Assessing the longitudinal relationship between whole egg consumption and cognition in Chinese older adults

Background Given China's fast-growing aging population, cognitive decline is a leading public health concern. Eggs are an affordable food rich in several shortfall nutrients that may benefit cognitive health. Aim This study assessed the longitudinal relationship between whole egg consumption and cognition among older adults in China. Methods Individual-level data of 4737 Chinese adults 55+ years came from the China Health and Nutrition Survey (CHNS) 1997-2006 waves. Daily egg consumption was measured using 3-day 24-h dietary recalls. Cognitive functioning was assessed with immediate and delayed recall of a 10-word list, counting backward from 20, and serial 7 subtraction. Multivariate mixed-effects regressions were performed to estimate the longitudinal associations between daily whole egg consumption and cognitive functioning in older Chinese adults. Results Approximately 46% of CHNS participants were whole egg consumers, and their daily intake averaged 47.4 g. The overall cognitive functioning test scores, separate scores for cognitive functioning subdomains, and the prevalence of cognitive impairment at the baseline were modestly higher among whole egg consumers than nonconsumers. However, after adjusting for individual characteristics, multivariate mixed-effects regressions did not find daily whole egg consumption to be associated with cognitive functioning among CHNS participants. By contrast, several demographic and socioeconomic factors, such as age, education attainment, and health insurance coverage, were found to correlate with older Chinese adults' cognition. Conclusion This study has measurement and design limitations. Future research should investigate the causal impact of habitual egg intake on different domains of cognition using experimental designs with an extended follow-up period.