RESUMEN
Introduction: Cardiorespiratory fitness (CRF) in young adulthood is a determinant of chronic disease risk. To better understand whether CRF might also behave as a modifiable risk factor, we examined the associations between longitudinal changes in 2.4 km run times and health outcomes in a cohort of healthy young men. Methods: Our dataset comprised individual run times and health outcomes captured in four national registries. Cox proportional hazards models were used to examine the association between baseline run times and relative hazards of first major adverse cardiovascular events (MACE) and all-cause mortality (ACM). Relative hazards associated with longitudinal change in run times were estimated using models that were adjusted for run-time at baseline. Results: The study sample comprised 148 825 healthy men ages 18-34 years who had undergone at least two routine fitness tests that were 5-9 years apart. During 1 294 778 person-years of follow-up, we observed 1275 first MACE and 764 ACM events occurring at mean ages of 43.2 (SD 6.0) years and 39.2 (SD 6.6) years, respectively. A 1% increase in run-time per annum was associated with a 1.13 (95% CI 1.10 to 1.16) times greater hazard of first MACE and a 1.06 (95% CI 1.02 to 1.10) times greater hazard of ACM. The association between longitudinal change in run times and first MACE was preserved in sensitivity analyses using models adjusted for body mass index at baseline. Conclusion: Among men under the age of 35 years, longitudinal change in run times was associated with the risk of cardiovascular disease two decades onwards.
RESUMEN
Objective: We examined the association between cardiorespiratory fitness (CRF), body mass index (BMI), incidence of major acute cardiovascular events (MACE), and all-cause mortality (ACM). Methods: We conducted a retrospective cohort study involving 212,631 healthy young men aged 16 to 25 years who had undergone medical examination and fitness testing (2.4 km run) from 1995 to 2015. Information on the outcomes of major acute cardiovascular events (MACE) and all-cause mortality (ACM) were obtained from the national registry data. Results: During 2,043,278 person-years of follow-up, 371 first MACE and 243 ACM events were recorded. Compared against the first run-time quintile, adjusted hazard ratios (HR) for MACE in the second to fifth quintiles were 1.26 (95% CI 0.84-1.91), 1.60 (95% CI 1.09-2.35), 1.60 (95% CI 1.10-2.33), and 1.58 (95% CI 1.09-2.30). Compared against the "acceptable risk" BMI category, the adjusted HRs for MACE in the "underweight," "increased risk," and "high-risk" categories were 0.97 (95% CI 0.69-1.37), 1.71 (95% CI 1.33-2.21), and 3.51 (95% CI 2.61-4.72), respectively. The adjusted HRs for ACM were increased in participants from the fifth run-time quintile in the "underweight" and "high-risk" BMI categories. The combined associations of CRF and BMI with MACE showed elevated hazard in the "BMI≥23-fit" category, which was more pronounced in the "BMI≥23-unfit" category. The hazards for ACM were elevated across the "BMI<23-unfit," "BMI≥23-fit," and "BMI≥23-unfit" categories. Conclusion: Lower CRF and elevated BMI were associated with increased hazards of MACE and ACM. A higher CRF did not fully compensate for elevated BMI in the combined models. CRF and BMI remain important targets for public health intervention in young men.