Area-related sociodemographic factors and the risk of severe COVID-19: a longitudinal study of the total adult population in Sweden.

Abstract

Introduction: For public health purposes, it is essential to understand which population groups and their areas of residence are affected by a disease as COVID-19 and to what extent these groups are reached by preventive measures.

Aim: We investigated how individual-level and area-level characteristics are associated with COVID-19 morbidity and vaccine uptake.

Methods: A population-based observational study including the total adult population age 18 and older in Sweden from 1 January 2020 to 1 April 2022, except individuals living in nursing homes. Associations between both individual and area-level characteristics and COVID-19 morbidity (hospitalisation, admission to intensive care unit and death) and vaccine uptake were analysed using Cox proportional hazards regression and adjusted for age, sex, comorbidity and socioeconomic and demographic factors.

Results: In the fully adjusted model, the hazard ratio (HR) for COVID-19 hospitalisation was 34% lower for individuals living in the most affluent neighbourhoods (HR 0.66, 95%CI 0.63-0.68) compared to individuals in the most deprived neighbourhoods. For intensive care unit (ICU)-admission and COVID-19 death, the risks were 53% (HR 0.47, 95%CI 0.42-0.53) and 47% (HR 0.53, 95%CI 0.48-0.59) lower, respectively. When stratified by cross-classified sociodemographics, this pattern was consistent within all strata. A composite area-level measurement had a better predictive value compared to single measures.

Conclusions: Living in deprived neighbourhoods is associated with substantially higher risk of COVID-19 hospitalisation, ICU-admission, mortality and lower vaccine uptake. This risk factor remained strong even when taking individual level characteristics into account and within strata of individual-level factors.