Health Effects of Vitamin D Supplementation: Lessons Learned From Randomized Controlled Trials and Mendelian Randomization Studies.
Study Goal
The researchers aimed to evaluate the effects of vitamin D supplementation on bone health, fractures, falls, cancer, cardiovascular disease, immune system disorders, multiple sclerosis, and mortality in community-dwelling adults.
Results Summary
The study found that vitamin D supplementation did not significantly reduce bone loss, fractures, falls, cancer incidence, hypertension, or cardiovascular risk in generally healthy populations. However, it suggested potential benefits for cancer mortality, immune system function (especially in vitamin D-deficient individuals or those with autoimmune diseases), and all-cause mortality.
Population
Community-dwelling adults, excluding older adults in residential communities or those with vitamin D deficiency or osteoporosis.
Effective Dosage
Not specified
Duration
Not specified
Interactions
None mentioned
| Intervention | Direction | Endpoint | Population | Dosage | Impact | Claim # |
|---|---|---|---|---|---|---|
vitamin D supplementation | no change | bone loss | generally healthy populations | - | does not decrease | #1 |
vitamin D supplementation | no change | fractures | generally healthy populations | - | does not decrease | #2 |
vitamin D supplementation | no change | falls | generally healthy populations | - | does not decrease | #3 |
vitamin D supplementation | no change | cancer incidence | generally healthy populations | - | does not decrease | #4 |
vitamin D supplementation | no change | hypertension | generally healthy populations | - | does not decrease | #5 |
vitamin D supplementation | no change | cardiovascular risk | generally healthy populations | - | does not decrease | #6 |
supplemental vitamin D | decrease | cancer mortality | - | - | suggest an effect | #7 |
vitamin D supplementations | increase | immune system | people with poor vitamin D status, autoimmune diseases, and multiple sclerosis | - | existence of extraskeletal benefits | #8 |
vitamin D | decrease | all-cause mortality | - | - | may reduce | #9 |
Vitamin D plays an important role in calcium homeostasis and many cellular processes. Although vitamin D supplements are widely recommended for community-dwelling adults, definitive data on whether these supplements benefit clinically important skeletal and extraskeletal outcomes have been conflicting. Although observational studies on effects of vitamin D on musculoskeletal and extraskeletal outcomes may be confounded by reverse causation, randomized controlled studies (RCTs) and Mendelian randomization (MR) studies can help to elucidate causation. In this review, we summarize the recent findings from large RCTs and/or MR studies of vitamin D on bone health and risk of fractures, falls, cancer, and cardiovascular disease, disorders of the immune system, multiple sclerosis, and mortality in community-dwelling adults. The primary analyses indicate that vitamin D supplementation does not decrease bone loss, fractures, falls, cancer incidence, hypertension, or cardiovascular risk in generally healthy populations. Large RCTs and meta-analyses suggest an effect of supplemental vitamin D on cancer mortality. The existence of extraskeletal benefits of vitamin D supplementations are best documented for the immune system especially in people with poor vitamin D status, autoimmune diseases, and multiple sclerosis. Accumulating evidence indicates that vitamin D may reduce all-cause mortality. These findings, in mostly vitamin D-replete populations, do not apply to older adults in residential communities or adults with vitamin D deficiency or osteoporosis. The focus of vitamin D supplementation should shift from widespread use in generally healthy populations to targeted vitamin D supplementation in select individuals, good nutritional approaches, and elimination of vitamin D deficiency globally. © 2023 American Society for Bone and Mineral Research (ASBMR).