Bone Mineral Density Linked to Concentrations of 25(OH)D in Summer
Summer levels of serum 25(OH)D appeared to be the strongest predictor of bone mineral density at the total hip.
HealthDay News -- Summer levels of serum 25-hydroxyvitamin D (25[OH]D) are associated with bone mineral density (BMD) of the total hip, according to a study published in the Journal of Internal Medicine.
Karl Michaëlsson, MD, from Uppsala University in Sweden, and colleagues examined the relative importance of serum 25(OH)D for BMDy by season in a subcohort of 5002 Swedish women randomly selected from a large population-based cohort.
The researchers found that there was a gradual increase in BMD of the total hip in samples collected during summer, up to a serum 25(OH)D level of 40 nmol L−1. Compared with those with serum 25(OH)D levels above 80 nmol L−1, adjusted BMD was 11% lower in women with serum 25(OH)D concentrations below 30 nmol L−1 and 6% lower in those with serum 25(OH)D concentrations 30 to 40 nmol L−1 during summer. Compared with concentrations above 80 nmol L−1, low serum 25(OH)D concentrations (less than 30 nmol L−1) during summer correlated with increased adjusted relative risk of osteoporosis.
There were no differences in mean BMD values between categories of serum 25(OH)D in winter.
"To determine a serum 25(OH)D cut-off level for vitamin D deficiency, it may be necessary to take into account the season of blood collection," the researchers wrote.
Disclosures: The researchers report no conflicts of interest.
- Michaëlsson K, Wolk A, Byberg L, Mitchell A, Mallmin H, Melhus H. The seasonal importance of serum 25-hydroxyvitamin D for bone mineral density in older women. J Intern Med. 2016 Sept 25. doi: 10.1111/joim.12563 [Epub ahead of print]