Plasma 25-hydroxyvitamin D concentration in patients with hip fracture in Hong Kong.

The serum concentration of 25-hydroxyvitamin D level and plasma albumin-adjusted calcium, phosphate, and alkaline phosphatase levels were studied in 200 patients with hip fracture (age range 49-93 years) and 427 elderly subjects living in the community (age range 60-90 years). The mean serum 25-hydroxyvitamin D levels in controls were higher than in temperate countries, but the 25-hydroxyvitamin D concentration was significantly lower in the patients than the controls for all sex and age groups. There was little difference in albumin-adjusted calcium and alkaline phosphatase levels, but the phosphate level was higher in the patients than in the controls. None of the patients with a low 25-hydroxyvitamin D level had a blood picture suggestive of osteopathy resulting from vitamin D deficiency or frank osteomalacia. Hip fracture patients with a low 25-hydroxyvitamin D level were much less ambulant and went outdoors much less frequently than hip fracture patients with a normal vitamin D level. A low vitamin D level was a risk factor for hip fracture in Hong Kong Chinese, and may be prevented by frequent outdoor exposure.