Long-term study of borderline hypertension among male industrial workers

Out of 1,236 men aged 40-59 years working in the same industrial plant, 253 (20.5%) had borderline arterial hypertension (BH). These employees and 237 matched normotensives were followed for several years. After 13 years, 343 participants, 70% of the initial number were studied. Arterial hypertension developed in 79.1% of the group with initial BH, most frequently in those with systolic-diastolic, and less often with systolic or diastolic BH. In normotensives, hypertension was diagnosed in 30.0% (P less than 0.001). All participants showed a correlation between blood pressure rise and initial value. A smaller number of men in the group with initial BH (36%) continued to work compared with normotensive men (48.1%) (P less than 0.01). The relationship between ability to work and blood pressure level became more prominent when we took into account final diagnosis: 65.7% of the actual normotensives, 56.4% of the borderline hypertensives and 47.5% of the hypertensives were still working after 13 years. Death rate was also higher in the group with BH (15.4%) than in the controls (8.4%) (P less than 0.01). The highest death rate was found when BH was combined with other coronary risk factors.