Association of Dietary Quality with Cognitive Function in Chinese Adults Aged 55 Years and Above: A Longitudinal Study

Diet is an important modifiable factor for brain health and aging. Present study aimed to explore association of dietary quality with cognitive function and poor cognition in middle-aged and older adults participating in the China Health and Nutrition Survey (CHNS). A longitudinal study with a twenty-year follow-up. Data were drawn from the CHNS 1997, 2000, 2004, 2006, 2015 and 2018. Subjects aged 55 years and more who participated in at least two waves and had completed data on socio-demographics, lifestyle, disease history, anthropometrics, dietary measure and cognitive assessment were eligible in present study. Baseline diet were assessed by 3-day 24-hour dietary recalls and used to evaluate diet quality via China Elderly Dietary Guidelines Index 2022 (CDGI 2022-E). Cognitive function was examined using part items of the Telephone Interview for Cognitive Status-modified. Three-level linear mixed effects models and three-level mixed effects logistic regression models were performed to estimate the association between diet quality and cognitive function and odds of poor cognition, respectively. At baseline, 4173 subjects with median age of 63.7 years were recruited. Median of CDGI 2022-E total score was 44.7. Median score of global cognition was 16.0, and the proportion of people with poor cognitive function was 13.9%. Difference in global cognitive score was observed by tertiles of CDGI 2022-E (p<0.05). Significant associations of high diet quality with increment in global cognitive score [β (95%CI): 0.704 (0.394∼1.015)], composite cognitive z score [0.086 (0.045∼0.128)] and standardized verbal memory score [0.221 (0.122∼0.320)] were observed in total subjects. Consistent associations were also found in those below 65 years at baseline. The likelihood of poor cognition in the highest tertile of CDGI 2022-E decreased by 18% (95%CI: 0.698∼0.965) relative to the lowest tertile group in total population. High diet quality may be beneficial for improving cognitive function and delaying cognitive decline in Chinese middle-aged and older population.