C allele of the rs2209972 single nucleotide polymorphism of the insulin degrading enzyme gene and Alzheimer's disease in type 2 diabetes, a case control study.

BACKGROUND AND OBJECTIVE In the last few decades we have witnessed an interesting transformation of the population pyramids throughout the world. As the population's life expectancy increases, there are more chronic diseases such as diabetes mellitus and dementias, and both of them have shown an association. GENERAL OBJETIVE To determine the association between Alzheimer's disease in diabetic patients and the insulin degrading enzyme in outpatients of a second level Hospital in Monterrey, Mexico. MATERIALS AND METHODS This was a case control study in which we included outpatients from the Geriatrics Clinic of a Hospital in Northeastern Mexico. Cases were patients with a Mini Mental Score Exam (MMSE) below 24 and DSM-IV criteria for Dementia. Controls were patients who had MMSE scores greater than 24. RESULTS Data from 97 patients were analyzed. Regarding physical examination and the results of laboratory tests, there were no differences between the two groups (p>0.05). A 98% prevalence of the insulin degrading enzyme was documented in the sample studied. We found an association between a homozygous status for the CC genotype and Dementia with an estimated Odds Ratio (OR) of 2.5 (CI 95% 1.6-3.3) on the bivariate test, while, on the multivariate analysis, the OR was estimated 3.3 (CI 95% 1.3-8.2). CONCLUSIONS Evidence shows that cognitive impairment is more frequent among those exposed to the C allele of the rs2209972 SNP of the insulin degrading enzyme gene.