People With Allergic Conditions – Such As Hay Fever and Eczema – May Have a Lower Risk of COVID-19 Infection

Older age, male gender and other medical conditions unrelated to increased risk… As opposed to Asian ethnicity, obesity, overpopulation, social contacts and people-oriented roles.

People with allergic conditions such as hay fever, rhinitis and atopic eczema may have a lower risk of COVID-19 infection, especially if they also have asthma, finds a large, population-based study of British adults, published online in the respiratory journal Thorax.

And contrary to the findings of recent studies, older age, male gender and other underlying conditions are not linked to an increased risk of infection, the study shows.

But Asian ethnicity, obesity, household overcrowding, socializing with other households indoors and fulfilling roles different from health and social care are all independently associated with an increased risk of developing COVID-19, the findings show. .

A growing body of evidence suggests that at least some risk factors for developing COVID-19 may differ from those predisposing to serious illness and the need for intensive care, the researchers say.

To explore this further and discover the contribution demographic, socioeconomic, lifestyle, diet, medical treatment and underlying conditions can make to the risk of developing COVID-19, the researchers gathered detailed information about possible risk factors for the infection in adults. in the UK between May 2020 and February 2021.

All participants were asked to provide information about their age, household circumstances, job, lifestyle, weight, height, long-term medical conditions, medication use, vaccination status, diet and supplement intake when they entered the study and then again in subsequent months.

Of the 16,081 eligible people, 15,227 completed at least one subsequent monthly follow-up questionnaire 30 days or more after participating in the study; and 14,348 completed the last questionnaire on or before February 5, 2021.

The mean age of the participants was 59; 70% were female; and 95% identified their ethnicity as white.

A total of 446 participants (nearly 3%) had at least one episode of confirmed COVID-19 infection, as determined by a Pap smear (PCR or lateral flow) test during the study period, and 32 were hospitalized.

The researchers took into account a range of potentially influential factors: age: gender: duration of study participation: ethnicity: test frequency: ethnicity; education; deprivation; household income; housing type; number of persons per bedroom; school children at home; owned by a dog; shielding; socializing with other households; visits to shops and other indoor public places; traveling to work or study; status of frontline worker; fysical activity; alcohol use; weight (BMI); asthma; allergies; use of immunosuppressive drugs, inhaled corticosteroids, and bronchodilators; BCG vaccination status; fruit, vegetable and salad intake; and use of dietary supplements.

Certain factors therefore emerged as independently associated with an increased likelihood of developing COVID-19.

People of Asian/Asian British ethnicity were more than twice as likely to be infected as their white counterparts.

Similarly, overcrowding in households; socializing with other households in the previous week; number of visits to covered public places; a people-oriented role other than in health and social care; and overweight/obesity were all associated with an increased risk.

And the greater the number of people sharing a household and the more visits to indoor public spaces, the greater the chance of becoming infected, the findings showed.

But atopic (allergen-caused) disease, including eczema/dermatitis and hay fever/allergic rhinitis, was independently associated with a 23% lower chance of developing the infection than in people without atopic disease or asthma.

And in those with atopic disease and asthma, the risk was even lower: 38%. This association held true even after taking steroid inhalers into account.

Taking drugs to dampen the immune system’s response (immunosuppressants) was also associated with a 53% lower chance of COVID-19 infection, although this may reflect greater shielding against infection by these patients, the researchers said.

But age, gender, other medical conditions, diet and supplement use were not associated with infection risk.

This is an observational study and as such cannot determine a cause. And the researchers acknowledge some limitations to their study.

These include no oversight of Pap smear testing and reliance on the results of routine tests usually triggered by symptoms, potentially missing those with asymptomatic infection.

The participants also volunteered, so some ethnic minorities, especially people of black, African and Caribbean ethnicities, were underrepresented in the study.

Nevertheless, the researchers conclude, “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 hospitalized cohorts.”

Reference: “Risk Factors for the Development of COVID-19: A Population-Based Longitudinal Study (COVIDENCE UK)” by Hayley Holt, Mohammad Talaei, Matthew Greenig, Dominik Zenner, Jane Symons, Clare Relton, Katherine S Young, Molly R Davies, Katherine N Thompson, Jed Ashman, Sultan Saeed Rajpoot, Ahmed Ali Kayyale, Sarah El Rifai, Philippa J Lloyd, David Jolliffe, Olivia Timmis, Sarah Finer, Stamatina Iliodromiti, Alec Miners, Nicholas S Hopkinson, Bodrul Alam, Graham Lloyd-Jones, Thomas Dietrich, Iain Chapple, Paul E Pfeffer, David McCoy, Gwyneth Davies, Ronan A Lyons, Christopher Griffiths, Frank Kee, Aziz Sheikh, Gerome Breen, Seif O Shaheen and Adrian R Martineau, 30 November 2021, Thorax.
DOI: 10.1136/thoraxjnl-2021-217487