Dissertation Defense: Qianhui Jin

"Assessing Diverse Periconceptional Dietary Approaches and Their Impact on Postpartum Cardiometabolic Risk: Toward Flexible Dietary Guidelines", School of Public Health Department of Epidemiology. Committee: Lisa M. Bodnar (committee chair), EPIMalamo E. Countouris, Department of MedicineSamaneh Farsijani, EPIMarian Jarlenski, HPMAbstract: Cardiometabolic conditions are increasingly common among reproductive-aged women in the US. Diet during the periconceptional period may be an important modifiable factor for prevention, yet its relation to postpartum cardiometabolic risk remains largely unknown. This dissertation examined three dimensions of periconceptional diet, plant-based dietary patterns, dietary diversity, and synergy between fruit and vegetable intake, in relation to postpartum cardiometabolic outcomes. We analyzed data from the Nulliparous Pregnancy Outcomes Study: monitoring mothers-to-be Heart Health Study, a pregnancy cohort followed to a mean of 3 years postpartum. Usual dietary intake in the 3 months around conception was estimated from a food frequency questionnaire. Using doubly robust estimators with ensemble machine learning algorithms, we quantified associations between each dimension of periconceptional diet and postpartum metabolic syndrome and hypertension while adjusting for sociodemographic, medical, behavioral, and neighborhood confounders. First compared with a periconceptional dietary pattern characterized as “Animal foods, high refined grains and added sugars”, dietary patterns characterized as “Mediterranean-based” and “Plant forward, high grains” were associated with 2 to 3 fewer cases of metabolic syndrome at a mean of 3 years postpartum. Second, greater periconceptional dietary diversity, measured as the number of distinct food and beverage items consumed that are encouraged for nutritional adequacy in the Dietary Guidelines for Americans, was associated with lower metabolic syndrome risk. The adjusted risk of decreased from 1