Effect of Vitamin D on Falls (A Meta-analysis)

Taking vitamin D supplements by older people can cut falls by over 20%, according to new research. A meta-analysis published in the Journal of the American Medical Association looked at data from ten randomised controlled trials. Abstract Context - Falls among elderly individuals occur frequently, increase with age, and lead to substantial morbidity and mortality. The role of vitamin D in preventing falls among elderly people has not been well established. Objective To assess the effectiveness of vitamin D in preventing an older person from falling. Data Sources - MEDLINE and the Cochrane Controlled Trials Register from January 1960 to February 2004, EMBASE from January 1991 to February 2004, clinical experts, bibliographies, and abstracts. Search terms included trial terms: randomized-controlled trial or controlled-clinical trial or random-allocation or double-blind method, or single-blind method or uncontrolled-trials with vitamin D terms: cholecalciferol or hydroxycholecalciferols or calcifediol or dihydroxycholecalciferols or calcitriol or vitamin D/aa[analogs & derivates] or ergocalciferol or vitamin D/bl[blood]; and with accidental falls or falls, and humans. Study Selection - We included only double-blind randomized, controlled trials (RCTs) of vitamin D in elderly populations (mean age, 60 years) that examined falls resulting from low trauma for which the method of fall ascertainment and definition of falls were defined explicitly. Studies including patients in unstable health states were excluded. Five of 38 identified studies were included in the primary analysis and 5 other studies were included in a sensitivity analysis. Data Extraction - Independent extraction by 3 authors using predefined data fields including study quality indicators. Data Synthesis - Based on 5 RCTs involving 1237 participants, vitamin D reduced the corrected odds ratio (OR) of falling by 22% (corrected OR, 0.78; 95% confidence interval [CI], 0.64-0.92) compared with patients receiving calcium or placebo. From the pooled risk difference, the number needed to treat (NNT) was 15 (95% CI, 8-53), or equivalently 15 patients would need to be treated with vitamin D to prevent 1 person from falling. The inclusion of 5 additional studies, involving 10 001 participants, in a sensitivity analysis resulted in a smaller but still significant effect size (corrected RR, 0.87; 95% CI, 0.80-0.96). Subgroup analyses suggested that the effect size was independent of calcium supplementation, type of vitamin D, duration of therapy, and sex, but reduced sample sizes made the results statistically nonsignificant for calcium supplementation, cholecalciferol, and among men. Conclusions - Vitamin D supplementation appears to reduce the risk of falls among ambulatory or institutionalized older individuals with stable health by more than 20%. Further studies examining the effect of alternative types of vitamin D and their doses, the role of calcium supplementation, and effects in men should be considered. Additional information on Vitamin D • Food sources of Vitamin D Fortified foods are the major dietary sources of vitamin D (4). Prior to the fortification of milk products in the 1930s, rickets (a bone disease seen in children) was a major public health problem in the United States. Milk in the United States is fortified with 10 micrograms (400 IU) of vitamin D per quart, and rickets is now uncommon in the US (7). One cup of vitamin D fortified milk supplies about one-fourth of the estimated daily need for this vitamin for adults. Although milk is fortified with vitamin D, dairy products made from milk such as cheese, yogurt, and ice cream are generally not fortified with vitamin D. Only a few foods naturally contain significant amounts of vitamin D, including fatty fish and fish oils (4). The table of selected food sources of vitamin D suggests dietary sources of vitamin D. • Exposure to sunlight Exposure to sunlight is an important source of vitamin D. Ultraviolet (UV) rays from sunlight trigger vitamin D synthesis in the skin (7, 8). Season, latitude, time of day, cloud cover, smog, and sunscreens affect UV ray exposure (8). For example, in Boston the average amount of sunlight is insufficient to produce significant vitamin D synthesis in the skin from November through February. Sunscreens with a sun protection factor of 8 or greater will block UV rays that produce vitamin D, but it is still important to routinely use sunscreen whenever sun exposure is longer than 10 to 15 minutes. It is especially important for individuals with limited sun exposure to include good sources of vitamin D in their diet.