Low vitamin D levels increased the risk of hip fracture in older patients, according to research published in the Journal of Clinical Endocrinology & Metabolism.
Kristin Holvik, PhD, of the University of Bergen in Norway and colleagues looked at participants from four community health studies between 1994 and 2001 that in total included over 20,000 patients aged 25-79. The researchers then looked at electronic hospital discharge registers over the next ten years from baseline, seeing which participants got hip fractures and which did not according to these registers.
A total of 1,175 patients – 307 men and 868 women – had a hip fracture over the next ten years according to the registers. For those that got hip fractures, the researchers measured vitamin D levels from stored blood samples that were collected at baseline in the original studies. They also measured vitamin D levels from stored blood samples in 1,438 random controls – people in the original studies that did not get hip fractures.
Holvik and colleagues report that after adjusting for potential confounders, including gender, age, body mass index, and study center, they found that patients with the lowest vitamin D levels (<17 ng/ml) had a 38% increased risk of hip fracture compared to those with the highest levels (>27 ng/ml). The association was stronger in men and was not significant in women.
The authors noted a preventative effect with levels above 30 ng/ml compared with levels below 20 ng/ml. The study was the largest cohort type study to find an increased risk of hip fracture with low vitamin D levels.
This research corroborates previous findings that vitamin D status predicts fracture in older adults.
Holvik K, et al. Low serum levels of 25-hydroxyvitamin D predict hip fracture in the elderly. A NOREPOS study. Journal of Clinical Endocrinology and Metabolism, 2013.