The study will measure the long-term impact of three hypertension control interventions implemented in three automobile manufacturing plants in 1978, and terminated in 1981. The effectiveness of the three interventions at maintaining high levels of blood pressure control in the three experimental sites (as compared with a fourth control site) was established during this initial project period. However, the period was too short to identify the benefits eventually expected from improved hypertension control, i.e., fewer cardiovascular events, and consequently lower health benefit costs and less sickness absenteeism. The proposed study will assess (a) continued maintenance of good control within the hypertensive populations at the experimental sites, and (b) changes in absenteeism and health benefit utilization rates among the hypertensives, as compared with matched normotensives at the respective sites, and as compared with hypertensives at the control site. All hypertensives and matched normotensives will be re-screened during the first year of the study, and data on attendance and health benefit utilization will be collected for the time period since termination of the initial study through the end of 1984. Data will be merged with datasets from the initial study and multivariate analysis techniques will be utilized to identify factors associated with maintenance of good control, as well as factors associated with low sickness absenteeism and low health benefit utilization (especially as related to cardiovascular disease). Differential rates of attrition from the plant, and their possible association with hypertension, will also be explored.