DIFFERENCES IN VITAMIN D^sub 3^ DOSING REGIMENS IN A GERIATRIC COMMUNITY-DWELLING POPULATION

This study aims to determine the efficacy of a low-dose and a higher dose of vitamin D^sub 3^ in maintaining 25-hydroxyvitamin D (25(OH)D) levels at or above 30 ng/mL. This was a single site, double-blind, randomized exploratory clinical trial that enrolled adults 65 years of age and older. Within strata of baseline 25(OH)D levels subjects were randomized in a 1:2 ratio to receive either 400 IU or 2,000 IU vitamin D^sub 3^ daily for 6 months. The main outcome measures were changes in serum 25(OH)D levels according to baseline 25(OH)D levels and dose of vitamin D^sub 3^. At baseline, 41 of 105 participants had low 25(OH)D levels. After 6 months of vitamin D^sub 3^ supplementation, 21 of 32 participants receiving 400 IU and 14 of 59 participants receiving 2,000 IU of vitamin D^sub 3^ still had low 25(OH)D levels. The largest increases in serum 25(OH)D levels were observed in subjects with baseline levels