Diet quality trajectories from infancy to age 18 and their association with diet quality at age 26

Abstract Background and objectives Dietary habits during childhood and adolescence show strong stability. However, no studies have investigated dietary trajectories from infancy to adulthood. We therefore aimed to 1) identify diet quality trajectories from age 1 to 18 years and 2) explore how trajectories are associated with diet quality at age 26 years. Methods The study included 620 individuals from the Special Turku Coronary Risk Factor Intervention Project (STRIP), started in infancy (n = 1062). Food and nutrient intake was assessed annually from age one to age 18, and again at age 26 using 4-day food records. A food-based diet score (range 0-33) was calculated to indicate diet quality. Group-based modelling was used to model trajectories of diet quality between the ages of 1 and 18 years. Linear regression analyses were used to investigate associations between the diet quality trajectory groups and diet quality at age 26 years. Results By the age of 18, we found five diet quality groups: 1) low (19% of participants) with a mean diet score of 12 points, 2) decreasing (25%) with a mean diet score of 15 points, 3) increasing (15%) with a mean diet score of 16 points, 4) intermediate (31%) with a mean diet score of 18 points, and 5) high (10%) with a mean diet score of 22 points. The diet quality trajectory groups were associated with 0.4 (decreasing), 2.5 (medium), 3.8 (increasing) and 4.1 (high) points higher diet scores at age 26 compared to the low diet quality trajectory group (p < 0.001 for all). Discussion Five distinct dietary trajectories were found from infancy to late adolescence, with a clear difference between the groups with the lowest and highest diet quality. However, the differences in diet quality levelled out by the age of 26 years. Our results suggest that diet quality established already in childhood moderately predicts diet quality into adulthood. Key messages • Diet quality established in childhood moderately predicts diet quality in young adulthood. • Five distinct dietary trajectories were found from infancy to late adolescence, with a clear difference between the groups with the lowest and highest diet quality.