TUESDAY, Aug. 9 (HealthDay News) -- Familial risk factors are significant predictors of venous thromboembolism (VTE) among unaffected siblings between the ages of 10 to 69 years, and although the absolute risk increases with age, the relative contribution of familial factors decreases with age, according to a study published online Aug. 8 in Circulation.
Bengt Zöller, M.D., Ph.D., from Lund University in Malmö, Sweden, and colleagues investigated the age- and gender-specific familial risks of in siblings (aged 0 to 75 years) hospitalized due to VTE. Data were collected by linking 45,362 hospitalization records from the Swedish Multigeneration Register with the Hospital Discharge Register from 1987 to 2007. Age- and gender-adjusted incidence ratios and familial standardized incidence ratios were compared between siblings affected with VTE and siblings not affected with these conditions.
The investigators identified a familial standardized incidence ratio of 2.45, with 2,393 (5.3 percent) of siblings affected, with gender-specific differences noted in incidence rates. The absolute risks increased with age, and a significantly increased familial risk was seen from age 10 to 69 years, although the familiar standardized incidence ratio decreased from 4.77 for ages 10 to 19 years to 2.08 for ages 60 to 69 years. For siblings who had two and three or more affected probands, the familial standardized incidence ratios were 51.87 and 53.69, respectively. Spouses predicted low familial risks among 3,900 spouse cases observed with standardized incidence ratio of 1.07.
"Familial factors are important for the development of VTE, at least from the age of 10 to 69 years. The relative contribution of familial factors decreases with age, although the absolute risk increases," the authors write.