Regular physical activity in a healthy elderly population is associated with lower peripheral iPLA2 activity

Abstract

Background:Blood concentration of vitamin D could be related to cognitive impairments and may be a risk factor for disorders such as Alzheimer’s disease (AD). In the current study, we examined the relationship between 25(OH)D, cognition and AD in persons aged 65 years or over in the Canadian Study on Health and Aging (CSHA). Methods: Study 1 included 327 participants from the CSHA. These participants were diagnosed as normal or cognitively impaired not demented at baseline. 25-hydroxyvitamin D3 (25(OH)D3) was measured at baseline. Serum 25(OH)D3 was measured by an automated Elecsys vitamin D3 method. Cognition was measured using the Mini-Mental State Examination (MMSE). We used multiple linear regression to examine whether participants’ MMSE scores differed in groups with 25(OH)D3 concentration above or below 75 nmol/L at baseline, adjusting for age, education, and sex. Study 2 was a nested case-control study of CSHA participants, wherein we compared persons diagnosed with AD (n 1⁄4 60) and timematched controls (n 1⁄4 120). We conducted Study 2 to examine the association between 25(OH)D3 concentrations and AD. Baseline 25(OH)D3 concentrations in Study 2 were categorized by quartiles and entered into a conditional logistic regression model adjusted for baseline MMSE, education, and sex.Results:MeanMMSE scores after 5 or 10 years of followup did not differ according to baseline concentration of 25(OH)D3 before or after adjustment for age, education and sex (p> 0.05). Baseline 25(OH) D3 concentrations were also not associated with the odds of developing AD before or after adjustment for baseline MMSE, education, and sex (p> 0.05).Conclusions:Our findings do not suggest associations between lower 25(OH)D3 concentrations and lower cognition in nondemented CSHA participants, nor did we find an association between baseline 25(OH)D3 and AD.