Background: Whether higher cardiorespiratory fitness (CRF) attenuates the mortality risk associated with higher adiposity in adults with hypertension (HTN) is poorly understood.
Methods: Participants were 13,155 men (mean age, 47.7 (s.d., 9.9) years) who completed a baseline health examination and maximal treadmill exercise test during 1974-2003. All men had HTN at baseline based on resting systolic blood pressure of > or =140 mm Hg or diastolic blood pressure > or =90 mm Hg. CRF was quantified as the duration of a symptom-limited maximal treadmill exercise test, and was grouped for analysis as low (lowest 20%), moderate (middle 40%), and high (upper 40%). Distributions of body mass index (BMI), waist circumference (WC), and percent body fat (%BF) were grouped according to standard clinical guidelines.
Results: During a mean follow-up of 12 years, 883 deaths (355 cardiovascular disease (CVD)) were recorded. Multivariate hazard ratios (HRs) (95% confidence interval) for all-cause mortality, using low-fitness as the reference group, were 0.58 (0.48-0.69) and 0.43 (0.35-0.54) for moderate-fit and high-fit groups, respectively. We observed a similar pattern for CVD mortality. High-fit/obese men had no greater risk of all-cause (1.59 (0.95-2.67)) or CVD (1.23 (0.44-3.41)) death, high-fit/abdominal-obese men had no greater risk for all-cause (1.20 (0.80-1.78)) or CVD (0.62 (0.25-1.53)) death, and high-fit/percent body fat (%BF)-obese men had no greater risk for all-cause (1.19 (0.90-1.56)) or CVD (0.86 (0.52-1.43)) death compared with their high-fit/normal counterparts.
Conclusions: Fitness is a powerful effect modifier in the association of adiposity to mortality in men with HTN, negating the all-cause and CVD mortality risk associated with obesity.