41-50 (887, 21.1%) > 50 (331, 16.55%) > 50 (524, 23.8%) > 50 (855, 20.3%) Mean age ± SD (36.9 ± 9.1) Mean age ± SD (41.6 ± 13.4) Mean age ± SD (39.3 ± 11.8) BMI (kg/m2) * Normal (209, 10.45%) Normal (242, 11.0%) Normal (451, 10.7%) Overweight (1048, 52.4%) Overweight (1109, 50.3%) Overweight (2157, 51.3%) Obese (743, 37.15%) Obese (853, 38.7%) Obese (1596, 38.0%) Mean BMI ± SD (28.9 ± 3.6) Mean BMI ± SD (29 ± 3.71) Mean BMI ± SD (29 ± 3.67) Smoking Yes (504, 25.0%) Yes (327, 14.8%) Yes (831, 19.8%) No (1496, 75.0%) No (1877, 85.2%) No (3373, 80.2%) Comorbidity None (1952, 97.6%) None (1752, 79.5%) None (3704, 88.1%) Diabetes mellitus (26, 1.3%) Diabetes mellitus (220, 10%) Diabetes mellitus (246, 5.9%) Hypertension (22, 1.1%) Hypertension (232, 10.5%) Hypertension (254, 6.0%) Occupation Clerk (584, 29.2%) Clerk (342, 15.5%) Clerk (926, 22.0%) Executive (292, 14.6%) Executive (302, 13.7%) Executive (594, 14.1%) Housewife (87, 4.35%) Housewife (392, 17.8%) Housewife (479, 11.4%) Technicians (703, 35.15%) Technicians (416, 18.9%) Technicians (1119, 26.6%) Worker (334, 16.7%) Worker (752, 34.1%) Worker (1086, 25.8%) Previous renal surgery Yes (1154, 57.7%) - - No (846, 42.3%) - - Number of stones One (879, 44.0%) - - Two (522, 26.0%) - - Multiple (599, 30.0%) - - Location of stones Ureter (330, 16.5%) - - Renal pelvis (512, 25.6%) - - Upper Calyx (303, 15.15%) - - Middle Calyx (411, 20.55%) - - Lower Calyx (444, 22.2%) - - Size of stones 5-10 mm (551, 27.55%) - - 11-15 mm (935, 46.75%) - - 16-20 mm (514, 25.7%) - - Laterality Right (958, 47.9%) - - Left (1042, 52.1%) - - Density of stones < 500 HU (1093, 54.65%) - - > 500 HU (907, 45.35%) - - Archivio Italiano di Urologia e Andrologia 2024; 96(1):12022 3 Occupational hazard in urolithiasis patients Regarding occupations, technicians comprised the largest group (26.6%), accounting for 35.15% of KS cases and 18.9% of non-KS cases. They were followed by workers (25.8%), representing 16.7% of KS cases and 34.1% of non-KS cases, and clerks (22%), comprising 29.2% of KS cases and 15.5% of non-KS individuals (Table 1). More than half of the KS cases (57.7%) had a history of previous renal surgery. Among KS cases, 44% had a sin- gle stone, 30% had multiple stones, and 26% had two stones, which were almost evenly distributed in terms of laterality. The most common locations were the renal pelvis (25.6%), lower calyx (22.2%), and middle calyx (20.55%). Stone sizes were commonly distributed between 11-15 mm (46.75%) with a density smaller than 500 HU in 54.65% (Table 1). In comparing the two groups, age, gender, occupation, and race were significantly distributed in subjects with and without KS (p-value < 0.05), while BMI was not sig- nificantly different (p-value > 0.05). Asian males aged 31-40, working as technicians, were the group significantly more prone to urolithiasis (Table 2). In comparing age, BMI, and gender with stone characteris- tics (number, size, density), only stone size was differently distributed by age (p-value < 0.05). The 11-15 mm stone size was the most frequent in all age groups, although in patients between ages 31-40 years, the rate of 11-15 mm stones was higher (49%) than in the other age groups. All three stone characteristics were significantly correlat- ed with occupation; stones were mostly single in clerks, housewives, technicians, and workers, while in execu- tives, stones were mostly multiple (p-value < 0.001). The most common stone size among clerks and techni- cians was within the 11-15 mm range, while executives more frequently presented with smaller stone sizes in comparison to other occupations (p-value < 0.001). Stone density was more frequently < 500 HU in workers, technicians and housewives and > 500 in executives and clerks (p-value < 0.001). Table 2. The correlation of age, BMI, gender, and occupation with having KS. Part. 1 Variables Age (yrs.) BMI Total 18-23 24-30 31-40 41-50 > 51 P-value * Normal Overweight Obese P-value * Having stone Yes 2000 0 488 851 330 331 < 0.001 209 1048 743 0.401 No 2204 155 347 621 557 524 242 1109 853 Part. 2 Variables Gender Occupation Race Total Male Female P-value* Clerk Executive Housewife Technician Worker P-value * Total African American Asian European Middle eastern P-value * Having stone Yes 2000 1682 318 0.003 584 292 87 703 334 < 0.001 1816 132 3 979 1 701 < 0.001 No 2204 1776 428 342 302 392 416 752 2204 245 12 1081 23 843 * Chi-square test. BMI: body mass index. KS: kidney ston. Table 3. The correlation of age, BMI, gender, and occupation with stone characteristics. Part. 1 Variables Age (yrs.) BMI Total 24-30 31-40 41-50 > 50 P-value* Normal Overweight Obese P-value * Stone number One 879 215 366 147 151 0.867 90 471 318 0.474 Two 522 124 232 89 77 59 278 185 Multiple 599 149 253 94 103 60 299 240 Stone size 5-10 mm 551 109 249 102 91 0.027 58 304 189 0.55 11-15 mm 935 250 401 139 145 97 476 362 16-20 mm 514 129 201 89 95 54 268 192 Stone density < 500 HU 1093 271 466 181 175 0.9 105 588 400 0.255 > 500 HU 907 217 385 149 156 104 460 343 Part. 2 Variables Gender Occupation Total Male Female P-value * Clerk Executive Housewife Technician Worker P-value * Stone number One 879 732 147 0.612 363 38 39 310 129 < 0.001 Two 522 445 77 107 106 16 199 94 Multiple 599 505 94 114 148 32 194 111 Stone size 5-10 mm 551 459 92 0.642 29 142 36 205 139 < 0.001 11-15 mm 935 794 141 551 35 21 284 44 16-20 mm 514 429 85 4 115 30 214 151 Stone density < 500 HU 1093 920 173 0.923 266 56 62 465 244 <0.001 > 500 HU 907 762 145 318 236 25 238 90 * Chi-square test. BMI: body mass index. Yrs: years, HU: Hounsfield units. Archivio Italiano di Urologia e Andrologia 2024; 96(1):12022 K. Hassan Bhatti, R. Bapir, N. Sohail, et al. 4 DISCUSSION In the course of this study, we conducted an assessment of the role of occupation in urolithiasis and examined the cor- relation of occupation and other several intrinsic factors with KS characteristics in the population of Qatar. In this study, only validated studies were used for discussion (15). Factors estimated to contribute to the pathogenesis of nephrolithiasis include genetic predisposition, gender, geographic location, dietary habits, insufficient fluid intake, and socioeconomic status (16). It has been well established that males are more suscepti- ble to nephrolithiasis than females due to exposure to risk factors (16-18). A review study indicated an elevated prevalence of expo- sure to occupational hazards among men. These hazards include engaging in repetitive tasks, extended periods of sitting or standing at work, physically demanding labor involving lifting and manual material handling and expo- sure to occupational ultraviolet radiation from sunlight. The review found no evidence in any study suggesting that women had a higher susceptibility than men to these specific occupational hazards, most of which are recog- nized as risk factors for the development of KS (18). Another study indicated that the increased occurrence and prevalence of KS in men could be attributed to high- er rates of obesity and alcohol consumption in men com- pared to women, leading to heightened production of oxalic acid in men (17). Urolithiasis predominantly impacts adults in the third to fourth decade of life, with a generally observed male-to- female ratio ranging from 1.5:1 to 2.5:1 (19). Some stud- ies, particularly in the United States, suggested a potential decline in this ratio to below 1.5:1 (20-22). Another study conducted in Morocco reported a male-to-female ratio of 2.03:1, while Hossain et al. documented a ratio of 2.68:1 in Japan (19, 23). In Bouatia's study, the age group most susceptible to KS was between 31 and 60 years old, with a peak incidence observed at the age of 53 (19). In addition to the intrinsic factors, some studies also mentioned high BMI or obesity as a factor for KS forma- tion (17, 19, 24, 25). In line with the literature, the findings of our study revealed that males were significantly more affected by nephrolithia- sis. This association was attributed to the nature of the patients' work, which often involved exposure to sunlight, high temperatures, or a sedentary work style in the work- place. The male-to-female ratio among our KS cases was 5.3:1, significantly higher than the ratios reported in previ- ous studies. The mean age of KS cases was 36.9 ± 9.1, consistent with the literature. While some authors have reported an association between BMI and KS formation, our findings, to the contrary, indi- cate no significant role of BMI in nephrolithiasis. In our study, the races most significantly affected by KS were Asian, followed by Middle Eastern and African pop- ulations, underscoring the correlation between KS forma- tion and geographical location, as indicated in the litera- ture (16). In terms of stone composition, most studies reported sim- ilar findings. In a renal stone clinic in Southampton, in a population of 2800 patients, the predominant stone com- position was calcium oxalate (89%), with a ratio of 1:4 for calcium oxalate to mixed calcium oxalate phosphate stones. Pure calcium phosphate stones were infrequent, accounting for only 2% of cases. In Sweden, approximate- ly 85% of urinary tract stones were classified as calcium stones, encompassing both calcium oxalate and calcium phosphate varieties (26, 27). In another study involving 888 cases, calcium oxalate and calcium phosphate were identified as the most common primary components of the stones (28). In a series of 802 patients with 828 KS, Bouatia et al. identified calcium oxalate as the main component, followed by uric acid and calcium phosphate (19). Unfortunately, due to the nature of the study design, we could not represent any data regarding stone composition in our cases. However, the stone density in 54.65% of our cases was < 500 HU, and according to the literature, stones with < 500 HU were usually uric acid stones. Therefore, we estimate that stones in more than half of our cases were uric acid type (29). Our findings revealed that the majority of patients at risk of KS formation were the technicians and the clerks. The technicians with KS accounted for 35.15% of our dataset. They may spend a significant amount of time outdoors, often exposed to adverse weather conditions, including high temperatures and direct sunlight. These environ- mental factors, notably high-temperature environments and prolonged sun exposure, are recognized as significant risk factors in the etiology of urinary stone formation, especially uric acid stones (30). Nevertheless, workers, akin to technicians, are exposed to elevated temperatures and sunlight. However, in this study, their association with KS formation did not reach the same level of signifi- cance as observed with technicians. In 1945, Pierce et al. studied the effects of high-tempera- ture exposure as a risk factor for the formation of urolithi- asis in American troops in desert areas (31). Later on, multiple studies indicated the association between the incidence of stone and working in ambient temperatures, under the sun, and perspiration (10, 30, 31). Better et al. studied the increased incidence of nephrolithi- asis in lifeguards who are exposed to the sun more than the normal population (10). Lu et al. reported an increase in the prevalence of radiolucent stones among workers in a steel factory who were exposed to heat (11).The correla- tion between urolithiasis and ambient temperature, as well as heat exposure, can be attributed to several factors, including low urine volume with saturation of stone-form- ing salts in urine due to perspiration (32). Perspiration also leads to acidic urine with a reduction of uric acid solubility, which also contributes to stone for- mation (31). The incidence of urolithiasis peaks in the summer, which further supports the impact of ambient temperatures on stone formation (8). This assumption aligns perfectly with our region, charac- terized by a dry and subtropical desert climate. Another hypothesis for the development of stone in warmer climates is that sunlight leads to higher levels of Vitamin D (32), although it is not concretely supported (33-35). A substantial portion of our dataset (43.8%) in the KS Archivio Italiano di Urologia e Andrologia 2024; 96(1):12022 5 Occupational hazard in urolithiasis patients group consisted of individuals employed in clerical and executive positions. This notable prevalence can be attributed to a myriad of factors. Executive professionals occupied pivotal roles within our dataset, characterized by their accountability for formulating high-level deci- sions and overseeing the management of organizations or departments. Their responsibilities encompassed strategic planning, leadership, and frequent engagement in meet- ings and office-based activities. Clerical personnel within our dataset primarily performed administrative functions such as data entry, record-keeping, and meticulous man- agement of paperwork. They often worked indoors with executives. Staying indoors and the sedentary features of these occupations have the potential to place individuals in a vulnerable position regarding the development of metabolic syndrome, elevated BMI, and infrequent urina- tion. Consequently, it is plausible to assert that such occupational pursuits may indirectly elevate the suscepti- bility of individuals to urolithiasis (8). Infrequent urina- tion due to prolonged working hours and low urine vol- ume are other occupational risks for the development of urolithiasis. Individuals in various professions such as taxi drivers, aviation personnel, teachers, and healthcare workers are at risk due to these factors (7, 8, 36). On the other hand, the potential for urolithiasis develop- ment in factory workers is exacerbated by occupational exposure to metallic substances. Jarup et al. documented an increased prevalence of KSs in individuals exposed to Cadmium (37). Additionally, Liu and colleagues identified an association between KSs and the presence of heavy met- als such as Arsenic and Cadmium, while Chromium, Mercury, and Lead did not manifest discernible associations with this condition (4). In the present study, we were unable to explore any rela- tionships between metallic substances and KS formation due to the absence of data regarding the extent of expo- sure among cases or workers. Finally, there is insufficient knowledge on the correlation of stone characteristics with intrinsic and extrinsic factors for stone formation. A study by Krambeck et al. reported no significant differ- ence in stone size and location in relation to age. Nonetheless, older individuals were more likely to have stones with a larger diameter or staghorn calculi (28). A meta-analysis of 15 studies involving 13.233 patients found no significant correlation between BMI and stone size (25). In the present study, all stone characteristics, including number, size, and density, were found to be significantly correlated only with occupation, whereas stone size showed a correlation with age. In contrast to the study by Krambeck et al., the stone size of 11-15 mm was the most frequent in all age groups, particularly in patients aged 31-40 years; no evidence suggested that older patients had larger stone sizes. Furthermore, consistent with the meta-analysis by Wang et al., BMI did not exhibit a sig- nificant impact on stone size. Our study had several limitations. The primary con- straints included the retrospective nature of the work, which may have omitted certain data that could directly or indirectly influence the results. Specifically, informa- tion about alcohol consumption status, urination volume, daily water intake, and the presence of kidney diseases or other diseases that could enhance KS formation may not have been adequately captured. CONCLUSIONS This study has provided insights into different working activities that may increase the risk of urinary stone forma- tion in the Qatari population. Our findings suggested an elevated risk of urolithiasis among certain occupational groups, particularly technicians, who frequently work out- doors in high-temperature environments. Similarly, the sedentary nature of clerical and executive positions, charac- terized by prolonged indoor working hours can also indi- rectly contribute to the risk of urolithiasis. Implementing proactive measures and awareness plans targeted at these at-risk groups may significantly contribute to reducing the incidence of urolithiasis among the workforce. DECLARATIONS • Ethical approval: This study does not involve any human or animal testing. • Availability of data and material: All data and materi- als are kept by the first and corresponding authors. • Competing interests: None. • Funding: No source to be stated. • Authors' contributions: Kamran Hassan Bhatti, Rawa Bapir, and Nadeem Sohail were major contributors to the study. Hiwa O. Abdullah, Faaz Salah Gomha, Ahmed H.A. Shaat, Aftab Ahmed Channa, Nali H. Hama, Khalid Mohammed Abdelrahman, and Bryar Othman Muhammed were involved in the literature review, the writing of the manuscript, and data analysis and interpretation. Fahmi H. Kakamad, Berun A. Abdalla, and Jihad Ibrahim Hama were involved in the design of the study, and the critical revision of the manuscript. All authors have read and approved the final manuscript. • Acknowledgments: None to be declared. REFERENCES 1. Wigner P, Grebowski R, Bijak M, et al. The molecular aspect of nephrolithiasis development. Cells. 2021; 10:1926. 2. Ziemba JB, Matlaga BR. Epidemiology and economics of nephrolithiasis. Investigative and clinical urology. 2017; 58:299-306. 3. Najeeb Q, Masood I, Bhaskar N, et al. Effect of BMI and urinary pH on urolithiasis and its composition. Saudi journal of kidney dis- eases and transplantation. 2013; 24:60-6. 4. Liu Y, Zhang C, Qin Z, et al. Analysis of threshold effect of urinary heavy metal elements on the high prevalence of nephrolithiasis in men. Biological Trace Element Research. 2022:1-1. 5. Worcester EM, Coe FL. Nephrolithiasis. Primary Care: Clinics in Office Practice. 2008; 35:369-91. 6. Bouatia M, Benramdane L, Idrissi MO, Draoui M. An epidemio- logical study on the composition of urinary stones in Morocco in rela- tion to age and sex. African journal of urology. 2015; 21:194-7. 7. Linder BJ, Rangel LJ, Krambeck AE. The effect of work location on urolithiasis in health care professionals. Urolithiasis. 2013; 41:327-31. 8. Malieckal DA, Goldfarb DS. Occupational kidney stones. Current opinion in nephrology and hypertension. 2020; 29:232-6. Archivio Italiano di Urologia e Andrologia 2024; 96(1):12022 K. Hassan Bhatti, R. Bapir, N. Sohail, et al. 6 9. Bird VY, Chastain-Gross R, Sutkowski R, et al. Pseudomonas aeruginosa as an etiologic agent of nephrolithiasis in deep water divers. Journal of Endourology Case Reports. 2017; 3:4-6. 10. Better OS, Shabtai M, Kedar S, et al. Increased incidence of nephrolithiasis (N) in lifeguards (LG) in Israel. Phosphate and min- erals in health and disease. 1980:467-72. 11. Lu IC, Yang CC, Huang CH, et al. The Risk Factors for Radiolucent Nephrolithiasis among Workers in High-Temperature Workplaces in the Steel Industry. International Journal of Environmental Research and Public Health. 2022; 19:15720. 12. Roberson D, Sperling C, Shah A, et al. Economic considerations in the management of nephrolithiasis. Current urology reports. 2020; 21:1-9. 13. Pathan SA, Mitra B, Bhutta ZA, et al. A comparative, epidemio- logical study of acute renal colic presentations to emergency depart- ments in Doha, Qatar, and Melbourne, Australia. International Journal of Emergency Medicine. 2018; 11:1-6. 14. Jure Snoj. Population of Qatar by Nationality in 2019. Priya D’Souza, 15 August 2019, https://priyadsouza.com/population-of- qatar-by-nationality-in-2017/ 15. Aso S. Muhialdeen, Jaafar Omer Ahmed, Hiwa O. Baba, et al. Kscien’s List; A New Strategy to Discourage Predatory Journals and Publishers (Second Version). Barw Medical Journal. 2023; 1. 16. Hara A, Yang WY, Petit T, et al. Incidence of nephrolithiasis in relation to environmental exposure to lead and cadmium in a popu- lation study. Environmental research. 2016; 145:1-8. 17. Heo J, Son J, Lee W. Epidemiology of urolithiasis with sex and work- ing status stratification based on the national representative cohort in republic of Korea. Safety and health at work. 2022; 13:482-6. 18. Biswas A, Harbin S, Irvin E, et al. Sex and Gender Differences in Occupational Hazard Exposures: a Scoping Review of the Recent Literature. Curr Environ Health Rep. 2021; 8:267-280. 19. Bouatia M, Benramdane L, Idrissi MO, et al. An epidemiological study on the composition of urinary stones in Morocco in relation to age and sex. African journal of urology. 2015; 21:194-7. 20. Daudon M, Traxer O, Lechevallier E, et al. Épidémiologie des lithiases urinaires. Prog Urol. 2008; 18:802-14. 21. Michelle L, Bernd H. History, epidemiology and regional diversi- ties of urolithiasis. Pediatr Nephrol. 2010; 25(1):49-59. 22. Denstedt JD, Fuller A. (2012). Epidemiology of Stone Disease in North America. In: Talati, J., Tiselius, HG., Albala, D., YE, Z. (eds) Urolithiasis. Springer, London. 23. Hossain RZ, Ogawa Y, Hokama S, et al. Urolithiasis in Okinawa, Japan: a relatively high prevalence of uric acid stones. International Journal of Urology. 2003; 10(8):411-5. 24. Chang MA, Goldfarb DS. Occupational risk for nephrolithiasis and bladder dysfunction in a chauffeur. Urological research. 2004; 32:41-3. 25. Wang D, Tan J, Geng E, et al. Impact of body mass index on size and composition of urinary stones: a systematic review and meta- analysis. International braz j urol. 2023; 49:281-98. 26. Walker V, Stansbridge EM, Griffin DG. Demography and bio- chemistry of 2800 patients from a renal stones clinic. Annals of clin- ical biochemistry. 2013; 50:127-39. 27. Tiselius HG. Who forms stones and why?. European Urology Supplements. 2011; 10:408-14. 28. Krambeck AE, Lieske JC, Li X, et al. Effect of age on the clinical presentation of incident symptomatic urolithiasis in the general pop- ulation. The Journal of urology. 2013; 189:158-64. 29. Kim JC, Cho KS, Kim DK, et al. Predictors of Uric Acid Stones: Mean Stone Density, Stone Heterogeneity Index, and Variation Coefficient of Stone Density by Single-Energy Non-Contrast Computed Tomography and Urinary pH. J Clin Med. 2019; 8:243. 30. Li Z, Li Y, Wang X, et al. Extreme temperature exposure and urolithiasis: A time series analysis in Ganzhou, China. Frontiers in Public Health. 2022; 10:1075428. 31. Pierce LW, Bloom B. Observations on urolithiasis among American troops in a desert area. The Journal of urology. 1945; 54:466-70. 32. Fakheri RJ, Goldfarb DS. Association of nephrolithiasis preva- lence rates with ambient temperature in the United States: a re- analysis. Kidney international. 2009; 76:798. 33. Ferraro PM, Taylor EN, Gambaro G, et al. Vitamin D intake and the risk of incident kidney stones. The Journal of urology. 2017; 197:405-10. 34. Letavernier E, Daudon M. Vitamin D, hypercalciuria and kidney stones. Nutrients. 2018; 10:366. 35. Bargagli M, Ferraro PM, Vittori M, et al. Calcium and vitamin D supplementation and their association with kidney stone disease: a narrative review. Nutrients. 2021; 13:4363. 36. Hari SB, Morrow MS. Rethinking nephrolithiasis in military avia- tion. Aviation, Space, and Environmental Medicine. 2012; 83:445-8. 37. Jarup L, Elinder CG. Incidence of renal stones among cadmium exposed battery workers. Br J Ind Med. 1993; 50:598-602. Correspondence Kamran Hassan Bhatti, MD kamran.bhatti@gmail.com Nadeem Sohail, MD Faaz Salah Gomha, MD Ahmed H.A. Shaat, MD Khalid Mohammed Abdelrahman, MD Urology Department, Hamad Medical Corporation, Alkhor, Qatar Rawa Bapir, MD Nali H. Hama, MD Berun A. Abdalla, MD Hiwa O. Abdulla, MD hiwaabdullah588@gmail.com Smart Health Tower, Madam Mitterrand Street, Sulaimani, Kurdistan, Iraq Aftab Ahmed Channa, MD Urology Unit, Islam Medical College, Sialkot, Pakistan Bryar Othman Muhammed, MD Smart Health Tower (Raparin Branch), Karux Street, Rania, Sulaimani, Kurdistan, Iraq Fahmi H. Kakamad, MD (Corresponding Author) fahmi.hussein@univsul.edu.iq Doctors City, Building 11, Apartment 50, Sulaimani, Iraq Road Number: GFG6+M6F Sulaymaniyah, Iraq Jihad Ibrahim Hama, MD Research Center, University of Halabja, Halabja, Kurdistan, Iraq Conflict of interest: The authors declare no potential conflict of interest.