Longitudinal changes in diet quality and food intake before and after diabetes awareness in American adults: the Coronary Artery Risk Development in Young Adults (CARDIA) study

Introduction Limited longitudinal research is available examining how American adults make dietary changes after learning they have diabetes. We examined the associations between diabetes awareness and changes in dietary quality and food intake in a prospective cohort from the Coronary Artery Risk Development in Young Adults (CARDIA) study.Research design and methods A nested case-control design was used. In the original CARDIA study, black and white participants were recruited from four US urban areas and partitioned into one control group (no diabetes over 30-year follow-up) and three case groups (early-onset, intermediate-onset, later-onset diabetes groups) based on timing of diagnosis and first awareness of diabetes. Estimated mean A Priori Diet Quality Score (APDQS), and food subgroup intake were examined at three CARDIA examinations (year (Y)0, Y7, and Y20). The mean APDQS with 95% CIs and food intake (servings/day) were compared across the one control group and three case groups using exam-specific and repeated measures linear regression.Results Among 4576 participants (mean age: 25 +/- 4 years; 55% female; 49% black race), 653 incident cases (14.3%) of diabetes were observed over 30 years. APDQS was lowest at Y0 when the diabetes-free participants were aged 18-30 years (61.5-62.8), but increased over 20 years with advancing age across all groups (64.6-73.3). Lower APDQS in young adulthood was associated with a higher incidence of diabetes later in life. Diabetes awareness was associated with a net increase of 2.95 points in APDQS. The greatest increase of APDQS was when people learned of their diabetes for the first time (an increase of 5.71 in early-onset and 6.64 in intermediate-onset diabetes groups, respectively).Conclusions Advancing age and diabetes awareness were associated with more favorable dietary changes leading to improved diet quality. Optimal diet quality and healthy food intake in young adulthood seem important to prevent diabetes later in life.