Polyunsaturated fatty acids and reduced odds of MCI: the Mayo Clinic Study of Aging

Abstract

Mono- and polyunsaturated fatty acids (MUFA, PUFA) have been associated with a reduced risk of dementia. The association of these fatty acids with mild cognitive impairment (MCI) is not fully established. The objective of the study was to investigate the cross-sectional association of dietary fatty acids with MCI in a population-based sample. Participants aged >or= 70 years on October 1, 2004, were evaluated using the Clinical Dementia Rating Scale (participant and informant), a neurological evaluation, and neuropsychological testing. A panel of nurses, physicians, and neuropsychologists reviewed the data for each participant in order to establish a diagnosis of MCI, normal cognition, or dementia by consensus. Participants also completed a 128-item food-frequency questionnaire. Among 1,233 non-demented subjects, 163 (13.2%) had MCI. The odds ratio (OR) of MCI decreased with increasing PUFA and MUFA intake. Compared to the lowest tertile, the OR (95% confidence interval) for the upper tertiles were 0.44 (0.29-0.66; p for trend = 0.0004) for total PUFA; 0.44 (0.30-0.67; p for trend = 0.0004) for omega-6 fatty acids; 0.62 (0.42-0.91; p for trend = 0.012) for omega-3 fatty acids; and 0.56 (0.38-0.83; p for trend = 0.01) for (MUFA+PUFA):saturated fatty acid ratio after adjustment for age, sex, number of years of education, and caloric intake. In this study, higher intake of PUFA and MUFA was associated with a reduced likelihood of MCI among elderly persons in the population-based setting.

Fig

Flow-chart of subjects included in the analyses. Subjects who were not eligible to receive the food frequency questionnaire included 45 subjects who died (n = 22) after the baseline assessment, refused further participation (n = 22), or were non-English speaking (n = 1) and could not complete the questionnaire. Subjects who were excluded had missing responses on more than 10 of the 128 ‘How often’ questions on frequency of consumption of foods (n = 268), reported extreme caloric intake (low intake = < 800 [in men] or < 600 [in women] kcal/day; high intake = > 6,000 [in men] or > 5,000 [in women] kcal/day) or were demented at the time of the evaluation (n = 10).