Association of microalbuminuria and high–normal 24-hour urinary albumin excretion with metabolic syndrome and its components in the general Chinese population: cross-sectional study

OBJECTIVE: Microalbuminuria (MAU) has been described as a risk factor for metabolic syndrome (MetS). However, the association between MetS components with MAU and 24-hour urinary albumin excretion (UAE) has not been clearly explained in the general Chinese population. We aimed to analyse the associations between MAU and high–normal 24-hour UAE with MetS and its components. DESIGN: Cross-sectional observational study. SETTING: Four selected counties/districts in China’s Shandong and Jiangsu Provinces. PARTICIPANTS: A total of 2261 participants aged 18–69 years were included in this study. Participants with missing physical examination data or incomplete urine collection were not included in the analysis. RESULTS: The prevalence of MAU was 9%, and the mean 24-hour UAE was 18 mg/d. The prevalence of MAU was significantly higher for the MetS, high blood pressure (BP), high triglyceride (TG) levels, low high-density lipoprotein cholesterol (HDL-C) and hyperglycaemia groups but not for the central obesity group. Both MAU and mean 24-hour UAE were significantly increased in association with a number of MetS components. The adjusted prevalence OR (POR) for MetS with MAU was 2.95 (95% CI 2.15 to 4.04) compared with those without MAU. MAU was significantly associated with three components of MetS: high BP (POR=1.86, 95% CI 1.31 to 2.64), high TG levels (POR=1.80, 95% CI 1.31 to 2.46) and hyperglycaemia (POR=1.84, 95% CI 1.34 to 2.53). No significant association between MAU and central obesity or low HDL-C was found. The presence of MetS gradually increased according to the normal-range 24-hour UAE quartiles: POR=1.00, POR=1.22, POR=1.14 and POR=2.02, respectively. Hyperglycaemia also increased significantly according to the normal-range 24-hour UAE quartiles. CONCLUSIONS: MAU and elevated 24-hour UAE within the normal range were closely associated with MetS in the Chinese population, which may provide a basis for the development of early interventions to decrease the effects of MetS.