Trajectories of job insecurity and the probability of poorer mental health among prime working-age Australian women and men.

Precarious and insecure employment arrangements are important social determinants of health. Prior evidence has consistently found perceived job insecurity to be associated with poorer mental health. Nonetheless, several key under-researched areas remain in the existing evidence base. This study addresses some of these gaps by examining trajectories of job (in)security and assessing the effect of various persistent job security trajectories on subsequent mental health of both men and women. Utilising 15 waves of data from the Household, Income and Labour Dynamics in Australia (HILDA) Survey, we employed group-based trajectory modelling (GBTM) to identify trajectories of job (in)security through men and women's prime working years (from baseline age of 28-38yrs to 41-51yrs) across 14 years (waves 5-18), before subsequently examining the associations between these estimated trajectories and mental health at wave 19 (aged 42-52yrs). We identified four distinct trajectories of job (in)security for both men and women: persistently secure, becoming more secure, becoming less secure, and persistently insecure. Examining the association between these trajectories and mental health, we found that chronic exposure to any amount of persistent job insecurity (improving, worsening or persistently insecure) is detrimental to the mental health of both men and women. Furthermore, a somewhat incremental or dose dependant effect was found, with persistent job insecurity associated with the largest declines in mental health scores. Given mental health disorders are a substantial cause of disability globally, our study provides evidence that developing policy and practice interventions to reduce job insecurity (as an increasingly recognised and highly modifiable social determinant of mental health) has considerable potential to enact positive population health improvements.