Objective: The association between dietary copper (Cu) intake and cognitive decline remains uncertain. We aim to investigate the longitudinal association of dietary Cu with cognitive decline in Chinese elderly.
Methods: A total of 3,106 Chinese adults aged older than or equal to 55 years from China Health and Nutrition Survey (CHNS) were included. Dietary nutrients information was collected by 24-hours dietary recalls in combination with a food-weighted method. The 5-year change rates in global or composite cognitive scores based on a subset of items from the Telephone Interview for Cognitive Status-modified (TICS-m) was calculated as the last-survey score minus the baseline score, then divided by the follow-up time (unit, years) and multiplied by five.
Results: The median follow-up duration was 5.9 years. There was a nonlinear association of dietary Cu intake with the 5-year change rates in global or composite cognitive scores, with the inflection point at approximately 1.3 mg/day of dietary Cu intake. Accordingly, for the composite cognitive score, compared to the first quantile (<1.28 mg/day), those with dietary Cu in quantiles 2-8 (≥1.28 mg/day) had a significantly slower cognitive decline rate (B, 0.30; 95% CI, 0.13, 0.47). Similar results were found for the global cognitive score. Moreover, the inverse association between dietary Cu and cognitive decline was stronger in those with lower dietary fat intake and lower levels of physical activity (All p-interactions <0.05).
Conclusion: There was a nonlinear inverse association of dietary Cu intake with cognitive decline in the elderly, with an inflection point at approximately 1.3 mg/day of dietary Cu intake.
Keywords: Chinese elderly; Cognitive decline; dietary copper intake; dietary fat intake; physical activity.
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