Job strain and ambulatory blood pressure levels in a population-based employed sample of men from northern Italy

Objectives. The purpose of this cross-sectional study was to examine the associations between categories of perceived job strain and blood pressure, measured by clinical and ambulatory devices on a population-based sample of employed men in northern Italy. Methods. The study included 527 employed normotensive or mild hypertensive nonmedicated men enrolled in an age-gender stratified random sample of 821 25- to 64-year-old residents of the city of Monza (in the vicinity of Milan). The job-strain categories were classified according to the traditional quadrant-term approach and also a new approach based on the comparison of extreme tertile categories in order to enhance contrasts. Clinical blood pressure was measured according to the standardized MONICA procedure; 24-h, work, leisure, and nighttime blood pressure values were obtained with an ambulatory device. Disparities, calculated as differences between clinical and ambulatory measurements, were also analyzed. Results. Among normotensive working men the highest mean for systolic blood pressure was found in the high-strain group, and progressively lower values were found in the passive, active and low-strain categories. These patterns were observed for both the clinical and ambulatory measurements. Among the mild hypertensive subjects, lower mean values for ambulatory systolic and diastolic blood pressure were found in the passive and high job-strain categories when the tertile term approach was adopted. The passive group also showed the highest mean difference between the clinical and ambulatory measurements; this finding indicates that they may be more susceptible to alarm reactions. Conclusions. The results indicate that job strain affects blood pressure in population-based samples and the effect is consistent across sociocultural contexts.