Published: 29 June 2022
Women, people aged 50-60, and people with poor pre-pandemic mental or physical health are more at risk of long COVID, according to research funded by the NIHR and UK Research and Innovation.
Around two million people in the UK are affected by long COVID, experiencing symptoms for 12 weeks or more after they’ve been infected.
The new research looked at data from 10 UK long-term studies established before the pandemic, which have tracked participants over many years. Data from these studies were combined with 1.1 million anonymised electronic health records from English general practices.
The researchers then used these data to investigate whether demographic and health characteristics - such as age, sex and existing medical conditions - affected how common long COVID was in the study group.
The study, published in Nature Communications, found that the proportion of people who self-reported having COVID and also reported symptoms for longer than 12 weeks ranged between 7.8% and 17%, while 1.2% to 4.8% reported “debilitating” symptoms.
The proportion of people with symptoms for 12 or more weeks generally rose with increasing age, ranging from one in 13 (7.8%) younger adults to one in six (17%) middle-aged people. Using a stricter definition of long COVID as impacting routine daily activities, the researchers found that it affected 1.2% of 20-year-olds who had COVID-19, but 4.8% of people in middle age.
Women were 50% more likely to report long COVID than men. The following additional factors were associated with increased risk of long COVID:
- having poor pre-pandemic mental health or poor general health
- having asthma
- being overweight or obese.
Non-white ethnic minority groups had lower odds of reporting long COVID (about 70% less likely).
Chief Investigator Professor Nishi Chaturvedi, from University College London, said: “Getting consistent findings from this combination of many different studies gives us greater confidence that our findings are robust, which is critical given that we know so little about long COVID.”
First author Dr Dylan Williams, also at UCL, added: “Our findings hint at the mechanisms behind long COVID. Next we need to identify the predispositions that might explain, for example, why women or individuals with asthma appear to be at higher risk. Could a liability to suffer from autoimmunity or allergies play a role? Establishing concrete research avenues to go down will eventually lead to benefits for people with long COVID.”
The research is part of the UKRI-NIHR funded multi-institution CONVALESCENCE study, which includes researchers at the Universities of Bristol, Edinburgh, Glasgow, Oxford, as well as the London School of Hygiene & Tropical Medicine and the Bradford Royal Infirmary.