The factors associated with proteinuria were examined in a large multiracial Asian population participating in a screening program aimed at the early detection of renal disease. Of 213,873 adults who participated, 189,117 with complete data were included. Malay race, increasing age, both extremes of body mass index (BMI), self-reported family history of kidney disease (FKD), and higher systolic and diastolic BP measurements (even at levels classified as being within the normal range) were independently associated with dipstick-positive proteinuria. The odds ratios (OR) for proteinuria increased progressively with age. There was a J-shaped relationship between BMI and proteinuria (OR of 1.3, 1.00, 1.3, 1.6, and 2.5 for BMI of < or =18.00, 23.00 to 24.99, 25.00 to 27.49, 27.50 to 29.99, and > or =30.00 kg/m(2), respectively, compared with BMI of 18.01 to 22.99 kg/m(2)). OR for proteinuria according to systolic and diastolic BP were significantly increased beginning at levels of 110 and 90 mmHg, respectively. In addition, the Malay race was associated with a significantly higher OR for proteinuria, compared with the Chinese race (OR of 1.3). Finally, FKD was significantly associated with proteinuria (OR of 1.7), whereas a family history of diabetes mellitus and a family history of hypertension were not. When family histories were analyzed by clustering, isolated FKD remained a significant determinant of proteinuria and the magnitude of the effect was not significantly different from that observed in the presence of a coexisting family history of diabetes mellitus or hypertension. This is the first study to evaluate factors associated with proteinuria in an Asian population. The epidemiologic study of renal disease in this population suggests that risk factors for renal disease might differ significantly among racial groups.