Vitamin D status in relation to one-year risk of recurrent falling in older men and women

Background: Falls frequently occur in the elderly and are a major cause of morbidity and mortality. Objective: The objective of the study was to prospectively investigate the association between serum 25-hydroxyvitamin D [25(OH)D] levels and risk of recurrent falling in older men and women. Design: This was a prospective cohort study. Setting: An age- and sex-stratified random sample of the Dutch older population was determined. Subjects: Subjects included 1231 men and women (aged 65 yr and older) participating in the Longitudinal Aging Study Amsterdam. Measurements: Baseline serum 25(OH)D was determined by a competitive protein binding assay. During 1 yr, falls were prospectively recorded by means of a fall calendar. Results: Low 25(OH)D (<10 ng/ml) was associated with an increased risk of falling. After adjustment for age, sex, education level, region, season, physical activity, smoking, and alcohol intake, the odds ratios (95% confidence interval) were 1.78 (1.06-2.99) for subjects who experienced two falls or more as compared with those who did not fall or fell once and 2.23 (1.17-4.25) for subjects who fell three or more times as compared with those who fell two times or less. There was a statistically significant effect modification by age, and stratified analyses (<75 and ≥ 75 yr) showed that the associations were particularly strong in the younger age group; the odds ratios (95% confidence interval) were 5.21 (2.03-13.40) for two falls or more and 4.96 (1.52-16.23) for three falls or more. Conclusions: Poor vitamin D status is independently associated with an increased risk of falling in the elderly, particularly in those aged 65-75 yr.