The joint contribution of physical activity, insomnia symptoms, and smoking to the cost of short-term sickness absence.

Physical inactivity has been associated with both insomnia symptoms and smoking. Further, they are all independently associated with increased sickness absence (SA) from work. However, joint contribution of either physical activity (PA) with insomnia symptoms or with smoking to SA and, especially, their direct cost for the employer is poorly understood. Therefore, we aimed to examine these joint associations with short-term (<15 days) SA cost. The Helsinki Health Study is a cohort of midlife employees of the City of Helsinki, Finland (baseline n = 8960, response rate 67%). During 2000-2002, the participants were mailed a survey questionnaire that gathered information on health behavior and sociodemographic characteristics. SA, salary, and time of employment were followed up through the employer's personnel register between 2002 and 2016 for those with a written consent to the use of their register data (78% of the participants). Individual salary data were used to calculate the direct cost of short-term SA. Data were analyzed with a two-part model. Inactive participants with frequent insomnia symptoms had 2526€ (95% CI 1736€-3915€) higher cost of short-term SA than vigorously active participants without insomnia symptoms. Furthermore, inactive smokers had 4166€ (95% CI 2737€-5595€) higher cost for the employer over the follow-up than vigorously active non-smokers. In conclusion, this study showed that PA and insomnia symptoms as well as PA and smoking are jointly associated with short-term SA cost. The results emphasize encouraging employers to improve work environments so that they promote active lifestyle, good sleep, and non-smoking in order to reduce the cost of SA.