Urinary albumin excretion and prevalence of microalbuminuria in a general Chinese population: a cross-sectional study

Background: Microalbuminuria has been shown to be a risk factor for cardiovascular and renal disease in patients with hypertension and diabetes as well as in the general population. Urinary albumin excretion over 24 h is considered a 'gold standard' to detect microalbuminuria. Few studies have used 24-h urinary albumin excretion to analyze the prevalence of and related factors for microalbuminuira in a general Chinese population. Methods: This study included 1980 adults aged 18-69 years from the Shandong-Ministry of Health Action on Salt and Hypertension (SMASH) Project 2011 survey. Blood pressure, height, weight and waist circumference were measured, and a venous blood and timed 24-h urine samples were collected from each participant. Linear and logistic regression analyses were used to test associations between established cardiovascular risk factors and microalbuminuria. Results: The median (25th-75th percentile) of 24-h urinary albumin excretion was 6.1 mg/d (4.5-8.7 mg/d) for all adults, 6.0 mg/d (4.4-8.5 mg/d) for men and 6.2 mg/d (4.6-8.9 mg/d) for women. The overall prevalence of microalbuminuria was 4.1% (95% confidence interval [CI]: 3.2-5.0%), 3.7% (95% CI: 2.9-4.5%) for men and 4.6% (95% CI: 3.7-5.5%) for women. Microalbuminuria was present in 8.1% (95% CI: 6.9-9.3%) of individuals with hypertension, 11.4% (95% CI: 10.0-12.8%) of those with diabetes and 15.6% (95% CI: 14.0-17.2%) of those with both. Multiple logistic regression analysis indicated that systolic blood pressure (odds ratio [OR] 1.02; 95% CI: 1.01-1.03) and fasting blood glucose (OR 1.19; 95% CI: 1.05-1.35) were the independent risk factors for microalbuminuria. Conclusions: Adults in the general population of Shandong Province have a moderate prevalence of microalbuminuria. Those with hypertension and diabetes are at high risk of having microalbuminuria, suggesting the need for screening and early intervention for microalbuminuria among these individuals.