Fish consumption and cognitive decline with age in a large community study.

BACKGROUND

Dietary intake of fish and the omega-3 fatty acids have been associated with lower risk of Alzheimer disease and stroke.

OBJECTIVE

To examine whether intakes of fish and the omega-3 fatty acids protect against age-related cognitive decline.

DESIGN

Prospective cohort study.

SETTING

Geographically defined Chicago, Ill, community.

PARTICIPANTS

Residents, 65 years and older, who participated in the Chicago Health and Aging Project.

MAIN OUTCOME MEASURE

Change in a global cognitive score estimated from mixed models. The global score was computed by summing scores of 4 standardized tests. In-home cognitive assessments were performed 3 times over 6 years of follow-up.

RESULTS

Cognitive scores declined on average at a rate of 0.04 standardized units per year (SU/y). Fish intake was associated with a slower rate of cognitive decline in mixed models adjusted for age, sex, race, education, cognitive activity, physical activity, alcohol consumption, and total energy intake. Compared with a decline rate in score of -0.100 SU/y among persons who consumed fish less than weekly, the rate was 10% slower (-0.090 SU/y) among persons who consumed 1 fish meal per week and 13% slower (-0.088 SU/y) among persons who consumed 2 or more fish meals per week. The fish association was not accounted for by cardiovascular-related conditions or fruit and vegetable consumption but was modified after adjustment for intakes of saturated, polyunsaturated, and trans fats. There was little evidence that the omega-3 polyunsaturated fatty acids were associated with cognitive change.

CONCLUSIONS

Fish consumption may be associated with slower cognitive decline with age. Further study is needed to determine whether fat composition is the relevant dietary constituent.