It’s worth being careful with claims like that. Dementia and Alzheimer’s didn’t suddenly appear in the 1970s; diagnosis, longer lifespans, and better reporting changed dramatically around that time. When people live longer, age-related neurodegenerative diseases become more visible. That doesn’t mean environmental or lifestyle factors should be ignored—but it does mean the trend isn’t proof of a single hidden cause. Complex diseases usually come from a mix of genetics, aging, medical advances, and modern risk factors, not one secret event.