Overcrowding and exposure to secondhand smoke increase risk for COVID-19 infection among Latinx families in the greater San Francisco Bay Area

INTRODUCTION: Environmental risk factors, including community level pollution burden and exposure to smoking and secondhand smoke, have not been evaluated in relation to risk for infection with COVID-19 in high risk, urban Latinx families. METHODS: We evaluated risk factors for COVID-19 infection in three, preexisting, longitudinal, Latinx family cohorts in the San Francisco Bay Area from May through September 2020 (N=383 households, 1875 people). All households were previously recruited before the pandemic. For the COVID-19 sub-study, participants responded to a telephone interview where we assessed food consumption patterns, housing and employment status, and history of COVID-19 infection. Secondhand smoke exposure was based on previously collected selfreported data, and environmental pollution exposure was determined from census tract residence. Non-parametric tests and multiple logistic regression were used to assess independent predictors of COVID-19 infection. RESULTS: Larger household size increased risk for infection (OR=1.58; 95% CI: 1.12–2.23, p<0.01) as did increasing number of children in household (OR=3.79; 95% CI: 1.51–9.56). Any exposure to secondhand smoke was also associated with increased risk for COVID infection (OR 4.69; 95% CI: 1.01–21.85) and having a greater number of family members eating at home was protective against infection (OR=0.10; 95% CI: 0.02–0.52, p<0.01). CONCLUSIONS: Crowding, as indicated by larger household size, increases risk for COVID-19 infection in Latinx families, as does exposure to secondhand smoke. Public policy and health interventions need to ensure that multiunit residential complexes do not allow exposure to secondhand smoke between units, that individuals eat in the home environment, and that large households can safely separate individuals exposed to COVID-19.