Population Vitamin D Stores Are Increasing in Tasmania, and This Is Associated With Less BMD Loss Over 10 Years

Context Vitamin D deficiency is a common, modifiable determinant of musculoskeletal health. Objective There are limited data that examine the longitudinal change in population 25-hydroxyvitamin D (25[OH]D) and none that evaluate the long-term skeletal outcomes of longitudinal vitamin D status. Methods A prospective cohort analysis was conducted of community-dwelling adults aged 50 to 80 years who had 25(OH)D assessed by radioimmunoassay and bone mineral density (BMD) by dual-energy x-ray absorptiometry at baseline (n = 1096), 2.5 (n = 870), and 10 (n = 565) years. Sun exposure was quantified by questionnaire and supplement use at clinic review. 25(OH)D less than 50 nmol/L was considered deficient. Participants were provided with their 25(OH)D results. Results Over 10 years 25(OH)D increased (52.2 ± 17.0 to 63.5 ± 23.6 nmol/L, P Conclusions Population 25(OH)D concentration increased because of a combination of increased sun exposure and supplement use. Maintaining or achieving vitamin D sufficiency was associated with less BMD loss over 10 years.