The COVID-19 pandemic and associated lockdowns significantly impacted mental health globally, with vulnerable populations disproportionately affected. While public health interventions addressed the pandemic's spread, the role of individual lifestyle factors in mitigating these negative psychological and social effects remained unclear, particularly in interaction with socioeconomic deprivation. Modifiable lifestyle factors such as BMI, smoking, alcohol consumption, physical activity, sleep duration, and diet have been linked to mental disorders and overall mortality outside the pandemic context. Previous research hinted at the individual benefits of factors like physical activity or diet in reducing psychological distress during the pandemic, but the combined effect of multiple lifestyle factors and their interaction with socioeconomic status were yet to be explored. This study aimed to assess the association between a combination of pre-pandemic lifestyle factors and mental health outcomes (depression, anxiety, and well-being) during the COVID-19 pandemic in England, further investigating the role of socioeconomic deprivation in modifying this relationship. Understanding this complex interplay is crucial for developing effective public health strategies and individual-level interventions to promote mental well-being, especially among vulnerable groups.

Existing literature extensively documents the adverse psychological impacts of the COVID-19 pandemic, including increased rates of depression, anxiety, and other mental health issues. Studies highlighted the vulnerability of older adults and socioeconomically deprived individuals. Although initial high levels of psychological symptoms might decrease over time, certain groups remained at risk long-term. Furthermore, the long-term psychiatric consequences of SARS-CoV-2 infection added to the mental health burden. While some research touched upon the role of individual lifestyle factors like physical activity and diet in mitigating pandemic-related stress, a comprehensive examination of the combined impact of multiple lifestyle factors and their interaction with socioeconomic deprivation was missing. This gap in the literature underscores the need for this study, which aimed to provide a more nuanced understanding of the factors influencing mental health outcomes during the pandemic.

This prospective analysis utilized data from the English Longitudinal Study of Ageing (ELSA), a nationally representative longitudinal cohort of adults aged 50 and older in England. The study leveraged wave 9 data (2018-19), preceding the pandemic, and two waves of the ELSA COVID-19 substudy (June/July and November/December 2020). Participants who did not experience self-isolation or stay-at-home orders during the pandemic were excluded. Socioeconomic deprivation was assessed using individual-level factors (income, wealth, education) and the Index of Multiple Deprivation (IMD). A composite healthy lifestyle score was constructed by combining seven modifiable lifestyle factors: BMI, smoking status, alcohol consumption, physical activity, sedentary time, sleep duration, and fruit and vegetable intake. Mental health outcomes were measured using the CES-D 8 for depression, GAD-7 for anxiety, and ONS-4 for well-being. Cox proportional hazards models were used to analyze the association between lifestyle factors, socioeconomic deprivation, and mental health outcomes, adjusting for several covariates (age, sex, ethnicity, marital status, employment, disability, comorbidities, and pre-pandemic mental health conditions). Sensitivity analyses were performed using individual-level socioeconomic factors and after excluding participants with a history of mental disorders. Interactions between lifestyle and deprivation were tested.

The study included 5049 participants (mean age 68.1 years, 57.2% female). 41.6% had favorable lifestyles, 48.9% intermediate, and 9.5% unfavorable. Compared to the favorable lifestyle group, those in the intermediate and unfavorable groups showed increased risks of depression (HR for trend: 1.17, 95% CI 1.09–1.26), anxiety (HR for trend: 1.23, 95% CI 1.07–1.42), and low well-being (HR for trend: 1.39, 95% CI 1.20–1.61). A clear dose-response relationship was observed: individuals with seven healthy lifestyle factors had a 48% lower risk of depression, 42% lower risk of anxiety, and 58% lower risk of low well-being compared to those with 0-2 factors. Socioeconomic deprivation, assessed by IMD, was independently associated with increased risks of all three mental health outcomes. No significant interactions between lifestyle factors and socioeconomic deprivation were found, indicating independent effects. The most deprived individuals with unfavorable lifestyles exhibited the highest risk for all mental health outcomes. Sensitivity analyses broadly supported these findings.

This study provides robust evidence for the independent contributions of both lifestyle factors and socioeconomic deprivation to mental health during the COVID-19 pandemic. The lack of interaction suggests that interventions should target both areas simultaneously. The dose-response relationship between the number of healthy lifestyle factors and mental health outcomes emphasizes the importance of promoting a holistic approach to lifestyle change. Findings highlight the need for integrated interventions addressing both individual lifestyle choices and broader societal inequalities. The consistent association across different measures of socioeconomic deprivation strengthens the study's conclusions. While the study doesn't establish causality, it strongly suggests the importance of addressing these factors in pandemic preparedness and mental health promotion.

This study demonstrates a significant association between pre-pandemic healthy lifestyle factors and reduced mental health risks during the COVID-19 pandemic, independent of socioeconomic deprivation. Both lifestyle and socioeconomic factors independently influence mental health outcomes. Interventions should focus on promoting healthy lifestyles while simultaneously addressing socioeconomic inequalities. Future research could investigate causal relationships through methodologies like Mendelian randomization and explore culturally appropriate and effective interventions tailored to various socioeconomic groups.

As a observational study, this research cannot definitively establish causality. Self-reported data on lifestyle factors might be subject to recall bias. The study is limited to a specific population (English adults aged 50+). The generalizability of the findings to other populations requires further investigation. Although adjusting for pre-pandemic mental health conditions reduces the likelihood of reverse causality, some residual confounding may remain.