Serum levels of 25-hydroxyvitamin D, 24,25-dihydroxyvitamin D and parathyroid hormone in patients with femoral neck fracture in southern Finland.

Serum concentrations of 25-hydroxyvitamin D (25-OHD), 24,25-dihydroxyvitamin D [24,25(OH)2D] and immunoreactive parathyroid hormone (PTH) were determined in elderly patients with fracture of the femoral neck and in age-matched controls during summer, winter and early spring in southern Finland. The expected seasonal variation in 25-OHD values was observed in both patients and controls, though the patient group had significantly lower values during winter (P less than 0.02) and spring (P less than 0.01). The 24,25(OH)2D:25-OHD ratio remained constant in both patients and controls throughout the study. A significant negative correlation between PTH and 25-OHD values was found in the patient group. Thus, vitamin D deficiency may contribute to the high incidence of femoral neck fractures in elderly people, and the increased PTH activity, observed in many patients with these fractures, is secondary to vitamin D deficiency.