Blood was drawn in March and April, 2009 from 420 Mongolian women, 18–44 years of age. Serum
25(OH)D concentrations were measured, anthropometric measurements were performed and information
was collected by interview on lifestyle, dietary and reproductive factors. Logarithm-transformed
25(OH)D levels were compared across risk factor categories by analysis of variance. Linear regression
analysis was used to assess the independent associations of factors with vitamin D status. Cutaneous
vitamin D3 synthesis was assessed between December and July using a standard 7-dehydrocholesterol
ampoule model.