Mildly elevated serum total bilirubin levels are negatively associated with carotid atherosclerosis among elderly persons with type 2 diabetes

Abstract

Diabetes is strongly associated with several mechanisms of tissue damage such as oxidative stress. Serum bilirubin may have a beneficial role in preventing oxidative changes in cardiovascular disease (CVD). Limited information is available on whether serum bilirubin is an independent confounding factor for carotid atherosclerosis among elderly persons with type 2 diabetes. The study subjects were 169 men aged 79 ± 8 (mean ± SD) years and 205 women aged 81 ± 8 years that were enrolled consecutively from patients in the medical department. Carotid intima-media thickness (IMT) and plaque were derived via B-mode ultrasonography. Multiple linear regression analysis showed that serum total bilirubin (β = −0.160) was significantly associated with carotid IMT. Compared to subjects with a serum total bilirubin of tertile-1 (0.13–0.58 mg/dL), the multivariate-adjusted odds ratio (95% confidence interval) of carotid IMT ≥1.0 mm including plaque and carotid plaque was 0.46 (0.23–0.93) and 0.32 (0.17–0.60) in the Tertile-3 group (0.87–1.93 mg/dL), respectively. Next, data were further stratified by gender, age, smoking status, medication and prevalence of CVD. There were no significant differences in serum total bilirubin levels between selected subgroups. Our data demonstrated a negative association between serum total bilirubin and carotid atherosclerosis among elderly persons with type 2 diabetes.

• Atherosclerosis
• carotid artery
• confounding factor
• Serum total bilirubin
• ultrasonography
• type 2 diabetes

Declaration of interest

The authors declare that they have no competing interests. This study was supported, in part, by a grant-in-aid from the Foundation for the Development of the Community (2014).