Association between Body Mass Index and Risk of Aortic Stenosis in Women

Background Overweight and obesity are increasing globally, as are life expectancy and disorders associated with aging, including calcific aortic stenosis (AS). Studies investigating the correlation between high body mass index (BMI) and AS are contradictory and inconclusive. This study examines a potential association between BMI and early AS in women. Methods By linking the Swedish Medical Birth Register (MBR) and the Swedish National Patient Register (NPR), we included women between 18 and 55 years with a first childbirth from 1982 to 2020. Diagnosis of subsequent AS and comorbidities were defined according to the International Classification of Diseases (ICD) 8, 9, and 10 codes. The women were divided into eight groups based on their BMI, with BMI 20 kg/m 2 -<22.5 kg/m 2 as reference. Cox proportional hazards regression models were used to investigate the difference in the risk of being diagnosed with AS. Results The mean age at inclusion among 1,722,798 women was 28 years, and the mean BMI was 24 kg/m 2 . Some 21% were overweight (BMI 30 kg/m 2 -<35 kg/m 2 ) and 10.7% were obese (BMI≥35 kg/m 2 ). During a median follow-up of 19.5 years, 2,513 women (0.15%) were diagnosed with AS. The age-adjusted risk of being diagnosed with AS, compared to a reference group with BMI 20 -<22.5 kg/m 2 , increased with higher BMI to 2.8 (95%CI 2.43-3.24) times higher in women with BMI 30 -<35 kg/m 2 , and to 3.67 (95%CI 2.91-4.64) times higher in those with severe obesity (BMI ≥35 kg/m 2 ). Similar results were found after excluding AS of rheumatic and congenital etiology. Conclusions Higher BMI correlated with a higher risk of developing AS in women, regardless of etiology, beginning with increased risk even within the upper normal range, reaching a three times higher risk in women with severe obesity. Clinical perspective What is new? This study investigates a subpopulation seldom included in valvular heart diseases studies, younger women, showing that women with overweight and obesity have approximately three times higher risk to be diagnosed with AS. Even women in the BMI group considered high-normal (BMI 22.5 -<25 kg/m 2 ) had higher risk for AS compared those with BMI 20 -<22.5 kg/m 2 . What are the clinical implications? The percentage of individuals with overweight and obesity increases and in the same time, AS becomes more prevalent as the population ages. Considering that there is no medical treatment that can ameliorate AS prognosis, prevention by maintaining a low-normal or normal BMI becomes even more important.