Epidemiologists have long noted that there appears to be some sort of correlation between type 2 diabetes — the type that's associated with obesity, and which often appears later in life — and Alzheimer's disease. Now a number of brand-new studies, presented at a major Alzheimer's conference in Madrid, has strengthened that link. In one, Swedish researchers looked at 1,173 people over 75 and concluded that people with borderline type 2 diabetes — that is, chronically elevated blood sugar — were about 70% likelier to develop Alzheimer's than those with normal sugar levels. Another study, based in the U.S., looked at the medical records of 22,852 type 2 diabetics, none of whom had any sort of dementia at the outset, and found that the more elevated their blood sugar tended to be, the bigger the risk they'd develop Alzheimer's. Several other studies hinted, though did not prove, that a class of anti-diabetes drugs called glitazones may lower Alzheimer's risk.
It's still not clear why diabetes and Alzheimer's should be related. One possibility is that the excess insulin the body churns out to try and control blood sugar inflames the blood vessels — which would also explain how diabetes leads to heart disease. But while it isn't yet exactly certain what's going on, the result is a kind of good news/bad news story. The bad news is that type 2 diabetes has been on a dramatic increase as Americans have gotten more obese over the past couple of decades — which means the Alzheimer's epidemic that's already expected simply as a result of the aging of the massive Baby Boom generation could be even bigger than anyone thought. The good news is that by inching closer to an understanding of precisely what it is that causes Alzheimer's — or even getting closer to one possible cause — doctors may be able to stave off the disease by the time Baby Boomers begin moving into their 70s and 80s.