Cross-national comparison of the relationship between working hours and employment status and sleep duration and quality among Australia, Germany, Japan and the United Kingdom. A research protocol.

BackgroundThere is a significant gap in sleep duration across countries with 56 percent of the Japanese population sleeps less than seven hours per day against around 30 percent in the United Kingdom (UK), Germany, and Australia. Similarly, labour market characteristics differ across these countries, with average working hours being higher in Australia and Japan compared to the UK and Germany, but with a significant number of contract and part-time workers. This research aims to address how employment status and working time associate with sleep time and sleep quality across Japan, the UK, Germany, and Australia. MethodsWe use and harmonize four representative panel datasets, Understanding Society in the UK, the Japan/Keio Longitudinal Panel Survey in Japan, the German Socio-Economic Panel, and the Household, Income and Labour Dynamics in Australia. We use parallel analyses and focus on years 2009 to 2021 and include all respondents aged 20 to 69. We use fixed and mixed effects model using sleep time (log) as a linear outcome and self-reported sleep quality, trouble falling asleep and loss of sleep over worry as binary outcomes. Exposures include the employment status (model 1), working time (model 2) and the interaction between employment security and working time (model 3). We control for socio-demographic and socio-economic layers of adjustment and analyses are stratified by age-group, gender and whether respondents work in professional occupations. ResultsExpected results include descriptive statistics on sleep time and quality, employment status distribution and working time among four countries and details by gender. Estimates from fixed and mixed effects are compared using a Hausman test. Coefficients are shown for sleep time and other sleep quality measurements are in odds ratios with 95%CI. ConclusionUsing parallel analyses on four panel datasets from Japan, the UK, Germany, and Australia, the study will address to what extent sleep duration and quality vary and sub-groups and whether employment status and working time patterns contribute to explain sleep differences across both countries. FundingJW receives funding from the following sources: the European Research Council (ERC) and the Belgian National Scientific Fund (FNRS). Conflicts of interestsThe authors report no conflict of interest. JW is a member of the Belgian Health Data Agency (HAD) user committee. Data availabilityAccess to the Japan Household Panel Survey micro-data is available upon request via the Keio University (Japan) research portal: https://www.pdrc.keio.ac.jp/en/paneldata/datasets/jhpskhps/ Access to Understanding Society (UKHLS) micro-data is available upon request via the UK data archive: https://www.data-archive.ac.uk/ Access to German Socio-Economic Panel (SOEP) micro-data is available upon request via: https://www.eui.eu/Research/Library/ResearchGuides/Economics/Statistics/MicroDataSet Access to the Household, Income and Labour Dynamics (HILDA) micro-data is available upon request via: https://dataverse.ada.edu.au/dataverse/DSSLongitudinalStudies