title: Race and Resting-State Heart Rate Variability in Brazilian Civil Servants and the Mediating Effects of Discrimination: An ELSA-Brasil Cohort Study.
abstract: African Americans are characterized by higher heart rate variability (HRV), a finding ostensibly associated with beneficial health outcomes. However, these findings are at odds with other evidence that blacks have worse cardiovascular outcomes. Here, we examine associations in a large cohort from the ELSA-Brasil study and determined whether these effects are mediated by discrimination.
  
  
  
  Three groups were compared on the basis of self-declared race: "black" (n = 2,020), "brown" (n = 3,502), and "white" (n = 6,467). Perceived discrimination was measured using a modified version of the Everyday Discrimination Scale. Resting-state HRV was extracted from 10-minute resting-state electrocardiograms. Racial differences in HRV were determined by regression analyses weighted by propensity scores, which controlled for potentially confounding variables including age, sex, education, and other health-related information. Nonlinear mediation analysis quantified the average total effect, comprising direct (race-HRV) and indirect (race-discrimination-HRV) pathways.
  
  
  
  Black participants displayed higher HRV relative to brown (Cohen's d = 0.20) and white participants (Cohen's d = 0.31). Brown relative to white participants also displayed a small but significantly higher HRV (Cohen's d = 0.14). Discrimination indirectly contributed to the effects of race on HRV.
  
  
  
  This large cohort from the Brazilian population shows that HRV is greatest in black, followed by brown, relative to white participants. The presence of higher HRV in these groups may reflect a sustained compensatory psychophysiological response to the adverse effects of discrimination. Additional research is needed to determine the health consequences of these differences in HRV across racial and ethnic groups.
authors.affiliation: From the Center for Clinical and Epidemiologic Research (Kemp, Bittencourt, Pereira, Santos, Benseñor, Lotufo), University of São Paulo, São Paulo, Brazil; School of Psychology and Discipline of Psychiatry (Kemp), University of Sydney, Sydney, New South Wales, Australia; Department of Psychology (Kemp), Swansea University, Swansea, United Kingdom; Department of Psychology (Koenig, Thayer), The Ohio State University, Columbus, Ohio; Heart Institute (Pereira) and Faculdade de Medicina (Santos, Benseñor, Lotufo), University of Sao Paulo, Sao Paulo; Collegiate of Biological Sciences (Dantas), Federal University of Vale do São Francisco, Petrolina, Pernambuco; Department of Physiological Sciences (Mill), Federal University of Espírito Santo, Vitória; Escola Nacional de Saúde Pública (Chor), Fundação Oswaldo Cruz, Rio de Janeiro; Hospital das Clínicas and Faculty of Medicine (Ribeiro), Federal University of Minas Gerais, Belo Horizonte; and Clinical Medicine (LIM 20) (Benseñor, Lotufo), University of São Paulo, São Paulo, Brazil.
authors.forename: Andrew H
authors.initials: AH
authors.lastname: Kemp
authors.forename: Julian
authors.initials: J
authors.lastname: Koenig
authors.forename: Julian F
authors.initials: JF
authors.lastname: Thayer
authors.forename: Marcio S
authors.initials: MS
authors.lastname: Bittencourt
authors.forename: Alexandre C
authors.initials: AC
authors.lastname: Pereira
authors.forename: Itamar S
authors.initials: IS
authors.lastname: Santos
authors.forename: Eduardo M
authors.initials: EM
authors.lastname: Dantas
authors.forename: José G
authors.initials: JG
authors.lastname: Mill
authors.forename: Dora
authors.initials: D
authors.lastname: Chor
authors.forename: Antonio L P
authors.initials: AL
authors.lastname: Ribeiro
authors.forename: Isabela M
authors.initials: IM
authors.lastname: Benseñor
authors.forename: Paulo A
authors.initials: PA
authors.lastname: Lotufo
mesh_terms: D000328:Adult; D000368:Aged; D044383:Black People / Q000706:statistics & numerical data; D001938:Brazil / Q000208:ethnology; D000071296:Government Employees / Q000706:statistics & numerical data*; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008875:Middle Aged; D044469:Racial Groups / Q000706:statistics & numerical data*; D063505:Racism / Q000208:ethnology / Q000706:statistics & numerical data*; D044465:White People / Q000706:statistics & numerical data; D001741:Black or African American