Dietary calcium intake at breakfast is associated with a lower risk of cognitive impairment than at dinner in Chinese adults: the CHNS cohort study.

Background and objectives: If the proportion of calcium intake over a whole day is related to the risk of cognitive impairment in adults is still largely unknown. This research aimed to examine the relation of dietary calcium intake at dinner versus breakfast with the risk of cognitive impairment by using data from the China Health and Nutrition Survey (CHNS).

Methods and study design: A total of 2,099 participants (including 668 cognitive impairment) in the CHNS (1997-2006) were included. The participants were categorized into 5 groups in accordance with the ratio of dietary calcium intake at dinner and breakfast (Δ = dinner/breakfast). After adjustment was conducted for a series of confounding factors, Cox hazard regression modelling was performed to discuss the relation of Δ with cognitive impairment. Dietary substitution models were used to explore the changes in cognitive impairment risk when a 5% dietary calcium intake at dinner was replaced with dietary calcium intake at breakfast.

Results: Participants in the highest distribution of Δ showed a greater susceptibility to cognitive impairment than those in the lowest quintile, with an adjusted hazard ratio of cognitive impairment of 1.38 (95% CI: 1.08-1.76). When maintaining total calcium intake, substituting 5% of dietary calcium intake at dinner with calcium intake at breakfast was related to an 8% decrease in the risk of cognitive impairment.

Conclusions: Higher dietary calcium intake at dinner was associated with an increased risk of cognitive impairment, emphasizing the importance of appropriately distributing dietary calcium intake between breakfast and dinner.