Researchers have identified new genetic variations that may be associated with the risk of developing nonfatal venous thrombosis in postmenopausal women, according to a study in the February 7 issue of JAMA.

Deep vein thrombosis (blood clots in the thigh or leg) and pulmonary embolism (blood clots in the arteries leading to the lungs) cause significant illness and death in adult women, according to the background information in the article. The authors note that despite improved preventive treatments in high-risk patients, the incidence of venous thrombosis (VT) has not decreased.

In this study, Nicholas L. Smith, Ph.D., M.P.H., from the University of Washington, Seattle, and colleagues examined the association of common genetic variation in 24 clotting-related candidate genes with the risk of first-time VT in postmenopausal women. Study participants were 349 perimenopausal and postmenopausal women 30 to 89 years of age who sustained a first VT event between January 1995 and December 2002. The control group of 1,680 women included perimenopausal and postmenopausal women of the same age range who had no prior history of deep vein thrombosis or pulmonary embolism. Through blood samples taken from the study participants, the researchers analyzed genetic markers called haplotypes and changes in the DNA sequence called single nucelotide polymorphisms (SNP).

"Only the tissue factor pathway inhibitor gene demonstrated global association with risk. Five significant SNP associations were identified across three of the candidate genes (factors V, XI and protein C) in SNP analyses," the researchers report. Two of those associations had been previously reported. The researchers note that another 22 variants across 15 genes were also identified and classify them as "interesting associations."

"After accounting for multiple testing, five SNPs associated with VT risk were identified, three of which have not been previously reported. Replication of these novel associations in other populations is necessary to corroborate these findings and identify which genetic factors may influence VT risk in postmenopausal women," the authors conclude.

Note: This article has been adapted from a news release issued by JAMA and Archives Journals.