Abstract 32: Racial Differences in Cardiorespiratory Fitness Between African and Caucasian Americans: A Meta-analysis

Abstract

Introduction: Cardiorespiratory fitness (CRF) is an independent risk factor for cardiovascular disease (CVD). Recent data suggests that African Americans (AA) have reduced levels of CRF compared to Caucasian Americans (CA). However, this viewpoint has not been widely accepted and it is unclear whether racial differences in CRF may be of a large enough magnitude to increase the risk of CVD. Methods: A literature review was conducted for studies comparing CRF levels between AA and CA adults. Studies were eligible for inclusion if CRF was assessed by an exercise test (submaximal or maximal), CRF was compared between AA and CA adults, examined an adult study population, and was published in a peer-reviewed journal. Potential studies were excluded if the sample included children or adolescents, the sample size was less than 15 participants in each racial group, or the study evaluated participants who had significant health conditions. Meta-analyses were performed comparing CRF between AAs and CAs in two analyses: 1) all studies compared using metabolic equivalents (METs) and 2) restricted only to studies that quantified CRF by directing measuring maximal oxygen consumption (considered the gold standard). Both fixed effects and random effects models were fit to these data. Because of the heterogeneity only results from the random effects models are reported. Analyses were performed using R (version 3.1, R Foundation for Statistical Computing, Vienna, Austria. URL https://www.R-project.org/) and the rmeta package (version 2.6). Results: There were 27 studies (n=131,084) that that met the criteria for the meta-analysis (23 studies excluded). In both the analyses for METs (27 studies, Summary effect: 0.91, CI: 0.8 to 1.0) and directly measured VO 2 max (16 studies, Summary effect: 3.2, CI: 2.1 to 4.3) as the criteria for CRF, AA had lower fitness compared to CA adults. Conclusions: The present study suggests that AAs have lower CRF compared to CAs based on epidemiological studies and clinical trials whether directly measured using indirect calorimetry or maximal METs estimated from exercise testing. A difference of 0.91 METs is associated with ~13.7% higher risk of CVD based on previous epidemiological data. Thus, lower CRF in AA adults may represent a health disparity risk factor and interventions to improve CRF in sedentary AAs may be warranted.