Pre-clinical studies have discovered the neuroprotective function and the benefit for cognitive function of choline. However, it remains unclear whether these benefits observed in animal studies also work in humans. The aims of this study are to examine the effects of dietary choline intake on cognitive function and cognitive decline during ageing in middle-aged and elderly Chinese. We included 1887 subjects aged 55 similar to 79 years with 6696 observations from the China Health and Nutrition Survey cohort study. The subjects were followed up for 6 to 21 years, with an average of 12.2 years. A dietary survey was conducted over 3 consecutive days with a 24 h recall, using household weight-recording methods. Based on the China Food Composition, data from USDA, and published literature, the dietary choline intake was calculated as the sum of free choline, phosphocholine, phosphatidylcholine, sphingomyelin, and glycerophosphocholine. Cognitive function was assessed using a subset of the Telephone Interview for Cognitive Status-modified (TICS-m) items. In order to eliminate the different weight of scores in each domain, the scores were converted by dividing by the maximum score in each domain, which ranged from 0 to 3 points. Higher cognitive scores represented better cognition. We used two-level mixed effect models to estimate the effects of dietary choline intake on cognitive score and cognitive decline rate in males and females, respectively. The average dietary choline intake was 161.1 mg/d for the baseline. After adjusting for confounders, the dietary choline intake was significantly associated with higher cognitive score in both males and females. The cognitive score in the highest quartile group of dietary choline was 0.085 for males and 0.077 for females-higher than those in the lowest quartile group (p < 0.01 for males, p < 0.05 for females). For every 10-year increase in age, the cognitive score decreased by 0.266 for males and 0.283 for females. The cognitive score decline rate of the third quartile group of dietary choline was 0.125/10 years lower than that of the lowest quartile group in females (p < 0.05). Dietary choline intake not only improves cognitive function, but also postpones cognitive decline during the aging process. The findings of this study highlight the neuroprotective benefit of choline in the middle-aged and elderly Chinese population, especially among females.
