DePaula

An Empirical Study on Behavioral Responses to AIDS

The AIDS epidemic has significantly curtailed the lifespan in a number of developing countries, particularly on the African continent. The purpose of this pilot project is to study behavioral responses to the AIDS epidemic using recently collected data from the Malawi Diffusion and Ideational Change Project (MDICP). Specifically, the goal is to examine how people's perceptions about local rates of infection, about their own or their spouse's HIV status and their perceived risk of infection affects their behavior with regard to decisions to get tested for HIV, to engage in extramarital affairs and to use barrier methods of contraception. Husbands' and wives' decisions will be modeled in a framework that incorporates decision-making of multiple interacting agents in a dynamic, uncertain environment with imperfect monitoring of actions. This modeling is innovative because it builds on recently developed empirical methods in industrial organization that have never before been used in this type of context. The goal of this pilot project is to develop the model, calibrate the model and evaluate its fit to the data, and explore its use in assessing the effects of interventions, such as providing incentives for HIV testing. This project will lay the foundations for a subsequent NIH and/or NSF grant proposal on the investigation of behavioral responses to the AIDS epidemic. This topic is related to aging insofar as we are studying a population that is at higher risk for premature death and therefore close, or at higher risk of being close, to the end of their lifespan. The individuals in the MDICP sample also face issues often associated with older populations, such as how to cope with the risk of disease, the burden of disease, incapacitation, and impending end of lifespan. There are also some features of the data that are more unique to this population, such as decisions about whether to engage in preventative behaviors to prevent others from contracting disease.

Jedrziewski

With individudals living longer and the aging of the Baby Boomer cohort, the US is experiencing a demographic revolution. Given that risk of dementia increases substantially with age, this aging revolution will drastically increase the prevalence of dementia unless interventions to prevent or delay it are found. Physical activity has been identified as a potential intervention to lower the risk of dementia and/or improve/maintain cognitive function. Therefore, we propose to undertake a pilot study using data from 2 Waves (1992 and 2004) of the National Long-term Care Survey (NLTCS) to examine potential associations between physical activity and cognitive health (i.e. risk of dementia and cognitive function). The NLTCS, longitudinal in structure, is a large, nationally-representative sample of individuals from both the community and institutions. Our specific aims include: (1) to examine the relationship between physical activity and risk of Alzheimer's disease (AD) and other dementias; (2) to examine the relationship between physical activity and change in cognitive function from baseline to follow up; (3) to explore the relationship between dose of physical activity and risk of dementia, as well as change in cognitive function; and (4) to explore the effectiveness of various types of physical activity on cognitive health. We will use logistic regression analysis, controlling for potential confounding factors such as age, education, race, cardiovascular factors and socialization, with physical activity as our independent variable of interest. Dependent variables will include incident AD, dementia and cognitive impairment, as well as change in cognitive function.

Kohler, H / Helleringer

A population-based study of the transmission and diversification of HIV-1 using molecular genetic and complete sexual network data

Genetic sequencing allows reconstructing the specific HIV transmission chains through which the virus has diffused and evolved within a population. From the perspective of social science AIDS research, this represents a unique opportunity: such techniques (i) provide objective measurements of the (sexual) connections between members of a population, and (ii) allow new measurements of the HIV-1 diffusion process—the actual transmission of HIV and the diversification of the virus during transmission in sexual networks—whose determinants have largely been understudied. The main aim of this application is therefore to study empirically the social determinants of the transmission and diversification of HIV-1 in a sub-Saharan setting where the prevalence of HIV-1 infection is high. The specific aims of this project include: (1) Create the first large-scale complete-sexual-network study with detailed phylogenetic data in sub-Saharan Africa by complementing the already funded second wave of a unique population-based survey of sexual networks on Likoma Island (Malawi) with genetic sequencing of all identified HIV-1 cases in the study population (N 230). (2) Use the molecular-genotype data to establish chains of HIV infection, and use these reconstructed transmission patterns to (a) assess the validity of sexual network data collected during the survey; and (b) investigate the relationship between reported risk behaviors and actual transmission of HIV-1 along sexual networks. And, (3) investigate the impact of sexual network structures on the rate at which recombinant forms of the virus, dual infections as well as superinfections emerge within a population.

Margolis

The Effects of Nutrition and Disease on Child Growth and Adult Health

This study is designed to investigate the effects of nutrition and disease on child growth and adult health. Among the principal outcome variables to be investigated are insulin resistance and diabetes. The main input variables are birth weight, breastfeeding, and childhood nutrition and disease. We will use multilevel, multivariate models to investigate these relations. The rich longitudinal data available from the INCAP project in El Progreso, Guatemala will enable us to estimate directly the impact of childhood disease and nutrition on adult outcomes. We will be able to investigate the extent to which these relations can be captured by the more commonly-available data on height and lower leg length. Because childhood infectious diseases can impair organ function, we anticipate that the effects of infectious diseases will not be fully captured by height and leg length. The role of childhood nutrition may also not be fully captured by height since previous research has suggested that birth weight and growth velocity impact adult health. The availability of an experimental design while help clarify the relation between nutrition and adult health, since location with respect to treatment is exogenous with respect to household characteristics that might otherwise exert an influence on childhood nutrition and growth. Last, this project will investigate cohort differences in height and leg length and predict the ways in which the future disease burden will change in Guatemala.

Park

Age Variation in the Relationship between Health Literacy and Self-Rated Health

A growing body of research is interested in the roles of health literacy in affecting health outcomes. Improving health literacy among Americans is one of the health goals specified in Health People 2010 by the U.S. Department of Health and Human Services. However, there are some important gaps in the existing literature. Most research has primarily focused on very specific groups of people within specific health care settings using measures of health
literacy that are designed only for medical setting. Moreover, the potential variation by age and gender in the association between health literacy and health outcomes has not been systematically examined. In this study, I empirically test two hypotheses using data from a nationally representative sample of 18,102 American adults (2003 National Assessment of Adult Literacy; NAAL): 1) health literacy is positively associated with self-rated health for both men and women, net of such covariates as race/ethnicity, immigrant status, parental education, educational attainment, poverty, welfare receipts, household income and health insurance coverage; 2) the effect of health literacy on self-rated health increases by age for both men and women. I measure the effect of health literacy as the gaps in the likelihood of having higher levels of self-rated health status among three groups of people with different levels of health literacy. I use ordered regression models that predict the likelihood of having higher levels of self-rated health by health literacy and other covariates using the whole sample of men and women, separately, to test Hypothesis 1. Then, I examine the association between health literacy and self-rated health across separate age groups to see how the association changes by age (Hypothesis 2).