Health, Health Disparity and Biodemography

 

CSDA researchers are increasingly involved in innovative health-related research. In part it is due to increased ties with the University at Albany School of Public Health. The Dean of the School of Public Health, Phillip Nasca, (CSDA Advisory Board member) has taken an active interest in CSDA. Gage (Anthropology) and Strully (Sociology) have secondary appointments in Epidemiology and Biostatistics, and Horton has a secondary appointment in Health Policy, Management and Behavior in the School of Public Health. A unique feature of the University at Albany’s School of Public Health is that it is a collaborative effort between the University and the New York State (NYS) Health Department, i.e. many faculty in the School of Public Health are NYS Health Department employees. This brings with it an emphasis on NYS e.g. see Bell’s (Health Policy and Management) data collection efforts. All told more than half of CSDA associates contribute to this theme. The liaison with the School of Public Health has brought with it formal participation in CSDA by several recently hired biostatisticians. Both Yucel and DiRienzo (both in Epidemiology and Biostatistics) are active members of the CSDA associate community. A final mechanism for the increased interest in health disparities is the CSDA working group in biodemography, initiated by Gage (Anthropology),and comprised of Bushway (Criminal Justice), Schiller (Education), Strully (Sociology), Moslehi (Epidemiology and Biostatistics), and Yucel (Epidemiology and Biostatistics).

While fertility and reproduction has not been a traditionally strong topic among CSDA researchers, a number of young scholars, all of whom have been supported by CSDA junior scholar awards, have begun studying aspects of reproduction. Genetic Epidemiologist Moslehi (Epidemiology and Biostatistics) has published widely on the genetics of quantitative traits, including BMI (obesity), but primarily studies the genetics of reproduction, and reproductive health, with a focus on cancer of the reproductive system. In general, analyses of the genetics of reproduction in the demographic literature have considered only behavioral aspects of fertility. Moslehi, however, has examined direct effects of genetics on the biological aspects of reproduction including associations of BRCA mutations and female fertility and offspring sex ratio, as well as, DNA repair genes and fetal and placental development. Results from both of these have been presented at the meetings of the PAA meetings.

Gage (Anthropology) studies the relationship of birth weight to infant mortality among various racial and ethnic groups. He has developed a statistical method of controlling for hidden heterogeneity, Covariate Density Defined mixture of regressions (CDDmr), which uses the density distribution of biomarkers to identify this heterogeneity. This innovative statistical method has shown that the pediatric paradox (i.e. lower black infant mortality compared to whites at low birth weights) is due to heterogeneity in the birth cohort, probably a result of fetal loss. One implication of this work is that black infant mortality disparities are much larger than those commonly estimated from uncorrected data. A second phase of the project in collaboration with DiRienzo (Epidemiology and Biostatistics) has explored the social and biological covariates that contribute to these racial and ethnic disparities and whether they operate causally through biomarkers such as birth weight. This required the development of marginal structural models using Covariate Density Defined mixture of regressions. Analysis of birth weight using a variety of exogenous covariates (race, education, maternal age etc.) as instruments indicates that birth weight is not on the causal pathway to infant mortality. Significant indirect effects, when they exist, are in the wrong direction; lower birth weight appears to have a protective effect. Birth weight probably should not be included as a control in studies of social effects on infant mortality.

Environmental effects on birth outcomes comprise the research of several other CSDA associates. Strully (Sociology) has recently completed an innovative study of the effects of poverty on infant health. It uses changes in state earned income tax credits (EITC) as a natural experiment to estimate the causal effects of poverty on birth weight. The findings suggest that the EITC increases birth weight. Bell (Health Policy and Management) conducts the University at Albany subcontract of the National Birth Defects Prevention Study (NBDPS), and specializes in the analysis of genetics medications, environmental, and occupational exposures and their association with birth defects, the second leading cause of infant mortality in New York State. The New York Center includes the use of newborn bloodspots for biomarkers and evidence of environmental contaminants. Bell has published widely on the effects of agricultural pesticides and pollutants on the risk of birth defects. Jurkowski and Bell have recently conducted an assessment of migrant and seasonal farm worker’s health in New York State.

Gage and DiRienzo, with Lee (CSDA Staff), Brutsaert (formerly Anthropology, now at Syracuse) and Ploubidis (psychologist, London School of Hygiene and Tropical Medicine) have begun to apply the Covariate Density Defined mixture of regression methodology to the fetal programming hypothesis, that nutrition during fetal development may have health effects later in life, in particular for cardiovascular disease, diabetes and metabolic syndrome in general. These findings are based on the observation that birth weight is highly negatively correlated with these chronic diseases. In this regard, one problem with the fetal programming hypothesis is that birth weight is positively associated with BMI (obesity) in adulthood, while BMI in adulthood is positively correlated with chronic disease. Preliminary applications of CDDmr to childhood obesity suggest that CDDmr identifies a subpopulation of “programmed” births which account for 97% of obese cases. They are planning analyses to determine if this same subpopulation is a latent statistical biomarker of chronic disease in adults.

Gage and Brutsaert are conducting two additional fetal programming studies on childhood outcomes. Funded by an R03, they have examined the impact of birth weight and other birth outcomes on the physical performance of young adults, using an experimental protocol, response to training. In particular they have shown that low ponderal index (birth weight/length3) is associated with decreased muscle strength and faster fatigue rates. This is consistent with lower energy expenditures and increases in obesity in programmed births in adulthood. Further analyses indicate that VO2max is not affected, but low ponderal index is associated with low lactate levels during exercise. CSDA’s fetal programming research extends beyond the borders of the US. Gage and Brutsaert have collected preliminary data concerning fetal programming in activity levels in children in Curre Costa Rica. In preliminary data low ponderal index is negatively correlated with activity levels monitored in real time, over week long periods, using accelerometers. The preliminary data collection was funded through CSDA working-group support to determine if the accelerometers would work in an isolated rural Costa Rican population.

Strully (Sociology) has used a junior investigator award and the CSDA Biodemography and Adolescent Health working groups (discussed below), to leverage a K01 award that combines reproduction and infectious disease. The project uses the Adolescent Health dataset to explore how racial-ethnic segregation and inequality across schools and neighborhoods shape the structure of sexual networks, and how differences in sexual networks may lead to different epidemic outcomes in communities with varying racial-ethnic and socioeconomic make-ups. This project, combined with Moslehi’s studies of the genetics of reproduction, Moore’s (Guttmacher Institute) on reproduction and HIV and Chatterji’s (Economics) interests in pregnancy and depression represent the potential emergence of a reproductive health foci at CSDA, something we plan to promote in the next five years.

Other health research looks at older children. Former CSDA associate Davison and current associate Jurkowski (both former CSDA junior scholars) with Deane (Sociology) contribute to studies of obesity in children with a large ARRA Challenge grant to develop prevention programs designed by families for families. This early childhood obesity prevention study is focused on low-income and minority families, who have disproportionately high obesity rates, living in Troy New York. The project includes a community based participatory research (CBPR) component intended to empower family caregivers and community based organizations (CBOs) to address obesity. This project has produced a number of papers concerning practical aspects of increasing activity levels in children. It dovetails nicely with Shaw’s proposed studies of physical activity in adults and Brutsaert and Gage’s studies of fetal programming and activity levels in children. While Davison has moved from the University at Albany to Harvard, the project remains here under Jurkowski’s leadership.

Other research related to children moves from a focus on activity to the effect of economics on children’s health. Chatterji and Lahiri (Economics) have made a major methodological contribution in this area by applying methods that have been used to estimate and decompose income-related health inequality among adults to child health. They find that the main factor underlying income-related child health inequality is family income itself, although other factors, such as maternal education, also play a role. Decomposition of income-related health mobility indicates that health changes over time are more favorable to children with lower initial family incomes vs. children with higher initial family incomes. In a related paper, they find that health at birth is an important determinant of children’s educational outcomes, but it does not appear to be an important mechanism of disparities in educational outcomes.

In the adult years, Chatterji (Economics, one of CSDA’s junior scholars) has examined racial disparities in access to and adequacy of treatment for depression, effects on employment, and maternal leave length. These projects have used instrumental variables, propensity scoring, and changes in public policy to identify disparities. The results suggest that for mothers who worked prior to child bearing, returning to work within a year of the birth is associated with fewer depressive symptoms. However, longer leaves during that first year are associated with further reductions in depressive symptoms and depression. With respect to race and ethnicity, Chatterji finds that the likelihood of both having access to and receiving adequate care for depression were significantly different for Asians and African Americans in contrast to non-Latino whites. Simply relying on present health care systems without consideration of the unique barriers to quality care that ethnic and racial minority populations face is unlikely to affect the pattern of disparities observed. Populations reluctant to visit a clinic for depression care may have correctly anticipated the limited quality of usual care.

With Junior Investigator seed grant support from CSDA, Moslehi has identified a possible candidate loci for early post-menopausal breast cancer in women. This has potentially profound implications for the evolution of aging in humans. Despite extensive research only a few loci associated with aging have been discovered to date, e.g. APOE. Others have been suggested but not conclusively. This is surprising because mutations should accumulate post reproduction (the so called “wall of death”). This would be the first such loci identified in humans. She is currently pursuing funding from the Komen Foundation and NHGRI to replicate these findings in an independent sample.

Chatterji (Economics) and Lahiri (Economics) have collaborated in a study of racial and ethnic disparities in awareness of chronic disease. They explore two alternative definitions of awareness, and estimate a 3-step sequential model which accounts for selection along measured and unmeasured factors into: (1) participating in biomarker collection, (2) having chronic illness (hypertension or diabetes), and (3) being aware of illness. Their findings suggest that current estimates of racial/ethnic disparities in chronic disease are sensitive to selection, and also to the definition of disease awareness used. Contrary to prior studies reporting that African-Americans are more aware of having hypertension than non-Latino whites, their findings refute this once self-selection and severity are considered. Likewise, prior studies show mixed evidence of racial/ethnic disparities in awareness of diabetes, but after accounting for selection, they find that African-Americans and Latinos are less aware of having diabetes compared to non-Latino whites.

At the end of life Young (Epidemiology and Biostatistics) and Shaw (Health Policy and Management) are examining the effects of access to services on health outcomes, particularly issues related to physical activity, among the aged using ethnographic techniques. Economist Dewar (Public Health) has addressed care issues at the end of life and works in particular on palliative-care models culminating in a 2009 text entitled Essentials of Health Economics. This research was originally supported by a working-group grant from CSDA. Chatterji (Economics) and Lahiri (Economics) are studying how onset of diabetes and control of diabetes affects employment, retirement, and disability among the elderly. In addition, they are examining whether local and national economic fluctuations exacerbate health disparities because they have larger effects on economic and health outcomes of those with behavioral disorders vs. those without such disorders. They are beginning to study the effects of education on the prevalence of and timely diagnosis of chronic disease.

An emerging focus within CSDA concerns the dynamics of infectious diseases. We believe that this is a growth area for research in human health and demography. The development of routine methods of sequencing the DNA of infectious organisms has demonstrated the rapidity with which human pathogens can evolve. Moreover, ecologists have shown that the traditional scenario of host-pathogen co-evolution, increasing the resistance of the host and reducing the virulence of the pathogen, is grossly oversimplified if not incorrect. In fact, virulence is a complex function of the social and spatial structures of the host and pathogen populations, as well as of pathogen-pathogen interactions. Gage and CSDA associates George Robinson (Biology), Strully (Sociology) and DeWitte (Anthropology), McNutt (Epidemiology and Biostatistics) Moore (Guttmacher), have begun to address these issues in collaboration with several other members of the Albany Biology faculty (Wang, Caraco and Stewart) and researchers from Wadsworth Laboratories (Conn and Kramer). Research in this area includes Gage’s review of the role of infectious disease in the emergence of chronic disease during modern times, which was the subject of a symposium titled “Moving the Middle to the Foreground, Revisiting the Second Epidemiological Transition”, April 18-19 2011 South Carolina Institute of Archaeology and Anthropology, where Gage was a plenary speaker. DeWitte (Anthropology) also presented. A volume is forthcoming. Robinson (Biology) and Caraco (Biology) have ongoing work on the ecology of Lyme disease and its spread. Strully’s recent K01 award of adolescent sexual networks involves HIV as an outcome. Similarly, South and Trent (whose work traditionally falls within the immigration and life course themes) have examined the skewed sex ratios in China and its effects on the risk of sexually transmitted diseases. McNutt (Epidemiology and Biostatistics) has examined the race/ethnic barriers to vaccination to human papillomavirus and the population dynamics of leishmaniasis and tularemia in the Republic of Georgia for which she has recently received funding.

CSDA research in the health, health disparities, and biodemography theme addresses many of the issues considered in the recent NICHD vision statement. In particular, research touches on aspects of “reproduction”, “pregnancy” and “developmental biology”, although a major thrust of this theme’s research involves “early origins of health, disease, growth, and development. The biodemography initiative at CSDA is supported by a well-developed working group, which has been funded by an ARRA supplement to the R24. We plan to capitalize on the achievements of the health and biodemography working group over the next five years. We will continue developing both the biomarker and infectious disease facets of our biodemography program, including organizing a National and International conference on the use of biomarkers in the population sciences in the second or third year of the R24. The conference will draw upon the contributions of the biodemography working group at CSDA, as well as the Biotechnology group at the College of Nanoscale Science and Engineering at the University at Albany, a rapidly expanding college at the frontier of nanoscience research. The conference will also serve as a catalyst for our long-term goal of forming cross-disciplinary collaborations with the Nano Engineering group. Already, the latter group is developing cost-effective, noninvasive technology to track multiple biomarkers, which could aid biologically-informed social science research. We will encourage CSDA associates, besides those currently involved with the Nano-engineering group (e.g. DiRienzo and Bell), to form scientific alliances for future population-nano-technology initiatives.

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