OP45 Allostatic load and effort-reward imbalance: associations over the working-career

Background Although associations between work stressors and stress-related biomarkers have been reported in cross-sectional studies, the use of single time measurements of work stressors could be one of the reasons for previously inconsistently reported associations. This study examines whether repeated reports of work stress towards the end of the working career predicts allostatic load, a measure of chronic stress related physiological processes. Methods Data from waves 2 to 6 of the English Longitudinal Study of Ageing (ELSA) were analysed, with a main analytical sample of 2663 older adults (aged 50+) who had at least one measurement of effort-reward imbalance between waves 2–6 and a measurement of allostatic load at wave 6. From this main analytical sample, a subsample of 1020 respondents had their allostatic load measured at wave 2. Cumulative work stress over waves 2–6 were measured by the effort-reward imbalance model. Negative binomial regression models were used to estimate the association between effort-reward imbalance and allostatic load after controlling for covariates (categorized age, gender, ethnicity, smoking status, general health, number of medications used, depressive symptoms using the Centre for Epidemiologic Studies Depression Scale, physical activity, and alcohol use in the last 12 months). Results Employees with effort-reward imbalance at the more recent waves 5 (0.09, –0.002–0.17) and 6 (0.13, 0.03–0.22) had higher levels of wave 6 allostatic load compared to those who did not report any imbalance at those waves. The predicted levels of allostatic load by cumulative reports of effort-reward imbalance from the model controlling for wave 2 allostatic load showed that workers who reported two or more occasions of effort-reward imbalance had a higher estimate of the allostatic load index (0.11, 95% CI 0.01 to 0.22) compared to workers who never reported effort-reward imbalance. Conclusion The study finds some evidence that older adults aged 50+ living in England who repeatedly reported work related stressors had higher levels of the allostatic load index than those who did not report any effort-reward imbalance. This association was robust to controlling for a range of potential health and socio-demographic confounders, as well as baseline levels of allostatic load. The findings of a dose-response association between effort-reward imbalance and allostatic load, as well as the timing of the stressor and stress response, suggest that exposure to work-related stressors may have adverse consequences for physiological health through increasing adverse levels of stress related biomarkers.