Study under review: Association between calcium or vitamin D supplementation and fracture incidence in community-dwelling older adults: a systematic review and meta-analysis
Among older adults, hip fracture increases the risk of mortality threefold, and 27% of people over the age of 65 will die within a year following an operation to fix a fractured hip. After eight years, there is roughly an 80% higher risk of death. Older people who survive hip fractures will find their quality of life is diminished, with mobility and ability to care for oneself being the most affected. While fractures in general present a large health concern, hip fractures are particularly troublesome because they account for about 70% of total fracture-related healthcare costs.
Calcium and vitamin D are key nutrients that regulate bone formation. Most bone tissue is mineralized collagen fibers, one of many composite materials present in nature. Calcium is one of the primary elements in hydroxyapatite, a key mineral that makes up bone and gives it much of its rigid structure. Vitamin D helps maintain calcium levels and indirectly regulates the mineralization of bone tissue. Some of the ways it does this are shown in Figure 1.
Due to the roles calcium and vitamin D play in bone formation and maintenance, it has been hypothesized that supplementation with calcium and/or vitamin D may increase bone strength and reduce risk of fracture among older adults. There have been a myriad of randomized controlled trials and meta-analyses examining this hypothesis, but the results are often contradictory.
There are many reasons why these studies have had conflicting results, including different dosages and combinations of calcium and vitamin D, as well as disparate participant populations. Furthermore, previous meta-analyses have examined studies that include both community-dwelling (living within the community) and institutionalized (e.g., nursing homes) participants. Institutionalized individuals are generally sicker, and have lower levels of vitamin D than non-institutionalized individuals, suggesting that the benefit observed in earlier trials in these populations may not extend to community-dwelling participants. The present study was a systematic review and meta-analysis studying the effect of calcium and/or vitamin D supplementation on fractures in only community-dwelling older adults.
Fractures, specifically hip fractures, among older adults increase mortality and decrease quality of life. Calcium and vitamin D are two well known nutrients that regulate bone formation and contribute to bone strength. The present study was a systematic review and meta-analysis examining whether supplementation with calcium and/or vitamin D was associated with a lower risk of fractures in community dwelling older adults.
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