Correlational Associations Between Ambient and Household Particulate Matter Exposure and Body Mass Index Across Childhood and Adolescence in Thailand

While previous studies have established inverse relationships between (particulate matter) PM exposure and the body mass index (BMI), this study is the first to demonstrate that the strength of this relationship varies significantly according to the PM source type and age group, particularly across developmental stages. Through a comprehensive 31-year analysis in Thailand that uniquely captured the transition from traditional to modern energy sources, this research investigated the relationship between PM exposure and a high BMI among children and adolescents across different demographic groups, using a correlational analysis of time point data from the Global Burden Disease (GBD) study (1990–2021). The analysis examined the association between a high BMI and two categories of PM exposure—ambient (outdoor) and household (indoor)—through cross-correlation, Spearman correlation, and mixed-effects models. The results reveal a significant inverse relationship between household PM exposure and a high BMI, particularly pronounced in younger age groups (2–9 years), with household PM showing consistently stronger associations compared to ambient PM. Among children aged 2–4 years, household PM exposure exhibited a strong negative correlation with a high BMI without a time lag, suggesting persistent effects of the household air quality on physical development. Conversely, ambient PM exposure showed relatively weaker associations, with only slight positive correlations observed in certain subgroups. Further analysis indicated that decreases in household PM exposure correlated with longitudinal increases in a high BMI, with this relationship diminishing during adolescence. These findings provide crucial insights for targeted public health interventions and offer a model for understanding PM-BMI relationships in other developing nations experiencing similar transitions.