Association between heatwave exposure and rapid kidney function decline: a longitudinal cohort study from CHARLS

The worldwide prevalence of renal disease is substantial, with a significant impact on public health and the economy due to the high rates of mortality and morbidity associated with this condition. It is anticipated that projected rises in temperature in a warm climate will have a significant impact on kidney health, with older adults potentially experiencing the most pronounced effects.

In the China Health and Retirement Longitudinal Study, we assessed daily heatwave exposure individually for 6450 participants and kidney function decline during follow-up from 2011 to 2015. Kidney function, assessed by estimated glomerular filtration rate (eGFR), were tested at the baseline and endpoint surveys. 12 heatwave definitions combining four thresholds and three durations were used. The investigation used the number of heat wave days from 2011 to 2015 as a metric for heat wave exposure according to each of the previously specified criteria of a heat wave. Rapid kidney function decline was defined as a decrease in eGFR ≥ 3mL/min/1.73 m²/year. Multivariate logistic regression models was employed to evaluate the association between heat wave and the risk of rapid eGFR decline.

The results showed that the rise in middle to high-intensity heat wave events was connected with a significant risk of rapid kidney function decline. Moreover, we confirmed that the connections between heat wave and rapid kidney function decline were robust after further adjustment of age, gender, medical history, drinking status, smoking status, and biochemical.We observed that males, urban residents, and smoked or drank alcohol were identified as vulnerable populations.

This study found that increased heatwave exposure was associated with a higher risk of rapid kidney function decline in older adults.