Diet quality and depressive symptoms in a cohort of American Indians: The Strong Heart Family Study

Background: Higher diet quality has been shown to be associated with a lower risk of depression compared to lower diet quality, though this relationship has not been studied in American Indians (AIs). We examined the relationship of diet quality with incidence of depressive symptoms in a prospective, family-based cohort of 1,100 AIs ≥14 years of age from 12 AI communities in Arizona, Oklahoma, North Dakota, and South Dakota. Methods: Information on past year diet was collected using food frequency questionnaires at baseline. Diet quality was determined using the Alternative Healthy Eating Index-2010 (AHEI). Depressive symptoms were measured at follow-up 5 years later, on average, using the Center for Epidemiologic Studies Depression Scale; scores were categorized as no depressive symptoms (scores <10), mild symptoms (scores 10-15), moderate symptoms (scores 16-24), and severe symptoms (scores >24). The primary outcome was report of moderate/severe depressive symptoms or taking antidepressants. We used GEE-based multivariate logistic regression to estimate odds ratios (OR) of depression onset associated with each 10-point increase in AHEI score, adjusted for relevant demographics, health status and psychosocial factors. Results: We did not find evidence of a prospective relationship between diet quality and onset of depressive symptoms; a 10-point increase in AHEI score was associated with 16% higher odds of developing depressive symptoms or antidepressant use (OR 1.16, 95% CI 0.96, 1.39). Conclusion: Our results are discordant with findings in other populations. Additional prospective studies that include more robust measures of diet and depression over multiple time points are needed to better understand this relationship.