Vitamin D Doesn't Improve Postmenopausal Outcomes

New research finds no evidence to support the common practice of administering high-dose cholecalciferol—a form of vitamin D—to older, postmenopausal women.

A team including investigators from the University of Wisconsin compared the effects of placebo, low-dose cholecalciferol and high-dose cholecalciferol on 1-year changes in total fractional calcium absorption, bone mineral density, Timed Up and Go, and 5 sit-to-stand tests, and muscle mass in postmenopausal women with vitamin D insufficiency.
_________________________________________________________________________________________________________________________________________________________________________

RELATED CONTENT
Health Practitioner's Guide to Prescribing Vitamin D
Vitamin D vs Arthritis: Wrong Tool for the Job
_________________________________________________________________________________________________________________________________________________________________________

The authors conducted a randomized, double-blind, placebo-controlled clinical trial at a single center in Madison, Wisconsin, from May 1, 2010, through July 31, 2013, and a final visit occurring on Aug. 8, 2014. In total, 230 postmenopausal women, age 75 and younger, with baseline 25(OH)D levels of 14 through 27 ng/mL, and no osteoporosis were studied.

After baseline absorption was controlled for, calcium absorption increased 1% in the high-dose group, but decreased 2% among the low-dose patients, and 1.3% percent in the placebo group, according to the authors, who note that they found no changes in spine, mean total-hip, mean femoral neck, or total-body bone mineral density, trabecular bone score, muscle mass, and Timed Up and Go or 5 sit-to-stand test scores between groups. They also found no differences between groups in terms of differences in the number of falls, fallers, physical activity, or functional status.

“The recommendation to keep serum vitamin D levels higher than 30 ng comes from experts' opinion, and was published by the Endocrine Society,” says Karen Hansen, MD, MS, associate professor of medicine at the University of Wisconsin, and lead author of the study.

Unfortunately, “most if not all labs across the country report serum levels <30 ng as ‘abnormal,’ and I think it is time for these labs to reconsider how they define normal serum levels, given the growing evidence that higher levels do not enhance musculoskeletal health, she says. Hansen also notes her belief that “the Institute of Medicine recommendations are what providers should focus on. [If patients] take 600 to 800 IU of vitamin D a day to avoid vitamin D deficiency, and if the serum level is 20 ng/mL or higher, this is just fine.”

With respect to what postmenopausal women can do for their bone and muscle health, Hansen recommends advising regular exercise, stopping smoking, avoiding excess alcohol, eating a healthy diet that provides ~1200 mg of calcium from all sources, and taking the recommended daily allowance for vitamin D, which is 600 IU a day if less than 70 years old, and increasing to 800 IU at and above age 70.

—Mark McGraw

Reference

Hansen K, Johnson E, et al. Treatment of Vitamin D Insufficiency in Postmenopausal Women: A Randomized Clinical Trial. JAMA Intern Med. 2015.