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Vitamin D Levels and Cognition in Elderly Adults in C hina
Author(s) -
Chei ChoyLye,
Raman Prassanna,
Yin ZhaoXue,
Shi XiaoMing,
Zeng Yi,
Matchar David B.
Publication year - 2014
Publication title -
journal of the american geriatrics society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.992
H-Index - 232
eISSN - 1532-5415
pISSN - 0002-8614
DOI - 10.1111/jgs.13082
Subject(s) - medicine , odds ratio , confidence interval , quartile , prospective cohort study , vitamin d and neurology , cohort study , cohort , cross sectional study , cognition , logistic regression , mini–mental state examination , depression (economics) , gerontology , cognitive impairment , psychiatry , disease , pathology , economics , macroeconomics
Objectives To evaluate the association between vitamin D level and cognitive impairment in individuals aged 60 and older. Design Cross‐sectional cohort study. Setting Chinese L ongitudinal H ealthy L ongevity S urvey, a community‐based cohort study in areas in C hina where the density of centenarians is exceptionally high. Participants Individuals with mean age of 84.9 ± 12.7 (N = 2,004). Measurements Participants’ cognitive state was evaluated using the M ini‐ M ental S tate E xamination ( MMSE ). Vitamin D was measured in plasma using an enzyme‐linked immunoassay. Results The cross‐sectional association between quartiles of plasma vitamin D level and cognitive impairment ( MMSE score <18) was modeled using logistic regressions. Plasma vitamin D levels were lower in individuals with cognitive impairment (31.9 ± 15.3 nmol/L) than in those without (45.6 ± 19.6 nmol/L). There was a reverse association between plasma vitamin D and cognitive impairment. After adjusting for age, sex, chronic conditions, smoking and drinking habits, outdoor activities, depression, and activity of daily living limitations, the association remained significant. The multivariable‐adjusted odds ratio for lowest versus highest vitamin D levels was 2.15 (95% confidence interval ( CI ) = 1.05–4.41) for cognitive impairment, and the multivariable odds ratio associated with a 1‐standard deviation decrement in plasma vitamin D was 1.32 (95% CI = 1.00–1.74) for cognitive impairment. Conclusion Low plasma vitamin D levels were associated with greater odds of cognitive impairment. Further prospective studies in A sian populations are needed to examine the causal direction of this association.