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 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 from 1972 to 1987) to cardiovascular health from the Swedish CArdioPulmonary bioImage Study (2013-2018). In 2025, a total of 8,930 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's Life's Essential 8 score (0-100 points; 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 with normal weight (BMI: 18.5-24.9 kg/m²), AORs of having poor cardiovascular health for overweight (BMI: 25.0-29.9 kg/m²) and obesity (BMI ≥30 kg/m²) were 2.42 (95% CI=2.00, 2.92) and 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 4 decades of follow-up. Although further studies are needed, the promotion of a healthy body weight and cardiorespiratory fitness in youth may be of importance for later cardiovascular health.