[T-A]

From the article, describing the now-retracted paper:

“In people with hearing loss,” the authors wrote, “hearing aid use is associated with a risk of dementia of a similar level to that of people without hearing loss.” They proposed “up to 8% of dementia cases could be prevented with proper hearing loss management.

From the article, describing the replication work which led to its retraction:

Mur and his colleagues intended to build on the article with a related analysis on the same UK Biobank data. But when he couldn’t replicate the main findings, Mur scrutinized the paper more deeply. [...] Most notably, he found that hearing aid use did not correspond to a lower rate of dementia for people with hearing loss, as the authors reported. He found the opposite: among people with hearing loss, the dementia rate was higher for those using hearing aids.

[krackers]

Isn't there an obvious confounding variable here where probably the hearing-aid using population has bad hearing, and if their hearing aid was not updated then it's more likely they would develop dementia? So the results from the paper could technically be true for the subset of hearing aid users that don't go for checkups.