Yes, but there are other studies that make this link. The link is apparently strong enough that some prefer the phrase “type three diabetes” as a way to describe Alzheimers.
“Currently, there is a rapid growth in the literature pointing toward insulin deficiency and insulin resistance as mediators of AD-type neurodegeneration, but this surge of new information is riddled with conflicting and unresolved concepts regarding the potential contributions of type 2 diabetes mellitus (T2DM), metabolic syndrome, and obesity to AD pathogenesis.”
That’s still far from established at the level to warrant the original expression of absolute certainty. Considering that people have been studying it for decades, and that it’s like 70% heritable, it’s unlikely that everyone missed something as simple as “they are eating too much sugar” – something like this is likely to involve multiple genetic and lifestyle risk factors. I would defer to the researchers who still characterize it as a hypothesis - for example, this article is recent but is still careful not to overstate the case:
Part of why that matters is that you will have no trouble finding people who ate little sugar and still developed it, or sweet fiends who didn’t, and presenting such a simple explanation can feel cruel to people who saw their loved ones die a pretty ugly death since it sounds like you’re saying it’s a choice.
