title: High serum bilirubin levels and diabetic retinopathy: the Hisayama Study.
abstract: OBJECTIVE
  To assess the association between serum total bilirubin levels and diabetic retinopathy prevalence in participants of the Hisayama Study who had diabetes and impaired glucose metabolism.
  
  
  METHODS
  Population-based, cross-sectional study.
  
  
  METHODS
  Of 3119 participants of the Hisayama Study Eye Examinations in 2007, Japan, 1672 aged ≥40 years with either diabetes or impaired glucose metabolism (defined by a 75-g oral glucose tolerance test) were enrolled in the present study.
  
  
  METHODS
  Diabetic retinopathy was assessed via ophthalmic examination after pupil dilatation. The presence and the severity of diabetic retinopathy were determined by grading of color fundus photographs using the modified Airlie House classification system. Association of diabetic retinopathy with serum bilirubin quartiles was assessed using logistic regression model adjusting for age and known risk factors for diabetic retinopathy.
  
  
  METHODS
  Prevalent diabetic retinopathy.
  
  
  RESULTS
  Diabetic retinopathy was present in 70 of 1672 (4.2%) participants. The prevalence of diabetic retinopathy in persons with the highest bilirubin quartile (≥0.9 mg/dL) was 2.7%, compared with the prevalence of 3.4%, 5.1%, and 5.1% in those with the first (<0.6 mg/dL), second (0.6-0.69 mg/dL), and third quartiles (0.7-0.89 mg/dL). After adjusting for factors known to be associated with diabetic retinopathy, the prevalence was significantly lower among persons with the highest bilirubin quartile compared with those with the lowest quartile (odds ratio [OR], 0.25; 95% confidence interval [CI], 0.09-0.72) or compared with those in the 3 lower quartiles (OR, 0.25; 95% CI, 0.11-0.58).
  
  
  CONCLUSIONS
  Elevated serum bilirubin levels may be protective against diabetic retinopathy among persons with either diabetes or impaired glucose metabolism, independent of known risk factors for diabetic retinopathy.
authors: Department of Ophthalmology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan. miho-m@med.kyushu-u.ac.jp
authors: Miho
authors: M
authors: Yasuda
authors: Yutaka
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authors: Kiyohara
authors: Jie Jin
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authors: Wang
authors: Satoshi
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