Incidence of long-term sickness absence in Japan following the COVID-19 pandemic

Although the COVID-19 pandemic has caused widespread disruptions to working life, its impact on long-term sickness absence (LTSA) remains poorly understood.

To examine if the registered number of LTSA episodes, i.e. a significant indicator of productive loss at the workplace, has changed before and after the spread of COVID-19 among a Japanese working population.

Data came from the Japan Epidemiology Collaboration on Occupational Health Study, in which a study-specific registry was launched to collect information on LTSA from April 2012 to December 2022. An autoregressive moving-average model was applied to incident LTSA data from April 2012 to January 2020 for forecasting from February 2020 to December 2022. We analysed and compared predicted versus observed LTSA incidences, focusing on all-cause and cause-specific LTSA, including mental disorders and other causes.

All-cause LTSA fell below the lower 95% prediction interval (PI) in May 2020 and exceeded the upper PI in October 2020, October 2021, and July 2022. For mental health-related LTSA, declines were noted in March and May 2020, followed by peaks exceeding the upper 95% PI in October and November 2020, and July and October 2021. LTSA due to other causes remained low throughout most of the study period, although it did not fall below the PIs.

Long-term sickness absence declined in the early phase of the COVID-19 pandemic but subsequently remained at relatively high levels. LTSA due to mental disorders persisted at elevated levels until the end of the study period.