Association between household size and COVID-19: A UK Biobank observational study
Gillies CL., Rowlands AV., Razieh C., Nafilyan V., Chudasama Y., Islam N., Zaccardi F., Ayoubkhani D., Lawson C., Davies MJ., Yates T., Khunti K.
SummaryObjectiveTo assess the association between household size and risk of non-severe or severe COVID-19.DesignA longitudinal observational study.SettingThis study utilised UK Biobank linked to national SARS-CoV-2 laboratory test data.Participants401,910 individuals with available data on household size in UK Biobank.Main outcome measuresHousehold size was categorised as single occupancy, two-person households and households of three or more. Severe COVID-19 was defined as a positive SARS-CoV-2 test on hospital admission or death with COVID-19 recorded as the underlying cause; and non-severe COVID-19 as a positive test from a community setting. Logistic regression models were fitted to assess associations, adjusting for potential confounders.ResultsOf 401,910 individuals, 3612 (1%) were identified as having suffered from a severe COVID-19 infection and 11,264 (2.8%) from a non-severe infection, between 16 March 2020 and 16 March 2021. Overall, the odds of severe COVID-19 was significantly higher among individuals living alone (adjusted odds ratio: 1.24 [95% confidence interval: 1.14 to 1.36], or living in a household of three or more individuals (adjusted odds ratio: 1.28 [1.17 to 1.39], when compared to individuals living in a household of two. For non-severe COVID-19 infection, individuals living in a single-occupancy household had lower odds compared to those living in a household of two (adjusted odds ratio: 0.88 [0.82 to 0.93].ConclusionsOdds of severe or non-severe COVID-19 infection were associated with household size. Increasing understanding of why certain households are more at risk is important for limiting spread of the infection.