Occupational heat stress and heavy workload induce 'productivity losses’- Epidemiological evidence from a large cross-sectional study in Indian occupational settings.

Abstract

Background: Climate change is expected to exacerbate heat stress at the workplace in tropical settings. The health impacts of heat stress have been well documented in India and elsewhere. But Productivity Losses (PL) due to heat stress among workers has received less attention in Indian work settings and therefore vital to study the current status of heat impacts on the worker's health and productivity, so that appropriate control intervention can be implemented to avert present and future economic losses. Methods: We used a mixed-method approach to assess the perceived PL among~2892 workers from 25 occupational sectors in India. We conducted seasonal WBGT exposures, measured standard heat-strain indicators and captured self-reported productivity losses through questionnaires and observations.Results: WBGT heat exposures exceeded the Threshold Limit Values for moderate/heavy work for 74% workers (29.1°C±3.1°C). 16.1% of workers reported PL that was significantly associated with WBGT exposures (OR: 1.3; 95% CI: 1.03-1.66; p=0.0001), and heavy workload (OR: 1.5; 95% CI: 1.28 - 1.94; p=0.0001). Quantified heat-strain indicators such as a rise in Core Body Temperature, Sweat Rates, and Urine Specific Gravity were significantly associated with WBGT exposures. Though there was no significant difference in PL between informal and formal sectors, outdoor workers with exposures above TLV had 1.5 times higher risk of PL compared to indoor workers (95% CI: 1.27-2.00; p=0.0001). The impact of the season was significant on the PL with summer having 1.8 times higher PL compared to the cooler season (95% CI: 1.44-2.40; p=0.0001). Conclusions: Productivity losses due to workplace heat stress are evidenced in the study and are expected to increase in the rising temperature scenario. Intervention, adaptation and prevention strategies with a focus on workers’ and a concerted effort must be made to promote workers' adaptive capacity and inform policy decisions in the imminent hotter world.