Central obesity is an independent risk factor for microalbuminuria in both the general Korean women and nondiabetic nonhypertensive subpopulation: Association of microalbuminuria and metabolic syndrome from the Korea National Health and Nutrition Examination Survey 2011–2012

Highlights

• Central obesity is the most important risk factor for microalbuminuria in the nondiabetic nonhypertensive women.

• Gender difference exists in the contribution power of central obesity to the development of microalbuminuria.

• Early screening strategies to prevent microalbuminuria are suggested especially for women with central obesity.

Abstract

Background

We investigated the major contributing component of metabolic syndrome (MetS) that results in microalbuminuria (MAU) in the general population as well as in nondiabetic nonhypertensive subjects.

Methods

The study population consisted of a total of 9961 subjects (4429 men and 5532 women) who participated in the Korea National Health and Nutrition Examination Surveys conducted in 2011 and 2012. MAU was defined as a urine albumin-to-creatinine ratio of > 3.39 mg/mmol. After analyzing the contribution of each five MetS components for the presence of MAU with adjustment for other risk factors in the total population, we further examined the contribution of these components to MAU in the nondiabetic nonhypertensive subpopulation.

Results

The most significantly associated factors for MAU in both genders were high blood pressure, followed by impaired fasting glucose, and high triglycerides. In addition, central obesity contributed significantly to MAU only in women. For the nondiabetic nonhypertensive subpopulation, high blood pressure in both genders and central obesity in women were important risk factors for MAU. We suggest two possible hypotheses for the gender different phenomenon.

Conclusions

Central obesity was an independent risk factor for MAU in the general Korean women as well as in the nondiabetic nonhypertensive women.

Introduction

Metabolic syndrome (MetS) is a constellation of common metabolic disorders that result from impaired glucose tolerance, dyslipidemia, hypertension, and central obesity [1]. The diagnostic criteria for MetS have undergone several updates and changes. The first criteria proposed by the World Health Organization in 1998 included components of diabetes, hypertension, dyslipidemia, obesity, and microalbuminuria (MAU). However, MAU has been excluded from the subsequent diagnostic criteria for MetS, as suggested by the European Group for the Study of Insulin Resistance (1999), National Cholesterol Education Program Third Adult Treatment Panel (2001), American Association of Clinical Endocrinologists (2003), and International Diabetes Federation (2005). Although there have been some suggestions to adjust the MetS criteria based on clinical outcomes and racial variances, MAU was not emphasized as a component of MetS until recently [2]. However, the important association between MAU and MetS has been supported by several recent studies [3], [4].

It has been traditionally determined that an increased excretion of albumin alone (> 30 mg/day) is a sensitive marker of progressive diabetic glomerulopathy in type I diabetes patients [5]. MAU has also been recognized as an early sign of renal damage and an independent predictor for end-stage renal disease in patients with type I and type II diabetes and also in the general population. More importantly, MAU has been emphasized as an important criterion for the definition of chronic kidney disease (CKD), as suggested by Kidney Disease Improving Global Outcomes (KDIGO) group in 2012 [6]. In the new guideline, MAU was introduced as an equally indispensible component for the definition of CKD with the traditional criterion, estimated glomerular filtration rate (eGFR). This modification was based on the fact that MAU was strongly independently associated with not only cardiovascular complication of CKD [7], but also total mortality of CKD [8], indicating the importance of MAU than ever.

According to the recent reports on the association between MAU and MetS, high blood pressure and high fasting glucose level were commonly suggested as the major risk factors for MAU [3], [4]. However, other metabolic parameters have not been studied well about their levels of contribution for the development of MAU. Especially, only few studies focused on the low risk healthy population without having diabetes or hypertension in searching for the risk factors of MAU [9].

The purpose of this study was to investigate the major contributing components of MetS that result in MAU in the general Korean population as well as in the nondiabetic nonhypertensive subpopulation.