Aim: To test three hypotheses in an Italian sample of call center workers: higher levels of perceived work stress are associated with more frequent common mental disorders (GHQ-12) and a lower Work Ability Index; combining the Job Strain (JS) and Effort/Reward Imbalance (ERI) models increases explained variance in health over and above either model when applied separately; compared with outbound operators, inbound call handlers are expected to report a lower health status,which is due to a more intense exposure to task-related work stress factors in the latter.
Design: A multi-center cross-sectional study, conducted by means of interviews and self-administered questionnaires.
Setting and participants: Call handlers working in the Italian branch of a telecommunication multinational company. In all, 1,106 permanent workers were examined (35.9%of the total target population, 98.9% response rate). The majority were women (76.5%);mean age was 33.3 (SD: 3.9) and company seniority 8.0 (SD: 2.1). Nearly 60% worked as inbound call handlers, about one third as outbound operators.
Exposures: Work stress was measured with the well-known JS and ERI models. Three exposure levels (based on tertiles) were identified for each scale.
Outcomes: Common mental disorders were measured with the GHQ-12 questionnaire. Subjects with a GHQ-12 score 4 were classified as "cases". The Work Ability Index (WAI) was used to evaluate work ability. Being in the "poor" or "moderate" categories of the WAI indicated a low work ability status. Cronbach's alphas were 0.70 for all scales.
Results: Multivariate Poisson regressions showed that both models were linked to more frequent common mental disorders and a lower WAI. Moreover, combined models demonstrated an advantage in terms of explained variance in health. Finally, performing inbound call handling was associated with a lower WAI in comparison with engaging in outbound activities. Mediation analyses showed that such association is explained by the higher levels of psychological job demands and Job Strain experienced by inbound operators.
Conclusions: Our results highlight the relevance of work stress as a risk factor for lower psychological health, and especially for a poorer WAI among call center workers. The combined use of the two models increases completeness of work stress assessment in this sector.The higher levels of work stress and the lower WAI observed among inbound operators are due to objectively less favourable task-related characteristics.