ME Epidemiology - prevalence, peak ages of onset and gender ratio

Roughly 80% of those diagnosed with autoimmune diseases are female. This article puts the figure at 77%. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3328995/
I'm not sure if that's collectively or if it holds true for each autoimmune disease.

On the other hand, ~80% of autism cases are male.

Without a biomarker, though, other factors could tilt the apparent prevalence by sex in ME/CFS. For example, doctors might diagnose women more readily than men, and/or men might actively avoid a diagnosis to a greater degree than women.

The M/F ratio may also vary by severity. There might be an increased percentage of men among very severe cases, but I have no idea if that's been borne out by any kind of study.

 

Autism presents differently in females and support services are only now getting to grips with this- very slowly. (similar to how females present differently with heart attacks etc - the whole gender ratio may be changing as more research becomes gender balanced) The male /female ratio may be subject to change in future.

 

This study found that 30% of those diagnosed with “CFS/ME” were male which is a little higher than what tends to see in ME/CFS patient organisations. I couldn’t find the number directly on a quick search but calculated it from a female:male ratio of 2.35:1.

https://www.ncbi.nlm.nih.gov/m/pubmed/28358988/?i=5&from=white crawley collin

Trends in the incidence of chronic fatigue syndrome and fibromyalgia in the UK, 2001-2013: a Clinical Practice Research Datalink study.
Collin SM, et al. J R Soc Med. 2017.

Authors
Collin SM1, Bakken IJ2, Nazareth I3, Crawley E1, White PD4.

 

Meh, Crawley and White. Unreliable.

 

Additionally, many autistic people don't see their autism as a disease. If they have GI problems, they want medical treatment for that. But their autism is just a different way of thinking, like being an introvert or extrovert. They want services and supports to figure out how to navigate a world that doesn't appreciate or understand them, but they don't see autism as a medical issue.

 

The first spike correlates with the age of first sexual contact by females in Norway.

The second spike correlates with the mean age of first-time mothers in Norway.

Males and females have the same age of sexual initiation usually so it is why the spikes are the same, and why the second one is not. Even a non-significant rise in males should be expected because the increased presumed stress of novel fatherhood.

This study potentially delineates two separate etiologies: progesterone mediated autoimmune shift and infectious onset, and shows the two syndromes should be isolated.

 

Another 2.4 year prospective study. (mean baseline age of entire population was 44.9, 57% women)

https://papers.ssrn.com/sol3/papers.cfm?abstract_id=3427300

New onset 0.08%/year, mean age of 48.0. 56% of new cases were women.

"Lifetime diagnosis at baseline" was 1.3%. (note this was self-reported)

 

Study was cohort participatory and not observational and generally reflects who participates in these studies uncompensated. I do not have any comments on it directly other than the context I posited above.

 

Strangely, being much sicker now, I have less significant symptoms. In the ME days it was always said the danger point was when you started to feel better because it was easy to do too much. We know more now so maybe newer patients are smarter but this always applied to me.

Now that I can barely walk or do anything much I rarely get the paralysis or lack of speech and vision I did when I was going to school every day. Then I had kids and was forced to do things when I felt too ill so I was in a bad way by evening. Now I do much less altogether and have different things which come for a few months and go for a while.

Now I think about it, things are also easier because I have adapted my life. I have a stairlift, dark glasses, a wet room and so on and have learnt easy ways of cooking.

The same thing happens with MS; you see people struggle to walk but when they start to use a wheelchair full time they are much brighter, looking more disabled but less sick.

 

I need to clarify that the age doesn't really tell us much. The average age at enrolment in the study was 44.9, and the study only went for 2.4 years so this study can't really capture what happens at other ages.

 

I think this study just shows that self-reported diagnosis of CFS is not very reliable. It does make me wonder who all those people are that report a diagnosis of CFS because there seems to be more of them than what one would expect.

Could you explain what you mean by this? The study said that "The sample population of the Lifelines study is broadly representative of the total Dutch population." Mean baseline age was 44.9 with a large standard deviation of 13.2. I think it includes all ages older than 18.

 

Unless they provide a histogram, and account for participation biases... There may still be a lack of sample size to make any conclusions about an earlier age peak too.

 

Just found this: https://ourworldindata.org/gender-ratio#sex-ratio-at-birth

Interesting.

 

It may not be relevant to what they are saying here, but one x chromosome is switched off in every cell in a woman. this is the barr body (?) that they used in sport to determine if someone was female or not.

This switching off is one reason why one of identical twins can have a genetic disease while the other does not.

 

Does anyone know if the high female:male ratio is only in adults or in both adults and children?

 

I think both?

 

Post copied from here
https://twitter.com/user/status/1265335568382275584


eta:
https://www.mdpi.com/2218-1989/10/5/216

 

Start of merged thread

I have been puzzling about incidence rates, prevalence and recovery rates for some years now. Am I correct in assuming an incidence rate reflects the probability that someone will fall ill with the condition during that year, that prevalence indicates the number or proportion of people with the illness in the community, and that recovery rates reflect the probability that someone will recover from the condition during that year?

If so I started to produce a spreadsheet looking at numbers in the UK. It is a very primitive one, but one I can modify to reflect reality a little more closely. But I am not confident of my mathematical analysis these days, so have attached it.

I assumed a population of 64 million in the UK, a life expectancy of 80, no difference between males and females, no death rates, a uniform spread of people in each age group, and no recovery. I know these are daft simplifications, but it gets the layout going.

The problem is that to reach a total of 250,000 people with ME in the UK, and assuming that anyone from 12 to 75 can be diagnosed with ME, I need a prevalence rate of 0.6%.

A uniform prevalence rate is reasonable (I know people suggest there are peaks, but the PACE trial had a pretty uniform age distribution).

Before I start to tweak things, am I on the right tracks?

 

To what if I may ask? What is the goal?

It seems that you have calculated the prevalence rate needed to get to a population of 250.000 ME/CFS patients in the UK assuming only people aged 12 to 75 can be diagnosed with it.

But the 250.000 figure in the UK is probably just a rough estimate based on US prevalence figures. I suspect someone quickly extrapolated the 0.42% figure from the Chicago study to the whole of the UK population (so including the youngest and oldest persons) a while ago. So I'm not sure why you need to reach the 250.000 figure.