SvanePetersen et al_protocol job control and disability pension.pdf
Creators: name: Svane-Petersen, Annemette
name: Madsen, Ida E.H.
name: Framke, Elisabeth
name: Sørensen, Jeppe K.
name: Rugulies, Reiner
name: Burr, Hermann
name: Melchior, Maria
name: Sivertsen, Børge
name: Stansfeld, Stephen
name: Virtanen, Marianna
Publisher: name: figshare
Year: 2019
Subjects: subject: 111705 Environmental and Occupational Health and Safety
subject: FOS: Health sciences
subject: FOS: Health sciences
subject: 111706 Epidemiology

description: This protocol describes analyses similar to those described in a previous study protocol on job control and depression in the same cohort. Therefore, this protocol is an adapted version of this previously published protocol [1]. Previous research has shown that psychosocial working conditions are related to an increased risk of disability pension (DP) [2-10]. However, the existing literature on the topic is limited by at least four methodological concerns. First, most studies have been based on populations that were not followed from the beginning of the working life. In those cases the study populations may have been affected by healthy worker effect, which could lead to an underestimation of the associations between psychosocial working conditions and DP. This is because of the exclusion of individuals with DP - possibly related to their working conditions - prior to study baseline from the analyses. Second, results may be biased due to selection of employees into or out of jobs with adverse psychosocial working conditions, a selection which could be related to factors that increase the risk of subsequent DP, such as the health status of the employees. Such selection is probable given previous research linking social circumstances in childhood, such as socioeconomic position, to adulthood educational attainment, entry to the labour market and psychosocial working conditions [11-14]. If participants with adverse psychosocial working conditions are more likely to have risk factors for DP pre-existing labor market entry, such as childhood symptoms of mental and behavioral disorders, childhood socioeconomic status and parental labor market attachment during childhood [15-19], that have not been accounted for in the analyses, this could lead to an overestimation of the associations between psychosocial working conditions and DP. Third, in most studies, the duration of exposure to adverse psychosocial working conditions is unknown. Associations between cumulated exposure and increased risk of DP are known from studies of physical working conditions [20], and this notion is supported by a study suggesting that job control throughout the work life is associated with subsequent risk of disability pension [21]. However, evidence is lacking concerning whether longer duration of lower levels of/lack of job control is associated with higher risk for disability pension than shorter duration of lower levels of/lack of job control. Fourth, most existing studies have used self-reported data for assessing psychosocial working conditions. This may cause reporting bias, as health and dispositional differences between individuals are known to affect their response style [22, 23]. Such bias could lead to an overestimation of the associations between job control and DP. To address these limitations, we will examine the prospective associations between job control and the risk of DP in The Danish work life course cohort (DAWCO), a cohort of all individuals aged 15-30 who entered the Danish workforce for the first time during the years 1995 to 2009. To avoid reporting bias, and to assign exposure to the complete register-based cohort, we assess the level of job control of the participants by a job exposure matrix (JEM), and record this measure yearly to account for the duration of exposure. We analyse data longitudinally and relate exposure in the current year to the risk of DP four years later. We choose this four year time-lag because the average time between full-time employment and DP is four years for those DAWCO individuals who become disability pensioners, and in order for psychosocial working conditions to affect the risk of DP, the individual must have been in employment at the time of measuring the working conditions. We focus on job control, amongst the many dimensions of the psychosocial working conditions, because this factor has been associated with DP in previous research [2], but due to methodological concerns regarding residual confounding (see p. 3-4 for details), it is unclear whether or not the observed associations indicate a causal effect of low job control on risk of DP. The aim of this protocol is to document the planned analyses before they are commenced, to avoid post hoc decision making and to document that the analyses are confirmatory and hypothesis testing.