UCLA

Although much has been documented about the foodborne pathogens Salmonella and Toxoplasma gondii and their respective mechanisms for causing acute disease, less is known about the burden these infections may place on certain populations and how chronic diseases contribute to these pathogens' impact on morbidity and mortality - i.e., how co-occurring chronic conditions or their treatments, such as steroid use, might mediate or accelerate disease severity and the pathways that can lead to premature death. One hypothesized mechanism in this continuum between infectious and chronic disease is the alteration or weakening of the immune response by such conditions (or their treatment) as HIV, diabetes, malignancies, and a range of autoimmune disorders.

A series of research studies were conducted to examine the burden of toxoplasmosis and salmonellosis outcomes in the United States and how co-occurring chronic conditions or their treatments might influence disease severity (Chapters 1 and 2). In addition, an evaluation of an intervention that made improvements to the nutrient content of school meals to reduce chronic disease risk (obesity) among children in grades K-12 (Chapter 3) was performed to describe the emerging impact of food quality interventions in the school cafeteria setting. The latter population is considered particularly vulnerable to foodborne infections and developing obesity - an independent risk factor for many chronic diseases in adulthood, including diabetes and some forms of cancer. Chapter 1 presents an analysis of the U.S. Multiple Cause-of-Death dataset, which showed a decline in the number of toxoplasmosis deaths with an HIV co-diagnosis during 2000-2010. However, in toxoplasmosis deaths without such a co-diagnosis, a decline was not observed. Chapter 2 presents a study using the U.S. Nationwide Inpatient Sample, which showed an increase in salmonellosis hospitalizations as well as costs. Positive associations were

demonstrated between increased number of chronic conditions and four key hospitalization outcomes - in-hospital death, total charges, length of stay, and disease severity. Chapter 3 presents a series of studies, which enumerated reductions in key nutrients such as calories, sugar, and sodium content in school meals after 5 school districts in the U.S. implemented healthy food procurement interventions in their cafeterias.

Collectively, findings from this dissertation expand the current understanding of how foodborne illness outcomes can be affected by co-occurring chronic diseases, as well as demonstrates the substantial reach of nutrition interventions in the U.S. National School Breakfast and Lunch programs. These findings have important implications for national as well as local food policies and nutrition program planning.