Immigration from Ethiopia to Israel exposed subjects from an underdeveloped environment to that of a westernised, developed country. In previous cross-sectional analyses we found that residence in Israel for more than 2 years was associated with a rise in blood pressure which, in turn, was associated with a rise in lipids and insulin levels. Herein we report longitudinal follow-up and baseline examination of 53 young male Ethiopians who resided in a relatively controlled environment (agricultural boarding schools) for 2 years after immigration. Their mean age, when re-examined, was 23 +/- 3 years. Body mass index (20 +/- 2 kg/m2) and triceps' skinfold (71 +/- 32 mm) were not different from baseline values. However, over the 2 years blood pressure rose from 118 +/- 9/62 +/- 11 to 129 +/- 13/71 +/- 10 mmHg, P < 0.0001 for both systolic and diastolic pressures. At 2 years 11 of 53 subjects (20.7%) had hypertension. Total high-density lipoprotein cholesterol and triglyceride levels increased from 131 +/- 27, 36 +/- 8 and 65 +/- 22 mg/dl to 146 +/- 29, 43 +/- 10 and 98 +/- 42 mg/dl, respectively; P < 0.00001 for all. Surprisingly, glucose tolerance (to oral 75 g load) improved and the sum of insulin (first and second hour post-load) decreased significantly and was not correlated with blood pressure changes. Only systolic blood pressure was an independent predictor of incident hypertension (r2 = 0.33, P < 0.0001) in multiple regression analysis.(ABSTRACT TRUNCATED AT 250 WORDS)