Poor control of blood sugar levels may explain why elderly women with diabetes are significantly more likely to show mental decline over the years, compared with nondiabetic women. The study involved 999 Caucasian men and women participating in the Rancho Bernardo Study Cohort. The participants, who were about 70 years old on average, included individuals with diabetes, prediabetes, and others without diabetes.
At the beginning of the 4-year study, all of the patients performed similarly on 3 cognitive tests. The results showed that after 4 years, the diabetic women had a 4-fold increased risk of a "major cognitive decline" on 1 test, but not on the other 2 tests, compared with nondiabetic women. The effect was more prevalent among women with poorly controlled blood glucose levels. The men, however, showed no marked changes in cognitive test scores after 4 years, reported the researchers in the Archives of Internal Medicine (June 28, 2004).