Vitamin D inadequacy among post-menopausal women: a systematic review

Background: Vitamin D inadequacy has been studied extensively, due to concerns about ageing populations, associations with osteoporosis and other disorders (including non-musculoskeletal), and high prevalence. Aim: To review recent reports on the prevalence of vitamin D inadequacy among post-menopausal women with and without osteoporosis and/or other musculoskeletal diseases. Design: Systematic review. Methods: We reviewed publications in the past 10 years reporting prevalence estimates for vitamin D inadequacy, reported as serum 25(OH)D values below various levels. Thirty published studies in the English language were identified, from January 1994 through April 2004. Results: In osteoporotic populations, the prevalence of 25(OH) vitamin D concentration < 12 ng/ml ranged from 12.5% to 76%, while prevalence rates reached 50% to 70% of patients with a history of fracture(s) using a cut-off of 15 ng/ml. In post-menopausal women, the prevalence of 25(OH) vitamin D concentrations <= 20 ng/ml ranged from 1.6% to 86% for community-living and institutionalized women, respectively. The most common factors associated with inadequate vitamin D levels included limited sun exposure, lack of dietary vitamin D intake, nursing home environment, wintertime, and increasing age (over 70 years). Discussion: The prevalence of inadequate vitamin D levels appears to be high in post-menopausal women, especially in those with osteoporosis and history of fracture. Vitamin D supplementation in this group might offer scope for prevention of falls and fracture, especially in elderly and osteoporotic populations.