Resting Heart Rate and Risk of Cancer Mortality
Menée aux Etats-Unis à partir de données portant sur 50 108 participants (âge moyen : 43,8 ans), cette étude analyse l'association entre la fréquence cardiaque au repos, la santé cardiorespiratoire et la mortalité par cancer (période de suivi : 1974-2002 ; durée moyenne de suivi : 15 ans ; 1 090 décès par cancer)
Background: Increased resting heart rate (RHR) is a predictor of mortality. RHR is influenced by cardiorespiratory fitness (CRF). Little is known about the combined associations of RHR and CRF on cancer mortality. Methods: 50,108 men and women (mean age 43.8 years) were examined between 1974 and 2002 at the Cooper Clinic in Dallas, Texas. RHR was measured by electrocardiogram and categorized as <60, 60-69, 70-79, or >=80 beats/min. CRF was quantified by maximal treadmill test and dichotomized as unfit and fit corresponding to the lower 20% and the upper 80%, respectively, of the age- and sex-specific distribution of treadmill exercise duration. The National Death Index was used to ascertain vital status. Cox regression was used to compute hazard ratios (HRs) and 95% confidence intervals (CIs) for cancer mortality across RHR categories. Results: During a mean follow-up of 15.0 (8.6) years, 1,090 cancer deaths occurred. Compared with RHR <60 beats/min, individuals with RHR >=80 beats/min had 35% increased risk of overall cancer mortality (HR, 1.35; CI, 1.06-1.71) after adjusting for confounders, including CRF. Compared with "fit and RHR <80 beats/min", HRs (95% CIs) for cancer mortality were 1.41 (1.20-1.66), 1.51 (1.11-2.04), and 1.78 (1.30-2.43) in "unfit and RHR<80", "fit and RHR >=80", and "unfit and RHR >=80 beats/min", respectively. Conclusions: RHR >=80 is associated with an increased risk of overall cancer mortality. High CRF may help lower the risk of cancer mortality among those with high RHR. Impact: RHR along with CRF may provide informative data about an individual's cancer mortality risk.