The RATIO study: oral contraceptives and the risk of peripheral arterial disease in young women.

With regard to oral contraceptives, much research has concentrated on venous thrombosis and on the coronary and cerebral forms of atherosclerotic disease, while peripheral arterial disease (PAD) has received little attention. In this case-control study, we assessed oral contraceptive use and the risk of PAD in young women using a population-based case-control study. The women were 18-49 years of age, and had been admitted to a collaborating hospital between January 1990 and October 1995, and had a diagnosis of PAD. Participants were patients with PAD (n = 152), and control women (n = 925), identified by random digit dialing. The diagnosis of PAD was based almost exclusively on intra-arterial angiography. Patients and control subjects filled out the same structured questionnaire, which included questions on medical history, cardiovascular risk factors, and contraceptive use. The adjusted odds ratio for PAD in women using any type of oral contraceptives vs. no use, was 3.8 (95% CI 2.4-5.8). When first generation oral contraceptive use was compared with no use, the odds ratio was 8.7 (95% CI 3.6-21.3). For second and third generation oral contraceptives, the adjusted odds ratios (compared with non-users) were 2.6 (95% CI 1.4-4.9) and 3.0 (95% CI 1.4-6.6), respectively. This is the first study on oral contraceptive use and PAD in humans. All types of oral contraceptives were associated with an increased risk of PAD.