[Association between low vitamin D levels and cognitive impairment in Chilean older adults: findings of the National Health Survey 2016-2017]. / Asociación entre bajos niveles de vitamina D y deterioro cognitivo en personas mayores chilenas: Resultados de la Encuesta Nacional de Salud 2016-2017.

ABSTRACT

INTRODUCTION: Recent studies have shown that low vitamin D levels constitute a potential risk factor for the development of cognitive impairment. The present study aimed to investigate the association between vitamin D levels and the suspicion of cognitive impairment in Chilean older adults. MATERIAL AND METHOD: We performed a cross-sectional study, including 1,287 participants ≥ 65 years (56.8% were women, age range 65 to 97 years) from the Chilean National Health Survey. Cognitive impairment was assessed using the Mini Mental State Examination (MMSE). Participants were classified into three groups according to their vitamin D levels (> 29 ng/ml sufficient, 12-29 ng/ml deficit, and < 12 ng/ml severe deficit). The association between vitamin D levels and cognitive impairment was explored using logistic regression analysis, adjusted for confounding factors. RESULTS: The prevalence of vitamin D deficit and vitamin D severe deficit was 37.7% and 21.0%, respectively. Compared to older adults with sufficient levels of vitamin D, those with severe deficits had a 94% (OR 1.94 [95% IC 1.27; 1.66], p = 0.002) higher odds of cognitive impairment (unadjusted model). Adjusting according to sociodemographic factors, lifestyle, adiposity, sunlight exposure, and multimorbidity slightly attenuated the association to 61% (OR 1.61 [95%IC 1.03; 2.19], p = 0.046), but remain significant. CONCLUSION: A severe deficit of vitamin D was associated with higher odds of cognitive impairment in Chilean older adults independent of major confounding factors. Future studies are needed to provide causal evidence between vitamin D and the suspicion of cognitive impairment.