BACKGROUND: Belonging to certain ethnic groups, socioeconomic status and cramped living conditions are assumed to affect the risk of infection with SARS-CoV-2 . We wanted to examine correlations between a selection of sociodemographic variables and infection rates in Oslo's districts . MATERIAL AND
METHOD: Aggregated data on districts obtained from Oslo City Government's statistics database were collated with cumulative figures for PCR-confirmed cases of SARS-CoV-2 as of 3 December 2020 . We selected some variables from the living conditions indicators that showed a strong correlation with infection rates . The composite variable 'socioeconomic status' included income, education and labour market attachment . 'Household density' included the proportion of people in cramped living conditions and multi-family households . We performed an unadjusted and adjusted standard multiple linear regression analysis of the impact of immigrant ratio, socioeconomic status and household density on infection rates .
RESULTS: Immigrant ratio, socioeconomic status and household density were all associated with infection rates in the districts . Pearson's correlation coefficients (95% CI) were 0.97 (0.93 to 0.99), -0.93 (-0.97 to -0.86) and 0.88 (0.77 to 0.98) respectively, all with p <0.001 . In the adjusted model, immigrant ratio was still associated with the infection rate, B = 3.95 (2.16 to 5.73), p <0.001, however there was no longer a statistically significant association between socioeconomic status or household density and infection rates . INTERPRETATION: Immigrant ratio seems to be an important risk factor for infection in Oslo . Our analysis suggests that the correlation may be due to factors other than low socioeconomic status and high household density.