Non-exercise estimated cardiorespiratory fitness and cancer incidence:The NIH-AARP diet and health study

Background Non-exercise estimated cardiorespiratory fitness(NEE-CRF)has been shown to be associated with mortality,although its association with cancer incidence is unknown.The study aimed to assess the prospective association between NEE-CRF and cancer incidence in a large cohort of men and women.Methods The National Institutes of Health-American Association of Retired Persons diet and health study is a prospective cohort that included 402,548 participants aged 50–71 years who were free from cancer at baseline(1995–1996)(men(n=238,835)and women(n=163,713))and were followed until December 31,2015.The exposure variable was NEE-CRF expressed in metabolic equivalents.NEE-CRF was estimated using a validated equation of self-reported predictors on demographics and lifestyle behaviors derived from baseline questionnaires.Primary outcomes were total cancer incidence and incidence of prostate,breast,lung,and colorectal cancers.Cox proportional hazards models were analyzed for the association between NEE-CRF and cancer incidence outcomes adjusted for established cancer risk factors.Results During 13.7±3.2 years of follow-up(mean±SD),64,344 men and 31,315 women developed a new cancer.For every 1-metabolic equivalent higher NEE-CRF,the hazard ratios and 95%confidence intervals(95%CIs)were 0.96(95%CI:0.94–0.97)and 0.88(95%CI:0.84–0.92)of total and colorectal cancer incidence among men,and 0.95(95%CI:0.93–0.97)and 0.94(95%CI:0.91–0.97)of total and breast cancer incidence among women,respectively(all p<0.001).NEE-CRF was not associated with incidence of prostate and lung cancers in men or colorectal and lung cancers in women.Conclusion These results suggest that higher CRF levels,as assessed by the applied non-exercise estimated method,may provide preventive benefits against the development of cancer,while low CRF could potentially serve as a modifiable cancer risk factor.Integrating NEE-CRF into screening paradigms and referring low-fit individuals to improve CRF could complement the public health prevention strategy against cancer.

Cardiorespiratory fitness and cancer in women:A prospective pilot study

Purpose:To assess the association between cardiorespiratory fitness(CRF)and the incidence and mortality from cancer in women,and to evaluate the potential public health implications for cancer prevention.Methods:Maximal exercise testing was performed in a pilot cohort of 184 women(59.3 ± 15.2 years)who were followed for 12.0 ± 6.9 years.Cox hazard models adjusted for established cancer risk factors and accounting for competing events were analyzed for all-type cancer incidence and mortality from cancer.Population-attributable risks and exposure impact number were determined for low CRF(<5 metabolic equivalents(METs))as a risk factor.Results:During the follow-up,11.4% of the participants were diagnosed with cancer and 3.2% died from cancer.CRF was inversely and independently associated with cancer outcomes.For every 1-metabolic equivalent increase in CRF,there was a 20% decrease in the risk of cancer incidence(hazard ratio(HR)= 0.80,95% confidence interval(CI):0.69-0.92;p=0.001)and a 26% reduction in risk of cancer mortality(HR = 0.74,95%CI:0.61-0.90;p=0.002).The population-attributable risks of low CRF were 11.6% and 14% for incidence and mortality of cancer,respectively,and the respective exposure impact numbers were 8 and 20.Conclusion:Greater CRF was independently associated with a lower risk of incidence and mortality from cancer in women.Screening for low CRF as a cancer risk factor and referring unfit individuals to a supervised exercise program could be a public health strategy for cancer prevention in middle-age women.