Associations of adolescent BMI and physical fitness with cardiovascular health in middle age: a population-based prospective study of Swedish men

Abstract

Introduction: Early-life determinants of middle-age cardiovascular health are poorly understood. This study examines associations of body mass index (BMI) and physical fitness in male adolescents with cardiovascular health measured by the Life's Essential 8 score in middle age.

Methods: A population-based cohort study linked BMI and physical fitness from the Swedish Military Conscription Register (men conscripted 1972-1987) to cardiovascular health from the Swedish CArdioPulmonary bioImage Study (SCAPIS, 2013-2018). In 2025, 8930 men (mean age 18.3 years) were analyzed after 38.2 years of follow-up. Physical fitness included cardiorespiratory fitness (maximal cycle-ergometer test), and muscular strength (isometric dynamometry of knee extension, elbow flexion, and handgrip). Cardiovascular health was evaluated using the American Heart Association Life's Essential 8 score (0-100; poor health <60). Associations were assessed using linear and binomial logistic regressions and restricted cubic splines.

Results: BMI and cardiorespiratory fitness exhibited J-shaped and linear associations, respectively, with cardiovascular health. Compared to normal weight (BMI: 18.5-24.9 kg/m2), adjusted odds ratios (ORs) of having poor cardiovascular health for overweight (BMI: 25.0-29.9 kg/m2) and obesity (BMI ≥30 kg/m2) were OR 2.42 (95% confidence interval [CI] 2.00-2.92) and OR 5.38 (95% CI 2.99-9.70). No statistically significant associations were observed between muscular strength and cardiovascular health.

Conclusions: Obesity and low levels of cardiorespiratory fitness in male adolescents were associated with lower cardiovascular health in middle age, after nearly four decades of follow-up. Although further studies are needed, promotion of a healthy body weight and cardiorespiratory fitness in youth may be of importance for later cardiovascular health.