RESUMEN
Using data from the Health, Aging, and Body Composition study, we examined whether low 25-hydroxyvitamin D (25[OH]D) concentrations were associated with prevalent or incident cognitive impairment. Serum 25(OH)D concentrations were measured in 2,786 older adults and categorized as <20 ng/mL, 20 to <30 ng/mL, or ≥30 ng/mL. Cognitive impairment was defined as a score >1.5 standard deviations below race and education specific means on either digit symbol substitution test or modified mini-mental state test. Logistic regression determined the odds of cognitive impairment at baseline and year 5 by 25(OH)D category. 25(OH)D concentrations were <30 ng/mL in 57.3% of whites and 84.6% of blacks. After excluding participants with baseline cognitive impairment (n = 340), 13% of whites and 13% of blacks developed cognitive impairment by year 5. In whites, 25(OH)D concentrations <30 ng/mL were not associated with prevalent or incident cognitive impairment. Black participants with 25(OH)D concentrations <20 ng/mL had a higher odds of prevalent, but not incident cognitive impairment (OR (95% CI): 2.05 (1.08-3.91), p = 0.03) compared to participants with 25(OH)D concentrations ≥30 ng/mL. Low 25(OH)D concentrations were associated with twofold higher odds of prevalent cognitive impairment in blacks.
Asunto(s)
Envejecimiento , Disfunción Cognitiva/epidemiología , Deficiencia de Vitamina D/complicaciones , Vitamina D/análogos & derivados , Anciano , Población Negra , Composición Corporal , Disfunción Cognitiva/sangre , Disfunción Cognitiva/complicaciones , Disfunción Cognitiva/etnología , Estudios de Cohortes , Femenino , Servicios de Salud para Ancianos , Estado de Salud , Humanos , Incidencia , Masculino , Pennsylvania/epidemiología , Prevalencia , Tennessee/epidemiología , Vitamina D/sangre , Población BlancaRESUMEN
OBJECTIVES: To examine the relationship between 25-hydroxyvitamin D (25(OH)D) levels and cognitive performance over time in older adults in the Health, Aging and Body Composition (Health ABC) Study. DESIGN: Prospective cohort study. SETTING: Community-dwelling participants in Pittsburgh, Pennsylvania, and Memphis, Tennessee. PARTICIPANTS: Well-functioning adults aged 70 to 79 at baseline with serum 25(OH)D measured at the 12-month follow-up visit and cognitive function measured at baseline and 4-year follow-up visit (N = 2,777). MEASUREMENTS: Vitamin D status was categorized as 25(OH)D levels of less than 20.0 ng/mL, 20.0 to 29.9 ng/mL, or 30.0 ng/mL or greater. Cognition was measured using the modified Mini-Mental State Examination (3MS) and Digit Symbol Substitution Test (DSST). Linear regression models adjusting for multiple covariates, including age, education, sex, race, site, season, physical activity, and comorbidities, were used in the analysis. RESULTS: Sixty-eight percent of participants had 25(OH)D levels of less than 30.0 ng/mL. Lower 25(OH)D levels were associated with lower baseline cognitive scores on the 3MS (adjusted mean 89.9, 95% confidence interval (CI) = 89.4-90.4 for <20.0 ng/mL; adjusted mean 90.8, 95% CI = 90.4-91.3 for 20.0-29.9 ng/mL; adjusted mean 90.6, 95% CI = 90.2-91.1 for ≥ 30.0 ng/mL; P trend = .02) and the DSST (adjusted mean 35.2, 95% CI = 34.5-36.0 for <20.0 ng/mL; adjusted mean 35.9, 95% CI = 35.2-36.6 for 20.0-29.9 ng/mL; adjusted mean 37.0, 95% CI = 36.3-37.8 for ≥ 30.0 ng/mL; P trend = .01). Participants with low 25(OH)D levels had greater declines in 3MS scores over 4 years than those with higher levels (least square mean change -1.0, 95% CI = -1.5 to -0.6 for <20.0 ng/mL; least square mean change -0.8, 95% CI = -1.2 to -0.3 for 20.0-29.9 ng/mL; least square mean change -0.2, 95% CI = -0.7 to 0.2 for ≥30.0 ng/mL; P = .05). There was no significant difference in DSST decline according to 25(OH)D level. CONCLUSION: Low 25(OH)D levels were associated with worse global cognitive function and greater decline over time according to the 3MS. Intervention trials are needed to determine whether vitamin D supplementation can reduce cognitive decline.
