Table 1.
Study characteristics for the 29 included articles.
| Citation | Equity angle | Pandemic | Context | Unit of Analysis | Outcomes | Measure of Association | Covariates/Adjustments |
|---|---|---|---|---|---|---|---|
| Økland, 2019 (Økland & Mamelund, 2019) | Racial-ethnic | 1918 | US | a | a | a | a |
| Gamble, 2010 (Gamble, 2010) | Racial-ethnic | 1918 | US | a | a | a | a |
| Frankel, 1919 (Frankel & Dublin, 1919) | Racial-ethnic | 1918 | US | Individual | Influenza-pneumonia incidence, mortality | Comparison of rates | Age, sex, race/ethnicity |
| Brewer, 1918 (Brewer, 1918) | Racial-ethnic | 1918 | Army Camp (US) | Regiment | Influenza incidence | Comparison of rates | Number of weeks |
| Mamelund, 2006 (Mamelund, 2006) | SES | 1918 | City (Norway) | Individual | Influenza mortality | Hazard ratio | Age, gender, marital status, social class, apartment size |
| Mamelund, 2018 (Mamelund, 1918) | SES | 1918 | City (Norway) | Individual | ILI incidence | Probability differences, probability ratio | Gender, SES (number of rooms), pandemic wave |
| Sydenstricker, 1931 (Sydenstricker, 1931) | SES | 1918 | Nine cities in the US | Individual | Influenza mortality, incidence | Comparison of rates, rate ratio | Household size, crowding, sex, age |
| Bengtsson, 2018 (Bengtsson et al., 2018) | SES | 1918 | Norway | Individual | Excess influenza mortality | Comparison of rates, relative risk | Age, marital status, number of children, migrant status, urban status, and county of residence |
| Clay, 2019 (Clay et al., 2019) | SES | 1918 | US | Ecological (cities) | Excess mortality | Comparison of rates | Percentage of urban residents in 1910, proximity to WWI base, coal capacity |
| Wilson, 2018 (Wilson et al., 2018) | SES | 1918 | City (New Zealand) | Ecological (suburbs) | Influenza mortality | Rate ratio | NA |
| Grantz, 2016 (Grantz et al., 2016) | SES | 1918 | City (US) | Ecological (Census tracts) | Influenza & pneumonia mortality, transmissibility | Risk ratio | Population density, homeownership, unemployment, age |
|
Britten, 1932 (Britten, 1932) |
Racial-ethnic, SES |
1918 |
Cities, County (US) |
Individual |
Influenza-pneumonia incidence; onset, duration, severity of disease; mortality |
Comparison of rates |
Age, sex |
| Rutter, 2012 (Rutter et al., 2012) | SES | 2009 | UK | Ecological (LSOAs)* | Influenza mortality | Rate ratio | Age, gender |
| Balter, 2010 (Balter et al., 2010) | SES | 2009 | City (US) | Ecological (neighborhoods) | Hospitalizations | Comparison of rates | Age |
| Lowcock, 2012 (Lowcock et al., 2012) | SES | 2009 | Province (Canada) | Individual | Hospitalizations | Comparison of proportions, odds ratio | Age, gender |
| Navaranjan, 2014 (Navaranjan et al., 2014) | Racial-ethnic | 2009 | Province (Canada) | Individual | Incidence | Odds ratio | Age, sex, children in household, material deprivation, chronic conditions, receipt of 2008 seasonal vaccine, tested prior to June 11th, 2009, length of stay in Canada, total deprivation, high proportion of neighborhood with low income, material deprivation, post-secondary education, chronic condition, residence in Toronto |
| Quinn, 2011 (Quinn et al., 2011) | Racial-ethnic | 2009 | US | Individual | Risk of exposure, susceptibility, access to care | Odds ratio | Age, gender, presence of children in household, income, education |
| Dee, 2011 (Dee et al., 2011) | Racial-ethnic | 2009 | US | Individual | ILI, hospitalization, pediatric deaths | Comparison of proportions | Age |
| Soyemi, 2014 (Soyemi et al., 2014) | Racial-ethnic | 2009 | State (US) | Individual | Hospitalizations, influenza mortality | Comparison of proportions, rate ratio | Age, gender |
| Truelove, 2011 (Truelove et al., 2011) | Racial-ethnic | 2009 | State (US) | Individual | Hospitalizations, mortality, ICU admissions | Rate ratio | Age, clinical condition, hospital course |
| Castrodale, 2009 (Castrodale, 2009) | Racial-ethnic | 2009 | States (US) | Individual | Influenza mortality | Comparison of rates, rate ratio | Age |
| Placzek, 2014 (Placzek & Madoff, 2014) | Racial-ethnic; SES | 2009 | State (US) | Individual | Influenza-related ICU stay | Comparison of rates, odds ratio | Age, gender, admission type, interactions between race and gender |
| Kumar, 2012 (Kumar et al., 2012) | Racial-ethnic; SES | 2009 | US | Individual | ILI incidence | Comparison of means, odds ratio | Income, education, age, gender |
| Nyland, 2015 (Nyland et al., 2015) | Racial-ethnic; SES | 2009 | UK | Individual | Clinical outcomes, primary healthcare access, secondary healthcare access, in-patient care | Odds ratio | Age, sex, English Index of Multiple Deprivation score, recorded obesity, smoking and chronic obstructive pulmonary disease, admission delay > or equal to 4 days and severity at presentation for admission |
| Mayoral, 2013 (Mayoral et al., 2013) | Racial-ethnic; SES | 2009 | Spain | Individual | Hospitalizations | Odds ratio | Age, gender, unfavorable medical factors, vaccination, type of encounter |
| Thompson, 2011 (Thompson et al., 2011) | Racial-ethnic; SES | 2009 | State (US) | Individual | Hospitalizations | Rate ratio, odds ratio, risk ratio | Age, gender, obesity status, high-risk medical conditions, antiviral treatment |
| Levy, 2013 (Levy et al., 2013) | Racial-ethnic; SES | 2009 | City (US) | Individual | Hospitalizations | Odds ratio | Age, access to care, medical conditions, area of residence |
| Esteban-Vasallo, 2012 (Esteban-Vasallo et al., 2012) |
Racial-ethnic |
2009 |
City (Spain) |
Individual |
H1N1 infection, severe cases (hospital admission, chronic pathology, pregnancy, delay in hospital admission, and ICU admission) |
Comparison of rates, odds ratio, prevalence ratio |
Age, chronic pathology, pregnancy, delay in hospital admission |
| Wilson, 2012 (Wilson et al., 2012) | Racial-ethnic | 1918, 1957, 2009 | New Zealand | Ecological (country) | Mortality, hospitalizations | Rate ratio | Age |
a
multiple units of analysis or outcomes. SES = socioeconomic status. US=United States. UK=United Kingdom. ILI=Influenza-Like Illness. ICU=Intensive Care Unit. LSOA = lower super-output areas.