Vitamin D supplementation in elderly nursing home residents increases 25(OH)D but not 1,25(OH)2D.
Vitamin D metabolism in elderly individuals can be compromised by several mechanisms. We previously described reduced concentrations of 1,25-dihydroxyvitamin D [1,25(OH)2D] in 30% of elderly nursing home residents. The present study assesses the effect of vitamin D supplementation on 25-hydroxyvitamin D [25(OH)D] and 1,25(OH)2D. We performed a double-blind study in which 30 elderly nursing home residents were randomly given either 50 micrograms vitamin D or a placebo daily for 6 wk. Vitamin D metabolites, immunometrically assayed parathyroid hormone (IRMA-PTH), ionized calcium, and bone Gla hormone (BGP) were measured in serum at baseline and biweekly for 6 wk. Serum 25(OH)D concentrations increased significantly (P less than 0.0001) over the 6 wk in the treatment group but were unchanged in the placebo group. Serum 1,25(OH)2D, ionized calcium, BGP, and PTH were not significantly altered by the supplement. We conclude that vitamin D supplementation results in an increase in circulating 25(OH)D but not 1,25(OH)2D; however, the long-term effect on bone mineral metabolism remains unclear.
Regional Bone Center, Helen Hayes Hospital, West Haverstraw, NY 10993.
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Himmelstein
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Clemens
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Rubin
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Lindsay
D000368:Aged; D000369:Aged, 80 and over; D002117:Calcitriol / Q000097:blood*; D002118:Calcium / Q000097:blood; D005260:Female; D006801:Humans; D006887:Hydroxycholecalciferols / Q000097:blood*; D007477:Ions; D008297:Male; D009735:Nursing Homes; D009994:Osmolar Concentration; D015675:Osteocalcin / Q000097:blood; D010281:Parathyroid Hormone / Q000097:blood; D014807:Vitamin D / Q000494:pharmacology*
D006887:Hydroxycholecalciferols; D007477:Ions; D010281:Parathyroid Hormone; D015675:Osteocalcin; D014807:Vitamin D; D002117:Calcitriol; D002118:Calcium