Prenatal Heat Wave Exposure and Renal Function in Early Childhood: Findings from a Chinese Birth Cohort.

BACKGROUND: Heat waves have been linked to increased hospitalizations for renal diseases. However, evidence on the impact of prenatal heat exposure on renal function in early life remains limited. This study aimed to examine the association between maternal heat exposure during pregnancy and renal function in offspring during early childhood. METHODS: We included 1,278 mother-offspring pairs from a birth cohort in Fujian, China. Renal function was assessed using serum creatinine (Scr), blood urea nitrogen (BUN), and estimated glomerular filtration rate (eGFR). Heat waves were defined as combinations of temperature thresholds (i.e., P90, P92.5, or P95) and duration days (≥ 2, 3, or 4 consecutive days). Multivariable linear regression was used to estimate the associations after adjusting for potential confounders. RESULTS: Higher mean temperatures across different pregnancy trimesters were associated with increases in Scr, ranging from 5.23% to 6.86%, and in BUN, ranging from 9.66% to 13.13%. Consistent with these findings, heat wave exposure during the second trimester was linked to higher levels of both biomarkers in offspring (3.43%-14.53%). Moreover, a dose-response relationship was observed between the number of heatwave days and higher levels of Scr and BUN. CONCLUSIONS: Prenatal heat exposure was associated with higher values of Scr and BUN in early childhood, offering preliminary evidence to support further research on early-life heat exposure and renal function-related biomarkers in children.