Last month, a group of researchers presented some startling findings: Poor glycemic control (HbA1c less than or equal to 10 percent) predicts future dementia in individuals with Type 2 diabetes. This study is the largest of its kind to date and may serve to guide scientists toward new, cutting-edge treatment for dementia.
Aidin Rawshani, M.D., and his colleagues at the National Diabetes Register and Institute of Medicine, Gothenburg, Sweden, investigated glycemic control and the incidence of dementia in 353,214 patients who had Type 2 diabetes. None of the patients had any previous hospitalizations for dementia (including vascular, Alzheimer’s or unspecified) and were registered in the Swedish National Diabetes Registry between January 2003 and December 2012. All patients were more than 50 years old.
To determine whether or not poor glycemic control was linked to dementia, researchers observed the patients until a) they experienced their first hospitalization, b) they passed away or c) the study ended.
Researchers assessed the association between patients’ characteristics (such as poor glycemic control) and dementia. They also adjusted these assessments for other factors including age, sex, diabetes duration, income, marital status, education, smoking status, body mass index, systolic blood pressure, estimated glomerular filtration rate, atrial fibrillation, albuminuria, stroke, statin use, type of glucose-lowering treatment used and antihypertensive medication.
Out of the 353,214 patients in the study, researchers observed 13,159 total events of any dementia type. This includes 3,499 cases of Alzheimer’s dementia and 3,377 cases of vascular dementia.
The scientists found that higher HbA1c levels were associated with an increased risk of dementia among patients with Type 2 diabetes. Specifically, patients with poor blood glucose control (HbA1c less than or equal to 10 percent) demonstrated a 50 percent higher risk of being admitted to the hospital for dementia at some point in the future than those with good control (HbA1c of 6.7 percent). Individuals with very low levels of HbA1c (less than 6 percent) also demonstrated a roughly 50 percent increased risk of dementia.
Other predictors of dementia were also uncovered. Individuals with moderately increased albuminuria (a prognostic marker for kidney disease) have a greater risk of developing dementia compared with those without moderately increased albuminuria. Lack of physical exercise was also found to be associated with an increased dementia risk as well as increased diastolic blood pressure, stroke, atrial fibrillation and heart disease. Antihypertensive therapy and statin use were both inversely associated with dementia risk, indicating that they may represent ways to fight the onset of dementia.
What does this mean?
Finding new, effective ways of treating dementia is essential since the symptoms associated with it can be devastating for both the patients and their families. By continuing to study the association between HbA1c levels and dementia, researchers might uncover early warning signs and provide swift intervention. It’s also possible that, by treating high or very low levels of HbA1c before dementia emerges, doctors may be able to stop it in its tracks.
Of course, the association between poor glycemic control and dementia is currently just that: an association. Future research will help medical science better understand — and address — the link between hypoglycemia, hyperglycemia and dementia.