# Did trade unions protect employees’ mental health during the COVID-19 pandemic? A mixed effects model using UK data from Understanding Society

**Authors:** Theocharis Kromydas, Evangelia Demou, Alastair H Leyland, Srinivasa Vittal Katikireddi, Jacques Wels

PMC · DOI: 10.1136/bmjph-2024-001756 · 2025-05-21

## TL;DR

This study explores whether trade unions helped protect workers' mental health during the COVID-19 pandemic using data from the UK.

## Contribution

It is one of the first studies to examine the mental health impact of trade union presence and membership during the pandemic.

## Key findings

- Trade union presence was associated with modest protection against mental health risks during the pandemic.
- Union membership further reduced the negative mental health effects of the pandemic in unionized workplaces.
- Industry differences suggest the protective effects of unions may vary across sectors.

## Abstract

Few studies have addressed the relationship between trade unions and workers’ mental health during the COVID-19 pandemic.

We analysed panel data from Understanding Society collected before and during the COVID-19 pandemic (49 915 observations; 5988 respondents) to assess the relationship between union presence within the workplace and union membership and a binary measure of common mental disorders (CMD), the 12-Item General Health Questionnaire (>4, probable psychological distress). A mixed-effect log-linear model assessed effect heterogeneity across time and industries, with average marginal effects (AME) indicating effect differences between groups.

Of our sample, 49.1% worked in a unionised workplace, with 53.8% of them being union members. Approximately 25% of the entire workforce was trade union members. Psychological distress prevalence was higher during the pandemic (25.4%) compared with prepandemic (18.4%). Union presence ((AMEpre-pandemic: 1.0, 95% CI−0.66 to 2.70) (AME-pandemic: −0.2, 95% CI−1.91 to 1.58)) and union membership ((AMEpre-pandemic: 1.6, 95% CI −0.69 to 3.93) (AMEpandemic: −0.1, 95% CI −2.29 to 2.00)) were both associated with modest protection against CMD risk. Although, industry heterogeneity exists.

Trade union presence may have a protective effect on workers’ mental health in periods of crisis, such as during a pandemic. Within unionised workplaces, trade union membership further mitigated the negative effects of the pandemic on mental health. Collective negotiation may be protective in periods of uncertainty, benefiting all workers.

## Linked entities

- **Diseases:** CMD (MONDO:0007251)

## Full-text entities

- **Diseases:** Psychological distress (MESH:D012128), COVID-19 (MESH:D000086382)

## Figures

1 figure with captions in the complete paper: https://tomesphere.com/paper/PMC12104941/full.md

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Source: https://tomesphere.com/paper/PMC12104941