Venous thromboembolism does not share familial susceptibility with retinal vascular occlusion or glaucoma: a nationwide family study.

Inherited hypercoagulable states (i.e. thrombophilia) have been suggested to be involved in retinal vascular occlusion but results are divergent. Vascular micronutrition and ischemia have been hypothesised to be involved in the pathogenesis of glaucoma. This nationwide study determines the importance of family history of venous thromboembolism (VTE) as a risk factor for retinal vein occlusion (RVO), retinal artery occlusion (RAO), primary open angle glaucoma (POAG) and primary angle-closure glaucoma (PACG). A total of 6,007,042 Swedish individuals were studied. Data from the Swedish Multigeneration Register for subjects aged 0-78 years old for the period 1997-2010 were linked to the Swedish Hospital Discharge Register and the Hospital Outpatient Register. Main exposure measure was family history of VTE in first-degree relatives (parents and/or siblings). Main outcomes were hazard ratios (HRs) for RVO, RAO, POAG, and PACG. During follow-up 9036 individuals developed RVO, 2137 individuals developed RAO, 29,176 individuals developed POAG and 1498 individuals developed PACG. There was no association between family history of VTE and risk of RVO (HR = 1.04, 95 % CI 0.98-1.10), RAO (HR = 1.00, 95 % CI 0.89-1.13), POAG (HR = 0.96, 95 % CI 0.93-0.99), and PACG (HR = 0.92, 95 % CI 0.80-1.06) in the crude age and sex adjusted model. The results were similar in the fully adjusted model: RVO (HR = 1.04, 95 % CI 0.99-1.11), RAO (HR = 1.01, 95 % CI 0.89-1.13), POAG (HR = 0.97, 95 % CI 0.94-1.00), and PACG (HR = 0.91, 95 % CI 0.79-1.05). Family history of VTE is not a risk factor for RVO, RAO, POAG and PACG. Thus, it is unlikely that strong and common genetic variants associated with VTE are of importance for these disorders.