Abstract
We investigated associations between body mass index (BMI) in adolescence with development of aortic valve stenosis (AVS) in early adulthood, and clinical outcomes among those who develop AVS. We used data from 1 701 390 men (mean age, 18.3 ± 0.8 years) enrolled in compulsory conscription for military service in Sweden from 1969 to 2005. Anthropometrics, blood pressure, fitness, muscle strength and IQ were recorded at baseline. Over a median follow-up of 32 years (IQR, 24–41 years), 5766 men were diagnosed with AVS (mean age 54.7 ± 9.4 years). After multivariable adjustment, individuals with a BMI of < 18.5 kg/m(2), compared to those with a low-normal BMI (20.0–<22.5 kg/m(2)) showed lower risk (HR 0.70; 95% CI 0.61–0.80) of AVS. Higher BMI categories were progressively associated with increased risk, reaching HR 1.91 (95% CI 1.12–3.25) for BMI 35–50 kg/m². Further on, those diagnosed with AVS were followed for a median of ~ 5.5 years. The multivariable-adjusted HR for all-cause mortality, cardiovascular mortality, and heart failure for obese (BMI 30–50 kg/m(2)), compared to BMI < 20.0 kg/m(2) in men diagnosed with AVS, were 4.69 (95% CI 2.61–8.44), 4.09 (95% CI 1.72–9.73), and 2.76 (95% CI, 1.36–5.60), respectively. Higher BMI in youth, even within the conventional normal range, is associated with an elevated risk of developing AVS in early adulthood, whereas low BMI appears protective. Long-term exposure of obesity in individuals with AVS is associated with worse survival and higher risk of cardiovascular events. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1038/s41598-026-44041-2.