Evaluating the effects of heat strain and air pollution on kidney health

Rising global temperatures raise concerns about climate change's health impacts. Agricultural workers are particularly vulnerable due to prolonged exposure to heat and environmental pollutants, including airborne particulate matter (PM), which may increase their risk for kidney injury. This study explores the relationships between core body temperature (CBT), markers of hydration, PM exposure, and kidney injury, offering insights into public health risks related to climate change.

We conducted a longitudinal study of 148 sugarcane workers in Guatemala, monitoring them over 378 person-workdays. CBT and personal PM exposure were recorded throughout the workday, while markers of hydration and kidney function were assessed pre- and post-shift. Linear mixed-effects models were used to assess the relationships between these exposure factors, dehydration markers, and serum creatinine changes, an indicator of kidney injury.

CBT exceeded 38.0 °C on 53 % of workdays, with 15 % surpassing 38.5 °C. Higher urinary specific gravity (β: 3.82, 95 % CI: 0.84, 6.80), serum uric acid (β: 2.46, 95 % CI: 0.70, 2.14), average heat index (β: 1.33, 95 % CI: 0.53, 2.14), and CBT exceeding 38.5 °C (β: 8.95, 95 % CI: 2.89, 15.02) were significantly associated with cross-shift increases in serum creatinine. Despite substantial PM₅ exposure, no significant association with creatinine changes was found.

Heat strain and dehydration are significant contributors to kidney injury in agricultural workers, highlighting critical public health risks. These findings emphasize the urgent need for interventions to mitigate heat-related health hazards, including workplace protections, hydration strategies, and climate adaptation policies to safeguard vulnerable populations worldwide.