C-reactive protein and peripheral artery disease among Japanese elderly: the Tsurugaya Project.

We investigated the cross-sectional relationship between ankle brachial index and cardiovascular disease risk factors, including C-reactive protein (CRP), among Japanese elderly, a topic which has had little prior epidemiologic study. Our study population comprised 946 subjects aged at least 70 years in whom both CRP and ankle brachial index were measured. The participants were classified into a low (ankle brachial index<0.9) and normal ankle brachial index group. We found that current smoking, high-density lipoprotein cholesterol <40 mg/dl, a low body mass index (continuous variable), hypertension, diabetes and statin use were all significantly related to a lower ankle brachial index. Higher log-transformed CRP level was significantly related to a lower ankle brachial index after adjustment for the cardiovascular risk factors mentioned above (p <0.01). The odds ratios for low ankle brachial index compared to 0-1 risk factors were 5.79 (95% confidence interval [CI]: 2.99-11.20) for 2 risk factors and 17.45 (95% CI: 6.78-49.91) for 3 or more risk factors; independently of other risk factors, the odds ratio for CRP>1.0 mg/l was 2.10 (95% CI: 1.13-3.88) compared to lower CRP values. Thus, a high level of CRP is related to a low ankle brachial index among Japanese elderly as well as Western subjects. This is the first study to report the relationship between CRP and low ankle brachial index among Japanese elderly.