Does exposure to PM10 decrease age at menarche?

There has been a consistent decrease in age at menarche in South Korea. A potential risk factor for early menarche is exposure to particulate matter (PM), because endocrine-disrupting compounds emitted into air from anthropogenic sources may be incorporated into PM. The objective of this study was to examine the association between pre-menarcheal exposure to PM ≤ 10 μm in diameter (PM10) and age at menarche in adolescents of South Korea using Korea National Health and Nutrition Examination Survey (KNHANES) 2010–2012 data. We used self-reported age at menarche of 639 girls aged 13–17 years in this study. The cut-off age for early menarche was set to 12 years. Based on each subject's address, 1-year, 2-year, and 3-year averages of annual mean PM10 concentrations (models 1–3) were linked to KNHANES. Models were adjusted for body mass index (BMI), city size, household income level, maternal age at menarche, and second-hand smoke exposure at home. SURVEYREG and SURVEYLOGISTIC procedures were used to address the complex survey design of KNHANES. Overall analysis showed that exposure to PM10 has a significant effect on decreasing age at menarche. Multiple linear regression results suggested that each 1 μg/m3 increase in 1-year, 2-year, 3-year averages of annual mean PM10 concentrations accelerated age at menarche by 0.046 years (95% CI: −0.064, −0.027; p