Low serum bilirubin concentration is associated with coronary artery calcification (CAC).
BACKGROUND
Bilirubin is a potent antioxidant and previous studies have reported the relationship between low serum bilirubin concentration and atherosclerosis. The purpose of this study was to assess the correlation between serum bilirubin concentration and coronary artery calcification (CAC).


METHODS
This study consisted of 637 participants and we evaluated the relationship between CAC score determined by multislice computed tomography and serum bilirubin concentration.


RESULTS
An inverse correlation was found between serum bilirubin concentration and log(CAC+1) (r=-0.361, P<0.0001). Multiple regression analysis also demonstrated that age (beta=0.261, P=0.0125), systolic blood pressure (beta=0.153, P=0.0237), uric acid (beta=0.126, P=0.0441), estimated glomerular filtration rate (beta=-0.139, P=0.0416) and serum bilirubin concentration (beta=-0.281, P<0.0001) were independent determinants of log(CAC+1). An increment of 1 micromol/L in serum bilirubin concentration was associated with 14% decrease in the odds for CAC score > or =400 after adjustment for several risk factors. Both age and SBP were also positively associated with CAC score > or =400, but the odds ratio for CAC score > or =400 was greater for every 1 micromol/L increment in serum bilirubin concentration than for every 1-year increment in age and 1-mmHg increment in SBP.


CONCLUSIONS
Low serum bilirubin concentration is associated with coronary artery calcification. Serum bilirubin concentration can be measured easily in the clinical laboratory and applied in medical practice, and low serum bilirubin concentration would be useful as a provisional new risk factor of CAC.
Tanaka
Muhei
M
Department of Endocrinology and Metabolism, Kyoto Prefectural University of Medicine, Graduate School of Medical Science, 465 Kajii cho, Hirokoji, Kawaramachi dori, Kamikyo ku, Kyoto, Japan.
Fukui
Michiaki
M
Tomiyasu
Ki-ichiro
K
Akabame
Satoshi
S
Nakano
Koji
K
Hasegawa
Goji
G
Oda
Yohei
Y
Nakamura
Naoto
N
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D050197:Atherosclerosis / Q000150:complications*; D001663:Bilirubin / Q000097:blood*; D002114:Calcinosis / Q000209:etiology*; D003324:Coronary Artery Disease / Q000097:blood / Q000209:etiology*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012307:Risk Factors
D001663:Bilirubin