Inclusion of 95 % range in the model to account for inter-individual variability increased the predicted intake of vitamin D needed to maintain serum 25(OH)D ≥ 50 nmol/l to 930 IU/d .
The response of elderly veterans to daily vitamin D3 supplementation of 2,000 IU: a pilot efficacy study.
OBJECTIVES To determine the prevalence of hypovitaminosis D ( serum 25-hydroxyvitamin D<32 ng/mL ; HVD ) in a population of elderly veterans and conduct a preliminary assessment of the efficacy of supplementation with cholecalciferol in correcting HVD . DESIGN R and omized , double-blind , placebo-controlled clinical trial . SETTING Geriatric clinic at the Bruce W. Carter Veterans Affairs Medical Center , Miami , Florida . PARTICIPANTS Veterans aged 70 and older . INTERVENTION Oral cholecalciferol 2,000 IU daily or placebo for 6 months . MEASUREMENTS Serum calcium , 25-hydroxyvitamin D , parathyroid hormone , and 24-hour urinary calcium . RESULTS Of the 34 participants who completed the study , 62 % had HVD at baseline . In the treatment group , mean serum 25-hydroxyvitamin D level rose from 28.4±7.9 ng/mL at baseline to 42.7±10.5 ng/mL at the end of the trial , but levels remained less than 32 ng/mL in three of 17 ( 18 % ) of the participants . In the placebo group , the baseline level of 27.7±8.3 ng/mL remained unchanged ( 28.8±8.7 ng/mL ) . Supplementation did not alter serum or urinary calcium levels and did not result in any adverse events . CONCLUSION These initial observations suggest that , in older veterans  , cholecalciferol 2,000 IU daily for 6 months is generally safe and corrects HVD in most but not all individuals
Inclusion of 95 % range in the model to account for inter-individual variability increased the predicted intake of vitamin D needed to maintain serum 25(OH)D ≥ 50 nmol/l to 930 IU/d .