Estimated cardiorespiratory fitness in childhood and cardiometabolic health in adulthood: 1970 British Cohort Study

Background: Associations of cardiorespiratory fitness in childhood and adulthood with adult cardiometabolic risk factors are poorly understood, not least because of the paucity of studies. Objectives: We investigated associations between nonexercise testing cardiorespiratory fitness (NETCRF) in childhood/adulthood and cardiometabolic risk factors in adulthood. Methods: Based on an established algorithm comprising gender, age, body mass index, resting heart rate, and self-reported physical activity at age 10, we computed NETCRF. Risk factors were assessed at age 46 in 5009 participants when NETCRF was again calculated. Linear regression was used to summarize associations between NETCRF in childhood and risk factors in adulthood and, additionally, the relationship between NETCRF in adulthood and risk factors in adulthood after adjusting for childhood NETCRF. Results: Inconsistent associations were observed between childhood NETCRF and adult risk factors. NETCRF in adulthood was associated with blood pressure [−5.8 (−6.7, −4.9)], glycated hemoglobin [−3.41 (−4.06, −2.76)], total cholesterol [−0.16 (−0.24, −0.08)], HDL cholesterol [0.19 (0.16, 0.22)], triglycerides [−0.68 (−0.85, −0.50)], and C-reactive protein [−0.29 (−0.35, −0.22)] in adult males. Similar associations were observed in adult females. Compared to those with low estimated fitness in both childhood and adulthood, participants with low fitness in childhood and high fitness in adulthood had a lower risk of two or more cardiometabolic risk factors (odds ratio: 0.25; 95% confidence interval: 0.19, 0.31). Conclusion: Associations between estimated fitness and risk factors are stronger in adulthood than from childhood to adulthood. Adults with previously sedentary childhoods may still gain benefits from improving their fitness.