Impact of Genetic Testing and Family Health History Based Risk Counseling on Behavior Change and Cognitive Precursors for Type 2 Diabetes.

Family health history (FHH) in the context of risk assessment has been shown to positively impact risk perception and behavior change. The added value of genetic risk testing is less certain. The aim of this study was to determine the impact of Type 2 Diabetes (T2D) FHH and genetic risk counseling on behavior and its cognitive precursors. Subjects were non-diabetic patients randomized to counseling that included FHH +/- T2D genetic testing. Measurements included weight, BMI, fasting glucose at baseline and 12 months and behavioral and cognitive precursor (T2D risk perception and control over disease development) surveys at baseline, 3, and 12 months. 391 subjects enrolled of which 312 completed the study. Behavioral and clinical outcomes did not differ across FHH or genetic risk but cognitive precursors did. Higher FHH risk was associated with a stronger perceived T2D risk (pKendall < 0.001) and with a perception of "serious" risk (pKendall < 0.001). Genetic risk did not influence risk perception, but was correlated with an increase in perception of "serious" risk for moderate (pKendall = 0.04) and average FHH risk subjects (pKendall = 0.01), though not for the high FHH risk group. Perceived control over T2D risk was high and not affected by FHH or genetic risk. FHH appears to have a strong impact on cognitive precursors of behavior change, suggesting it could be leveraged to enhance risk counseling, particularly when lifestyle change is desirable. Genetic risk was able to alter perceptions about the seriousness of T2D risk in those with moderate and average FHH risk, suggesting that FHH could be used to selectively identify individuals who may benefit from genetic risk testing.

Primary care physician decision making regarding severe obesity treatment and bariatric surgery: a qualitative study.

BACKGROUND: Less than 1% of severely obese US adults undergo bariatric surgery annually. It is critical to understand the factors that contribute to its utilization. OBJECTIVES: To understand how primary care physicians (PCPs) make decisions regarding severe obesity treatment and bariatric surgery referral. SETTING: Focus groups with PCPs practicing in small, medium, and large cities in Wisconsin. METHODS: PCPs were asked to discuss prioritization of treatment for a severely obese patient with multiple co-morbidities and considerations regarding bariatric surgery referral. Focus group sessions were analyzed by using a directed approach to content analysis. A taxonomy of consensus codes was developed. Code summaries were created and representative quotes identified. RESULTS: Sixteen PCPs participated in 3 focus groups. Four treatment prioritization approaches were identified: (1) treat the disease that is easiest to address; (2) treat the disease that is perceived as the most dangerous; (3) let the patient set the agenda; and (4) address obesity first because it is the common denominator underlying other co-morbid conditions. Only the latter approach placed emphasis on obesity treatment. Five factors made PCPs hesitate to refer patients for bariatric surgery: (1) wanting to "do no harm"; (2) questioning the long-term effectiveness of bariatric surgery; (3) limited knowledge about bariatric surgery; (4) not wanting to recommend bariatric surgery too early; and (5) not knowing if insurance would cover bariatric surgery. CONCLUSION: Decision making by PCPs for severely obese patients seems to underprioritize obesity treatment and overestimate bariatric surgery risks. This could be addressed with PCP education and improvements in communication between PCPs and bariatric surgeons.

Food Swamps, Obesity & Health Zoning Restrictions on Fast Food Restaurants

Protecting public health is the most legitimate use of zoning, and yet there is minimal progress in applying it to the obesity problem. Zoning could potentially be used to address both unhealthy and healthy food retailers, but lack of evidence regarding the impact of zoning and public opinion on zoning changes are barriers to implementing zoning restrictions on fast food on a larger scale. My dissertation addresses these gaps in our understanding of health zoning as a policy option for altering built, food environments.

Chapter 1 examines the relationship between food swamps and obesity and whether spatial mapping might be useful in identifying priority geographic areas for zoning interventions. I employ an instrumental variables (IV) strategy to correct for the endogeneity problems associated with food environments, namely that individuals may self-select into certain neighborhoods and may consider food availability in their decision process. I utilize highway exits as a source of exogenous variation .Using secondary data from the USDA Food Environment Atlas, ordinary least squares (OLS) and IV regression models were employed to analyze cross-sectional associations between local food environments and the prevalence of obesity. I find even after controlling for food desert effects, food swamps have a positive, statistically significant effect on adult obesity rates.

Chapter 2 applies theories of message framing and prospect theory to the emerging discussion around health zoning policies targeting food environments and to explore public opinion toward a list of potential zoning restrictions on fast-food restaurants (beyond moratoriums on new establishments). In order to explore causality, I employ an online survey experiment manipulating exposure to vignettes with different message frames about health zoning restrictions with two national samples of adult Americans age 18 and over (N1=2,768 and N2=3,236). The second sample oversamples Black Americans (N=1,000) and individuals with high school as their highest level of education. Respondents were randomly assigned to one of six conditions where they were primed with different message frames about the benefits of zoning restrictions on fast food retailers. Participants were then asked to indicate their support for six zoning policies on a Likert scale. Subjects also answered questions about their food store access, eating behaviors, health status and perceptions of food stores by type.

I find that a message frame about Nutrition and increasing Equity in the food system was particularly effective at increasing support for health zoning policies targeting fast food outlets across policy categories (Conditional, Youth-related, Performance and Incentive) and across racial groups. This finding is consistent with an influential environmental justice scholar’s description of “injustice frames” as effective in mobilizing supporters around environmental issues (Taylor 2000). I extend this rationale to food environment obesity prevention efforts and identify Nutrition combined with Equity frames as an arguably universal campaign strategy for bolstering public support of zoning restrictions on fast food retailers.

Bridging my findings from both Chapters 1 and 2, using food swamps as a spatial metaphor may work to identify priority areas for policy intervention, but only if there is an equitable distribution of resources and mobilization efforts to improve consumer food environments. If the structural forces which ration access to land-use planning persist (arguably including the media as gatekeepers to information and producers of message frames) disparities in obesity are likely to widen.

Obesity and Overweight among Black American Adolescent Females: The Role of Social Influences in Everyday Dietary Practices

Obesity and overweight disproportionately impact Black American adolescent females—placing them at a lifetime of elevated physical health risks. Despite this burden, the literature that explores the contributors to obesity and overweight among Black American adolescent females remains limited and unclear. This dissertation aims to develop knowledge related to obesity and overweight in Black American adolescent females, by appraising the current understanding of factors that contribute to their obesity and overweight, and explicating the everyday social influences on dietary practices. The primary study conducted for this dissertation used a mixed method, multiple case study design to examine the mother, daughter, and other household contributors to Black American adolescent daughters’ everyday practices of food consumption, acquisition, preparation, and planning. Findings reveal the importance of understanding the complex and dynamic ways mothers and other household members contribute to a holistic view of everyday dietary practices among adolescent daughters. By deeply examining the nuanced ways the multiple cases varied, context-dependent knowledge essential to understanding the complicated health challenge of obesity was produced. Subsequently, recommendations are provided for health providers and scholars to more holistically approach and examine obesity—particularly among populations who are disproportionately affected.

Viral Delivery of the Fat-1 Gene to Treat Post-Traumatic Arthritis with Diet-Induced Obesity

Post-traumatic arthritis (PTA) is arthritis that develops following joint injury, including meniscus and ligament tears. Current treatments for PTA range from over-the-counter medication to knee replacement; however, in the presence of obesity, the levels of pro-inflammatory cytokines, such as interleukin-1 (IL-1) and tumor necrosis factor alpha (TNF-α,) are more elevated than in non-obese individuals. The role of fatty acids, obesity, and PTA has been examined, with omega-3 fatty acids showing promise as an anti-inflammatory after injury due to its ability to suppress IL-1 and TNF-α. Due to the difficulty in switching patients’ diets, an alternative solution to increasing omega-3 levels needs to be developed. The Fat-1 enzyme, an omega-3 desaturase that has the ability to convert omega-6 to omega-3 fatty acids, may be a good target for increasing the omega-3 levels in the body.

In the first study, we examined whether Fat-1 transgenic mice on a high-fat diet would exhibit lower levels of PTA degeneration following the destabilization of the medial meniscus (DMM). Both male and female Fat-1 and wild-type (WT) littermates were put on either a control diet (10% fat) or an omega-6 rich high-fat diet (60% fat) and underwent DMM surgery. Arthritic changes were examined 12 weeks post-surgery. Fat-1 mice on both the control and high-fat diet showed protection from PTA-related degeneration, while WT mice showed severe arthritic changes. These findings suggest that the omega-6/omega-3 ratio plays an important role in reducing PTA following injury, and demonstrates the potential therapeutic benefit of the Fat-1 enzyme in preventing PTA in both normal and obese patients following acute injury.

Following this, we needed to establish a translatable delivery mechanism for getting the Fat-1 enzyme, which is not present in mammalian cells, into patients. In the second study, we examined whether anti-inflammatory gene delivery of the Fat-1 enzyme would prevent PTA following DMM surgery. In vitro testing of both lentivirus (LV) and adeno-associated virus (AAV) was completed to confirm functionality and conformation of the Fat-1 enzyme after transduction. Male WT mice were placed on an omega-6 rich high-fat diet (60% fat) and underwent DMM surgery; either local or systemic AAV injections of the Fat-1 enzyme or Luciferase, a vector control, were given immediately following surgery. 12 weeks post-surgery, arthritic changes were assessed. The systemic administration of the Fat-1 enzyme showed protection from synovial inflammation and osteophyte formation, while administration of Luciferase did not confer protection. These findings suggest the utility of gene therapy to deliver the Fat-1 enzyme, which has potential as a therapeutic for injured obese patients for the prevention of PTA.