Employees in health and social care are often simultaneously exposed to both physical and psychosocial challenges that may increase their risk for sickness absence. The study examines interaction effects of physical and psychosocial work conditions on the future risk for sickness absence among nurses and care assistants in Sweden. The study was based on 14,372 participants in any of the Swedish Work Environment Surveys conducted during the years 1993-2013 with linked register information on background factors and compensated sickness absence. Adjusted hazard ratio (HR), stratified by occupation, and measures of additive interaction effects were estimated. The combinations of high psychosocial job demands and heavy physical work and strenuous postures, respectively, significantly increased the risks for sickness absence among nurses (HR 1.43; CI 1.09-1.88 and HR 1.42; CI 1.16-1.74, respectively), as well as among care assistants (HR 1.51; CI 1.36-1.67 and HR 1.49; CI 1.36-1.63, respectively). The combinations of low job control and both heavy physical work (HR 1.44; CI 1.30-1.60) and strenuous postures (HR 1.42; CI 1.30-1.56) were also associated with excess risk for sickness absence among care assistants. We also found interaction effects among care assistants but not among nurses. The results indicate that the high sickness absence rate among care workers in Sweden can be reduced if the simultaneous exposures of high psychosocial and high physical challenges are avoided. Management policies for reduced time pressure, improved lifting aids, and measures to avoid awkward work postures are recommended. For care assistants, increased influence over work arrangements is likely to lower their sickness absence risk.
Keywords: care assistants; nurses; physical work; psychosocial work; sickness absence; synergy index.