Siblings of Patients Hospitalized for VTE Suffer Increased Risk of Disorder

According to a recent study from Sweden, siblings of individuals hospitalized for possibly deadly blood clots in the legs or pelvis have an increased chance of suffering from the same ailment in comparison to individuals with healthy siblings.

This nationwide study is the first to show a direct connection between venous thromboembolism (VTE) and genetic predisposition, sorted by age and gender.

"Hereditary factors — as determined by sibling history — are significant in determining the risk of venous thromboembolism in men and women between the ages of 10 and 69," reported senior study author Bengt Zöller, M.D., Ph.D., associate professor at the Center for Primary Health Care Research, Lund University in Malmö, Sweden.

"More importantly,” continued Zöller, “in a fraction of the families we studied, the risk for venous thromboembolism was unusually high — 50 to 60 times higher than those families who were not at risk, thus suggesting a strong genetic risk factor."

This risk was doubled for participants who had one sibling with VTE, but the risk shot up to fifty times greater for participants with two or more siblings who suffered from the ailment.

For the study, the researchers extracted data from nationwide Swedish registries from the years 1987 through 2007, including the Hospital Discharge Register and the Swedish Multigeneration Register.

The researchers focused on 45,362 hospitalized cases of VTE, where patients were aged between ten and sixty-nine years old; the average age was 50.7 years for men and 46.6 years for women.

The study, which was split 48.5% male 51.5% female, found that 2,393 cases, or 5.3%, showed a sibling history for the disease.

Further, the researchers found that, for males and females between ten and nineteen years of age who had a sibling history of the disease, the risk was nearly five times higher than for individuals without a sibling history.

For people between sixty and sixty-nine years old, the risk was doubled if they had a sibling history of VTE.

In general, the sibling related incidence rate of VTE was higher for women than for men, particularly between the ages of ten and forty. Over the age of fifty, however, the frequency rate was increased for males.

One factor the researchers noted had little impact on the disorder was age differences between siblings, which may imply that there was no major familial environmental effect.

Researchers also took a look at the relationship between spouses of individuals who suffered from VTE, but they found only a slight increased risk. As such, they concluded that the heightened familial risk may be caused by genetics, not family environmental factors.

"Our study underscores the potential value of sibling history as a predictor of the risk of venous thromboembolism," Zöller stated. "Further research is needed to uncover the sources of genetic and non-genetic occurrences of VTE."

The study was published in Circulation: Journal of the American Heart Association.