Determinants of SARS-CoV-2 Infection in the Older Adult Population: Data From the LOST in Lombardia Study

Abstract

Most COVID-19-related fatalities occurred among older adults, however to date, evidence on determinants of SARS-CoV-2 infection in this population is limited and mostly based on case series without a comparison group. A telephone-based cross-sectional study was conducted in November 2020 on a representative sample of 4,400 Italians aged ≥65 years residing in the Lombardy region. We determined the prevalence of a history of SARS-CoV-2 infection in the period between the beginning of the pandemic and the time of the interview. Thorough unconditional multiple logistic regression models, we estimated odds ratios (OR) of SARS-CoV-2 infection and the corresponding 95% confidence intervals (CI). We also evaluated if the infection was a determinant of a worsening in mental health wellbeing. Overall, 4.9% of participants reported a history of SARS-CoV-2 infection. No significant relationship between sex and SARS-CoV-2 infection was observed. SARS-CoV-2 infection was less frequently reported in subjects aged ≥70 (OR=0.55; 95% 0.41-0.74) compared to 65-69 years. No trend was observed after 70 years of age. Those with at least one chronic condition reported a lower infection rate compared to healthy subjects (OR=0.68 95% CI: 0.49-0.93). Separated/divorced participants less frequently reported infection than married/cohabiting ones (OR=2.33 95% CI: 1.29-4.20). Self-reported history of SARS-CoV-2 infection resulted being a determinant of an increase in depressive symptoms (OR=1.57; 95% CI: 1.17-2.10). This first large representative study of people aged 65 years or over suggests that in Italy the oldest subjects and those having chronic conditions less frequently expose themselves to SARS-CoV-2 infection during the pandemic.