Vitamin D deficiency and risk of hip fractures among disabled elderly stroke patients

Background and Purpose - Risk of hip fracture after stroke is 2 to 4 times that in a reference population. Osteomalacia is present in some patients wi th hip fractures in the absence of stroke, while disabled elderly stroke pa tients occasionally have severe deficiency in serum concentrations of 25-hy droxyvitamin D (25-OHD) (less than or equal to5 ng/mL). To determine the ef fects of vitamin D status on hip fracture risk, we prospectively studied a cohort of patients with hemiplegia after stroke who were aged at least 65 y ears. Methods - We compared baseline serum indices of bone metabolism, bone miner al density, and hip fracture occurrence in stroke patients with serum 25-OH D less than or equal to 25 nmol/L (%10 ng/mL; deficient group, n=88) with f indings in patients from the same cohort who had 25-OHD levels 26 to 50 nmo l/L (10 to 20 ng/mL; insufficient group, n=76) or greater than or equal to 51 nmol/L (greater than or equal to 21 ng/mL; sufficient group, n=72). Results - Over a 2-year follow-up interval, hip fractures on the paretic si de occurred in 7 patients in the deficient group and I patient in the insuf ficient group (P <0.05; hazard ratio=6.5), while no hip fractures occurred in the sufficient group. The 7 hip fracture patients in the deficient group had an osteomalacic 25-OHD level of <5 ng/mL. Higher age and severe immobi lization were noted in the deficient group. Serum 25-OHD levels correlated positively with age, Barthel Index, and serum parathyroid hormone. Conclusions - Elderly disabled stroke patients with serum 25-OHD concentrat ions less than or equal to 12 nmol/L (less than or equal to5 ng/mL) have an increased risk of hip fracture. Immobilization and advanced age cause seve re 25-OHD deficiency and consequent reduction of BMD.