Incidence of acute deep vein thrombosis in two districts. A phlebographic study.

The incidence of deep vein thrombosis (DVT), diagnosed by ascending phlebography, was calculated in two Swedish districts. The average incidence per thousand population and year was 0.85 in males and 0.68 in females. Before the age of 50 the incidence was very low and almost the same in both sexes. After age 50 the incidence in men markedly increased with age. A similar increase was found in women, but not before age 60. DVT occurring after age 50 was significantly more common in men than in women. The study strongly suggests male sex as a risk factor for DVT.