Informing Dietary Interventions for Obesity-Related Cancer Prevention in Mexican-Origin Hispanic Adults

Abstract

BACKGROUND: Obesity rates in the Hispanic population are the highest in the United States (US), with 47% of adults experiencing overweight or obesity. The prevalence of obesity is more concerning among Mexican-origin (MO) individuals with men experiencing the highest and women the second highest obesity prevalence in the country. Obesity is a major driver of cancer risk in this population and in fact, cancer remains a leading cause of death among Hispanics with 22% of all deaths attributed to this disease. Emerging research, however, shows that cancer patterns among Hispanics are more complex than previously thought with US-born Hispanics experiencing higher cancer risk and worse survival than foreign born. For example, research shows that in a Texas sample of Hispanic men, US-born individuals experienced 60% higher cancer deaths compared to their foreign-born counterparts. Similarly, a study comparing risk factors for liver cancer, one of the thirteen obesity-related cancers, showed that US-born individuals had higher odds for metabolic syndrome, type 2 diabetes, and obesity compared to foreign-born individuals. To date, however, the aggregation of Hispanics into one monolithic group has hindered the ability to identify important exposures exacerbating cancer rates. One such exposure includes differences in diet. Dietary acculturation may be a driving factor explaining differences in cancer patterns between US and foreign-born MO Hispanics. Importantly, these exposures warrant further, more in-depth investigation to inform future dietary interventions aimed at reducing the obesity-related cancer burden in the MO Hispanic population. OBJECTIVE: The objectives of this dissertation include 1) to investigate the influence of birthplace on metabolomic profiles of Hispanic men in order to generate hypotheses that could shed light in the observed differences of obesity-related cancer risk by nativity status, 2) to examine the relationship between adherence to a traditional Mexican diet pattern, as measured by the traditional Mexican diet score (TMexS), and hepatic steatosis and fibrosis, and 3) to conduct qualitative research among survivors of breast cancer and their caregivers to evaluate knowledge, attitudes and beliefs towards healthy diet behaviors and explore intervention delivery modalities of a future program for primary and secondary obesity-related cancer prevention. METHODS: Using a metabolomics approach, a secondary analysis of Hispanic men that participated in a weight loss intervention was conducted for Aim 1. Participants were grouped into foreign and US-born based upon their reported generation status. Then, metabolomic profile comparisons were conducted across groups at baseline and after receiving the intervention. For Aim 2, a secondary analysis of a cross-sectional observational study of MO Hispanic men and women was conducted. Using the 24-hour diet recall data, TMexS were calculated and their relationship to hepatic steatosis and fibrosis from transient elastography (Fibroscan®) was examined. Lastly, for Aim 3, qualitative interviews were conducted with MO Hispanic survivors of breast cancer and their caregivers to identify targets and delivery considerations for a future diet intervention. RESULTS: Results from Aim 1 indicate that metabolomic profile differences exist among foreign and US-born Hispanic men. The majority of the observed differences were regarding dietary metabolites which appear to reflect differences in consumption of more traditional Mexican foods (e.g., onions, garlic, fruits, vegetables, herbs, and spices). Results of Aim 2 showed that higher adherence to a traditional Mexican diet, as measured by the TMexS, was associated with lower hepatic steatosis among the US-born and among those who were not carriers of a risk allele identified to exacerbate liver disease. Lastly, among the themes identified in the interviews conducted as part of Aim 3, survivors and their caregivers reported a perceived notion of Mexican food being unhealthy and hindering their ability to adopt healthier habits given is part of their culture. CONCLUSION: Findings from this dissertation should be taken into consideration to inform future dietary interventions aimed at reducing primary and secondary obesity-related cancer among MO Hispanic adults, particularly, for those born in the US.