Free serum 25(OH)D is the same across races despite the lower total serum 25(OH)D in black women. Results comparing VDBP between races using a monoclonal vs a polyclonal assay were discordant.

OBJECTIVES To examine the effect of 25‐hydroxyvitamin D (25(OH)D) levels recommended by Endocrine Society guidelines (>30 ng/mL) on cognition in healthy older African‐American women over 3 years. DESIGN Randomized, double‐blind, placebo‐controlled clinical trial. SETTING Bone Mineral Research Center at New York University Winthrop Hospital. PARTICIPANTS Healthy postmenopausal African American women aged 65 and older (N=260; mean age 68.2 ± 4.9; 46% college education or higher). INTERVENTION Half of the women were randomized to receive vitamin D (adjusted to achieve a serum level > 30 ng/mL) with calcium (diet and supplement total of 1,200 mg), and half were randomized to receive placebo with calcium (1,200 mg). MEASUREMENTS Cognitive assessments every 6 months using the Mini‐Mental State Examination (MMSE) to detect cognitive decline. Mean MMSE scores were calculated over time for both groups. Those with MMSE scores less than 21 at baseline were excluded. RESULTS The average dose of vitamin D3 was 3,490 ± 1,465 IU per day, and average serum 25(OH)D at 3 years was 46.8 ± 1.2 ng/mL in the active group and 20.7 ± 1.1 ng/mL in the placebo group. Serum 25(OH)D concentration was maintained at greater than 30 ng/mL in 90% of the active group. Over the 3‐year period, MMSE scores increased in both groups (p < .001), although change over time was not significantly different between the groups. No adverse events associated with vitamin D were observed. CONCLUSION There was no difference in cognition over time between older African‐American women with serum concentrations of 25(OH)D of 30 ng/mL and greater than those taking placebo. There is no evidence to support vitamin D intake greater than the recommended daily allowance in this population for preventing cognitive decline. J Am Geriatr Soc 67:81–86, 2019.

Objective It is anticipated that an intake of vitamin D found acceptable by Endocrine Society Guidelines (10 000 IU/day) with co‐administered calcium supplements may result in frequent hypercalciuria and hypercalcaemia. This combination may be associated with kidney stones. The objective of this study was to compare the episodes of hypercalciuria and hypercalcaemia from calcium supplements co‐administered with 10 000 IU or 600 IU vitamin D daily. This design allows a comparison of the Institute of Medicine recommendation for the RDA of vitamin D along with the upper limit of calcium intake with the high intake of vitamin D suggested by the Endocrine Society. Context Harms of currently recommended high intake of vitamin D have not been studied. Design The design was a randomized controlled trial with 2 groups with evaluation every 3 months for one year: (a) CaCO3 1200 mg/day with 10 000 IU vitamin D3/day or (b) CaCO3 1200 mg/day with 600 IU vitamin D3/day. Patients This study was conducted in an ambulatory research centre in healthy, white postmenopausal women. Measurements Serum and 24‐hour urine calcium were measured. Results Hypercalcaemia and hypercalciuria occurred in both groups. At the final visit, 19/48 in the high dose D group had hypercalciuria. The odds of developing hypercalciuria were 3.6 [OR = 3.6(1.39, 9.3)] times higher in the high dose D group. The odds of developing hypercalcaemia did not differ between groups. Conclusions The safe upper level of vitamin D recommended by the Endocrine Society when accompanied by calcium supplements results in frequent hypercalciuria. The risk of kidney stones at these levels should be investigated.

There was no advantage from measuring free over total 25(OH)D in assessing the response of calcium absorption, PTH, and markers of bone turnover to vitamin D. Free 25(OH)D responded to increasing doses of vitamin D in a similar fashion to total 25(OH)D.

Black Americans have lower levels of serum 25(OH)D but superior bone health compared to white Americans. There is controversy over whether they should be screened for vitamin D deficiency and have higher vitamin D requirements than recommended by the Institute of Medicine (IOM). The purpose of this trial was to determine whether Vitamin D supplementation in elderly black women prevents bone loss. A total of 260 healthy black American women, 60 years of age and older were recruited to take part in a two-arm, double-dummy 3-year randomized controlled trial (RCT) of vitamin D versus placebo. The study was conducted in an ambulatory clinical research center. Vitamin D dose was adjusted to maintain serum 25(OH)D above 75 nmol/L. Bone mineral density (BMD) and serum were measured for parathyroid hormone (PTH), C-terminal crosslink telopeptide (CTX), and bone-specific alkaline phosphatase (BSAP) every 6 months. Baseline serum 25(OH)D was 54.8 ± 16.8 nmol/L. There was no group × time interaction effect for any BMD measurement. For all BMD measurements, except for total body and spine, there was a statistically significant negative effect of time (p < 0.001). An equivalency analysis showed that the treatment group was equivalent to the control group. Serum PTH and BSAP declined, with a greater decline of PTH in the treatment group. The rate of bone loss with serum 25(OH)D above 75 nmol/L is comparable to the rate of loss with serum 25(OH)D at the Recommended Dietary Allowance (RDA) of 50 nmol/L. Black Americans should have the same exposure to vitamin D as white Americans. © 2018 American Society for Bone and Mineral Research.