Abstract and Introduction
Abstract
Objective To examine the risk of thoracic aortic disease (TAD) when one or more first-degree relatives are affected, and to relate the risk of family history to the risk of other cardiopulmonary comorbidity.
Design Population-based, matched, case-control study.
Setting Registry-based investigation.
Patients All cases, nationwide, of TAD diagnosed 2001–2005 in individuals born 1932 or later (n=2436) were identified, and a random control-group (n=12 152) matched for age, sex and geography was generated. First-degree relatives were identified in the Multigeneration Registry. Family history of TAD was assessed by cross-linking nationwide health registries.
Interventions None.
Results Family history was present in 108 cases (4.4%), compared with 93 (0.77%) controls (p<0.0001). The risk of TAD increased with number of affected relatives: OR 5.8 (95% CI 4.3 to 7.7) vs OR 20 (2.2 to 179) with one versus two or more affected relatives. The relative risk of TAD was highest in the youngest (≤49 years) age group and slightly more pronounced in women than in men (OR 7.2 (4.2 to 12) vs OR 5.5 (3.9 to 7.7)). Among cardiopulmonary comorbidities, heart failure conferred the highest relative risk, OR 6.3 (4.1 to 9.8).
Conclusions Family history confers a significantly increased (sixfold to 20-fold) relative risk of TAD. The effect is more pronounced in women and in younger subjects, and is not conveyed by cardiopulmonary comorbidity. Knowledge of family history is important to counselling, treatment indications, surveillance and screening protocols.
Introduction
Familial aggregation of thoracic aortic diseases (TAD)—predominantly aneurysms and dissections—has been established in case series and cohorts derived from surgically treated patients. In such studies, family history is demonstrable in 14–20% of cases, promoting its role as an important risk factor for TAD. Family history of TAD has been associated with diagnosis at younger age and faster aortic growth, increasing sudden rupture risk and introducing uncertainty of adequate surgical timing. Family history has also been implied in late treatment failure (pseudoaneurysm or adjacent aneurysm formation requiring reintervention) in abdominal aortic aneurysm (AAA), suggesting progressive development of aortic disease and, eventually, worse prognosis. Knowledge on the magnitude of risk conveyed by family history, and its relation to other potential risk factors, is relevant to patient and family counselling, but also of importance in the planning of surveillance and definition of treatment indications. Acknowledging an increased burden of TAD, consideration must also be given to developing screening programmes, could adequate high-risk subgroups be identified. To accurately describe the impact of family history on the risk of TAD, population-based epidemiological data are needed. Based on Swedish nationwide registries of first-degree relatives, in-patient care and cause of death, a matched case-control study was designed to investigate the risk of developing thoracic aortic aneurysm or dissection associated with family history and adjusted for common cardiopulmonary risk factors.