Self-rated health is an independent predictor of future health outcomes, including morbidity and mortality. Therefore, in a public health context, for high proportions of populations to report very good or excellent subjective health is in itself an important end point. To achieve this, public health interventions need to be informed by knowledge of the determinants of both illness and wellbeing in different groups. In this study, I used self-rated health as the outcome measure, and studied the characteristics of individuals in a population who rated their health as excellent or very good (classed as `good' self rated health), versus those who rated it as only good, fair, or poor (classed as `poor' self-rated health). A broad range of risk and protective multi-domain determinants of health were included in the analysis as predictor variables. The study data were drawn from the CARDIA study, a United States cohort started in 1985 to investigate the development of coronary artery disease risk factors in a young adult population.

In the first analysis, I utilized classification tree methods to segment the study sample of 3649 individuals, to identify subgroups with some shared characteristics and relatively homogenous self-rated health status. Lifestyle, social and community influences, and living and working conditions were all associated with self-rated health. Combinations of these factors differed by population subgroup. Physical activity rating emerged as the most important variable in the single tree classification, and the model suggested interaction of lifestyle and medical factors with socioeconomic factors, income and education.

In the second analysis, the study sample was first divided into subsets based on total family income. I investigated the characteristics associated with self-rated health within each income subset using classification trees. The findings suggested a social gradient for several health determinants. The proportion of good self-rated health increased with higher income category, and the proportion of poor self-rated health decreased. Within population subgroups stratified by income, the combinations of factors that were associated with self-rated health, and the predictor variable that ranked as most important relative to self-rated health differed. This is suggestive of potentially important differences in the factors that are responsible for self-rated health and health inequalities among different income groups that have dissimilar social, cultural and economic contexts.

The third analysis extended the single classification tree analysis with the application of random forests. This method produced an ensemble of classification trees, which improved accuracy and produced more robust variable importance measures. Despite the inclusion of a wide range of predictor variables representing fixed factors, lifestyle and medical conditions, social and community influences, and living and working conditions, the model selected education and income as the highest-ranking variables associated with self-rated health in the study sample. This highlights the importance of addressing social determinants of health and inequities.

This dissertation contributes to the literature on the determinants of self-rated health, and adds a novel application of classification tree analysis and random forests methods to the study of self-rated health. Capturing the complex interplay of factors affecting health in populations can be difficult with parametric multivariate regression. These models may not capture the full array of variables influencing health. Recursive partitioning methods can serve as an initial tool to suggest population subgroups that might have homogenous risks of an outcome, and identify the relative importance of risk and protective factors in population subgroups for further inquiry. This knowledge is valuable in developing appropriate and targeted public health interventions that focus on specific needs.

The majority of new HIV infections occur among high-risk groups such as men who have sex with men (MSM) and transfemales. Segments of these populations are also more likely to be economically disadvantaged. Economic disadvantage or low socioeconomic status has been linked to disease acquisition, morbidities and mortality. Interventions have been proposed to address these health issues through the reduction of poverty. However, this approach to intervention does not address underlying structural factors such as high HIV prevalence in impoverished neighborhoods and thus in social and sexual networks.

The present analysis examines low individual socioeconomic status and /or social and sexual network factors and their relationship to HIV acquisition risk among three populations at high-risk for HIV infection. Geographic analysis examined residential patterns and neighborhood patterns of HIV prevalence in San Francisco. Data collected in San Francisco from White MSM, Black MSM and transfemales were analyzed using Poisson regression to determine the factors associated with engaging in more episodes of potentially serodiscordant unprotected receptive anal intercourse.

As expected, transfemales and Black MSM were more likely to live in areas of higher HIV prevalence and lower income compared to White MSM. Interestingly the areas of higher HIV prevalence and lower income were also the areas with greater numbers of HIV prevention and care services. Black MSM and transfemales had lower socioeconomic status (SES) scores compared to White MSM. Black MSM were more likely to report serodiscordant partnerships and higher numbers of potentially serodiscordant unprotected sex acts. Decreasing SES and increasing neighborhood HIV/AIDS case density did not predict serodiscordant partnerships in any group. Increasing neighborhood HIV prevalence predicted an increase in the number of potentially serodiscordant unprotected sex acts among transfemales and Black MSM but only significantly so for transfemales.

HIV prevention interventions must also consider neighborhood factors such as neighborhood HIV prevalence in addition to considering individual level behavior change

Latino-Hispanic construction workers in the United States are at significantly higher risks for injuries and fatalities at construction worksites than their White and African-American counterparts. Currently the main mode of dissemination of workplace safety information is through direct translation of work safety material delivered at the worksite. Current research, however, suggests that even when translated into Spanish, many of these materials are not culturally or linguistically effective modes of preventable risk education and persuasion.

One promising method for far-reaching, cost-effective, and culturally relevant education may be found in the Entertainment-Education (EE) health communication strategy. EE leverages popular entertainment media - such as movies, television shows, music, theater and/or radio - by embedding specific health messages within a storyline and using the power of narrative to stimulate positive health choices. Spanish-language soap operas (telenovelas) are an entertainment media format culturally embraced by Latino Spanish-speaking audiences and have been effectively utilized by health educators and public health officials to promote changes in knowledge, attitudes, and behaviors for a variety of health issues.

The Centers for Disease Control/National Institute of Occupational Safety and Health (CDC/NIOSH) worked with two public health partners and the Spanish language TV chain Telemundo to develop and implement an entertainment education intervention that utilized a telenovela embedded with construction worksite safety information. A statistical analysis of audience survey data collected both before and after the airing of the workplace storyline showed improvements in knowledge outcomes but not in changes in perceptions or behavioral intention outcomes. Detailed analyses revealed that survey respondents who reported recognition of the telenovela workplace storyline were more likely to identify key safety messages embedded within the storyline than respondents who did not recognize the storyline.

In addition to the quantitative data, semi-structured key informant interviews were conducted with eight (8) individuals associated with the intervention project. The objective of these interviews was to explore how the partnership between public health institutions and media organizations affected the development, implementation, and evaluation of this project. Project stakeholders voiced challenges which stemmed from the chaotic nature of network television, tensions between developing entertaining vs. accurate educational messaging, and difficulty in communicating actionable messages that would be effective in changing workplace behaviors. Despite these challenges partners felt confident that future endeavors using an EE strategy should be made in communicating other workplace safety issues to Latino and other vulnerable populations.

Improved collaboration between entertainment media writers/producers and public health experts is needed to create interventions with the power to change viewers behaviors over time. In addition, more refined research methods are needed to examine EE intervention development and outcomes.

This research investigates why typical strategies for promoting health, prolonging life, and preventing disease do not work in many communities. I use the liver fluke infection endemic in Khon Kaen, Thailand to explore the middle ground between Western science and Eastern culture. Prior work on the O.viverrini infection in Khon Kaen, Thailand has focused almost exclusively on developing effective medical treatment for the liver fluke infection. This dissertation employs a case study designed to explore the conditions that created and perpetuate the problem in the first place. In concrete terms, I analyze how the worldviews of local villagers shape their attitudes toward life (and death), which in turn determine if they engage in the high–risk behavior — eating undercooked fish — that makes them vulnerable to the infection. My research focuses on these people in–situ over a three–month period, and includes data from participant–observation, interviews, and video–recordings. This work seeks to illuminate how people’s thinking and reasoning skills, and personal/cultural identities affect their abilities to learn and act on new health concepts. This potentially provides a window into future educational strategies in a complex world.

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