Physical Activity and Depression During the COVID-19 Pandemic in Australia: A Within-pair Twin Study

Abstract

Abstract Background: Low levels of physical activity (PA) have been associated with depression. However, shared familial factors might confound this association, as PA and depression tend to cluster in families. We investigated the association between levels of PA during the COVID-19 pandemic and depression symptoms while controlling for shared factors by design, and assessed if being in lockdown modified this association. Methods: We applied within-individual and within-pair regression models to questionnaire data from adult same-sex twin pair members of Twins Research Australia collected between August and November 2020. Depression score was measured using the Depression, Anxiety and Stress Scale (DASS-21), and PA changes since the onset of the pandemic (and other PA measures) were self-reported. Adjusted models included body-mass-index, sleep adequacy, smoking, and alcohol consumption. Results Our sample of 1,148 twins was predominantly female (80%) and had a median age of 54 (Interquartile Range = 41–65). Reduced PA was associated with a higher depression score (β = 1.22, 95% Confidence Interval: 0.70–1.73, P < 0.001) in the adjusted within-individual model, but evidence of a within-pair association was weak (P = 0.023). Lockdown status was an effect modifier (P = 0.006); relative to the co-twin, an increased PA was associated with higher depression scores for those in lockdown but lower scores for those not under restrictions. Conclusions Shared familial factors might play a role in the association between PA and depression. Health interventions and educational campaigns for families rather than just individuals might be better suited to improve mental health outcomes, especially when opportunities for PA and exercise are limited.