LETTERS TO THE EDITOR
To the Editor:
Nielsen et al1 conducted a prospective study to determine the effect of bullying on subsequent all-cause disability retirement. Bullying significantly predicted disability retirement, although a significance disappeared by full-adjustment. In contrast, men, high educational level, good job control, and lower quantitative demands were protective for incident disability retirement.1 I have some concerns about their study.
First, Pietiläinen et al2 investigated the association between hospitalization and disability retirement with special reference to occupational classes: professional, semi-professional, routine nonmanual, and manual. Hospitalization showed an increased risk of disability retirement in the lower ranking occupational classes, which was a disease-specific trend of association. I suspect that the process from workplace bullying to subsequent all-cause disability retirement should be stratified by the cause of retirement with a special emphasis on physical and mental disorders.
Second, Virtanen et al3 examined the effect of low occupational class in employees with cardiovascular disease (CVD) on the risk of disability retirement. Hazard ratio (HR) of employees in the low occupational class without CVD for disability retirement was 2.13, and that of employees in the high occupational class with CVD was 2.18. In addition, HR of employees in the low occupational class with CVD for disability retirement was 4.49. They concluded that the combination of low occupational class and CVD had an acceleration effect on disability retirement. Comprehensive assessment of independent variables for incident disability retirement should be conducted to know the causal association.
Third, Milner et al4 reported that suicide ideation was positively associated with workplace bullying and negatively associated with higher job control and security. Workplace bullying would partly be related to suicide ideation, and prevention program of workplace bullying would decrease the prevalence of disability retirement.
Finally, occupational class is closely related to socioeconomic status,5 and several socioeconomic variables would also become confounders on the association between workplace bullying and disability retirement. As the authors handled enough number of samples, other confounders should be considered for the association by further study.
1. Nielsen MB, Emberland JS, Knardahl S. Workplace bullying as a predictor of disability retirement: a prospective registry study of Norwegian employees. J Occup Environ Med
2. Pietiläinen O, Laaksonen M, Lahelma E, Salonsalmi A, Rahkonen O. Occupational class inequalities in disability retirement after hospitalisation. Scand J Public Health
2017; [Epub ahead of print].
3. Virtanen M, Lallukka T, Ervasti J, et al. The joint contribution of cardiovascular disease and socioeconomic status to disability retirement: a register linkage study. Int J Cardiol
4. Milner A, Page K, Witt K, LaMontagne A. Psychosocial working conditions and suicide ideation: evidence from a cross-sectional survey of working Australians. J Occup Environ Med
5. Kawada T. Occupational class as the indicator of socioeconomic position. Occup Environ Med