Psychosocial work environment and ambulatory blood pressure: independent and combined effect of demand-control and effort-reward imbalance models.

BACKGROUND Two main theoretical models have been used to assess the impact of psychosocial work factors on blood pressure (BP): the demand-control model (DC) and the effort-reward imbalance (ERI) model. Little is known about their independent and combined effect. OBJECTIVE To examine the independent and combined effect of the DC and ERI models on ambulatory BP (ABP). METHOD Data were collected three times over 7 years from 3395 white-collar women and men using a repeated cross-sectional design. On each occasion, psychosocial work factors were measured using validated scales. ABP was measured every 15 min during a working day. Systolic and diastolic ABP means were examined in relation to contemporaneous and past exposure. Both models were mutually adjusted. A combined exposure variable was computed. RESULTS In men, high strain, and active, passive and ERI exposure were associated with ABP using contemporaneous exposure. However, the high strain/ABP association was not significant after adjustment for ERI. In women, no association was found with the DC model, while women exposed to ERI had higher ABP. Use of past exposure showed a stronger association between ABP and active exposure in men, while ERI associations were attenuated. Combined exposure to active jobs and to ERI was associated with ABP in both genders. CONCLUSIONS In men, associations with the DC model were mixed. Associations between high job strain and ABP were not independent of ERI exposure while both DC intermediate groups were independently associated with ABP. In women, no association was found with the DC model. ERI exposure was independently associated with ABP using contemporaneous exposure, but not using past exposure. Combined active and ERI exposure was also associated with ABP.