alt Hacker NewsWhat does "less muscle-mass" mean in terms of mortality statistics?
We already know women live longer than men on average, and also have less muscle-mass than men on average, so clearly it's not having too much of an impact on women.
Without looking into actual statistics here, Japan is known for having a high life expectancy, and stereotypically Japan's population is both relatively thin, and has relatively little muscle, so that also seems to defy that expectation.
What sort of mortality are you expecting here?
You seem to be working from base principles without consulting the literature.
https://pubmed.ncbi.nlm.nih.gov/28991040/ Conclusions: Low muscle strength was independently associated with elevated risk of all-cause mortality, regardless of muscle mass, metabolic syndrome, ...
https://www.amjmed.com/article/s0002-9343(14)00138-7/fulltex... Muscle mass is associated inversely with mortality risk in older adults independently of fat mass and cardiovascular and metabolic risk factors
And specifically GLP-1 usage is associated with significant loss of lean mass: https://pubmed.ncbi.nlm.nih.gov/38937282/ In some studies, reductions in lean mass range between 40% and 60% as a proportion of total weight lost ...
This might be a good start. There is quite a bit of material here and as might be expected much of it is fairly recent and gets a lot of this kind of skinny equals long life feedback that isn't strongly supported by clinical data.