Selected publications

2026

Wels, J., Bryson, A., Kambayashi, R., Kuwahara, S., Nakamura, A. (2026). Why Are Japan’s Trade Unions Actually Growing? A decomposition of population datasets. Institute of Economic Research (Hitotsubashi University) Discussion Paper Series A N°776.

Keanjoom, R, Choosumrong, S, Nakamura, K., Nguyen, HTL, Kitreerawuttiwong, N, Kirtsaeng, S, Gonzalez Hijon, J., Wels, J. (2026). Differential Associations of Heat Metrics with Wellbeing across 13 Thai Provinces: The Role of Social Vulnerability in a Longitudinal Cohort of Older Adults. MedRxiv https://doi.org/10.64898/2026.01.06.26343526.

2025

Nakamura, A., Kuwahara, S., Kambayashi, R., Bryson, A., & Wels, J. (2025). なぜ労働組合の組織率は政府統計では低下し，個人調査では上昇しているのか？ [Why is the unionization rate declining in government statistics but rising in individual surveys?]. Financial Review. Ministry of Finance, Policy Research Institute, in Japanese.

Wels, J., & Hamarat, N. (2025). Trends in assisted dying among patients with psychiatric disorders and dementia in Belgium: A health registry study. PLOS Medicine, 22(11), e1004522. https://doi.org/10.1371/journal.pmed.1004522

Hamarat, N., & Wels, J. (2025). Incidence of reported cases of euthanasia adjusted for demographic composition: a study of ten years of Belgian administrative data (2014–2023). BMC Public Health, 25(1), 3843. https://doi.org/10.1186/s12889-025-24839-x

Wels, J, Maddock J, Patalay P. (2025). Cross-Country Differences in Self-Rated Health: Decomposing the Influence of Depressive Symptoms. MedRxiv, 10.1101/2025.10.23.25338675.

Wels, J, Keanjoom R, Gonzalez Hijon J, Choosumrong S (2025). Differential Associations of Heat Metrics with Health Statistics: A Spatiotemporal Analysis of Temperature Indicators and Mortality Across Thailand Provinces. MedRxiv,10.1101/2025.10.01.25337088

Bryson, A., Kambayashi, R., Kuwahara, S., Nakamura, A. & Wels, J. (2025). What is Happening to Unionization in Japan?Hitotsubashi University, Institute of Economic Research Discussion Paper Series A No.770, 1-32.

Wels, J., & Hamarat, N. (2025). Incidence and prevalence of reported cases of euthanasia in Belgium, 2002 to 2023. JAMA Network Open 8(4), e256841.

[Previously published as: Wels, J., & Hamarat, N. (2024). Incidence and prevalence of euthanasia in Belgium. A study using administrative data on all cases of euthanasia reported between 2002 and 2023. MeRxiv, 10.1101/2024.10.16.24315619. https://doi.org/10.1101/2024.10.16.24315619]

Kromydas, T., Demou, E., Leyland, A. H., Srinivasa Katikireddi, V., & Wels, J. (2023). Did trade unions protect employees’ mental health during the COVID-19 pandemic? A mixed effect model using UK data from Understanding Society. BMJ Public Health. Accepted for publication.

[Previously published as: Kromydas, T., Demou, E., Leyland, A. H., Srinivasa Katikireddi, V., & Wels, J. (2023). Trade unions and mental health during an employment crisis. Evidence from the UK before and during the COVID-19 pandemic. MedRxiv, 2023.10.30.23297780, 1–24. https://doi.org/10.1101/2023.10.30.23297780]

Wels, J., & Fu, R. (2025). Associations of employment status, working time and job satisfaction with sleep duration and sleep quality among the 50+ population in Japan. Industrial Health. Accepted for publication

[Previously published as: Wels, J., & Fu, R. (2024). Associations of employment status, working time and job satisfaction with sleep duration and sleep quality among the Japanese 50+ population. MedRxiv, 2024.03.28.24305011. https://doi.org/10.1101/2024.03.28.24305011]

Shaw, R. J., Rhead, R., Silverwood, R. J., Wels, J., Zhu, J., Hamilton, O. K., di Gessa, G., Bowyer, R. C., Moltrecht, B., Green, M. J., Demou, E., Pattaro, S., Zaninotto, P., Boyd, A., Greves, F., Chaturvedi, N., Ploubidis, G. B., & Katikireddi, S. V. (2025).Associations between different measures of SARS-CoV-2 infection status and subsequent economic inactivity: A pooled analysis of five longitudinal surveys linked to healthcare records. PLOS One. Accepted for publication

[Previously published as: Shaw, R. J., Rhead, R., Silverwood, R. J., Wels, J., Zhu, J., Hamilton, O. K., di Gessa, G., Bowyer, R. C., Moltrecht, B., Green, M. J., Demou, E., Pattaro, S., Zaninotto, P., Boyd, A., Greves, F., Chaturvedi, N., Ploubidis, G. B., & Katikireddi, S. V. (2023). Associations between SARS-CoV-2 infection and subsequent economic inactivity and employment status: pooled analyses of five linked longitudinal surveys. MedRxiv, 10.1101/2023.07.31.23293422, 1–17. https://doi.org/10.1101/2023.07.31.23293422]

Maddock, J., Wels, J. (2025). Key considerations in understanding retirement’s health impact. Journal of Epidemiology and Community Health. jech-2024-222936.