A Reconsideration of the Role of Self-Identified Races in Epidemiology and Biomedical Research

A considerable number of studies in epidemiology and biomedicine investigate the etiology of complex
diseases by considering (self-identified) race as a relevant variable and focusing on the differences in risk
among racial groups in the United States; they extensively draw on a genetic hypothesisdviz. the hypothesis
that differences in the risk of complex diseases among racial groups are largely due to genetic
differences covarying with genetic ancestrydthat appears highly problematic in the light of both current
biological evidence and the theory of human genome evolution. Is this reason for dismissing selfidentified
races? No. An alternative promising use of self-identified races exists, and ironically is suggested
by those studies that investigate the etiology of complex diseases without focusing on racial
differences. These studies provide a large amount of empirical evidence supporting the primacy of the
contribution of non-genetic as opposed to genetic factors to the risk of complex diseases. We show that
differences in racedor, better, in racial self-identificationdmay be critically used as proxies for differences
in risk-related exposomes and epigenomes in the context of the United States. Self-identified race
is what we need to capture the complexity of the effects of present and past racism on people’s health
and investigate risk-related external and internal exposures, geneeenvironment interactions, and
epigenetic events. In fact patterns of racial self-identifications on one side, and patterns of risk-related
exposomes and epigenomes on the other side, constantly coevolve and tend to match each other.
However, there is no guarantee that using self-identified races in epidemiology and biomedical research
will be beneficial all things considered: special attention must be paid at balancing positive and negative
consequences.