Cumulative exposure to heavy metals (chromium, copper, lead, manganese, mercury, nickel, and titanium) and age at natural menopause

Exposure to heavy metals may lead to premature ovarian insufficiency. Research on the exposure to heavy metals and the age at menopause is scant. This study aimed to investigate the impact of heavy metal exposure on the age at the onset of natural menopause. Cox proportional hazards models were used to assess the risk of the onset of menopause. Logistic regressions were estimated to examine the relationship between heavy metals and early or premature menopause. Mean age at menopause was 47.3 (SD 5.5); 25.1% of women experienced either an early or a premature menopause. Hair nickel concentrations in the third and fourth quartiles of the distribution increased the risk of menopause and the odds of an early or premature menopause. High levels of chromium were marginally related to a lower risk of menopause. However, the likelihood of an early or premature menopause was 50% lower among women in the fourth quartile. Mercury concentrations show an increased risk of menopause only for the second quartile of the distribution. The odds of an early or premature menopause doubled for the second quartile. No significant relationships between hair copper, lead, manganese, and titanium concentrations and age at menopause were found.