Examining the Relationship between the WBGT Index and Leukocyte Levels: A Case Study of Foundry Workers Exposed to Heat Stress
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Abstract
Background: Iran’s hot and arid climate, combined with frequent exposure to heat-generating industrial processes, presents significant occupational health concerns. These environmental conditions may influence white blood cell (WBC) levels and their functions in response to heat stress. This study investigates the relationship between the Wet Bulb Globe Temperature (WBGT) index and WBC levels among workers in a foundry setting.
Methods: This descriptive-analytical study was conducted on 55 male workers from two sections of a foundry: the cast iron section (35 participants) and the CNC section (20 participants). Blood samples were collected from all participants. Heat stress was assessed using the WBGT index. Intervening parameters—such as noise, lighting, and metabolic rates—were measured for each work group. Data analysis was performed using SPSS version 16.
Results: In the case group, a decrease in total WBC count and lymphocyte levels was observed, along with an increase in neutrophil levels and the neutrophil-to-lymphocyte ratio. No significant relationship was found between heat stress and the composition of other WBC types, including basophils, monocytes, and eosinophils. Correlation analysis revealed strong associations between the WBGT index and total WBC count (R² = 0.93), neutrophils (R² = 0.85), lymphocytes (R² = 0.81), and overall WBC composition (R² = 0.82).
Conclusion: Chronic exposure to heat stress may lead to significant alterations in WBC levels, potentially weakening and suppressing the immune system. The blood parameters examined in this study can serve as biomarkers affected by heat stress and merit further investigation.
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13. Behera HK, Jena GR, Kumar D, Kumar S, Mishra DPD, Samal L, Dalai N. Ameliorative effect of vitamin C on hematobiochemical and oxidative parameters in ducks during summer. 2020.
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15. Abudabos AM, Al-Owaimer AN, Hussein EO, Ali MH. Effect of natural vitamin C on performance and certain haemato-biochemical values in broiler chickens exposed to heat stress. Pak J Zool. 2018;50(3).
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17. Hamrahian AH, Oseni TS, Arafah BM. Measurements of serum free cortisol in critically ill patients. N Engl J Med. 2004;350(16):1629–38.
18. Gaeini AA, Choobineh S, Satarifard S. Relationship between athlete’s men cortisol with leukocytosis and neutrophils numbers after exercise in cold, warm and normal temperatures conditions. J Fasa Univ Med Sci. 2012;1(4):238–43.
19. Contreras-Jodar A, Salama AA, Hamzaoui S, Vailati-Riboni M, Caja G, Loor JJ. Effects of chronic heat stress on lactational performance and the transcriptomic profile of blood cells in lactating dairy goats. J Dairy Res. 2018;85(4):423–30.
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22. Dehghan H, Mortazavi SB, Jafari MJ, Maracy MR, Jahangiri M. The evaluation of heat stress through monitoring environmental factors and physiological responses in melting and casting industries workers. Int J Environ Health Eng. 2012;1(1):21.
23. Hajizadeh R, Golbabaei F, Dehghan SF, Beheshti MH, Jafari SM, Taheri F. Validating the heat stress indices for using in heavy work activities in hot and dry climates. J Res Health Syst. 2016;16(2):90.
24. Rahman MM, Kim HB, Baek HJ. Changes in blood cell morphology and number of red spotted grouper, Epinephelus akaara in response to thermal stress. Dev Reprod. 2019;23(2):139.
25. Bao JW, Qiang J, Tao YF, Li HX, He J, Xu P, Chen DJ. Responses of blood biochemistry, fatty acid composition and expression of microRNAs to heat stress in genetically improved farmed tilapia (Oreochromis niloticus). J Therm Biol. 2018;73:91–97.
26. Xu Y, Lai X, Li Z, Zhang X, Luo Q. Effect of chronic heat stress on some physiological and immunological parameters in different breed of broilers. Poult Sci. 2018;97(11):4073–82.
27. Zafalon-Silva B, Zebral YD, Bianchini A, Da Rosa CE, Marins LF, Colares EP, et al. Erythrocyte nuclear abnormalities and leukocyte profile in the Antarctic fish Notothenia coriiceps after exposure to short- and long-term heat stress. J Therm Biol. 2017;40(9):1755–60.
28. Holt PS, Vaughn LE, Gast RK. Flow cytometric characterization of Peyer’s patch and cecal tonsil T lymphocytes in laying hens following challenge with Salmonella enterica serovar Enteritidis. Vet Immunol Immunopathol. 2010;133(2–4):276–81.
29. Azis A, Abbas H, Heryandi Y, Kusnadi E. Thyroid hormone and blood metabolites concentrations of broiler chickens subjected to feeding time restriction. Media Peternak. 2012;35(1):32.
30. Mohammadian F, Fallahati M, Abbasi M, Zokaei M. Changes in physiological and cognitive parameters in acute and combined exposure to different levels of noise and heat stress: Experimental study. J Health Saf Work. 2023;13(3).
31. Khazaei P, Sahlabadi AS, Ramezanifar S, Mehrifar Y, Khadiv E, Rastegari P, Gharari N. The effects of heat stress on bakery workers: A systematic review. Iran J Public Health. 2023;52(12):2528.
32. Krams I, Vrublevska J, Cirule D, Kivleniece I, Krama T, Rantala MJ, et al. Heterophil/lymphocyte ratios predict the magnitude of humoral immune response to a novel antigen in great tits (Parus major). J Comp Physiol B. 2012;161(4):422–8.
33. Asghari B, Zerehdaran S, Jafari AY, Hasani S, Lotfi E. Prediction of antibody against sheep red blood cells by the number of white blood cells of Japanese quail (Coturnix japonica). 2016.
34. Bolghanabadi S, Pour M, Tizro M. The relation between heat strain and hydration status among workers. J Occup Hyg Eng. 2016;3(3):16–23.
35. Moradi A, Gholami F. Effect of age and stress due to physical activity on blood cell count and red blood cell indices. Sci J Rehabil Med. 2018;3(3):141–6.
36. Senturk UK, Gunduz F, Kuru O, Kocer G, Ozkaya YG, Yesilkaya A, et al. Exercise-induced oxidative stress leads hemolysis in sedentary but not trained humans. J Appl Physiol. 2005;99(4):1434–41.
37. Kim WS, Lee JS, Jeon SW, Peng DQ, Kim YS, Bae MH, et al. Correlation between blood, physiological and behavioral parameters in beef calves under heat stress. Anim Sci J. 2018;31(6):919.
38. Adriani L, Mushawwir A, editors. Correlation between blood parameters, physiological and liver gene expression levels in native laying hens under heat stress. In: IOP Conf Ser Earth Environ Sci. 2020;IOP Publishing.
39. McCarthy DO, Ouimet ME, Daun JM. The effects of noise stress on leukocyte function in rats. Res Nurs Health. 1992;15(2):131–7.
40. Zheng KC, Ariizumi M. Modulations of immune functions and oxidative status induced by noise stress. J Occup Health. 2007;49(1):32–8.
41. Akhlaghi Pirposhteh E, Mortazavi SB, Farhang Dehghan S, Khaloo SS, Montazer M. Optimization and development of workwear fabric coated with TiO₂ nanoparticles in order to improve thermal insulation properties and air permeability. J Ind Text. 2024;54:15280837241258169.
2. Yang X, Li B, Li Y, Wang Y, Zheng CJ. A research on characteristics of human heat stress in dynamic hot environment. Procedia Eng. 2017;205:2749–54.
3. Stanton N, Salmon PM, Rafferty LA. Human factors methods: a practical guide for engineering and design. Farnham: Ashgate Publishing; 2013.
4. Bidel F, Jafari MJ, Khodakarim S, Salehi Sahlabadi A. Evaluation of the effect of heat stress on cognitive performance and physiological parameters of the students. Int J Occup Hyg. 2020;17(1):1–15.
5. Vangelova K, Deyanov C, Ivanova M. Dyslipidemia in industrial workers in hot environments. Cent Eur J Public Health. 2006;14(1):15.
6. Tawatsupa B, Lim LY, Kjellstrom T, Seubsman SA, Sleigh A. The association between overall health, psychological distress, and occupational heat stress among a large national cohort of 40,913 Thai workers. Glob Health Action. 2010;3(1):5034.
7. Tawatsupa B, Lim LL, Kjellstrom T, Seubsman SA, Sleigh A. Association between occupational heat stress and kidney disease among 37,816 workers in the Thai Cohort Study (TCS). J Epidemiol. 2012;22(3):251–60.
8. Jafari MJ, Pirposhteh EA, Dehghan SF, Khodakarim S, Jafari M. Relationship between heat stress exposure and some immunological parameters among foundry workers. Int J Occup Biol. 2020:1–9.
9. Yazdanirad S, Golbabaei F, Khoshakhlagh AH, Sarsangi V, Yaseri M, Mousavi SM. Development and validation of the tools for evaluating awareness and practice related to heat stress among the workers of warm workplaces. J Health Saf Work. 2022;12(1).
10. Nassiri P, Monazzam MR, Golbabaei F, Abbasinia M, Chavoshi M, Taheri F, Asghari M. Exposure to heat stress in the workplace: a systematic review. Int J Occup Hyg. 2018;15(2).
11. Hall JE, Hall ME. Guyton and Hall textbook of medical physiology. 14th ed. Philadelphia: Elsevier Health Sciences; 2020.
12. Ribeiro MN, Ribeiro NL, Bozzi R, Costa RG. Physiological and biochemical blood variables of goats subjected to heat stress – a review. J Anim Appl Res. 2018;46(1):1036–41.
13. Behera HK, Jena GR, Kumar D, Kumar S, Mishra DPD, Samal L, Dalai N. Ameliorative effect of vitamin C on hematobiochemical and oxidative parameters in ducks during summer. 2020.
14. Berian S, Gupta S, Sharma S, Ganai I, Dua S, Sharma N. Effect of heat stress on physiological and hemato-biochemical profile of cross bred dairy cattle. J Anim Res. 2019;9(1):95–101.
15. Abudabos AM, Al-Owaimer AN, Hussein EO, Ali MH. Effect of natural vitamin C on performance and certain haemato-biochemical values in broiler chickens exposed to heat stress. Pak J Zool. 2018;50(3).
16. Mündel T, Cox J, Jones DJ. Exercise, heat stress and the interleukin-6 response: support for temperature-mediated neuroendocrine regulatory mechanisms. Med Sport Sci. 2010;14:96–102.
17. Hamrahian AH, Oseni TS, Arafah BM. Measurements of serum free cortisol in critically ill patients. N Engl J Med. 2004;350(16):1629–38.
18. Gaeini AA, Choobineh S, Satarifard S. Relationship between athlete’s men cortisol with leukocytosis and neutrophils numbers after exercise in cold, warm and normal temperatures conditions. J Fasa Univ Med Sci. 2012;1(4):238–43.
19. Contreras-Jodar A, Salama AA, Hamzaoui S, Vailati-Riboni M, Caja G, Loor JJ. Effects of chronic heat stress on lactational performance and the transcriptomic profile of blood cells in lactating dairy goats. J Dairy Res. 2018;85(4):423–30.
20. International Organization for Standardization. Hot environments – estimation of the heat stress on working man, based on the WBGT-index (wet bulb globe temperature). ISO Standard No. 7243. Geneva: ISO; 1989.
21. Akhlaghi Pirposhteh E, Jafari MJ, Farhang Dehghan S, Khodakarim S, Hajifathali A. Investigating the relationship between heat stress and workers’ blood parameters in a foundry. J Mazandaran Univ Med Sci. 2019;21(6):618–27.
22. Dehghan H, Mortazavi SB, Jafari MJ, Maracy MR, Jahangiri M. The evaluation of heat stress through monitoring environmental factors and physiological responses in melting and casting industries workers. Int J Environ Health Eng. 2012;1(1):21.
23. Hajizadeh R, Golbabaei F, Dehghan SF, Beheshti MH, Jafari SM, Taheri F. Validating the heat stress indices for using in heavy work activities in hot and dry climates. J Res Health Syst. 2016;16(2):90.
24. Rahman MM, Kim HB, Baek HJ. Changes in blood cell morphology and number of red spotted grouper, Epinephelus akaara in response to thermal stress. Dev Reprod. 2019;23(2):139.
25. Bao JW, Qiang J, Tao YF, Li HX, He J, Xu P, Chen DJ. Responses of blood biochemistry, fatty acid composition and expression of microRNAs to heat stress in genetically improved farmed tilapia (Oreochromis niloticus). J Therm Biol. 2018;73:91–97.
26. Xu Y, Lai X, Li Z, Zhang X, Luo Q. Effect of chronic heat stress on some physiological and immunological parameters in different breed of broilers. Poult Sci. 2018;97(11):4073–82.
27. Zafalon-Silva B, Zebral YD, Bianchini A, Da Rosa CE, Marins LF, Colares EP, et al. Erythrocyte nuclear abnormalities and leukocyte profile in the Antarctic fish Notothenia coriiceps after exposure to short- and long-term heat stress. J Therm Biol. 2017;40(9):1755–60.
28. Holt PS, Vaughn LE, Gast RK. Flow cytometric characterization of Peyer’s patch and cecal tonsil T lymphocytes in laying hens following challenge with Salmonella enterica serovar Enteritidis. Vet Immunol Immunopathol. 2010;133(2–4):276–81.
29. Azis A, Abbas H, Heryandi Y, Kusnadi E. Thyroid hormone and blood metabolites concentrations of broiler chickens subjected to feeding time restriction. Media Peternak. 2012;35(1):32.
30. Mohammadian F, Fallahati M, Abbasi M, Zokaei M. Changes in physiological and cognitive parameters in acute and combined exposure to different levels of noise and heat stress: Experimental study. J Health Saf Work. 2023;13(3).
31. Khazaei P, Sahlabadi AS, Ramezanifar S, Mehrifar Y, Khadiv E, Rastegari P, Gharari N. The effects of heat stress on bakery workers: A systematic review. Iran J Public Health. 2023;52(12):2528.
32. Krams I, Vrublevska J, Cirule D, Kivleniece I, Krama T, Rantala MJ, et al. Heterophil/lymphocyte ratios predict the magnitude of humoral immune response to a novel antigen in great tits (Parus major). J Comp Physiol B. 2012;161(4):422–8.
33. Asghari B, Zerehdaran S, Jafari AY, Hasani S, Lotfi E. Prediction of antibody against sheep red blood cells by the number of white blood cells of Japanese quail (Coturnix japonica). 2016.
34. Bolghanabadi S, Pour M, Tizro M. The relation between heat strain and hydration status among workers. J Occup Hyg Eng. 2016;3(3):16–23.
35. Moradi A, Gholami F. Effect of age and stress due to physical activity on blood cell count and red blood cell indices. Sci J Rehabil Med. 2018;3(3):141–6.
36. Senturk UK, Gunduz F, Kuru O, Kocer G, Ozkaya YG, Yesilkaya A, et al. Exercise-induced oxidative stress leads hemolysis in sedentary but not trained humans. J Appl Physiol. 2005;99(4):1434–41.
37. Kim WS, Lee JS, Jeon SW, Peng DQ, Kim YS, Bae MH, et al. Correlation between blood, physiological and behavioral parameters in beef calves under heat stress. Anim Sci J. 2018;31(6):919.
38. Adriani L, Mushawwir A, editors. Correlation between blood parameters, physiological and liver gene expression levels in native laying hens under heat stress. In: IOP Conf Ser Earth Environ Sci. 2020;IOP Publishing.
39. McCarthy DO, Ouimet ME, Daun JM. The effects of noise stress on leukocyte function in rats. Res Nurs Health. 1992;15(2):131–7.
40. Zheng KC, Ariizumi M. Modulations of immune functions and oxidative status induced by noise stress. J Occup Health. 2007;49(1):32–8.
41. Akhlaghi Pirposhteh E, Mortazavi SB, Farhang Dehghan S, Khaloo SS, Montazer M. Optimization and development of workwear fabric coated with TiO₂ nanoparticles in order to improve thermal insulation properties and air permeability. J Ind Text. 2024;54:15280837241258169.
| Files | ||
| Issue | Vol 17 No 2 (2025) | |
| Section | Original Article(s) | |
| Published | 2025-12-09 | |
| Keywords | ||
| Heat Stress Wet Bulb Globe Temperature (WBGT) Foundry Leukocytes Lymphocytes Neutrophils | ||
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How to Cite
1.
Akhlaghi Pirposhteh E, Jafari MJ, Khodakarim S, Mohammadinejad A. Examining the Relationship between the WBGT Index and Leukocyte Levels: A Case Study of Foundry Workers Exposed to Heat Stress. Int J Occup Hyg. 2025;17(2):96-107.
