Body mass, cardiorespiratory fitness, and cardiometabolic risk over time: Findings from the Cooper Center Longitudinal Study.

Few studies have adequately assessed the simultaneous effects of changes in cardiorespiratory fitness (fitness) and body mass on cardiometabolic risk. Hence, the current study's aims were twofold: (1) To determine whether increases in body mass result in higher cardiometabolic risk after controlling for fitness changes; and (2) To assess whether increases in fitness result in lower cardiometabolic risk after controlling for weight changes. The study consisted of 3534 patients who came for preventive medicine visits ≥4 times over any 10-year period (1979-2019). The primary independent variables were body mass and fitness, and the dependent variable was metabolic syndrome (MetS) and its components. Mixed-effects regression was used to model the relationship between changes in body mass, fitness, and MetS. Results indicate that increasing body mass up to a 10-year period was significantly related to increasing risk of MetS while controlling for changes in fitness. Specifically, a 1-kg increase in body mass was associated with a 17% (OR = 1.17; 95% CI 1.15-1.19) increased odds for MetS, while adjusting for fitness changes. A 1-MET increase in fitness was related to a 23% (OR = 0.77; 95% CI 0.70-0.84) decrease in odds for MetS, while adjusting for body mass changes up to 10 years. Moreover, body mass change was significantly related to changes in all cardiometabolic components of MetS. Fitness change was significantly associated with changes in MetS components. Future interventions should focus concurrently on increasing fitness and on body mass loss (or maintenance) to improve cardiometabolic health.