Does exposure to PM decrease age at menarche?

BACKGROUND

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 (PM) and age at menarche in adolescents of South Korea using Korea National Health and Nutrition Examination Survey (KNHANES) 2010-2012 data.

METHODS

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 PM 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.

RESULTS

Overall analysis showed that exposure to PM has a significant effect on decreasing age at menarche. Multiple linear regression results suggested that each 1 μg/m increase in 1-year, 2-year, 3-year averages of annual mean PM concentrations accelerated age at menarche by 0.046 years (95% CI: -0.064, -0.027; p < .0001), 0.038 years (95% CI: -0.059, -0.018; p = 0.0003),and 0.031 years (95% CI: -0.047, -0.015; p = 0.0002), respectively. Adjusted ORs for a 1 μg/m increase in PM concentration were 1.08 (95% CI: 1.04 -1.12) for model 1, 1.06 (95% CI: 1.02 -1.10) for model 2, and 1.05 (95% CI: 1.01 -1.09) for model 3.

CONCLUSION

Our findings suggest that elevated PM concentration can decrease age at menarche. This is the first study that investigates the association between exposure to PM and age at menarche using a nationally representative sample of Koreans.