Finding the link between diabetes and Alzheimer's disease
A recent study in Japan has connected diabetes type 2 with Alzheimer's disease. The study results will appear in the August 25th online issue of Neurology. One thing that the researchers were concerned about is the rapid rise of both Alzheimer's disease and diabetes, and it was hoped with this research to find a link between the two devastating illnesses.
Methods of the research including autopsies of 135 Japanese adults, Comparisons were made between different indicators of type 2 diabetes with plaque deposits, called neurofibrillary tangles, in the brain. All those who were autopsied had died between the years 1998 and 2003. The study participants were part of an ongoing study on brain and heart health. 2 hour glucose tolerance tests, fasting blood sugar and insulin levels, and other tests were done. Researchers did adjust for age, sex, blood pressure, cholesterol, body-mass index, exercise, and cardiovascular disease. It was found that those with higher blood sugar levels were more likely to have an increase in the number of neurofibrillary tangles in their brains after death.
Relationship between diabetes and Alzheimer's still unknown
The relationship between type 2 diabetes and Alzheimer's is still unknown. It is still unknown whether there is a relationship. The study was correlational. The correlation here shows that some people with type 2 diabetes also have neurofibrillary tangles, a hallmark of Alzheimer's. Correlational studies are important, however, in the fact that further studies down the road may be able to find the pieces that fit together.
When evaluating research, it is important to look at the shortcomings of the study. The first was that the study was small. With small studies, making generalizations to other groups is difficult. Another was that the study did not track whether the participants had been treated for diabetes or not. This would make the study less likely to be able to say it had a link because if one was being treated and had lower sugar, then how would the findings of that autopsy connect with the rest of the study? Finally, the rates of diabetes and obesity in the study were low overall. This makes comparisons to other population much more difficult.
It is plausible that there is a connection between diabetes type 2 and Alzheimer's. Perhaps this study will motivate other research that is more in-depth and more accurate. The great thing about correlational studies is they set the foundation for more research to be done. The link between diabetes and Alzheimer's may yet be in our future.