IS INSULIN OR ITS PRECURSOR INDEPENDENTLY ASSOCIATED WITH HYPERTENSION - AN EPIDEMIOLOGIC-STUDY IN JAPANESE-BRAZILIANS

Japanese individuals living outside Japan are more susceptible to chro nic diseases included in the insulin resistance syndrome. Hyperinsulin emia and hypertension are associated, but large studies adjusting for confounders are still required. The present evaluated if insulin (I) o r proinsulin (PI) was associated with hypertension after adjustment fo r other risk factors, in first (n=238) and second (n=292) generation J apanese-Brazilians, aged 40 to 79 years, living in a developed city in Brazil. Blood pressure (BP) was measured by random-zero sphygmomanome try. People with mean systolic/diastolic BP >140/90 mm Hg or taking an tihypertensive drugs were considered hypertensive. Diagnosis of diabet es was based on results of an oral glucose tolerance test using WHO cr iteria. I and PI after fasting and 2 hours after glucose load were det ermined by specific immunofluorimetric assays. The first generation wa s older than the second (65.6+/-9.2 versus 53.6+/-8.4 years, P<.01) an d male/female ratios were 1.14 and 0.87, respectively. The age-adjuste d prevalence of hypertension was 29.2% with no difference between sexe s or generations. Higher body mass index (25.2+/-4.3 versus 23.8+/-3.3 kg/m(2)), waist-to-hip ratio (0.939+/-0.067 versus 0.919+/-0.073), pl asma glucose (6.3+/-2.3 versus 5.6+/-1.8 mmol/L), cholesterol (5.74+/- 1.19 versus 5.48+/-1.08 mmol/L), and creatinine (74+/-26 versus 83+/-3 6 mu mol/L) were found among the hypertensives (P<.05). Univariate ana lyses showed associations of obesity, diabetes, and dyslipidemia with hypertension. Logistic regression analyses demonstrated that 2-hour I (OR, 1.22; 95% CI, 1.02 to 1.46) and fasting PI (OR, 1.14; 95% CI, 1.0 0 to 1.31) remained significantly associated with hypertension, after adjustment for age, sex, generation, family history of hypertension, s moking habits, waist-to-hip ratio, serum creatinine, glucose intoleran ce, and dyslipidemia. Japanese-Brazilians have a higher prevalence of hypertension than the general population in Brazil. High levels of 2-h our I, seen in hypertensives, may be interpreted as independent risk f actors for hypertension in this population. Our findings suggest that fasting PI should be useful, in addition to insulin, to assess risk fa ctors for hypertension in epidemiological studies.