@FTMarinetti they can lower it a lot like -30% -40% i think, and considering how often theyre thrown at people and with the perspective of "cholesterol = bad" would assume a lot of that group are kept on them to ensure its kept low and away from "high" cholesterol what they see as "healthier", eg in uk for a healthy person they see <200 as good and for an at risk person 150. ironically they see the cutoff point for dropping below good levels by that study as a ceiling level, inverse. i know someone who got prescribed statins with only a mild elevation and no heart problems
then for the people that arent on more medications in that group indicated by the lower cholesterol, whatever other reason is causing their low cholesterol inducing poorer health (e.g cholesterol lowered in sepsis https://pubmed.ncbi.nlm.nih.gov/3940695/)
for the other side maybe cholesterol as a protective molecule makes up for some of the effects of lack of thyroid to a point? (e.g preventing cancer and death by infections) , but over that the thyroid / hormones might get too low regardless