Br J Surg. 2026 Aug 27;113(9):znag108. doi: 10.1093/bjs/znag108.
ABSTRACT
BACKGROUND: The aim was to investigate the increased risk for siblings to have similar aortic pathology (wide or small) in an abdominal aortic aneurysm (AAA) screening population with ultrasonographic measurement of infrarenal aortic diameter (IAD).
METHODS: The population-based cohort of men who had participated in the Stockholm AAA screening programme between 2010 and 2024 (107 336 men) were linked to the Swedish Multigeneration Registry (MGR), via the STRIREG cohort. All individuals except one had data available in the MGR. A subaneurysmal aorta (SAA) was defined as having an IAD of 25-29 mm, an AAA was defined as having an IAD of ≥30 mm, and a small aorta was defined as having an IAD of <17 mm. Descriptive statistics and cumulative probability models were stratified for relatedness. Quantitative genetic modelling was used to estimate heritability.
RESULTS: From 16 005 screened 65-year-old men, 8987 sibling pairs (7625 pairs of full siblings, 1152 pairs of half siblings, and 210 pairs of twins) were included. In total, 161 (1.0%) had an AAA, 155 (1.0%) had an SAA, and 2700 (16.9%) had a small aorta. IAD correlated stronger in twins than full siblings and weakest among half siblings (half siblings, r = 0.1; full siblings, r = 0.19; and twins, r = 0.52). Overall, 316 (2.0%) individuals had an IAD ≥25 mm and, if a sibling's IAD was 30 mm, the estimated probability of IAD ≥25 mm was 2.7% (95% c.i. 1.9% to 3.7%) in half siblings, 5.3% (95% c.i. 4.5% to 6.2%) in full siblings, and 21% (95% c.i. 10.2% to 38.2%) in twins. Heritability estimates were 0.41 for IAD, 0.61 for SAA/AAA, and 0.58 for small aorta.
CONCLUSION: This study provides further evidence for familial aggregation and heritability of IAD and pathologies of the infrarenal aorta, which reinforces the advice for screening of siblings, and especially twins, of individuals with an abnormal aortic diameter including subaneurysms.
PMID:42720511 | DOI:10.1093/bjs/znag108