Association between serum C-reactive protein levels and microalbuminuria: a population-based cross-sectional study in northern Iwate, Japan

Intern Med. 2004 Oct;43(10):919-25. doi: 10.2169/internalmedicine.43.919.


Objective: The presence of microalbuminuria is a renal marker of vascular endothelial damage, and is an independent and strong predictor of increased risk for cardiovascular mortality and morbidity. Elevated circulating C-reactive protein (CRP) levels have recently been reported to be a novel cardiovascular risk factor, and it has been suggested that this acute-phase protein impairs vascular endothelial function. The aim of the present study was to determine whether serum CRP level is a dependent or an independent risk factor of microalbuminuria in the general population.

Methods: Subjects of this cross-sectional study were apparently healthy individuals drawn from the general Japanese population (mean age, 62; men, 2,236; women, 4,217). Serum CRP levels were determined using a highly sensitive kit and urine albumin-creatinine ratio (UACR) was calculated using a single urine sample. Multivariate logistic regression analysis was used to determine which risk factors (ie, age, hypertension, diabetes, obesity, hypercholesterolemia, smoking, and CRP) might predict the presence of microalbuminuria.

Results: In addition to classical cardiovascular risk factors such as age, hypertension, diabetes and obesity, serum CRP levels are also significantly correlated with microalbuminuria in men (odds ratio = 1.42, 95% CI = 1.13-1.79; p < 0.01) and women (odds ratio = 1.25, 95% CI = 1.05-1.49; p < 0.01). When subjects with diabetes were excluded from the analysis, serum CRP levels continued to be a significant predictor for microalbuminuria (odds ratio = 1.35, 95% CI = 1.06-1.73; p < 0.05 for men: odds ratio = 1.23, 95% CI = 1.03-1.47; p < 0.05 for women).

Conclusions: The present study has shown that low-grade inflammation as represented by high sensitivity CRP levels may be significantly related to the presence of microalbuminuria. This suggests that microalbuminuria may be a useful marker representing systemic low-grade inflammation as well as being an established cardiovascular risk factor in apparently healthy individuals.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Albuminuria / epidemiology*
  • C-Reactive Protein / analysis*
  • Cohort Studies
  • Cross-Sectional Studies
  • Female
  • Humans
  • Japan / epidemiology
  • Logistic Models
  • Male
  • Middle Aged
  • Multivariate Analysis
  • Prospective Studies
  • Risk Factors
  • Surveys and Questionnaires


  • C-Reactive Protein