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1) 1) Interesting interview of Dr. Audrey Ryback by David Tuller. Her recent study showed that there are likely two age peaks for when people get ME/CFS. It helps to characterise ME/CFS as a unique clinical entity.

2) In the interview Ryback explains that this age pattern is notable and that it might reveal something about the underlying pathology of ME/CFS. There are basically two possible explanations.

3) One is that there are two different paths leading to ME/CFS, one for the early onset in late teens, and a different path for the second onset in your mid 30s. So, two different disease that look the same but are different under the hood.

4) The second possibility is that there is one biological process that has vulnerabilities at those particular ages. For example, the peaks might correspond to hormonal changes (puberty and peri-menopause).

5) They are confident the bimodal onset pattern exists because they found it in multiple data sources: the Norwegian healthcare data, the European survey and the DecodeME study. These have different biases, yet the pattern remained the same.

6) Interestingly, there wasn't a big difference between men and women in the onset pattern. If it were hormonal changes for example, we would expect to find a sex difference as well but that wasn’t the case.

7) They did find that people in the early onset are more severely affected, have more family members with ME/CFS and are more likely to report an infectious trigger. The latter was particularly the case for glandular fever although this didn’t fully explain the difference.

8 ) Ryback suggests that future studies should take age of onset into consideration when stratifying cohorts and looking at subgroups. As a next step, she is currently looking at electronic healthcare records in the UK and the diagnoses that precede ME/CFS.