Dietary antioxidants and cognitive function in a population-based sample of older persons. The Rotterdam Study

Antioxidants have been implicated in processes related to atherosclerosis, aging, and selective neuronal damage, all of which may ultimately affect cognitive function. In a sample of older persons, the authors examined the cross-sectional relation between cognitive function and dietary intake of beta-carotene and vitamins C and E. The data were derived from 5,182 community participants aged 55-95 years in the population-based Rotterdam Study in the period 1990 to 1993. Dietary intake was estimated from a semi-quantitative food frequency questionnaire and categorized into five levels of intake. Cognitive function was measured with the 30-point Mini-Mental State Examination (MMSE) and characterized as unimpaired (> 25 points) or impaired (< or = 25 points). Logistic regression analysis was used to estimate the odds ratio (OR) and 95% confidence interval (CI) for cognitive impairment. After adjustment for age, education, sex, smoking, total caloric intake, and intake of other antioxidants, a lower intake of beta-carotene was associated with impaired cognitive function (< 0.9 mg vs. > or = 2.1 mg intake, OR = 1.9, 95% CI 1.2-3.1; p for trend < 0.04). There was no association between cognitive function and intake of vitamins C and E. These cross-sectional observations are compatible with the view that beta-carotene-rich foods may protect against cognitive impairment in older people. The finding could also reflect unmeasured confounding, measurement error, or a change in food habits that resulted from rather than preceded the onset of cognitive impairment.