Associations between Diet Quality and Global Cognitive Ability across the Life Course: Longitudinal Analysis of the 1946 British Birth Cohort.

Background: Diet is a risk factor for later-life cognitive decline and dementia. The long-term relationship between diet quality and cognitive function is unknown. Objectives: This study investigated trends in diet quality and cognitive ability and their interrelationship across the life course. Methods: Using data from the 1946 British Birth Cohort ( Results: Three diet quality trajectories and 4 cognitive ability trajectories were identified. Sex, birth region, childhood social class, and leisure activities predicted trajectory group membership. In a joint trajectory model, the lowest cognitive ability group included mostly participants with lower (58%) or moderate (35%) diet quality. Conversely, the highest cognitive ability group included mostly participants with moderate (57%) and higher (36%) diet quality. The percentage of participants showing indications of likely dementia at age 68 to 69 y was 3.8% to 7.4% greater in the lower diet quality group compared with the moderate and higher groups, respectively. Conclusions: Findings indicate a link between diet quality and cognitive ability across the life course and a higher chance of likely dementia in individuals with lower diet quality from childhood to later adulthood. Consistent dietary alignment with dietary guidelines over time may positively impact cognitive outcomes throughout life, but more longitudinal studies are needed to confirm these findings.