Air pollution, temperature, and HbA1c levels among children in Mexico City, Mexico

Glycated hemoglobin (HbA1c), a strong indicator of diabetes, is affected by air pollution and temperature exposures. However, studies examining the association between HbA1c, temperature, fine particulate matter (PM2.5), and nitrogen dioxide (NO2) among children are scarce, especially looking at all exposures simultaneously. We investigated the associations between these exposures and HbA1c among children, known to be a highly susceptible group. We included children enrolled in the Programming Research in Obesity, Growth, Environment, and Social Stressors (PROGRESS) cohort based in Mexico City (2013–2019). We obtained exposures from spatiotemporal models. HbA1c levels were measured at 4–5 years, 6–7 years, and 8–11 years post-birth. We used multivariable linear mixed-effects models to assess the simultaneous associations of three-month averages of PM2.5, temperature, and NO2 exposures with natural log-transformed HbA1c levels. We fitted stratified models by sex and age group. We included 1186 HbA1c measurements from 503 children. In multi-exposures models 1-µg/m³ increase in PM2.5 was associated with 0.311 % (95 % CI:0.159, 0.464) relative increase in HbA1c and 1-degree Celsius increase in average temperature was associated with a − 0.626 % (95 % CI: − 0.977, − 0.274) relative decrease. We did not find an association with a 1-ppb increase in NO2 (-0.010 %. 95 % CI: − 0.126, 0.106). The stratified analysis found slightly different associations by sex and age. This study adds evidence of HbA1c increases associated with lower temperatures and higher PM2.5 exposure in an area with high air pollution and moderate temperature fluctuation. These glycemic changes may translate into increased diabetes risk in later life.