Association between diet quality and metabolic syndrome in African American children and adolescents

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Johns Hopkins University
Diet quality refers to dietary patterns that emphasize higher intake of healthy food components (such as fruits, vegetables, whole grains, polyunsaturated fatty acids) and encourage reduced intake of unhealthy food components (such as sugar-sweetened beverages, red/processed meat and sodium). Over the past 10-years, several distinct diet quality indices have been designed to characterize adherence to dietary recommendations or dietary patterns associated with reduced risk of chronic disease including cardiovascular disease. Using data from epidemiological and clinical studies as well as synthesizing evidence from a systematic review, this dissertation investigated the association between diet quality and metabolic syndrome in children and adolescents. This association was first investigated using a systematic review and meta-analysis to identify commonly utilized diet quality indices in youth populations. The search retrieved 1,801 articles, of which 19 articles met the eligibility criteria. Of these, 9 studies were included in quantitative analyses. Commonly utilized diet quality indices included were iterations of the Healthy Eating Index, followed by indices capturing the Mediterranean diet with less common indices including the Dietary Approaches to Stop Hypertension diet pattern score, study specific diet scores, the Dietary Inflammatory Index, among others. Evidence from an RCT and longitudinal analyses from one cohort survey showed that higher quality diet scores were associated with lower odds of metabolic syndrome in children and adolescents. The findings from cross-sectional studies suggested lower odds of metabolic syndrome with higher quality diets, however the strength of the evidence was less consistent. Using population-based data of African American adolescents from the National Health and Nutrition Examination Survey (NHANES) between 2005-2016, two diet quality indices were associated with prevalence of cardiometabolic measures and metabolic syndrome. Using survey-weighted logistic regression models, greater adherence to the Dietary Approaches to Stop Hypertension (DASH) Pattern Score was associated with lower prevalence of hypertensive blood pressure and greater adherence to the Alternative Healthy Eating Index (AHEI-2010) was associated with lower prevalence of metabolic syndrome. Thirdly, using clinical data from participants in the Reversing the Negative cardiovascular Effects on Weight (ReNEW) Clinic Cohort Study diet quality was associated with cardiometabolic measures. The ReNEW Clinic cohort study is prospective, longitudinal observational study of children referred to a multidisciplinary pediatric obesity clinic for evaluation and treatment of elevated blood pressure. Using linear regression models, participants with higher quality/lower inflammatory diets as measured by the AHEI-2010 and the Children’s Dietary Inflammatory Index (C-DII) trended towards more favorable cardiometabolic measures at baseline, but associations were non-significant. The findings from the existing scientific evidence, epidemiological and clinical studies illustrate that how diet quality is operationalized can affect the ability to detect an association between diet quality scores and metabolic syndrome. Findings from this dissertation add to the literature that diet quality, independent of changes in calorie or weight status, may be considered for prevention of metabolic syndrome in adolescents, reducing risk of developing chronic diseases in adulthood.
Diet Quality, African Americans, Children, Adolescents