LAUSR

Dear Editor Previous research found that childhood cancer survivors of African ancestry have significantly higher morbidity and mortality than those of European ancestry [1]. However, after adjusting for socio-economic factors, the magnitudes of racial health disparities are either substantially decreased or become statistically non-significant [1], suggesting that social and economic determinants may contribute to racial health disparities. Recently, we conducted epigenome-wide association studies (EWAS) for three key social determinants of health (SDOHs), namely, personal educational attainment, personal income, and neighborhood deprivation among survivors of childhood cancer, where 130 epigenome-wide significant SDOH-CpG associationswere identified amongEuropean ancestry survivors, and 25 of which were also validated in African ancestry survivors [2]. Notably, many SDOH-associated CpG sites are also associated with tobacco use. Although pulmonary impairment is an integral part of the overall disease burden, racial disparities in this specific group of conditions have not been documented, and potential underlying mechanistic causal pathways have not been studied. Moreover, other observational studies have shown that blood DNA methylation (DNAm) signature was associated with pulmonary functions [3–5]. In this cross-sectional study, we hypothesized that race and its associated SDOHs might contribute to the risk of pulmonary impairment, evaluated whether SDOH-associated CpG sites were associated with specific parameters of pulmonary function, and further applied mediation analysis to explore the potential mediating role of these DNAm