Dietary Total Antioxidant Capacity and Late-Life Cognitive Impairment: The Singapore Chinese Health Study.

BACKGROUND

With the dramatically rapid rate of aging worldwide, the maintenance of cognitive function in old age is a major public health priority. The association between total antioxidant capacity (TAC) of midlife diet and cognitive function in late life is still unclear.

METHOD

The study included 16 703 participants from a prospective cohort study in Singapore. Dietary intakes and selected supplementary use were assessed with a validated 165-item food frequency questionnaire at baseline (1993-1998). Two dietary TACs were calculated from the intake of antioxidant nutrients: the Comprehensive Dietary Antioxidant Index (CDAI) and the Vitamin C Equivalent Antioxidant Capacity (VCEAC). Cognitive function was assessed 20.2 years later using a Singapore-modified version of the Mini-Mental State Examination when subjects were 61-96 years old. Cognitive impairment was defined using education-specific cutoffs. Multivariable logistic regression models were utilized to estimate the associations between dietary TACs, component nutrients, and cognitive impairment.

RESULTS

A total of 2 392 participants (14.3%) were defined to have cognitive impairment. Both CDAI and VCEAC scores were inversely associated with odds of cognitive impairment in a dose-dependent manner. The odds ratio (95% confidence interval; p-trend) comparing the highest with the lowest quartile was 0.84 (0.73, 0.96; p-trend = .003) for the CDAI and 0.75 (0.66, 0.86; p-trend < .001) for the VCEAC. Higher intakes of vitamin C, vitamin E, carotenoids, and flavonoids were all inversely associated with cognitive impairment.

CONCLUSIONS

Higher dietary TAC was associated with lower odds of cognitive impairment in later life in a Chinese population in Singapore.