Western Diet as an Independent Predictor of Asthma Prevalence and Morbidity

Johns Hopkins University, Baltimore MD

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Abstract

DESCRIPTION (provided by applicant): Asthma is a common respiratory disease of increasing prevalence in the Unites States. Morbidity and mortality rates are extreme, and the prevalence of asthma is disproportionately high in poor, minority populations. Rising asthma prevalence overall has trended in parallel to transition to a Western diet pattern, typified by higher intakes of processes foods (e.g. meats and refined grains), n6-polyunsaturated fatty acids (PUFAs), high fat dairy products, and sugary desserts and drinks. Most diet and asthma research to date has focused on individual vitamins, minerals, and fatty acids. Results vary, and supplement trials have demonstrated mixed or negative results. Given the complex nature of human diet with interaction between components, there is increased interest in the concept that nutrients in asthmatics may act synergistically in foods and diet patterns, rather than in isolatio. Emerging evidence suggests that a diet high in fruit, vegetable, whole grain, n3-PUFAs, and antioxidant intake may be a respiratory healthy diet but confirmatory studies are needed. A countering question is whether there exists an unfavorable diet that worsens asthma. Proposed hypothesis: A Western dietary pattern, as defined above, will be significantly and independently associated with increased asthma morbidity in US adults. Independent links between asthma and a Western dietary pattern will be evaluated in two distinct cohorts: (1) the Atherosclerosis Risk in Communities (ARIC) a large cohort with participants from four communities across the US, and (2) a primarily poor, African-American, inner city Baltimore City cohort prospectively evaluated as part of the INHALE Study, a cohort of adult asthmatics undergoing comprehensive environmental and demographic characterization. Two novel aims are proposed. (1) To investigate the association between Western dietary pattern and asthma prevalence and morbidity in a large, prospective, US epidemiologic cohort study. A collaborative effort with ARIC investigators who have previously defined Western and prudent dietary patterns in the cohort will be employed to determine effects of Western diet pattern on asthma prevalence, symptoms, medications use, and hospitalizations in ARIC; questions otherwise unaddressed in this cohort. (2) To investigate the association between Western dietary pattern and asthma morbidity among a cohort of 70 urban, primarily African-American asthmatic adults in the INHALE Study. A Baltimore-specific quantitative food frequency questionnaire, 24-hour dietary recalls, and detailed anthropometric measures (to isolate the effects of diet from those of obesity), will be added to the parent protocol. Individual dietary pattern will be linked to asthma symptoms, hospitalizations, and medication use while controlling for potential covariates. This two-population approach will allow us to identify significant effects of diet, a potentially modifiable risk factor, on asthma prevalence and morbidity in both a large, US cohort and a smaller cohort of high-risk individuals. Study results will inform the need for dietary interventios aimed at improving asthma health outcomes.