Association Between Change in Nonexercise Estimated Cardiorespiratory Fitness and Mortality in Men

Abstract

Objective: To examine the association between change in nonexercise estimated cardiorespiratory fitness (eCRF) and mortality risk in adult men. Patients and Methods: A total of 10,445 men (mean age, 44.6±9.3 years) from the Aerobics Center Longitudinal Study underwent 2 comprehensive medical examinations and peak work rate tests between January 1, 1979, and December 31, 2002, with an average time between measures of 5.7±4.9 years. Participants were observed for 11.6±6.4 years after their second examination until death or December 31, 2003. The eCRF was calculated with the Jackson et al (2012) and Nes et al (2011) published nonexercise estimation equations. Cox proportional hazards models were performed to examine the association between change in eCRF and all-cause and cardiovascular disease (CVD) mortality. Results: There were 601 deaths (192 CVD deaths) during the follow-up period. For both eCRF equations, a higher eCRF at baseline was associated with significant reductions in mortality risk from all causes and CVD (P<.001). Change in eCRF by the Jackson equation remained significantly associated with all-cause mortality (P<.001) and CVD mortality (P=.02) after multivariable adjustment. Every 1 metabolic equivalent (3.5 mL·kg−1·min−1) increase in eCRF was associated with a 21% and 22% reduction in mortality risk from all causes or CVD, respectively. No significant associations were observed between change in eCRF by the Nes equation and all-cause (P=.69) or CVD (P=.85) mortality risk after multivariable adjustment. Conclusion: The association between change in nonexercise eCRF and mortality risk may be equation dependent.