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Research Shows Impact of Long-Term Vitamin D Insufficiency on Fracture Risk

A study presented in April at the World Congress on Osteoporosis, Osteoarthritis, and Musculoskeletal Diseases shows that long-term low levels of vitamin D intake are associated with a higher 10-year fracture risk in elderly women.

Vitamin D insufficiency in older adults has been shown to contribute to an increased risk of osteoporotic fractures. Previous studies have used single vitamin D measurements to investigate effects on bone. However, in elderly women, relatively little is known about the effects of long-term vitamin D insufficiency on bone health.

The study by Swedish researchers used sequential assessment of serum vitamin D to determine whether sustained hypovitaminosis D in elderly women leads to increased 10-year fracture incidence.

Study participants at baseline included 1,044 75-year-old Swedish women, with 715 attending the five-year follow up. Serum 25-hydroxyvitamin D [25(OH)D] levels were classified as low (< 50 nmol/L), intermediate (50 to 74 nmol/L) and high (> 75 nmol/L). Women with values in the same 25(OH)D category at both samplings were considered to have consistently low, intermediate, or high levels. Fracture data were followed for 10 years through X-rays.

The results showed that the incidence of hip fractures within 10 years was significantly lower in those women who were vitamin D sufficient (≥ 50 nmol/L) at baseline and maintained this level at five years. The proportion of women sustaining FRAX fractures was 26.2% and 30% in the group that had consistently high or intermediate 25(OH)D levels compared with 45.6% in the group with consistently low levels. The incidence of shoulder, radius, and vertebral fractures was not associated with 25(OH)D status in the study.

The majority of fractures occurred between five and 10 years after baseline (hip, 77%; FRAX, 64%). However, the time to first fracture (hip and FRAX) did not significantly differ among the three categories of 25(OH)D using either a single or serial measurement.

“This study concludes that in the population sample of elderly women, vitamin D insufficiency sustained over five years was associated with increased 10-year risk of osteoporotic fracture,” said Prof Kristina Akesson, of the clinical and molecular osteoporosis research unit at Lund University and chair of the International Osteoporosis Foundation Capture the Fracture Campaign.

She added, “This is part of a body of research which increasingly suggests that falls and fracture risk in the elderly could be lower by having higher vitamin D levels. The International Osteoporosis Foundation global recommendations for vitamin D advise daily intakes of 800 to 1,000 IU per day in seniors for fracture and falls prevention, and if the ongoing research shows that vitamin D levels are increased, it may be a relatively simple and low-cost public health measure that could have significant positive effects on the incidence of osteoporotic fractures with aging.”

The Capture the Fracture campaign specifically targets secondary fracture prevention by promoting the implementation of coordinator-based fracture liaison services in hospitals and clinics worldwide.

— Source: International Osteoporosis Foundation