(Reuters Health) – Vitamin D supplementation may not improve bone density and prevent fractures and falls in adults, a large new analysis suggests.
After combining the data from 81 randomized controlled trials, the researchers found no bone benefits from vitamin supplementation, according to the report in The Lancet Diabetes & Endocrinology.
"Our results show that adults have few vitamin D supplements for their bones to protect against fractures, except people from high-risk groups, such as people with a long-term lack of exposure to sunlight," said research co-author Dr. ir. Alison Avenell from the University of Aberdeen in the United Kingdom. "For example, older people in institutions who never go outside."
Vitamin D supplements have long been recommended for the elderly for the treatment and prevention of osteoporosis, the bone thinning disease. Avenell and her colleagues would like to see changes in the guidelines that divert people from the supplements.
For the new study, Avenell and her colleagues have searched the medical literature for studies that have investigated the impact of vitamin D supplementation on bone health. Eventually they came to 81 trials with a total of 53,537 participants. The length of time that the participants studied varied greatly, ranging from four weeks to five years. Women over the age of 65 were involved in more than three-quarters of the studies.
Although most studies lasted a year or less, "25 studies had a follow-up of more than a year," Avenell said in an e-mail. "There were eight trials with more than 33,000 participants who followed people for three to five years, so the majority of data comes from large, lengthy investigations."
The researchers did not calculate average or average age for participants in the studies, but most were 65 or older, noted Avenell.
Most of the tests did not focus on participants with bone problems. But, said Avenell, "a trial recruited people with low bone density, one with osteoporosis, six with people who had had previous fractures – including one of the largest with more than 5000 participants – 17 others were in elderly people from declining clinics, nursing homes or hospitals where there was an increased risk of fractures, with very few studies in healthy younger populations. "
When the researchers combined the data from all 81 studies, they discovered that vitamin D supplementation had no effect on the number of fractures and decreases. Also, the dosage of vitamin D did not seem to make any difference. Supplements also did not seem to increase bone density.
A major problem in studying vitamin D is that there is no consensus about what a healthy level of nutrient is, Avenell said.
"There is a lot of disagreement between different agencies that draw up guidelines all over the world," she added. "Our work would suggest that it is a lot less than people have thought."
Although the new findings may apply to the average person, they may be wrong for people whose bones have already been thinned out, Dr. said. Ethel Siris, director of the Toni Stabile Osteoporosis Center at NewYork-Presbyterian / Columbia University Irving Medical Center and a professor of medicine at Columbia University.
"The main reason why older women begin to lose bone mass and to have fractures is estrogen loss during menopause," said Siris. "A risk factor for worsening is low calcium or vitamin D. There is an argument about how much is needed, but if there is a bone problem, you want to be sure that you are adequately covered with regard to calcium and vitamin D. "
The risks associated with vitamin D are small, Siris said. "And although we prefer people to get their vitamin D through their diet, we will add a pill if necessary, and my patients can not afford to have a vitamin D deficiency."
The bottom line of the new study, Siris said, "it does not change my point of view regarding the types of people I care for."
Siris said she is worried that news about the new research will convince people who already have fragile bones to stop taking their vitamin D supplements. "People read (news stories) about these things and assume that what they read yesterday is the current truth," she added.
SOURCE: bit.ly/2LArJXX The Lancet Diabetes & Endocrinology, online October 4, 2018.
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