Loneliness and physical activity are important targets for research into the impact of COVID-19 because they have established links with mental health, could be exacerbated by social distancing policies, and are potentially modifiable. In this study, we aimed to identify whether loneliness and physical activity were associated with worse mental health during a period of mandatory social distancing in the UK.

Population-based observational cohort study.

Mental health data collected online during COVID-19 from an existing sample of adults aged 50 and over taking part in a longitudinal study of aging. All had comparable annual data collected between 2015 and 2019.

Three-thousand two-hundred and eighty-one participants aged 50 and over.

Trajectories of depression (measured by PHQ-9) and anxiety (measured by GAD-7) between 2015 and 2020 were analyzed with respect to loneliness, physical activity levels, and a number of socioeconomic and demographic characteristics using zero-inflated negative binomial regression.

In 2020, PHQ-9 score for loneliness, adjusted for covariates, was 3.23 (95% CI: 3.01–3.44), an increase of around 1 point on all previous years in this group and 2 points higher than people not rated lonely, whose score did not change in 2020 (1.22, 95% CI: 1.12–1.32). PHQ-9 was 2.60 (95% CI: 2.43–2.78) in people with decreased physical activity, an increase of .5 on previous years. In contrast, PHQ-9 in 2020 for people whose physical activity had not decreased was 1.66, 95% CI: 1.56−1.75, similar to previous years. A similar relationship was observed for GAD-7 though the absolute burden of symptoms lower.

After accounting for pre-COVID-19 trends, we show that experiencing loneliness and decreased physical activity are risk factors for worsening mental health during the pandemic. Our findings highlight the need to examine policies which target these potentially modifiable risk factors.