Blood Sugar Control Could Help Protect Neurologic Health in Patients with Diabetes

Owen Carmichael, PhD

New research from the results of a 1000-person study suggests improving blood sugar control could improve brain health for individuals with type 2 diabetes.

An analysis of data from the Look AHEAD (Action for Health In Diabetes) study, results of the study indicate improvements in glycemic control, but not weight status were linked to better subsequent cognitive performance.

"It's important to properly control your blood sugar to avoid the bad brain effects of your diabetes," said Owen Carmichael, PhD, professor and director of Biomedical Imaging at the Louisiana State University Pennington Biomedical Research Center, in a statement. “Don't think you can simply let yourself get all the way to the obese range, lose some of the weight, and everything in the brain is fine. The brain might have already turned a corner that it can't turn back from."

With an interest in how disease management might impact the cognitive function of in patients with type 2 diabetes, Carmichael and a team of colleagues hoped to design a study to describe associations between physiological markers and cognitive performance in patients with diabetes in the Look AHEAD study. A randomized controlled trial assessing the efficacy of intensive lifestyle intervention, the study provided data related to more than 5000 diabetic patients aged 45-76 years old.

Patients included in the study randomized to the intensive lifestyle intervention were prescribed to a daily calorie goal of 1200-1800 and a physical activity goal of more than 175 minutes per week with the aim of inducing weight loss to average more than 7% at 1-year and to be maintained over time.

As part of the ancillary studies, patients from the Look AHEAD study were invited to take part in cognitive assessments and 3920 participants provided at least 1 cognitive assessment between years 8-13 of follow-up. These assessments provided investigators information related to short-term memory, planning, impulse control, attention, ability to switch between tasks, verbal learning, and overall memory. For the purpose of the current analysis, investigators only included patients who provided 2 or 3 cognitive assessments, which yielded a cohort of 1089 individuals.

Of the 1089 included in the study, the mean age was 58.3±6.7 years, 58.8% were female, and 84.5% of patients had a BMI of 30 kg/m2 or greater. Investigators pointed out all 1089 patients underwent at least 2 cognitive assessments and a cohort of 315 patients completed all 3 cognitive assessments.

Upon analysis, results of the study suggested greater improvements in blood sugar control were associated with increased cognitive scores. Specific associations included fasting blood glucose and Rey Auditory Verbal Learning Test (P=.0148), fasting blood glucose and Digit Symbol Coding (P=.0360), and HbA1C and DSC (P=.0477).

However, investigators noted weight loss appeared to have mixed associations with cognitive scores—noting greater BMI reduction and worse auditory verbal learning test scores overall (P=.0053) while greater BMI reduction and better digit symbol coding scores were observed among patients who were overweight but not obese (P=.010).

Results of the study also indicated apparent associations were strongest among patients who were overweight but not obese at baseline. Additionally, investigators pointed out associations appeared to also be stronger Amon those with a history of cardiovascular disease at baseline.

"The results were worse for people who had obesity at the beginning of the study. That's a 'too little, too late' type of message," added Carmichael, in the aforementioned statement. "People with diabetes who let their obesity go too far, for too long may be past the point of no return, cognition-wise."

This study, “Long-term change in physiological markers and cognitive performance in type 2 diabetes: the Look AHEAD Study,” was published in the Journal of Clinical Endocrinology and Metabolism.