Objective   To study the major risk factors and high risk population of essential hypertension.

  Methods   The community-based case-control study was used.116 essential hypertensives, screened from a steel factory workers, not taking hypertensive medication, and 136 normotensives, screened from health workers in the same factory were selected as the subjects in this study.Classification tree analysis was performed to analyze the data.

  Results   The important risk factors of essential hypertension were BMI, WHR, alcohol drinking, cigarette smoking, hyperlipidemia, age, and sex.The major high risk population were that(1)people with overweight, centralized obesity, and alcohol drinking; (2)people with overweight, centralized obesity, old age, and male smoking cig arette; (3)people with overweight and hyperlipidemia; (4)people with centralized obesity, alcohol drinking, and cigarette smoking.The major high risk population were about 82.76% of the total cases in this study.The results of classification using learning sample were as follows: sensitivity was 82.76% and specificity was 74.26%;When using test sample, sensitivity was 71.55% and specificity was 61.03%.

  Conclusion   Different kinds of preventive measures should be taken according to the different types of high risk population of essential hypertension.In general population, to control the body weight and alcohol drinking, to abstain from cigarette smoking, and to control the levels of serum lipids should be important for hypertensive prevention.