Association between diastolic blood pressure and cumulative work time.

Diastolic blood pressure was viewed as a generic indicator of aging, and its association with cumulative work time was studied after controlling for age as a potential confounding factor. The study was conducted among production line workers at a Brazilian tannery in July 1993. The association between diastolic blood pressure and cumulative work time was verified by fitting a second-order linear regression model, where diastolic blood pressure was a function of worker's age and cumulative work time. By fitting the model, one can predict that, from the beginning of working life at the tannery, on average each 1-year period is associated with an increase of about 1. 5 mmHg in diastolic blood pressure. The fit obtained highlights a component directly associated with work as part of the rate of pressure increase in the study group. This component is twice as high as that directly associated with age.