Urinary albumin to creatinine ratio and incidence of metabolic syndrome in Korean population

Abstract

BackgroundUrinary albumin excretion even in non-pathologic range (<30mg/g) is associated with an increasing risk of CVD and blood pressure progression. Recently, several studies have suggested that urinary albumin excretion is positively associated with prevalence of MetS and its components in various participants. Moreover, there were some studies that have shown the association between change of urinary albumin excretion and arterial stiffness or carotid intima-media thickness. However, there are currently a small number of studies published that have been evaluated the association between MetS, which is also intermediate risk factor of CVD, and low-grade albuminuria. And to our knowledge, there were no studies that investigated the association between change of urinary albumin excretion and MetS.PurposeThe purpose of this study was to examine the prospective association of UACR with the risk of MetS incidence and its components and to evaluate the association of UACR change from baseline over follow-up period with the change in risk of MetS incidence in Korean general population.MethodsTo investigate the association between UACR levels and MetS, baseline survey was included 6,489 participants (2,653 men and 3,836 women) aged 40 to 70 years. We prospectively examined incident risk for MetS and its components among 1,686 participants (740 men and 946 women) without metabolic syndrome at baseline. The subjects were 40 to 70 years of age and from the Korean Genome and Epidemiology Study on Atherosclerosis Risk of Rural Areas in the Korean General Population cohort. All subjects received medical examination according to standard procedures.ResultsIn baseline survey, mean waist circumference, systolic and diastolic blood pressure, fasting plasma glucose and median triglyceride increased in a linear fashion in both genders according to UACR quartile. High-density

lipoprotein cholesterol was shown decreased in a linear fashion according to UACR quartile. Compared to the lowest quartile of UACR, the odds ratios (ORs) for prevalence of MetS in participants who were categorized in the highest quartile of UACR were 1.87 (95% confidence interval (CI), 1.43–2.45) and 1.90 (1.54–2.35) in men and women, respectively, when adjusted for age, baseline BMI and other covariates. During a mean of 2.6 years of follow-up, 129 men (17.4%) and 183 women (19.3%) developed MetS. In prospective study, the ORs for incident MetS comparing the highest with the lowest tertiles of UACR levels were not significant as 0.93 (0.56-1.52) and 1.25 (0.82-1.89) in men and women, respectively. Compared to the group of less than 10% UACR increase from baseline and less than 5mg/g increase from baseline, the ORs for incident MetS in the group of more than 20% UACR increase and the group of more than 10mg/g increase from baseline were 1.44 (1.05-1.97) and 2.00 (1.22-3.28), respectively. UACR change was associated with incident risk of MetS (highest versus lowest tertile : 0.62, 95% CI 0.47-0.92). After stratification of cutoff points of UACR (10.6mg/g), compared to the group of less than 10% UACR increase from baseline and less than 5mg/g increase from baseline, the ORs for incident MetS in the group of more than 20% UACR increase and more than 10mg/g increase were 1.66 (1.12-2.46) and 4.16 (1.91-9.08) at levels below the cut-off, respectively. Similarly, an UACR change was associated with decreased incidence of MetS (highest versus 2nd , lowest tertile : 2nd, 0.54, 95% CI 0.36-0.81; lowest, 0.31 95% CI 0.09-1.12). . In contrast, UCAR change was not associated with incident MetS at levels above the cutoff points.ConclusionOur findings demonstrate that UACR change was positively associated with incident MetS. Especially this association was maintained in the

group of below cutoff points of baseline UACR, within the very low-grade albuminuria (<10.6 mg/g). These findings suggest increasing UACR change in the range of less than current microalbuminuria threshold may be a predictor for new-onset MetS.