Women with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) tend to have more symptoms and co-occurring conditions than men, according to the world’s largest study of the disease.
The study, entitled DecodeME, reveals women who have the condition for more than 10 years are more likely to experience increasingly severe symptoms as they get older.
ME/CFS is estimated to affect more than 250,000 people in the UK, of all ages and from all social and economic backgrounds.
Its key feature, called post-exertional malaise, is a delayed dramatic worsening of symptoms following minor physical effort.
Other symptoms include pain, brain fog and extreme energy limitation that does not improve with rest. Causes are unknown and there is currently no diagnostic test or cure.
Experts from the University of Edinburgh analysed anonymous survey questionnaires from more than 17,000 people with ME/CFS.
Two-thirds of women, and slightly more than half of men, reported at least one active co-occurring condition.
Similarly, 39.2% of women and 28.6% of men reported at least one inactive co-occurring condition.
A condition was considered active if the participant had experienced symptoms in the preceding six months.
The most common active co-occurring condition was irritable bowel syndrome, with clinical depression, fibromyalgia, anaemia and hypothyroidism also featuring prominently.
Women also reported, on average, more symptoms than men – 42 compared with 36.
The most common of these symptoms were brain fog – a term commonly used to describe the cognitive impairment experienced by participants – unrefreshing sleep and muscle pain.
Participants were also asked to define the severity of their illness from mild to very severe using definitions from the UK’s National Institute for Health and Care Excellence guidelines.
Experts identified that being a woman and having ME/CFS for more than 10 years are risk factors for severe illness, with symptoms increasing in intensity as they age.
Professor Chris Ponting, study lead from the MRC human genetics unit at the University of Edinburgh’s Institute of Genetics and Cancer, said: “ME/CFS is a devastating disease affecting a UK population the size of Derby.
“We discovered that the disease is worse for women, in older people, and many years after their ME/CFS started.
“Our hope is that DecodeME’s genetic results will shed light on why certain groups are more susceptible to ME/CFS than others.”
Sonya Chowdhury, chief executive of Action for M.E. and chair of the management group of the study, said: “These findings highlight the very serious impact ME/CFS has on women who are disproportionately affected.
“It’s important to also recognise the impact that it has on men who have ME/CFS and we thank the 20,000 men and women who have already signed up to take part in this very important study.
“We still need more to join us, so if you are 16 or older, live in the UK and have a diagnosis of ME/CFS, please do take part now to help us decode ME at www.decodeme.org.uk/portal.”