Effect of immobilization on vitamin D status and bone mass in chronically hospitalized disabled stroke patients

Objective: to assess the influence of immobilization upon vitamin D status and bone mass in chronically hospitalized, disabled, elderly patients follo wing stroke. Design: cross-sectional study. Setting: department of geriatric neurology in a Japanese hospital. Subjects: 129 chronically hospitalized, disabled, elderly stroke patients a nd 28 age-matched controls. Results: we observed a deficiency of both 1,25-dihydroxyvitamin D (1,25-[OH ](2)D; 24.3 pg/ml) and 25-hydroxyvitamin D concentrations (25-OHD; 11.7 ng/ ml) in stroke patients compared with controls. A high serum ionized calcium (mean; 2.648 mEq/l) was an independent determinant of the Barthel index (6 6) and 1,25-[OH](2)D. When the patients were categorized into three groups by 25-OHD level (deficient, insufficient and sufficient), there was no diff erence in the mean 1,25-[OH](2)D levels. Parathyroid hormone levels were no rmal or low and did not correlate with 25-OHD, Serum bone turnover variable s and bone mineral density (BMD) of the second metacarpal in patients were significantly decreased compared to control subjects. Independent determina nts of BMD included Barthel index, 25-OHD and 1,25-[OH](2)D. Conclusions: 1,25-[OH](2)D deficiency in immobilized stroke patients is not caused by substrate (25-OHD) deficiency but by hypercalcaemia, Immobilizat ion-induced hypercalcaemia may inhibit parathyroid hormone secretion and th us 1,25-[OH](2)D production, resulting in decreased BMD. Immobilization its elf also may be responsible for decreased BMD. Exogenous 1,25-[OH](2)D (cal citriol) rather than dietary vitamin D supplementation may be required in d isabled elderly stroke patients who have a deficiency of 1,25-[OH](2)D in o rder to prevent hip fractures, which frequently occur in this population.