Constructing and validating an occupational job strain index based on five Norwegian nationwide surveys of living conditions on work environment

Abstract

Background It has been claimed that Nordic register data are a “goldmine” for research. However, one limitation is the lack of information on working conditions. Job exposure matrices (JEMs) are one solution to this problem. Thus, the three aims of this study were (i) to investigate the reliability of an occupation-based psychosocial JEM, i.e., a Job Strain Index (job strain or JSI abbreviated), (ii) to examine the construct and criterion-related validity of this measure of job strain (iii) and assesses the concurrent and the predictive validity of an occupation-based Job Strain Index for use in analyses of Norwegian register data. Method The study utilized five waves of the nationwide Norway Survey of Living Conditions in the Work Environment with a total sample of 43,977 individuals and register data with a total sample of 1,589,535 individuals. Job strain was composed of items belonging to the two dimensions of Karasek’s DC model, job demands and job control (1979). The reliability of the JSI and its dimensions and components were investigated by measuring the degree of agreement (Cohen’s kappa), sensitivity, specificity, and internal consistency (Cronbach’s alpha). Construct validity was assessed by confirmatory factor analysis, and criterion-related validity was measured by concurrent validity and predictive validity. The selected concurrent criteria were self-reported survey information on long-term sick absence, anxiety, depression, and sleeping difficulty. The predictive criteria were register information on receipt of disability benefits, mortality, and long-term sick leave. Results Agreement between individual and occupation-based job strain and components was fair to poor. The sensitivity and specificity of occupation-based job strain and its components varied from acceptable to low. The consistency of the items comprising job demand and job control was clearly acceptable. Regarding concurrent validity, significant associations between (both individual and occupational) job strain, and long-term sick leave and sleeping difficulty were observed for both genders. Occupation-based job strain indicated an elevated risk for anxiety and depression among men, but not among women. As for predictive reliability, significant associations between occupation-based job strain and all three health outcomes were observed for both men and women. Conclusion Our occupation-based JSI serves as a reliable and valid indicator of psychosocial job exposure that can be used in analyses of Norwegian register data where individual information on such conditions is missing.

Sickness absence among mothers caring for a child with disability: Examining the impact of mechanical and psychosocial occupational exposures

“…The exposure variables were Hermansen and Dahl’s (2022) validated Mechanical Job Exposure Index and Le et al’s (2023) validated Job Strain Index. Inspired by Hanvold et al (2019) , these two gender-specific job exposure matrix indices were constructed for use in Norwegian registry-based studies with the aim of addressing a lack of information on working conditions in Norwegian register data ( Hermansen & Dahl, 2022 ; Le et al, 2023 ). The indices were based on five Norwegian nationwide surveys of living conditions concerning work environment in 2006, 2009, 2013, 2016, and 2019.…”

“…The response options for the measures were dichotomized as exposed or not exposed. The Job Strain (Psychosocial) Index developed by Le et al (2023) was based on Karasek’s Demand-Control Model and combines job demands with job control. Four items were used to measure job demand: quantitative demands, conflicting ways of doing things, insufficient resources, and contradictory requests.…”

“…The job strain index also theoretically ranges from 0 to 100 percent, where higher values on the index represent higher degrees of demand and lower degrees of control. For a more detailed description of the mechanical index, see Hermansen and Dahl (2022) and for the job strain index, see Le et al (2023) . Our registry data included four-digit Norwegian standard STYRK-98 occupational codes for each employed mother; these codes were matched with the validated JEM scores.…”

“…They found that individuals with long exposure to stressful situations at work have poor health, which accords with the results of Warren et al (2004) , who used data from a longitudinal study in Wisconsin to report that psychosocially demanding jobs are associated with poor health outcomes. Using both self-reported surveys and registry data, Le et al’s (2023) study in Norway also found an association between psychosocial job exposure and long-term sick leave among both males and females.…”

Return to work after cancer–the impact of working conditions: A Norwegian Register-based Study.

“…For a more detailed description of the mechanical index, see Hermansen and Dahl (2022) [17]. See Le Hermansen, and Dahl (2023) [18] for a description of the job strain index.…”