Vitamin D and muscle
4 papers in the library, strongest Moderate.
Graded Moderate · Genetic analysis using data from 318,851 people of European ancestry; many traits were tested without correcting for multiple comparisons.
Papers 4
- Vitamin D Genes Tied to More Lean Mass, Not Stronger GripModeraten = 318,8512026MedicinePeople born with gene variants that raise vitamin D levels had slightly more fat-free mass in their arms and legs, which is mostly muscle. But these genes showed no link with grip strength or usual walking speed. The researchers used these measures to capture age-related muscle loss. The team used a method that treats inborn gene variants as a natural experiment. Data on vitamin D levels came from 318,851 people of European ancestry. Depending on the outcome, up to 13 gene variants served as stand-ins for a person's vitamin D level. Nobody took vitamin D pills. The study also looked at exercise, alcohol and waist-to-hip ratio, and found no clear link there. Only one of several calculation methods tied higher vitamin D to having never smoked. The authors themselves caution about the smoking result, because their main method did not confirm it. The study cannot say whether vitamin D supplements build muscle or prevent muscle loss. Many traits were also tested without statistical correction, and all data came from people of European ancestry.
- After Stroke, Low Vitamin D Tracks With More FallsModeraten = 8022026Clinical interventions in agingA stroke can set older people back badly. Those who also have atrial fibrillation, an irregular heart rhythm, are especially prone to lasting disability, low mood and falls. In a study from China, stroke patients with little vitamin D in their blood recovered less well. They also fell more often over the following year. Researchers at one hospital followed 802 people aged 65 or older after a stroke caused by a blocked blood vessel. Vitamin D was measured within 48 hours of admission. Just over 60 percent had low levels. This group had a 29 percent higher risk of a first fall during the next twelve months. At three months, they managed daily tasks less well on their own and more often had marked depressive symptoms. Falls were common overall: 327 of 742 people tracked fell at least once, more than two in five. No one in the study was given vitamin D. So the results cannot show whether raising vitamin D improves recovery or prevents falls, a point the authors stress themselves. Key details such as earlier falls, balance or memory were not recorded in a standard way and could partly explain the link. The researchers see the blood test mainly as a simple way to spot who is at risk.
- Swinging Vitamin D Levels Linked to Muscle Loss in Old AgePreliminaryn = 2152026Journal of investigative medicine : the official publication of the American Federation for Clinical ResearchFor muscles in old age, the level of vitamin D may not be the only thing that counts. How much it swings over time could matter too. Older people whose vitamin D readings went up and down more from test to test more often had age-related muscle loss. The link held after other factors were taken into account. Researchers looked back at the records of 215 people aged 65 or older. All were patients at a clinic for older adults. Their median age was 78. Each had two to four vitamin D tests on file. Muscle and fat were measured with a special X-ray scan. Almost two in three, 140 of 215, had muscle loss. Bigger swings were at first also tied to low fat-free mass, which is mostly muscle. The link was weak and only just passed the statistical test. A subgroup of 27 people showed similar patterns. But these did not hold up after a stricter check for running many tests at once. Records like these cannot show whether steadier vitamin D levels protect muscles. Still, the authors conclude that tracking vitamin D over a period may be more useful than a single test.
- Diabetes Plus Low Vitamin D Tied to More Muscle Loss in Old AgePreliminaryn = 7,5202026The journal of nutrition, health & agingOlder people with diabetes who also had low vitamin D in their blood more often had age-related muscle loss in an English group. Muscle loss here meant a weak grip together with low estimated muscle mass. Across all participants, though, there was no clear link once other factors were taken into account. Researchers looked at data from 7,520 people aged 50 or older in the US and England, each examined once. Low vitamin D meant 50 nanomoles per liter or less. In England, people with diabetes and low levels had muscle loss more often than people without diabetes and higher levels. The US group pointed the same way, but the result was not clear. The team also gave vitamin D3 to rats made artificially old and diabetic. Those rats gripped harder, and their muscles held about 72 percent less fat than rats lacking vitamin D. The authors call the human findings suggestive, not confirmatory. Because everyone was measured only once, it is unclear which came first: low vitamin D or weak muscles. Whether vitamin D protects people with diabetes from muscle loss was not tested; supplements were given only to rats.
How this map is computed
A mark's size is the number of papers we hold on that pairing. It is a count, not a weighting by study design or sample size.
The fill shows the strongest grade in the cell. One Strong paper among four Preliminary ones still fills it dark, so open the cell to see the rest.
Grades and verdicts are assigned by a named person, never by counting.
An empty cell means our library holds no paper on that pairing yet. It is a gap in our library, not proof that nobody has studied it.