Nakamura Motoyuki, Onoda Toshiyuki, Itai Kazuyoshi, Ohsawa Masaki, Satou Kenyu, Sakai Toshiaki, Segawa Toshie, Sasaki Junko, Tonari Yoko, Hiramori Katsuhiko, Okayama Akira
Second Department of Internal Medicine, Iwate Medical University School of Medicine, 19-1 Uchimaru, Morioka, Iwate 020-8505.
Intern Med. 2004 Oct;43(10):919-25. doi: 10.2169/internalmedicine.43.919.
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.
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.
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).
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.
微量白蛋白尿的存在是血管内皮损伤的肾脏标志物，并且是心血管疾病死亡率和发病率增加风险的独立且有力的预测指标。最近有报道称，循环中C反应蛋白（CRP）水平升高是一种新的心血管危险因素，并且有人提出这种急性期蛋白会损害血管内皮功能。本研究的目的是确定血清CRP水平是普通人群微量白蛋白尿的依赖危险因素还是独立危险因素。
这项横断面研究的受试者是从一般日本人群中抽取的表面健康的个体（平均年龄62岁；男性2236名，女性4217名）。使用高灵敏度试剂盒测定血清CRP水平，并使用单次尿液样本计算尿白蛋白-肌酐比值（UACR）。采用多变量逻辑回归分析来确定哪些危险因素（即年龄、高血压、糖尿病、肥胖、高胆固醇血症、吸烟和CRP）可能预测微量白蛋白尿的存在。
除了年龄、高血压、糖尿病和肥胖等经典心血管危险因素外，血清CRP水平在男性（比值比=1.42，95%可信区间=1.13-1.79；p<0.01）和女性（比值比=1.25，95%可信区间=1.05-1.49；p<0.01）中也与微量白蛋白尿显著相关。当将糖尿病患者排除在分析之外时，血清CRP水平仍然是微量白蛋白尿的显著预测指标（男性：比值比=1.35，95%可信区间=1.06-1.73；p<0.05；女性：比值比=1.23，95%可信区间=1.03-1.47；p<0.05）。
本研究表明，以高灵敏度CRP水平为代表的低度炎症可能与微量白蛋白尿的存在显著相关。这表明微量白蛋白尿可能是代表全身性低度炎症的有用标志物，也是表面健康个体中既定的心血管危险因素。
