Abstract-C-reactive protein (CRP) and microalbuminuria reflect intimately related components of the atherosclerotic disease process. Epidemiological studies found only modest associations between CRP and microalbuminuria. Blood pressure, one of the components of the metabolic syndrome in the general population, is the main determinant of microalbuminuria in diabetes and hypertension. We questioned whether CRP modifies the relationship of blood pressure and other cardiovascular risk factors with microalbuminuria in a cross-sectional study in 8592 inhabitants from Groningen, The Netherlands. The crude data showed an increase in the prevalence of microalbuminuria with increasing CRP quartiles (4.8, 9.6, 14. Key Words: cardiovascular diseases Ⅲ blood pressure Ⅲ risk factors Ⅲ kidney Ⅲ albuminuria C -reactive protein (CRP), a sensitive marker of (sub)clinical inflammation, is thought to represent the state of chronic low-grade inflammation of the arterial vessel wall at atherosclerotic sites. 1 CRP consistently predicts cardiovascular (CV) outcome. [2][3][4] Microalbuminuria is also an established risk marker for future cardiovascular events in various populations. 5,6 The appearance of low levels of albumin in the urine is thought to be the consequence of generalized endothelial damage along the vascular tree, including the glomerulus. 7 Blood pressure has been shown to be the main determinant of microalbuminuria in diabetes and hypertension. 8 Many other CV risk factors, which cluster within the metabolic syndrome, have been shown to relate to microalbuminuria in the population. 9,10 Because CRP and microalbuminuria reflect closely related components of the same disease processes, one might anticipate a strong relationship between them. However, studies that investigated this relationship in large populations only found weak associations. 11,12 Interdependence between CRP and other cardiovascular risk factors with the risk of microalbuminuria may have been overlooked.We questioned whether elevated serum CRP levels modify the relation of blood pressure and other CV risk factors with microalbuminuria.
Methods
Study DesignThis study is part of the PREVEND study (Prevention of REnal and Vascular ENdstage Disease) in Groningen, The Netherlands. PREVEND investigates the natural course of microalbuminuria in relation to renal and cardiovascular morbidity and mortality in the general population. All inhabitants aged 28 to 75 years (nϭ85 421) were asked to send in a morning urine sample and to complete a brief questionnaire on demographics and renal and cardiovascular morbidity. A total of 40 856 subjects responded. Pregnant women and subjects using insulin were excluded. All subjects with an albumin concentration of Ͼ10 mg/L in their morning urine sample plus a random sample of the population with a morning urine albumin excretion Ͻ10 mg/L were invited to our outpatient clinic. A detailed overview of this protocol is described elsewhere. 13 All subjects completed an extensive questionnaire on demographics, renal and cardio...