BACKGROUND:Albuminuria is an important predictor of risk of progressive renal disease, cardiovascular disease, and mortality; however, the prevalence in the general population is not well defined. We determined estimates of the population prevalence and associations of microalbuminuria and macroalbuminuria in Australian adults; 11,247 Australians aged > or = 25 years living in 42 randomly selected population clusters were tested for albuminuria (spot urine albumin:creatinine (mg/mmol): normal < 3.4, microalbuminuria 3.4 to 34, macroalbuminuria > 34). METHODS:Prevalence of micro- and macroalbuminuria were assessed with age, sex, obesity, smoking, hypertension (> or = 140/90 mm Hg or known diagnosis on treatment), glucose metabolism status (WHO criteria according to fasting glucose and oral glucose tolerance test), ischemic heart and cerebrovascular disease, and low glomerular filtration rate (calculated glomerular filtration rate < 60 mL/min/1.73m2). RESULTS:Microalbuminuria and macroalbuminuria proteinuria were present in 6.0% and 0.6% of the population, respectively. The majority of subjects with microalbuminuria (64%) and macroalbuminuria (76%) had hypertension, and approximately half of those with albuminuria had abnormal glucose metabolism. Of all participants with microalbuminuria, 25.9% had normal blood pressure and glucose metabolism, and in this group, alternative associations of microalbuminuria included obesity (13.5%), smoking (20.7%), and low glomerular filtration rate (12.3%). CONCLUSION:Albuminuria is present in a small percentage of the general adult population, but is highly prevalent in subjects with hypertension and/or abnormal glucose metabolism. The majority of cases of microalbuminuria and macroalbuminuria in the general population are among those with hypertension.