Diabetes mellitus is associated with cognitive decline and impaired performance in cognitive function tests among type 1 and type 2 diabetics. Even though the use of tight glucose control has been limited by a reported higher mortality, few reports have assessed the impact of treatment intensity on cognitive function. We conducted a meta-analysis to evaluate if an intensive glucose control in diabetes improves cognitive function, in comparison to standard therapy. We included 7 studies that included type 1 or type 2 diabetics and used standardized tests to evaluate various cognitive function domains. Standardized mean differences (SMDs) were calculated for each domain. We found that type 1 diabetics get no cognitive benefit from a tight glucose control, whereas type 2 diabetics get some benefit on processing speed and executive domains but had worse performances in the memory and attention domains, along with a higher incidence of mortality when using intensive glucose control regimes.

Background: Diabetes is a major contributor to dementia in the elderly. Identifying mild cognitive decline in younger individuals with diabetes could aid in preventing the progression of the disease. The aim of our study is to compare whether patients with diabetes experience greater cognitive decline than those without diabetes. Methods: We conducted a cross-sectional study using population-based recruitment to identify a cohort of individuals with diabetes and corresponding control group without diabetes of 55-65 years of age. We defined diabetes according to the American Diabetes Association and conducted a battery of standardized neuropsychological tests consisting of nine verbal and nonverbal tasks assessing three cognitive domains. We defined cognitive decline as an abnormal test in one or more of the domains. We used hierarchical regression to predict abnormal cognitive function by diabetes status, adjusting for gender, education, hypertension, and depression. Results: We included 142 patients with diabetes and 167 control group patients. Those with diabetes had a mean age of 59-4 years, 54% were women, the mean education level was 11-4.5 years of schooling, and their hemoglobin A1c was 8.6-2.5. They had an overall lower mean of all five executive function measures, all seven attention measures, and all five memory measures (P < 0.05). In multivariate analyses, all executive function beta coefficients for diabetes were significant, whereas attention had four out of seven and memory had four out of five. Conclusions: Diabetes is associated with cognitive decline in younger patients with diabetes. Preventive strategies should be developed for the prevention of dementia in younger populations.