For example, Cushing's syndrome is a disorder of extreme excess cortisol. The incidence is estimated to be somewhere between 1 in 100,000 and 1 in 26,000. In other words, it's an extremely rare condition. Suggesting that a congenital form of Cushing's syndrome is behind Alzheimer's wouldn't make sense.

There's a trend in alternative medicine to take a large collection of studies, reduce them to overly simplistic this-causes-that links, then to string them all together to generate misleading conclusions.

In this case, the comment is trying to claim that lifestyle factors combined with an extremely rare 1-in-100,000 condition from birth results in a set of hormonal changes that lead to damage to the insulating layer around your nerves. It's extreme speculation, not indicative of the actual science.

In general, be wary of anyone who claims to have solved complex medical conditions like Alzheimers that are still elusive to actual researchers. I hope it goes without saying that a random Hacker News commenter hasn't figured out what countless researchers have been working on for decades.