Non-exercise estimated cardiorespiratory fitness and mortality from all-causes, cardiovascular disease, and cancer in the NIH-AARP diet and health study

Aims: Impractical methods and relatively small cohort have limited the applications of non-exercise estimated cardiorespiratory fitness (NEE-CRF). This study aimed to assess the association between a pragmatic NEE-CRF method and mortality outcomes in a large prospective cohort.

Methods and results: A total of 330 769 participants [men (n = 186 469) and women (n = 144 300)] aged 50-71 years from the NIH-AARP Diet and Health Study were assessed at baseline (1995-96) and prospectively followed until 31 December 2015 (14.9 ± 2.1 years). Non-exercise estimated cardiorespiratory fitness was estimated using pragmatic and previously validated equation, and Cox hazard analysis for mortality was conducted. Non-exercise estimated cardiorespiratory fitness was 9.9 ± 1.5 metabolic equivalents (METs) in men and 7.2 ± 1.6 METs in women. In total, 34 317 men and 20 295 women died during the follow-up. Higher NEE-CRF was associated with lower mortality risk from all-causes, cardiovascular disease, and cancer. Compared to the lowest quartile of NEE-CRF, the hazard ratios and 95% confidence interval for all-cause mortality in the second, third, and fourth quartiles were: 0.82 (0.79-0.84), 0.74 (0.72-0.77), and 0.70 (0.67-0.73) for men, and 0.84 (0.81-0.88), 0.78 (0.75-0.82), and 0.72 (0.68-0.77) for women (P trend <0.001 for all). For each 1-MET increase in NEE-CRF, risks for mortality due to cardiovascular disease and cancer were 0.85 (0.82-0.88) and 0.89 (0.87-0.91) in men, and 0.84 (0.81-0.88) and 0.89 (0.87-0.91) in women, respectively (P < 0.001 for all).

Conclusion: Higher NEE-CRF is independently associated with lower mortality risk in a large prospective cohort of men and women. These results support the utility of the applied NEE-CRF method for risk stratification, prevention, and rehabilitation programs and application in large epidemiological studies.