Causal effect of diabetes duration on productivity by socio-economic position in Germany between 2009 and 2021.

Diabetes negatively impacts productivity, but the extent to which socio-economic factors influence this effect is unknown. This study examines how diabetes duration affects labour force participation and sick leave in Germany, focusing on socio-economic differences. We used self-reported data collected between 2009 and 2021 from the German Socio-Economic Panel Study, a longitudinal household survey. People with prevalent diabetes at baseline were excluded. To estimate the causal effect of diabetes duration on the outcomes, we employed marginal structural regression models for repeated measures, using stabilized inverse-probability-of-treatment-and-censoring weights to adjust for informative censoring, time-fixed (sex, age, socio-economic position, migration background) and time-varying confounding (body mass index, physical activity frequency, smoking status, previous outcome). We included interaction terms to assess diabetes-related productivity losses by subgroups of socio-economic position, sex, age and migration background. The analysis consisted of 35 906 observations from 18 456 individuals for the outcome labour force participation and 12 469 observations from 7244 individuals for the outcome sick leave days. A five-year increase in diabetes duration was associated with a labour force participation shortfall of 13.8% (95% confidence interval: 5.8; 21.1) and an increase of 6.8 sick leave days (-5.4; 19.0). Effects were more pronounced among individuals in lower socio-economic position and diminished with increasing socio-economic position. Diabetes-associated productivity losses predominantly affect people in low socio-economic position, reflecting a dual burden of higher diabetes prevalence and larger productivity losses.