Occupational Heat Stress and DNA damage among steelworkers in Southern India

Abstract

OPS 44: Occupational health studies with environmental implications, Room 411, Floor 4, August 27, 2019, 4:30 PM - 5:30 PM Background: Changing climatic scenario with rising temperatures will potentially subject millions of workers to risks of heat stress in tropical settings. Heat stress not only imposes a physiological strain on the exposed workers but also makes subcellular level changes including DNA damage in workers exposed to chronic high-heat environments. We explored the physiological and molecular level changes among such workers. Methodology: We used a cross-sectional study design and profiled the heat stress of about 1000 workers from 7 sectors viz., steel, garment, tire, brick, construction and agriculture and used a Quest Temp WBGT monitor to evaluate heat exposures and quantified heat strain indicators viz., Core Body Temperature, Sweat Rate and Urine Specific Gravity. We studied the DNA damage by enumerating the Micronuclei (MN) encountered in 120-steel industry workers exposed to chronic high-heat. Results: Heat stress was high in almost all the workplaces especially during summer months. Steel industry had the highest level of Wet Bulb Globe Temperature (WBGT) (Avg. 31.1±3.2°C) with ~90% workers having higher heat exposures above safe limits. A significant association was observed between the exposures to heat stress and heat strain (X2=4.45; p=0.035) and a significant increase in the MN-frequency was observed in exposed workers compared to the unexposed workers (X2=47.1; p<0.0001). The exposed workers had 23.3 times higher risk of DNA damage (OR=23.3; p<0.0001) compared to the unexposed workers even after adjusting for potential confounders. Years of exposure increased the risk of DNA damage (OR=15.5; p=<0.0001) and high-heat exposed workers had 81-times higher risk of DNA damage compared to the medium-heat exposed workers. Conclusion: Risks of exposures to chronic heat stress induces damages at a sub-cellular level. Further in-depth research studies are warranted and developing protective interventions to reduce exposure is imperative to avert health risks in the climate change scenario to protect millions of workers.