Association of anti-mullerian hormone levels with obesity in late reproductive-age women.

OBJECTIVE: To describe anti-mullerian hormone (AMH) levels in healthy late reproductive age women and test the hypothesis that AMH levels are lower in obese compared to non-obese women.
DESIGN: Cross-sectional study of AMH levels. Longitudinal analysis of a subgroup with 10 AMH measures over 8 years to support the cross-sectional results.
SETTING: A population-based cohort of healthy late reproductive-age women. PARTICIPANTS: Selected from the cohort to provide comparisons of body mass index (BMI), menopausal status, age and race (n = 122).
INTERVENTIONS: AMH levels were determined from blood samples collected in the parent study. MAIN OUTCOME MEASURE: Serum levels of AMH.
RESULTS: AMH levels were 65% lower in obese women compared to non-obese women (0.016 ng/mL and 0.046 ng/mL, respectively). The geometric mean ratio was 0.35; 95% CI 0.13, 0.92, P=.034. AMH levels were significantly lower in the menopausal transition compared to premenopausal women and were significantly lower in all age groups > or =40 years compared to the 35-39 year-old women. BMI remained significantly associated with AMH levels in multivariable models that included adjustments for menopausal status, age, race and cycle day. In the longitudinal analysis of a subgroup, obese women had significantly lower mean AMH levels over the 8-year interval compared to the non-obese women (0.459 ng/mL; CI 0.28, 0.75 and 0.566 ng/mL; CI 0.34, 0.94, respectively; P=.016), corroborating the cross-sectional study results.
CONCLUSIONS: Obese women have lower AMH levels compared to non-obese women in the late reproductive years. The findings offer further evidence of the complex relationships between obesity and reproductive hormone levels in women.