ME Epidemiology - prevalence and peak ages of onset

Simon M said:
Could you explain more? I think the Bakkens study had over 5,800 cases, taken from a retrospective analysis of the entire Norwegian health system across many years. Also, the anaecdotal evidence from PwME has always pointed to the same two age peaks (that was my impression long before I saw the Bakkens study).
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I might have to come back to this later - I think we have discussions about this on other threads. But the Norwegian study is doing an awful lot of the heavy lifting here. I'm pretty sure that there are other studies that have not found the 'twin peaks'.
Simon M said:
Onset there are two age peaks for onset: from puberty to early 20s and 30s-to-early 40s.
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For a start, look at that age range. Puberty, say 10 years, through to early 20s, say 22 or 23? Then another "peak" from 30s to early 40s. So, from 30 to 43? So is the suggestion that there is a gap of 7 years where onset is less common? Those are pretty broad peaks. The proposed situation is sounding more like a plateau with a bit of a valley in the late 20s to me.

I think there were issues with age and gender skews related to exposure in Norway attributed to outbreaks related to contaminated water. Also if the health system is much more likely to diagnose ME/CFS in a 19 year old woman who has had EBV and much less likely to diagnose ME/CFS in a 28 year man who has had Q fever, then rates will be incorrectly skewed by age and gender.

After the early 40s, people are more likely to attribute ME/CFS symptoms to 'getting old' or 'menopause'. Certainly their doctors will be much more likely to do that. Until we have a good biomarker, /I doubt that we will be able to get a good understanding of ME/CFS onset in older people.


Simon M said:
I would say all those are likely, but we 'know' it with lesser degrees of confidence than with GF. Most Q-fever studies lack proper diagnosis (questionnaire only), though I agree it's likely it's some kind of post-viral thing. Dubbo (Q fever, RRV) was quite small. I've read SARS-1 and Ebola studies - they do not sound to me like ME, do not properly apply ME /CFS criteria and ignore other possible causes of fatigue etc. such as organ damage. The link with Long Covid remains unproven: most researchers seem to think ME is probably a subset of LC.
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We know that a substantial proportion of people developing persistent symptoms after a Covid-19 infection meet ME/CFS criteria. Therefore, and given they don't have any other obvious pathology explaining their symptoms, they have ME/CFS. The numbers are too high to suggest that these people all had ME/CFS before their Covid-19 infection, or they developed ME/CFS from some other trigger. I don't think the relationship is known with a lower degree of confidence than for EBV. Similary for SARS-1. I'll give you Ebola as an ME/CFS trigger that we have less evidence for, because people haven't really looked hard at it, but the symptoms that people are left with sound very much like ME/CFS to me.
 
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I just read the The ME Association's web site and they claim that half of Long Covid patients meet the definition of ME, I couldn't find out which criteria they used. The total figure for was:

We estimate than more than 1.25 Million people in the UK live with a diagnosis of ME/CFS and Long Covid.
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Those figures seem way too high, it equates 1.86% of the population, nearly 1 in 60, similar to Esther Crawleys prevalence figures.

I believe that inflated prevalence and lack of gatekeeping amongst GPs is a major contributor to the widespread disbelief that we experience. They'll start to think everybody's getting it so it must be mass hysteria.
 
I don't follow your logic. It's clear very large numbers of people have Long COVID, and of these a significant proportion experience post exertional malaise, and other ME/CFS symptoms. The comparison with Crawley's figures of the past is surely irrelevant. Those figures were from before Covid added a lot more people with ME/CFS symptoms to the population.

I doubt it's prevalence that induces some clinicians to disbelieve us.
 
DigitalDrifter said:
I just read the The ME Association's web site and they claim that half of Long Covid patients meet the definition of ME, I couldn't find out which criteria they used. The total figure for was:
1.25 million with ME/CFS and Long Covid
Those figures seem way too high, it equates 1.86% of the population, nearly 1 in 60, similar to Esther Crawleys prevalence figures.
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I suspect they are too high but getting at prevalence is tricky. Gemma Samms and Chris Ponting published an estimage of 600k edit 390k based on hospital diagnoses of Post Viral Fatigue Syndrome, which is probably the best data we have. They found the highest rate in Cornwall for white people (there is a huge erhnic disparity, unsurprisingly, diagnoses rates are much lower for non-white groups, which is thought to bbe down to low diagnosis rates rather than low rates of illness). Applying that Cornish figure nationally gave 600k.

Long Covid is trickier: there is no agreed case definition, and there are likely to be multiple causes of LC. The 50% figure meeting ME criteria came from referrals to specialist tertiary clinics, so not representative of the broader LC population.

https://twitter.com/user/status/1783418869073301749
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this gives a wider figure of 1.5m LC affected in their daily lives, but 380k "limited a lot", which would be the ME equivalent. Last time I looked, only around half had cognitive issues (it's 95%+ consistently in ME), so the idea that "50% of everyone with LC has ME" is unrealistic, in my view.

If we used the EDIT 390k ME figure and 380k LC "limited a lot" in daily activities, that would give us around EDIT 800k. But you could slice the pie in many ways.
 
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Trish said:
It's clear very large numbers of people have Long COVID, and of these a significant proportion experience post exertional malaise
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I get the feeling that they're not using a strict enough definition of PEM. Some people say they have PEM because they feel a little fatigued or out of breath immediately after going for a walk. It's possible that the term has been hijacked or at least diluted.
 
Simon M said:
this gives a wider figure of 1.5m LC affected in their daily lives, but 380k "limited a lot", which would be the ME equivalent. Last time I looked, only around half had cognitive issues (it's 95%+ consistently in ME), so the idea that "50% of everyone with LC has ME" is unrealistic, in my view.

If we used the 600k ME figure and 380k LC "limited a lot" in daily activities, that would give us around 1 million. But you could slice the pie in many ways.
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Worth adding that the statisticians behind the ONS estimates put out a paper suggesting that around 20-30k ppl are out of work in the UK due to Long Covid. Extrapolating from that "limited a lot" category is quite difficult - there are just so many Long Covid phenotypes.

I think the simple truth is that we don't know how much of Long Covid is ME. It's been my greatest frustration with prevalence studies - they stratify patients by symptoms not diagnoses. Imo it would be far more useful to know what percentage of covid infections lead to ME/CFS or POTS or MCAS than to know what percentage of people may have fatigue after an infection.

The prevalence question has been a massive debate within the Long Covid community, and I've generally come down on the more cautious side of things, partly for political reasons; I've been concerned that there's a tension between saying 10-30% of covid cases lead to Long Covid while simultaneously defining Long Covid as this awful, life-changing illness; and I worry that there's a certain 'the boy who cried wolf' element to the high prevalence figures - they're too easy to disbelieve.

The prevalence question has been much more central to the "Long Covid question" than ME - it's probably been the most lively societal debate about Long Covid. But fwiw I don't think inflated or undercounted prevalence stats have been a major factor in the neglect of either illness (different story in regards to diagnostic criteria, particularly for ME). Much stronger forces at play; those decades of psychologisation; the confusing nature of these illnesses to outsiders; broader attitudes towards chronic illness and disability; the politicisation of covid; and the nature of these illnesses meaning we can't produce a political movement similar to that of the AIDS movement.
 
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RaviHVJ said:
Worth adding that the statisticians behind the ONS estimates put out a paper suggesting that around 20-30k ppl are out of work in the UK due to Long Covid. Extrapolating from that "limited a lot" category is quite difficult - there are just so many Long Covid phenotypes.
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That seems very low relative to the size of the 'limited a lot' category, and reports of LC more generally. Do you have a link to the paper? I think LC is also contributing to people working part time, which would also count as 'limited a lot'.

RaviHVJ said:
I think the simple truth is that we don't know how much of Long Covid is ME. It's been my greatest frustration with prevalence studies - they stratify patients by symptoms not diagnoses.
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We don't, and I agree with the issue of symptoms/self-report vs diagnoses.
However, I think the 'limited a lot' figure + requiring cognitive symptoms (about half of that category) at least gives us an upper limit: maybe 190k. (Cog symptoms are reported by 95%+ of PwME, eg. DecodeME data)

But we need much better data.
 
DigitalDrifter said:
I just read the The ME Association's web site and they claim that half of Long Covid patients meet the definition of ME, I couldn't find out which criteria they used. The total figure for was:


Those figures seem way too high, it equates 1.86% of the population, nearly 1 in 60, similar to Esther Crawleys prevalence figures.

I believe that inflated prevalence and lack of gatekeeping amongst GPs is a major contributor to the widespread disbelief that we experience. They'll start to think everybody's getting it so it must be mass hysteria.
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https://pubmed.ncbi.nlm.nih.gov/35079817/ I have used this reference to describe potential links between Long Covid and ME and suspect it may be where some of the 50% figure comes from. It is a relatively small study and from 2021 so there may be something more up to date but I have found it does help with some discussions about Long Covid and ME raising awareness and understanding with health professionals .
 
Lou B Lou said:
Yes, the term PEM is being both diluted and hijacked.
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In another thread @Trish, I think, did an excellent post distinguishing the various post activity fatigue states that are dangerously being confounded with PEM. Perhaps the most dangerous is more rapid ‘fatiguability’ that occurs in many conditions and definitely serves to dilute any understanding of PEM. Sometimes this may just be ignorance, but often it is done, perhaps more disingenuously, by the ‘lumpers’ the BPS crew that want to lump ME in with FND, MUS and lots of other conditions.
 
RaviHVJ said:
Worth adding that the statisticians behind the ONS estimates put out a paper suggesting that around 20-30k ppl are out of work in the UK due to Long Covid. Extrapolating from that "limited a lot" category is quite difficult - there are just so many Long Covid phenotypes.
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I'm not sure how to interpret this estimate of there being 20-30k people out of work due to LC at July 2022.

The study has many great aspects:
  • People were recruited from the huge Covid Infectition Study that recruited from randomly selected households and the data we collected propsectively, so no recall bias issues.
  • There is pre-onset employment and health data (i.e. they only included those who hadn't had has Covid at the start of the study
  • And a control group of people who had covid without reporting LC.
The study finds:
  • Modest increases in the risk of long-term inactivity (odds ratio of 1.45 30-<40 week post infection, 1.34 for 40-<52 weeks post-infection).
  • "Our estimates translate to 27 000 working-age adults in the UK being inactive because of their Long Covid symptoms in July 2022, representing approximately 0.5% of total labour market inactivity among the non-student, non-retired population"
However,
It uses uses the frustratingly broad. UK LC definition of any symptoms post covid for >12 weeks, and says:
Other studies suggest that 80 00025–96 00026 people might have left employment directly because of Long Covid by March 2022. These numbers are higher than our estimate as they represent cumulative exits from employment rather than point-in-time measures.]
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I don't really understand the bolded point. if it is right, the LC figure could be 150k+ who have left empmloyment by March 2024.

And the study does not measure people reducing their hours. Giving up work is such a big step, could part-time by 3x the rate of leaving employment, which would give 100k part-time or out of employment because of LC by July 2022?

We could do with proper analysis of the paper.
 
Trish said:
It's clear very large numbers of people have Long COVID, and of these a significant proportion experience post exertional malaise, and other ME/CFS symptoms.
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https://www.s4me.info/threads/offic...on-in-the-uk-updates.20817/page-7#post-482657
55% of respondents who self-reported long COVID said their symptoms get worse after either mental or physical effort, or both, while 30% said their symptoms did not get worse and 15% answered as "don't know".
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That's not necessarily PEM. Were the symptoms delayed? How long did they last? What percent experience LTSE?
 
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