This article was published on healthandcare.scot 

University of Edinburgh researchers have found that women with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) experience more symptoms and co-occurring conditions, particularly as they get older.

In the world’s largest study of ME/CSF to date, the researchers say that, while it has long been known that women are more likely to have the ME/CFS, the results reveal how their experiences differ.

The Edinburgh team analysed anonymous survey questionnaires returned from more than 17,000 people living with ME/CFS aged 16 and over – who were asked a mix of questions covering diagnosis and how long participants had been experiencing symptoms to whether they had co-occurring conditions.

While ME/CFS is a long-term neurological condition with a range of symptoms, the most common impact is extreme tiredness, while an excessive increase in symptoms can be triggered by normal levels of exertion.

Researchers described this key feature of ME/CFS as ‘post-exertional malaise’ – a delayed but dramatic worsening of fatigue and other symptoms following minor physical effort. ME/CFS is often marked by this extreme energy limitation that does not improve with rest.

The causes of this condition are unknown and there are no diagnostic tests – or a cure.

Women composed 83.5% of respondents in the DecodeME study – funded by Medical Research Council and the National Institute for Health and Care Research – confirming the well-established sex bias amongst ME/CFS patients.

Additionally, the study reveals that women who have ME/CSF for more than 10 years are more likely to experience increasingly severe symptoms as they age.

Women also reported, on average, slightly more symptoms of ME/CSF than men – 42 compared with 36.

The most common of these symptoms were ‘brain fog’ – the term used for cognitive impairment experienced by participants – unrefreshing sleep, and muscle pain.

Researchers say that gaining a better understanding of how ME/CFS develops and affects people differently is the first step towards identifying effective treatment options.

The study’s lead, Professor Chris Ponting 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.”

The study was supported by, and involved, the charity Action for M.E., the Forward M.E. alliance of UK charities, and people with lived experienced the condition.

Sonya Chowdhury, Chief Executive of Action for M.E. and Chair of the management group for the study, added:

“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.”

Co-occurring conditions

A difference across co-occurring conditions was revealed. Just over half (52%) of the men reported at least one active co-occurring condition – wherein the condition is considered active if the participant had experienced symptoms in the preceding six months. For women, two-thirds (66.7%) reported at least one active co-occurring illness.

This difference was similarly reported for inactive conditions, with more than 10% more women than men reported at least one inactive co-occurring condition.

Inactive conditions are those which participants have had in the past but had not experienced symptoms of within the six months preceding the survey.

The most common active co-occurring condition was irritable bowel syndrome reported 41.3% of the time, while clinical depression was diagnosed in 32.4% of participants.

Fibromyalgia – a long-term condition that causes pain all over the body – was also ‘featured prominently’, being actively experienced by 29.5% of participants.

Meanwhile, 14.1% of participants reported anaemia and 12.8% hypothyroidism reported as active co-occurring conditions.

Beyond this, the study found that participants differed in ME/CFS illness severity when stratified by their sex-at-birth.

Using the UK’s National Institute for Health and Care Excellence (NICE) guidelines for severity, participants were asked to define the severity of their illness from mild to very severe using definitions.

It concluded that being female is “significantly associated” with greater severity.

In the next stage of work, the team are studying at least 20,000 individual’s DNA samples to investigate whether the disease is partially genetic – and, if so, explore its underlying cause.

Professor Chris Ponting added that ongoing genetic analysis as part of the researcher team’s wider project will help provide more information:

“Our hope is that DecodeME’s genetic results will shed light on why certain groups are more susceptible to ME/CFS than others.”

To aid their efforts, the study team are calling on more people with ME/CFS, aged 16 and over and based in the UK to take part in the research – “to help us decode ME”.