A sibling history of blood clots may increase the risk for brothers and sisters

Having a sibling with a history of developing blood clots in the leg and pelvis may boost the likelihood of developing the condition.

A study released today in Circulation: Journal of the American Heart Assn. looked at how family relationships may factor into the risk of having venous thromboembolism, the development of blood clots in the veins. Swedish researchers looked at 45,362 cases of people ages 10 to 69 who were hospitalized for the condition.

People ages 10 to 19 who had a brother or sister with the clotting disorder were at almost five times greater risk for the disorder than those who didn’t have a sibling with the condition. For those ages 60 to 69 the risk was twice as great if they had a sibling with a history of the disorder.


When comparing genders, females ages 10 to 40 had a higher frequency rate for the condition than men, but after age 50, things switched, giving men a higher incidence rate.

“Our study underscores the potential value of sibling history as a predictor of the risk of venous thromboembolism,” said senior author Dr. Bengt Zoller in a news release. “Further research is needed to uncover the sources of genetic and non-genetic occurrences of (the disorder).”