Atopic diseases, particularly atopic asthma, were associated with decreased risk of developing COVID-19 in a longitudinal study of adults living in the United Kingdom published in the journal Thorax.
Risk factors for severe COVID-19 infection have been documented, including male sex, obesity, and Black or Asian ethnicity, however, “to our knowledge, studies to investigate whether behaviours influencing risk of such exposure might partly explain associations between older age, presence of comorbidities and lower risk of developing COVID-19 are lacking,” wrote authors led by Adrian R. Martineau, PhD, clinical professor of respiratory infection and immunity, Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, UK.
“Such studies could potentially shed light on other controversies relating to risk factors for developing COVID-19, such as the extent to which ethnic differences in disease susceptibility can be explained by behavioural, occupational and socioeconomic factors, and whether lifestyle, diet and use of micronutrient supplements may influence risk of developing COVID-19,” continued researchers.
To address this gap in knowledge, Martineau and colleagues launched the prospective, population-based cohort study COVIDENCE UK at the beginning of the COVID-19 pandemic to capture detailed information on a range of potential risk factors for COVID-19. The study ran from May 1, 2020 to February 5, 2021.
Researchers surveyed 14 348 UK adults (mean age, 59.4 years, 69.8% women, 94.9% White) about their age, household circumstances, job, lifestyle, weight, height, longstanding medical conditions, medication use, vaccination status, diet, and supplement intake at baseline and again in subsequent months, according to the study.
Logistic regression models were used to estimate multivariable-adjusted odds ratios (aORs) for associations between potential risk factors and odds of COVID-19 infection, noted investigators.
Approximately 3% of participants (n=446) experienced at least 1 episode of confirmed SARS-CoV-2 infection during 2 613 921 person-days of follow-up, of whom 32 were hospitalized.
After adjustment for age, sex, and duration of participation and testing frequency, investigators found that Asian/Asian British ethnicity, household overcrowding, indoor socializing, employment as a frontline worker outside of health and social care, and overweight or obesity were all independently associated with an increased risk of test-confirmed COVID-19, according to the study.
Atopic diseases (defined for the purpose of the study as eczema/dermatitis and/or hay fever/allergic rhinitis), however, were independently associated with decreased odds of developing infection (aOR=0.75; 95% CI, 0.59-0.97). In particular, participants with atopic disease and asthma had an even lower risk (38%) of COVID-19 infection (aOR=0.62; 95% CI, 0.41-0.93), which may reflect, “decreased expression of ACE2, the gene encoding the SARS-CoV-2 receptor, which has been reported in people with both high levels of allergic sensitisation and asthma,” according to investigators.
Contrary to previous research investigating risk factors for severe COVID-19, older age, male sex, and other comorbidities were not associated with increased risk of developing COVID-19.
“This large, population-based prospective study shows that there is limited overlap between risk factors for developing COVID-19 versus those for intensive care unit admission and death as reported in hospitalised cohorts,” concluded researchers.
Reference: Martineau AR, Holt H, Greenig M, et al. Risk factors for developing COVID-19: a population-based longitudinal study (COVIDENCE UK). Thorax. Published online November 30, 2021. DOI: 10.1136/thoraxjnl-2021-217487.