Prevalence and impact of vitamin D insufficiency in southern Chinese adults

Introduction: Vitamin D is a vital element for bone health but the problem of vitamin D deficiency is underestimated in Hong Kong. Methods: Serum 25(OH) D and parathyroid hormone (PTH) levels were evaluated in 382 community dwelling Chinese adults > 50 years for their relation with bone mineral density (BMD) and risks of osteoporotic fractures and falls.Results: The mean age of the subjects was 69 +/- 9 years. The mean 25(OH) D level was 28.3 +/- 10.8 ng/ ml with 62.8% of the subjects having levels < 30 ng/ml. 6.3% of the subjects had elevated PTH levels. A curvilinear relation between serum PTH and 25(OH)D was found, with PTH starting to increase when 25(OH)D level fell below 30 ng/ml (r = -0.233, p < 0.05). Although subjects with vitamin D < 30 ng/ml had significantly lower BMD, only sex, age and PTH but not 25(OH)D were predictors of BMD at the spine and hip. Subjects with elevated PTH levels had a 2.92-fold increased risk of falls and 2.94-fold increased risk of fractures at the hip and spine.Conclusions: Vitamin D insufficiency and its complication of secondary hyperparathyroidism is common even in subtropical region and is an important risk factor for low bone mass, falls and fractures. Copyright (c) 2007 S. Karger AG, Basel