To evaluate the prevalence of hyperuricemia in Taiwan. A multi-stage stratified sampling scheme was used in Nutrition and Health Survey, which was conducted in Taiwan between 1993 and 96. Complete biochemical and questionnaire data for 2754 males and 2953 females aged 4 years and older were included in the analysis. The colorimetric enzymatic method was used to measure plasma uric acid in fasting blood samples. Information on self-reported, physician-diagnosed gout was also obtained. The uric acid values of males were found to reach a peak between the ages of 13 and 18 and decrease slightly after 18. The uric acid values of females were stable before the age of 18, decreasing slightly between 19 and 44 years, and increasing in the mid to older age groups (> or = 45 years). Twenty-six percent of adult males (> or = 19 years) and 22% of older males (> or = 45 years) either had hyperuricemia (serum uric acid > 458.0 microM or 7.7 mg/dl) or were taking medication for it. Seventeen percent of adult females and 23% of older females either had hyperuricemia (serum uric acid > 392.57 microM or 6.6 mg/dl) or were taking medication for it. Both adult males and females in mountainous areas, who were primarily aboriginal, had the highest prevalence of hyperuricemia (> 50%) among the 7 survey areas. Mean body mass index (BMI), alcohol consumption, and prevalence of gout were among the highest in mountainous people compared to all included in the study. Multivariate analysis showed that mountainous area, age and BMI are important factors associated with hyperuricemia in males, whereas mountainous area, Class II townships, and BMI are the factors associated with hyperuricemia in females. We found a high prevalence of hyperuricemia in Han Chinese in Taiwan despite a lack both of obesity and high alcohol consumption. Mountainous people (mainly aborigines) in Taiwan have an even higher prevalence of hyperuricemia, which cannot be completely explained by obesity and alcohol consumption. Genetic components and other environmental factors may have contributed to this pattern of hyperuricemia.