People who are 'double jointed' have a heightened risk of developing long Covid, say researchers
People with generalised joint hypermobility – commonly known as being ‘double jointed’ – may have a heightened risk of developing long Covid.
That is the conclusion of a case-control study published today (20 March) in the open access journal BMJ Public Health.
Those with generalised joint hypermobility were 30 per cent less likely to have fully recovered from Covid-19 infection than those without hypermobile joints, and to be experiencing the persistent fatigue associated with long Covid, the findings indicate.
Other than older age, the likelihood of developing long Covid seems to be greater when associated with certain underlying health conditions, including fibromyalgia, irritable bowel syndrome, migraine, allergies, anxiety, depression and back pain, explain the researchers.
These risk factors have all been independently associated with joint hypermobility, whereby some, or all, of a person's joints have an unusually large range of movement.
The article’s first author is Jessica Eccles, who is based at the Department of Clinical Neuroscience at the Brighton and Sussex Medical School and Sussex Partnership NHS Foundation Trust’s Neurodevelopmental Service.
Is double jointedness a risk factor?
Dr Eccles and her fellow researchers wanted to find out whether double jointedness might be a risk factor for long Covid in its own right. They drew on 3,064 participants in the Covid Symptom Study Biobank, all of whom had had Covid-19 infection at least once.
These participants were surveyed in August 2022 to find out if they had hypermobile joints, if they had fully recovered from their last bout of Covid-19 infection, and if they were experiencing persistent fatigue.
Most (81.5 per cent) said they had had Covid-19 at least once. Of these, information on self-reported recovery was available for 2,854, of whom 2,331 (82 per cent) were women and 2,767 (97.5 per cent) were White. Their average age was 57 years (range 21-89).
Around one participant in three (914; 32 per cent) said they had not fully recovered from their last bout of Covid-19 infection, and of these, 269 (just under 30 per cent) had generalised joint hypermobility.
Among the 1,940 people who said they had fully recovered, almost one in four (439; just under 23 per cent) had hypermobile joints; 400 of them were women.
After accounting for potentially influential factors, including age, sex, ethnicity, deprivation level, educational attainment, and number of vaccinations received, joint hypermobility was strongly associated with a failure to recover fully from Covid-19 infection.
People who were double jointed were around 30 per cent more likely to say they had not recovered fully from Covid-19 infection than those with 'normal' joints. And joint hypermobility significantly predicted high levels of fatigue, which emerged as an instrumental factor in the failure to make a full recovery.
These results suggest further exploration of whether [joint hypermobility] is linked to a particular phenotype or subtype of those not recovering fully from Covid-19, including long Covid [Jessica Eccles et al]
Caveats and conclusions
As the study was observational study in nature, no firm conclusions can be drawn about whether joint hypermobility is a causal factor for long Covid. Dr Eccles and her colleagues also acknowledge that their findings have a number of limitations. For example, most of the study participants were women and were of White ethnicity.
They acknowledge that their analysis did not include or correct for other potentially influential factors – such as duration of symptoms and coronavirus variant, or pre-existing conditions, such as fibromyalgia, which is itself characterised by fatigue and brain fog.
As has been suggested before, long Covid is unlikely to be a single entity, but a medley of intersecting immunological, inflammatory, autonomic nervous system, respiratory and cardiovascular processes that lead to distinct symptom profiles affecting body and brain, say the researchers.
And there are probably several causes, and therefore no one treatment strategy, for long Covid, Dr Eccles and her colleagues point out, adding: ‘However, these results suggest further exploration of whether [joint hypermobility] is linked to a particular phenotype or subtype of those not recovering fully from Covid-19, including long Covid.’
Is joint hypermobility linked to self-reported non-recovery from COVID-19? Case–control evidence from the British COVID Symptom Study Biobank doi: 10.1136/bmjph-2023-000478
X (Twitter) handle for Dr Eccles: Jessica A Eccles @bendybrain
Author: I A McMillan
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