Elderly women, particularly those who are less active, can significantly reduce their risk of falling by taking a daily supplement of vitamin D, according to a new study. However, the supplement does not protect men in the same age group.
Daily supplementation with 700 IU of cholecalciferol and 500 mg of calcium citrate malate reduced the odds of falling by 46% in ambulatory older women and by 65% in less active women, noted Dr. Heike A. Bischoff-Ferrari of University Hospital Zurich, and colleagues.
The supplementation is not only “very inexpensive, well tolerated, and simple” but also has similar or greater benefit than more expensive and time-intensive interventions, added the authors (Arch. Intern. Med. 2006;166:424–30).
The findings are from a secondary analysis of a 3-year double-blind placebo-controlled study that looked at the effect of cholecalciferol-calcium on bone mineral density. Primary results of the study noted a 60% reduction of osteoporotic fractures with the supplement, compared with placebo. The secondary analysis examined the risk of falling during the study period for 199 men and 246 women aged 65 years or older.
Multivariate analysis controlled for age, gender, baseline body mass index, dietary calcium, baseline plasma 25-hydroxyvitamin D (25-OHD) levels, baseline plasma intact parathyroid hormone levels, activity level, baseline smoking status, baseline alcohol use, baseline comorbid conditions, baseline creatinine clearance and length of follow-up.
Overall, cholecalciferol-calcium supplementation did not significantly reduce the risk of falling compared with placebo, with 49% of men and 55% of women reporting at least one fall during the study period. However, multivariate analysis revealed that, compared with placebo, supplementation significantly reduced the odds of falling in women (odds ratio [OR] 0.54) and particularly in less active women (OR 0.35).
The treatment did not have the same effect on men, however, regardless of whether they were less active (OR 0.96) or more active (OR 1.01).
Baseline levels of 25-OHD, creatinine clearance or parathyroid hormone did not impact the effect of the supplement.
The gender difference in the effect of vitamin D supplementation has not been previously described because generally men have not been included in previous studies, noted the authors. One explanation for this gender difference in treatment effect could be that decreased muscle strength in women, compared with men, makes them more susceptible to falls, the investigators suggested. Vitamin D supplementation increases muscle strength thus protecting against falls.
They noted that length of treatment was another important factor in the study because the benefit of supplementation “increased with time and occurred primarily after 12 months of treatment.” Short-term benefits of supplementation have been noted in other studies, but “may be explained by a combination of older age, increased frailty, and significantly lower baseline 25-OHD levels in their participants,” they observed.
The fact that low baseline levels of 25-OHD did not enhance treatment effects in this study “may be explained by the rather high mean baseline 25-OHD levels observed in our study participants, which is likely owing to vitamin D fortification in dairy products and activity level of our healthy and relatively young community-dwelling older participants,” the investigators noted.