Man Kit Lei

Man Kit (Karlo) Lei is an assistant professor in the Department of Sociology and is affiliated with the Center for Family Research (CFR) and the Center on Biological Embedding of Social Events and relationships (CBESER) at UGA. Dr. Lei’s research interest is in the sociology of health and well-being. Broadly, his research combines theories and methods across disciplinary boundaries to examine the social determinants of health and aging across the life span, with a particular focus on minority populations and disadvantaged communities. Recently, his efforts have been primarily guided by three questions:

1. How does a better understanding of the social determinant impact health and aging?

2. How and why do early adversity experiences impact well-being across the life course?

3. Why do only some, and not all people, exposed to social adversity develop poor health?

(A) Social determinants of health and aging across the life course

Recently, he integrated theory and methods to better understand the social determinants of health. He proposed a comprehensive model using contextual and race-related stress to identify the biophysiological pathways through which exposure to stress among minority youth and adults creates vulnerabilities affecting health/aging. His study extended prior research concerning the effect of contextual and race-related stress on health/aging in several ways. First, in terms of method, he proposed marginal structural modeling with continuous predictors to control potential selection effects. Further, associations reported in previous studies between stress and health/aging may have been inflated by shared methods variance. His research addressed this limitation by using both blood-derived biomarkers (e.g., inflammation cytokines and cardiovascular disease risk, and DNA-methylation based measures) and self-reporting to assess physical health. Second, the biopsychosocial mechanisms whereby stress factors influence health/aging have been given little consideration. He found that successful smoking cessation makes people appear biologically younger. Further, his recent study reported that psychosocial resources, inflammation, and weathering are pathways whereby contextual stresses affect long-term health and well-being. Finally, he also revealed that neighborhood collective efficacy protects against adverse effects of social stress on health/aging. These findings expand sociological literature as well as contribute to the growing field of biosocial studies of health and illness.

(B) Early adversity and health outcomes in adulthood

His second research line has focused on how early adversity influences health/aging by becoming biologically embedded. He has identified the mechanisms by which early adversity affects health outcomes as crucial to advancing health research. His study provided evidence that childhood adversity "gets under the skin" to accelerate the onset of pubertal development, which in turn increases cardiovascular disease risk many years later. Further, in terms of method, many studies have relied on either retrospective or prospective adversity measures. Thus, the effect of different assessment methods on potential stress-buffering processes remains largely unknown. He indicated that although the retrospective and prospective childhood adversity measures are predictive of health outcomes, they may not be used interchangeably because of the poor-to-fair agreement between these two measures. Using either prospective or retrospective adversity measures, he also identified parental emotional support in adolescence, but not in adulthood, as a significant stress-buffering process.

(C) Resilience to social stress and adversity

The third essential thread of his recent work focuses on exploring resilience mechanisms and developing intervention models to prevent or attenuate the impacts of adversity on well-being. Past research has largely ignored the potential indirect moderation role of intervention. He proposed an indirect moderation model to examine an intervention-induced change in family processes as moderators of the erosive effect of neighborhood disadvantage, thereby more stringently testing their causal role in creating resilience. His research also replicated previous work on the erosive effects of discrimination on Black youth's depressive symptoms. He showed that change in protective parenting behavior produced by family-based interventions exerted a protective, buffering effect. These findings highlight the potential of family-based interventions to promote constructed resilience resources that can, in turn, protect marginalized people in the face of discrimination and disadvantage. In addition to understanding family resilience mechanisms, his recent study reviewed the neighborhood resilience literature. He found that resilience is a moderated-mediation mechanism and can occur at various levels, ranging from individual to neighborhood. This review paper proposes a multilevel structural resilience model that identifies three resilience pathways: (a) resilience as a mediator of social context and individual well-being; (b) resilience as a buffering mechanism that protects individuals from disadvantage; and (c) resilience as a moderated mediation mechanism that is both influenced by neighborhood context and, in turn, prevents stress and disadvantaged effect.