In a recently published prospective study, Villamor et al. found increased risk of early menarche in vitamin D-deficient girls compared to vitamin D-sufficient girls in Bogota, Columbia. The association was not fully explained by differences in body mass index-for-age z-scores. The mechanism for the association, if real, has not been elucidated, but could potentially involve vitamin D receptor polymorphisms. Early menarche and vitamin D deficiency are both associated with poor health outcomes, and further exploration of their association is important for women's health.