Familial Aggregation of Aortic Valvular Stenosis: A Nationwide Study of Sibling Risk

Background - Aortic valvular stenosis (AS) is the most common cause of cardiac valvular replacement surgery. During the last century, the pathogenesis of AS has undergone transitions in developed countries, from rheumatic heart disease to a degenerative calcific pathogenesis. Although a familial component has been described for a subset of cases with a bicuspid valve, data are limited on the overall familial aggregation of this disease. Methods and Results - Contemporary information on 6 117 263 Swedish siblings, of which 13 442 had a clinical diagnosis of AS, was collected from the nationwide Swedish Multi-Generation Register and the National Patient Register. A total of 4.8% of AS cases had a sibling history of AS. Having at least 1 sibling with AS was associated with a hazard ratio of 3.41 (95% confidence interval, 2.23-5.21) to be diagnosed with AS in an adjusted model. Individuals with >1 sibling with AS had an exceptionally high risk (hazard ratio, 32.84) but were uncommon (34 siblings from 11 sibships). In contrast, spouses of subjects with AS were only slightly more likely to be diagnosed with AS compared with subjects without spousal AS (hazard ratio 1.16 for husbands and 1.18 for wives). Conclusions - A sibling history of clinically diagnosed AS was associated with increased risk of AS. Spouses of patients with AS only had a modest risk increase, suggesting that shared adult environmental factors contribute less to the development of AS than genetic factors.