Purdue-Smithe AC, et al. - In this case-control study nested within the Nurses’ Health Study II, researchers prospectively assessed how total and free 25-hydroxyvitamin D (25[OH]D) and vitamin D–binding protein (VDBP) concentrations relate to the risk of early menopause. They also examined associations of 25(OH)D and VDBP with anti-Müllerian hormone (AMH) concentrations. They found that total and free 25(OH)D were not associated with the risk of early menopause. A possible association of VDBP with increased risk was suggested. They found no association between 25(OH)D and AMH concentrations.