Cmv Serostatus Has A Negative Effect On Cardiorespiratory Fitness And Insulin Sensitivity In Sedentary African-americans

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PURPOSE: Investigate the effects of Cytomegalovirus (CMV) serostatus on measures of physical (VO2max) and metabolic (Insulin Sensitivity) fitness in healthy adults before and after a 20-week exercise intervention. METHODS: Serum samples from a subsample (n=120) of the HERITAGE study (Bouchard et al., MSSE 1995) were analyzed for CMV serostatus. This subset was selected from the 60 men and 60 women with the greatest VO2 max increase in response to the 20 week intervention and included Caucasians (n=82) and African Americans (n=38). Baseline VO2max was assessed using a stationary cycle ergometer test and insulin sensitivity was measured using a 3-hour intravenous glucose tolerance test before and after the training program. RESULTS: Caucasians had a lower prevalence of CMV seropositive status than African-American (33% vs. 68%, p<001). In Caucasians, CMV serostatus was not associated with baseline aerobic capacity or insulin sensitivity. In African-Americans, CMV seropositive status was associated with impaired aerobic capacity pre- (2.39 ± .53 L/min vs 1.84 ± .67 L/min; p=.020; CMV seropositive vs CMV seronegative) and post-intervention (2.44 ± .75 L/min vs 3.03 ± .59 L/min; p=.028). Significant effects of CMV serostatus persisted after controlling for age, sex, body weight, and body fat percentage (p=.047, p=.047; pre- and post-intervention resp.). African-American CMV seropositive participants also had higher insulin responses to an IVGTT both pre- (1971.64 ± 1173.31 10 min.mU-1.mL-1 vs 849.16 ± 456.67 min.mU-1.mL-1; p=.014) and post-intervention (1873.88 ± 1212.65 min.mU-1.mL-1 vs 909.18 ± 432.38 min.mU-1.mL-1; p=.038). CMV serostatus still had significant effects on insulin sensitivity after controlling for age, sex, and aerobic capacity (p=.011, p=.016; pre- and post-intervention, resp.). CONCLUSIONS: In sedentary African American adults, CMV serostatus is significantly associated with lower VO2max and insulin sensitivity even while controlling for variables known to mediate fitness and glucose sensitivity, and the associations persisted after exposure to 20 weeks of a standardized exercise program. We conclude that CMV status is another personal characteristic that needs to be taken into account in the assessment of cardiorespiratory fitness and insulin sensitivity in this population.

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