Association of vitamin d with mild cognitive impairment and alzheimer's dementia in older mexican adults

ABSTRACT Background It has been proposed that Vitamin D helps reduce the accumulation of cerebral β-amyloid-42 by innate immune stimulation and phagocytosis activation. An association between low Vitamin D levels and Alzheimer’s dementia (AD) has been established. We determined the association between Vitamin D, mild cognitive impairment (MCI), and AD in older Mexican adults (> 65 years) Methods Cross-sectional study conducted at the memory clinic in a tertiary-level hospital in Mexico City. We evaluated subjects with MCI, AD, and normal cognition (NC) with available serum Vitamin D [25(OH)D] levels (past 6 months). Three categories were assigned according to 25(OH)D levels: sufficiency (> 30 ng/mL), insufficiency (21-29 ng/mL), and deficiency (≤ 20 ng/mL). Descriptive statistics, means and standard deviations were used. Logistic regression analyses adjusted by age, sex, and educational level were performed Results We evaluated 208 patients. Mean age was 79 ± 1 year, 65% (n = 136) were female; and mean educational level was 6.7 ± 2.3 years. Thirty-one subjects (14%) had NC; 42% (n = 88) had MCI; and 43% (n = 89) had AD. Prevalence of Vitamin D deficiency was 54%, more frequent in the AD group (64%) followed by the MCI (59%) and NC (13%) (p < 0.001) groups. In the multivariate logistic regression analysis, Vitamin D deficiency was associated with MCI (HR 25.02 [confidence interval 95% 4.48-139]; p < 0.001) and AD (HR 41.7 [5.76-301]; p < 0.001) after adjusting for confounders Conclusions Serum Vitamin D deficiency was associated with MCI and dementia; low levels produced a greater effect over executive functions.

Serum cobalamin levels in dementias.

The present study attempts to find a correlation between low serum B-12 levels and dementias. A total of 178 patients of dementia were seen at the cognitive disorder clinic from 1996 to 1998. Serum B-12 levels were studied in 100 patients. 15 patients (39.5%) of Alzheimer's dementia had reduced B-12 levels, while only 5 patients (13.9%) with vascular dementias and 3 patients (11.5%) with other types of dementias had reduced levels. The incidence of low serum B-12 was statistically significant in the Alzheimer's group when compared with the other groups, individually as well as combined together (p<0.05). The aetiopathogenesis and significance of these findings is discussed and the literature is reviewed.