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Approximately 30% of ambulatory older adults fall yearly ; 5% to 10% are seriously injured . Vitamin D deficiency increases body sway and decreases muscle mass and strength, increasing falls risk [3, 4]. Vitamin D supplementation reduces falls by 11% to 22% [5, 6]. To our knowledge, no studies report characteristics of ambulatory fallers associated with meeting the vitamin D recommended adequate intake (RAI). We report patient characteristics associated with vitamin D intake in a falls study.
We analyzed data from Safety Assessment for Elders (SAFE), a randomized, controlled study of multifactorial interventions to reduce falls (ClinicalTrials.org identifier NCT00140322). Eligible subjects were adults ages ≥65 years at high falls risk . At baseline and study end, researchers visited subjects’ homes to examine all medication and supplement bottles and record vitamin D intake.
Participants were randomized to receive mailed home safety information or a multifactorial intervention designed to decrease falls risk. In the active arm, subjects with a daily vitamin D intake <800 IU were asked to increase intake to ≥800 IU/day . Participants and their physicians received letters instructing them how to increase vitamin D intake. Participants were called monthly for eleven months to encourage adherence with recommendations.
Study outcomes were the rates and patient characteristics (Table) associated with meeting the age-specific vitamin D RAI of 400 IU (ages 51–70 years or 600 IU (ages ≥71 years) per day  at study entry and study end. Subjects with unknown vitamin D intake at baseline (n=18 of 500) were excluded. Forty-five of 482 subjects had missing data at one year; these individuals were similar to the remaining subjects (P > .05, candidate variables).
All data were analyzed using Analyze-It software (Leeds, UK) and summarized using the mean ± standard deviation (SD) or percentage points. Continuous study data were parametric, allowing analysis by independent sample t-test. Chi-square tests examined proportions. In all cases, a two-sided P value < .05 determined significant findings.
Vitamin D intake was recorded at baseline (n=482) and study end (n=446) from 500 subjects enrolled. Baseline demographics (Table) included a mean age of 79 ± 8 years and predominance of female (75%), Caucasian (97%) subjects. Participants reported an average of three falls yearly and a mean vitamin D supplement intake of 370 ± 320 IU daily. Only 28% of all subjects met the vitamin D RAI at study entry, increasing to 37% at study end (P = .007).
Five characteristics associated with greater likelihood of meeting the age-specific vitamin D RAI at baseline (Table). Participants meeting the RAI (n=135) were younger (76 ± 8 versus 80 ± 7, P < .001), more likely to be women (87% versus 70%, P = .003), suffer prior fracture (47% versus 37%, P = .05) and take calcium supplements (94% versus 57%, P < .001). Individuals who met the vitamin D RAI had better SF12 physical function scores (41 ± 11 vs. 39 ± 10, P = 0.04).
Subjects with known vitamin D intake at both entry and study end (n=437) increased vitamin D intake during participation (350 ± 300 IU to 410 ± 350 IU daily, P = .009). Two characteristics associated with increased intake. Subjects randomized to active falls interventions (33% versus 17%, P < .001) and those reporting regular exercise (29% versus 20%, P = .04) were statistically more likely to increase vitamin D intake during the one-year study.
Vitamin D is a safe, inexpensive strategy to reduce falls and associated medical costs. This study shows older fallers have a low rate of meeting the vitamin D RAI, especially men, older individuals, those without prior fracture and people avoiding calcium supplements. Patients and providers need greater education on the import of vitamin D for prevention of falls and fractures. Written instructions and regular phone follow-up appear to increase vitamin D intake in elderly fallers. This finding, if verified in additional studies, may prove an effective public health strategy to decrease falls in older adults.