Vitamin D Status May Impact Rate of Cognitive Decline
A faster cognitive decline was seen among older adults with vitamin D insufficiency, a new article published in JAMA Neurology has shown.
Researchers from Rutgers University and University of California, Davis, conducted a study (n=382) to examine the associations with baseline vitamin D status and change in subdomains of cognitive function as measured on assessment scales. Study participants' serum 25-OHD was measured and vitamin D status was classified as: deficient (<12ng/mL), insufficient (12–<20mg/nL), adequate (20–<50ng/mL), and high (≥50ng/mL).
At the start of the study, 17.5% of participants had dementia, 32.7% had mild cognitive impairment, and 49.5% were cognitively normal. The average 25-OHD level was 19.2ng/mL with 26.2% of participants being vitamin D deficient and 35.1% being insufficient.
African American and Hispanic study participants had lower average 25-OHD levels vs. their white peers (17.9ng/mL and 17.2ng/mL vs. 19.7ng/mL, respectively). Also, the rate of decline in episodic memory and executive function among vitamin D deficient and insufficient participants were higher than those with adequate vitamin D levels.
Vitamin D levels were not significantly tied to a decline in semantic memory or visuospatial ability. These findings support that vitamin D insufficiency was linked to significantly faster declines in both episodic memory and executive function performance, which may be tied to an increased risk for Alzheimer's dementia, noted study authors. Future well-designed clinical trials with an ethnically diverse study population that have hypovitaminosis D could be helpful for evaluating the effect of vitamin D replacement on preventing dementia.
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