Low serum concentrations of 25-hydroxyvitamin D in older persons and the risk of nursing home admission

BACKGROUND: The prevalence of vitamin D deficiency in nursing home patients is high. OBJECTIVE: We aimed to ascertain whether lower serum 25-hydroxyvitamin D [25(OH)D] concentrations increase the risk of future nursing home admission and early death. DESIGN: We included 1260 independent, community-dwelling persons aged > or =65 y who were participating in the Longitudinal Aging Study Amsterdam (1995-1996). Study outcomes were time to nursing home admission during 6 y of follow-up and time to death until 1 April 2003. RESULTS: Vitamin D deficiency [25(OH)D < 25 nmol/L] and insufficiency [25(OH)D = 25-49.9 nmol/L] were present in 127 (10.1%) and 462 (36.7%) subjects, respectively. During follow-up, 138 subjects (11.0%) were admitted to nursing homes, and 380 subjects (30.2%) died. The risk of nursing home admission for participants with 25(OH)D deficiency was 53 cases per 1000 person-years higher than that for those with high 25(OH)D (> or =75 nmol/L) concentrations (58 compared with 5 cases). After adjustment for potential confounders, the hazard ratio (95% CI) of nursing home admission was 3.48 (1.39, 8.75) for vitamin D-deficient, 2.77 (1.17, 6.55) for vitamin D-insufficient, and 1.92 (0.79, 4.66) for vitamin D-borderline persons as compared with persons with high 25(OH)D (P for trend = 0.002). The results remained after additional adjustment for frailty indicators. Lower 25(OH)D was associated with higher mortality risk, but this association was not significant after adjustment for frailty indicators. CONCLUSION: Lower serum 25(OH)D concentrations in older persons are associated with a greater risk of future nursing home admission and may be associated with mortality.