Cognitive function in a middle aged cohort is related to higher quality dietary pattern 5 and 25 years earlier: the CARDIA study.

BACKGROUND: Preserving cognitive function is an important public health issue. We investigated whether dietary pattern associates with cognitive function in middle-age.
METHODS: We studied 2435 participants in the community-based Coronary Artery Risk Development in Young Adults (CARDIA) study of black and white men and women aged 18-30 in 1985-86 (year 0, Y0). We hypothesized that a higher A Priori Diet Quality Score, measured at Y0 and Y20, is associated with better cognitive function measured at Y25. The diet score incorporated 46 food groups (each in servings/day) as the sum of quintile ranks of food groups rated beneficial, 0 for food groups rated neutral, and reversed quintile ranks for food groups rated adverse; higher score indicated better diet quality. Y25 cognitive testing included verbal memory (Rey Auditory-Verbal Learning Test (RAVLT)), psychomotor speed (Digit Symbol Substitution Test (DSST)) and executive function (Stroop).
RESULTS: Per 10-unit higher diet score at Y20, the RAVLT was 0.32 words recalled higher, the DSST was 1.76 digits higher, and the Stroop was 1.00 seconds+errors lower (better performance) after adjusting for race, sex, age, clinic, and energy intake. Further adjustment for physical activity, smoking, education, and body mass index attenuated the association slightly. Diet score at Y0 and increase in diet score over 20 years were also positively associated with each cognitive test.
CONCLUSIONS: A higher quality dietary pattern was associated with better cognitive function 5 years and even 25 years later in apparently healthy middle-aged adults.