Effort-reward imbalance at work and 5-year changes in blood pressure: the mediating effect of changes in body mass index among 1400 white-collar workers.

ABSTRACT

PURPOSE: A number of prospective studies have documented the effect of adverse psychosocial work factors (work stress) on high blood pressure (BP). Weight gain could be an important pathway by which work stress exerts its effect on BP. No previous prospective study has examined this mediating effect. The aim of the present study was to examine the mediating effect of body mass index (BMI) in the association between psychosocial work factors from Siegrist's effort-reward imbalance model (ERI) and ambulatory BP (ABP). METHODS: A prospective study was conducted among 1436 white-collar workers. Data were collected three times during a 5-year period. ERI was measured using validated scales, at each time. BMI was measured by a trained assistant. ABP was measured every 15 min during a working day. RESULTS: ERI exposure onset over 3 years was indirectly associated with ABP changes (0.49 mmHg; 95 % CI 0.05, 1.22), through BMI changes, in women with baseline BMI ≥25 kg/m2. An effect of similar magnitude and of borderline significance was observed for ERI chronic exposure. No mediating effect was observed among men, and using ERI exposure over 5 years. CONCLUSION: The mediating effect of BMI was of small magnitude and observed in certain subgroups and time frame only. Subgroup-specific mediating pathways might be involved to explain the effect of work stress on cardiovascular diseases risk.