How Much Vitamin D Is Enough?

of alendronate and vitamin D3 on fractional calcium absorption in a double-blind, randomized, placebo-controlled trial in postmenopausal osteoporotic women. the role of vitamin D and calcium in osteoporosis management: an expert roundtable discussion. calcium absorption in severe vitamin D deficiency. The effect of vitamin D on calcium absorption in older women. A, et al. Vitamin D supplementation increases calcium absorption without a threshold effect. Age-related changes in bone density, serum parathyroid hormone, calcium absorption and other indices of bone metabolism in Chinese women. Blake JM. Postmenopausal bone mineral density: relationship to calcium intake, calcium absorption, residual estrogen, body composition, and physical activity. The relation between calcium absorption, serum dehydroepiandrosterone, and vertebral mineral density in postmenopausal women. fractional calcium absorption increases the risk for hip fracture in women with low calcium intake. Annual high-dose oral vitamin D and falls and fractures in older women: a randomized controlled trial. efficacy of high-dose oral vitamin D 3 administered once a year: increased fracture risk is associated with 1,25 vitamin D level at 3-months post dose. Age-and sex-related changes in iliac cortical bone mass and remodeling. There is ongoing controversy regarding the definition of vitamin D insufficiency and the optimal treatment goal: should treatment aim to maintain a serum vitamin D level above 20 ng/mL or above 30 ng/mL? We found the randomized clinical trial by Hansen et al 1 informative because it enrolled women with low vitamin D levels and tested both a lower-dose treatment to maintain vitamin D levels greater than 20 ng/mL and a higher-dose treatment to maintain levels greater than 30 ng/mL. After 1 year of treatment, randomization to a higher dose of cholecal-ciferol resulted in slightly better fractional excretion of calcium compared with low-dose cholecalciferol or placebo, but these differences are not clinically meaningful. Of more clinical importance , neither dose of cholecalciferol improved bone density , strength, muscle mass, functional status, or fall rate. It is possible that treatment beyond 1 year would result in better outcomes , but these data provide no support for use of higher-dose cholecalciferol replacement therapy or indeed any dose of cho-lecalciferol compared with placebo. postmenopausal women: a randomized clinical trial [published online August 3, 2015]. JAMA Intern Med.