This cross-sectional study examines the association of socioeconomic characteristics with COVID-19 incidence and mortality in Japanese prefectures. Key Points Question Are the COVID-19 outcome disparities between Japanese regions associated with the socioeconomic characteristics of those regions? Findings In this cross-sectional study of the 47 prefectures in Japan, a higher burden of COVID-19 cases and deaths was observed in prefectures with lower household incomes; a higher proportion of the population receiving public assistance; a higher unemployment rate; higher numbers of retail, transportation and postal, and restaurant industry workers; more household crowding; and higher smoking and obesity rates. Meaning This study found an unequal pattern of COVID-19 outcomes that was associated with the socioeconomic circumstances in Japanese regions, suggesting that these disparities in COVID-19 outcomes are not unique to the US and Europe. Importance Socioeconomic factors in the disparities in COVID-19 outcomes have been reported in studies from the US and other Western countries. However, no studies have documented national- or subnational-level outcome disparities in Asian countries. Objective To assess the association between regional COVID-19 outcome disparities and socioeconomic characteristics in Japan. Design, Setting, and Participants This cross-sectional study collected and analyzed confirmed COVID-19 cases and deaths (through February 13, 2021) as well as population and socioeconomic data in all 47 prefectures in Japan. The data sources were government surveys for which prefecture-level data were available. Exposures Prefectural socioeconomic characteristics included mean annual household income, Gini coefficient, proportion of the population receiving public assistance, educational attainment, unemployment rate, employment in industries with frequent close contacts with the public, household crowding, smoking rate, and obesity rate. Main Outcomes and Measures Rate ratios (RRs) of COVID-19 incidence and mortality by prefecture-level socioeconomic characteristics. Results All 47 prefectures in Japan (with a total population of 126.2 million) were included in this analysis. A total of 412 126 confirmed COVID-19 cases (326.7 per 100 000 people) and 6910 deaths (5.5 per 100 000 people) were reported as of February 13, 2021. Elevated adjusted incidence and mortality RRs of COVID-19 were observed in prefectures with the lowest household income (incidence RR: 1.45 [95% CI, 1.43-1.48] and mortality RR: 1.81 [95% CI, 1.59-2.07]); highest proportion of the population receiving public assistance (1.55 [95% CI, 1.52-1.58] and 1.51 [95% CI, 1.35-1.69]); highest unemployment rate (1.56 [95% CI, 1.53-1.59] and 1.85 [95% CI, 1.65-2.09]); highest percentage of workers in retail industry (1.36 [95% CI, 1.34-1.38] and 1.45 [95% CI, 1.31-1.61]), transportation and postal industries (1.61 [95% CI, 1.57-1.64] and 2.55 [95% CI, 2.21-2.94]), and restaurant industry (2.61 [95% CI, 2.54-2.68] and 4.17 [95% CI, 3.48-5.03]); most household crowding (1.35 [95% CI, 1.31-1.38] and 1.04 [95% CI, 0.87-1.24]); highest smoking rate (1.63 [95% CI, 1.60-1.66] and 1.54 [95% CI, 1.33-1.78]); and highest obesity rate (0.93 [95% CI, 0.91-0.95] and 1.17 [95% CI, 1.01-1.34]) compared with prefectures with the most social advantages. Among potential mediating variables, higher smoking rate (RR, 1.54; 95% CI, 1.33-1.78) and obesity rate (RR, 1.17; 95% CI, 1.01-1.34) were associated with higher mortality RRs, even after adjusting for prefecture-level covariates and other socioeconomic variables. Conclusions and Relevance This cross-sectional study found a pattern of socioeconomic disparities in COVID-19 outcomes in Japan that was similar to that observed in the US and Europe. National policy in Japan could consider prioritizing populations in socially disadvantaged regions in the COVID-19 response, such as vaccination planning, to address this pattern.
【초록키워드】 COVID-19, Europe, vaccination, Mortality, cross-sectional, obesity, outcome, smoking, Population, Region, Characteristics, death, Japan, Japanese, incidence, association, Analysis, exposure, close contact, employment, rate ratio, Government, COVID-19 incidence, Asian, Factor, COVID-19 case, measure, participant, covariate, total population, finding, National, confirmed COVID-19 case, regions, objective, Gini coefficient, setting, lowest, Result, highest, analyzed, collected, proportion, reported, receiving, adjusted, unique, Importance, Point, Relevance, RRs, variables, with COVID-19, 【제목키워드】 COVID-19, Japan, disparity,