Impact of body mass index on aortic valve stenosis and its clinical outcomes in early adulthood: a long-term study of young men

Abstract Aims Studies investigating associations between body mass index (BMI), incidence of aortic valve stenosis (AVS), and clinical outcomes in AVS patients are scarce. Purpose To investigate the relationship between BMI in youth and subsequent diagnosis of AVS. A secondary aim was to determine the role of obesity in clinical outcomes in individuals diagnosed with AVS. Methods This was a nationwide, register-based cohort study of 1 701 390 men (mean age, 18.3 ±0.8 years) enrolled in compulsory conscription for military service in Sweden from 1969 through 2005. Anthropometrics, blood pressure, fitness, muscle strength and IQ were recorded at baseline. AVS cases and cardiovascular outcomes were identified according to the International Classification of Diseases (ICD)-10 registered in the National patient register and Cause of Death Register through the Swedish 12-digit personal identification number. BMI (kg/m2) was categorized as <18.5, 18.5–<20, 20–<22.5, 22.5–<25, 25–<27.5, 27.5 <30, 30–<35, and 35–<50 kg/m2. Cox proportional hazard models were used to estimate the association between adolescent BMI and future hospitalization for AVS while adjusting for potential confounders. The BMI reference was set as 20–<22.5. Those who developed AVS formed a subcohort that was followed until a first clinical cardiovascular outcome of death, cardiovascular mortality, Heart failure, Atrial fibrillation, myocardial infarction, or ischaemic stroke. Results During a median follow-up of 32 years (IQR, 24-41 years), 5766 cases (mean age 54.7±9.4 years) of AVS were diagnosed. After adjustment, underweight subjects with a BMI of <18.5 kg/m2, compared to those with a low-normal BMI (20.0–<22.5 kg/m2) showed lower risk (HR 0.70; 95% CI 0.61–0.80) of AVS. The multivariable-adjusted HR for AVS increased from HR 1.28; 95% CI 1.17–1.39 for BMI 22.5–<25 kg/m2 to HR 1.91; 95% CI 1.12–3.25 for those with BMI 35–50 kg/m2. Further on, individuals 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/m2), compared to BMI <20.0 kg/m2 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. Conclusions Elevated BMI in youth, even within the normal range, is associated with increased risk of developing AVS, while subnormal BMI was protective. Excess weight in youth diagnosed with AVS is associated with higher risk of subsequent clinical outcomes. These findings are novel, generating new questions as to potential mechanisms and implying more vigilant monitoring of patients with AVS and a history of obesity in youth.Figure 1Figure 2