Research Assistant Professor, Survey Research Center, Institute for Social Research
Research Assistant Professor, Division of Nephrology, Department of Internal Medicine, Michigan Medicine
Faculty Associate, Population Studies Center, Institute for Social Research
Director, Americans’ Changing Lives, Wave 6
Through my entire research program, I am committed to clarifying the social causes and biological mechanisms linking racial group membership to renal and cardiovascular disease inequalities. The major hallmark of my research is the integration of scientific knowledge from diverse disciplines, as this transdisciplinary approach to research allows for creative and innovative insights into the root causes and mechanisms of the seemingly intractable racial health inequalities. A significant portion of my research program falls at the intersection of sociology, geography, and environmental toxicology, examining the interrelated roles of racial residential segregation, neighborhood disadvantage, environmental hazards, and racial health inequalities.
Racial Inequalities in Health Throughout Adulthood: The Cumulative Impact of Neighborhood Chemical and Non-chemical Stressors on Epigenomic Pathways
Racial inequalities in healthy aging have been well-documented. Compared to White Americans, Black Americans experience illness and death at early ages and show steeper age-related declines in health. Our neighborhoods, as the site of where we live, learn, play, and pray, may serve as a powerful source of these racial inequalities. Racial residential segregation (which is the sorting of different racial groups into different neighborhoods through historical and current discriminatory policies and practices) has resulted in a racially unequal American neighborhood landscape. Neighborhoods with mostly Black residents experience more poverty, civic and commercial disinvestment, and more exposure to environmental hazards compared to neighborhoods with mostly White residents. While more researchers are documenting the role of neighborhoods in health inequalities, we may actually be underestimating the true impact of neighborhood context, because we often focus on specific health outcomes, such as cardiovascular disease or diabetes. However, there are likely shared biological mechanisms within the body that drive many of these diseases – and one such mechanism may be changes to our genomic structure, called epigenomics. While our genes do not change, the environment can have an impact on whether our genes are actually “expressed”. We will determine whether the accumulation of adulthood lived experience in racially-segregated neighborhoods is related to epigenomic patterns called DNA methylation. We will also specifically determine whether the accumulation of adulthood exposure to neighborhood industrial air pollution and disadvantage together are related to these patterns of DNA methylation. Finally, we will determine whether the DNA methylation patterns we see are related to racial inequalities in healthy aging. We hypothesize that racially-segregation Black neighborhoods, with their greater levels of industrial air pollution and social disadvantage, will be related to the types of patterns in DNA methylation that have been shown to be related to chronic diseases in molecular studies. In fact, we further hypothesize that these patterns in DNA methylation will be related to racial inequalities in cognitive function and the number of chronic diseases one has had. Clarifying the role of neighborhood context in racial inequalities in healthy aging is critical, as neighborhoods are not naturally- occurring. They develop and change through policies and are amenable to intervention. Identifying the role of DNA methylation that likely underlies many chronic diseases, will clarify the importance of neighborhoods and point to potential effective interventions.
The Interactive Roles of Neighborhood Characteristics and Genetic Risk in Racial Inequalities in CKD
Racial inequalities in kidney and end stage renal diseases (ESRD) have been well-documented and are independent of lower socioeconomic status (e.g., income, education), lower access to care, or other conventional risk factors. Research has identified numerous genetic risk factors of renal disease, particularly the APOL1 variants occurring in persons of African descent. However, these genetic factors primarily increase susceptibility, requiring other factors for the development of disease. A growing body of research indicates the importance of neighborhoods for health and health inequalities. Unequal neighborhood contexts may be an important and largely unexplored determinant of the increased kidney disease risk experienced by Blacks compared to Whites. In fact, neighborhood context may interact with genetic susceptibility to result in kidney disease inequalities. Clarifying the role of neighborhood is important as neighborhoods are neither random nor naturally-occurring. They develop and change through policies and are thus amenable to intervention. Despite the evidence indicating the importance of neighborhoods for the major risk factors and determinants of kidney disease, there is a dearth of empirical research on the role of neighborhoods in relation to kidney disease itself, particularly at pre-ESRD stages. Through my research project, I will use three cohorts (Health and Retirement Study, Multi-Ethnic Study of Atherosclerosis, and Nephrotic Syndrome Study Network) to examine the interactive associations between multiple measures of four neighborhood domains (racial residential segregation, social environment, built environment, and health care resources) and genetic risk (APOL1 and β-globin HBB genotypes, adjusting for genetic ancestry), as follows: Aim 1: Link state-of-the-art measures of four domains of neighborhood context to population-representative, epidemiological, and clinical cohort datasets containing markers of kidney disease. Aim 2: Examine longitudinal associations between neighborhood context and renal health, with adjustment for genetic ancestry and APOL1 genotype. Aim 3: Examine the modifying role of neighborhood context on longitudinal associations between APOL1 high-risk genotype status and renal health. With this training and dataset creation, I will then clarify the neighborhood characteristics that are most tightly linked to renal outcomes both directly and through their interactions with genetic risk loci. This research will set a solid foundation for research on neighborhood characteristics and inequalities in kidney disease. Not only will this research clarify the interdependent roles of neighborhood and genetic risk on these inequalities, but it will identify key neighborhood characteristics, which are amenable to change, related to kidney disease within and between racial groups.
Racial Inequalities in Poor Birth Outcomes: Clarifying the Role of Precarious Work (March of Dimes, with Angela Bruns, Lauren Schmitz, and Iris Gomez-Lopez).
Despite the fact that racial inequities in poor birth outcomes have been well-documented, the underlying causes of these inequities is poorly understood, making efforts to close this gap challenging. Employment and the workplace context are likely key social determinants of perinatal health, as evidence suggests that when pregnant women involuntarily work part-time hours, physically demanding jobs, and nighttime shifts, they run a greater risk of experiencing preterm birth and low birth weight. However, many studies rely on small samples and focus on employment only while pregnant. As with broader population health efforts, understanding racial inequities in the social and economic context of women of childbearing age outside the perinatal period will likely clarify where we can direct effective, efficient intervention efforts. Indeed, the employment and workplace context are critically underexamined aspects of women’s lives when it comes to its impact and on birth outcomes. In particular, the racially unequal growth of the “gig economy” and precarious work have been shown to explain 10-38% of the life expectancy gap across racial groups, and may hold a key to understanding important policy levers to close the racial gap in poor birth outcomes. Precarious work is defined here as employment that is uncertain and unpredictable, marked by workers’ loss of control over the conditions of their work, including the pace, nature, and scheduling of work, and future pay and benefit improvements. Precarious working conditions have become increasingly common. Furthermore, compared to White women, non-White women are more likely to engage in precarious work. We propose to examine the link between racial inequalities in precarious work and poor birth outcomes using state- and county-level variation in these factors over time using innovative data on precarious work from the US Department of Labor. There is a dearth of empirical work on the role that county and state employment and workplace policies (e.g., minimum wage increases, elimination of “just in time” scheduling) could play in reducing inequities in birth outcomes. Measures of precarious working conditions can provide more detailed information about the labor market than commonly used measures such as the local unemployment rate. Measures of precarious work also provide information about the job conditions workers face when they do find work, the availability of “good jobs” that allow workers to provide for families’ financial and care needs, and the chances that workers will experience economic security in the near and distant futures — all factors both outside and within the perinatal period that may impact birth outcomes and the inequities in these outcomes.
- Hicken MT, Hing A, Lee H. The weight of racism: Vigilance and racial inequalities in weight-related measures. Social Science and Medicine. 2018. 199:157-166.
- Hicken MT, Kravitz-Wirtz N, Durkee M, Jackson JS. Racial inequalities in health: Framing future research. Social Science and Medicine. 2018. 199:11-18.
- Hicken MT. Fundamental causes, social context, and modifiable risk factors in the racial/ethnic inequalities in blood pressure and hypertension: Invited commentary. American Journal of Epidemiololgy 2015. 182(4):354-357.
- Hicken MT. Measurement and modeling of race and health in Brazil: Continuing the discussion. Cadernos Saude Publica 2017. 33(Suppl 1). doi:10.1590/0102-311×00084216.
- Hicken MT, Dvonch JT, Schulz AJ, Mentz G, Max P. Psychosocial stress and vulnerability to the cardiovascular effects of fine particulate matter air pollution in Detroit. Environmental Research 2014. 133:195-203.
- Hicken MT, Gragg R, Hu H. How cumulative risks warrant a shift in our approach to racial health disparities: The case of lead, stress, and hypertension. Health Affairs 2011. 30(10):1895-1901.