Diabetes link to long-term mental decline
26th January 2018 – Older people with diabetes are more likely to experience a long-term deterioration in their memory and thinking skills than those who have normal blood sugar levels, according to new research.
The study led by Imperial College London suggests that efforts to delay the onset of type 2 diabetes or keep blood sugar levels under control might help prevent cognitive decline.
Previous studies and clinical trials have suggested that diabetes could be a risk factor for dementia.
The study, published in the journal Diabetologia, examines evidence for any link between diabetes, HbA1c levels - a measure of overall blood sugar control - and subsequent risk of mental decline in the general population.
Researchers examined data from 5,189 people with an average age of almost 66 who were enrolled in the English Longitudinal Study of Ageing. The information on health and cognitive abilities allowed them to examine what happened to these individuals over an average follow up of 8.1 years.
Cognitive decline and blood sugar
Their analysis revealed that a 1 mmol/mol increase in HbA1c was significantly associated with an increased rate of decline in thinking skills, memory and dealing with everyday life.
These results persisted even after other factors such as age, sex, education, cholesterol levels, alcohol consumption, smoking, blood pressure, mental health, and heart disease were taken into consideration.
A similar association was seen between an increased risk of cognitive decline and diabetes or prediabetes. However, a higher HbA1c status increased the risk of cognitive decline regardless of the presence of diabetes, say the researchers.
They conclude: "Future studies are required to determine the long-term effects of maintaining optimal glucose [sugar] control on cognitive decline in people with diabetes…Our findings suggest that interventions that delay diabetes onset, as well as management strategies for blood sugar control, might help alleviate the progression of subsequent cognitive decline over the long-term."
Proving cause and effect
Dr Emily Burns, acting head of research communications at Diabetes UK, comments in an emailed statement: "This study adds to growing evidence linking diabetes and high blood glucose levels to a quicker progression of cognitive decline, which can increase risk of developing dementia in the future.
"We now need to understand if and how diabetes causes this decline, or if these conditions simply share the same biological processes. This will be crucial in finding ways to help people with diabetes keep their brain healthy.
"There are ways you can lower your risk of developing type 2 diabetes and cognitive impairments, including dementia. These include maintaining a healthy weight, enjoying a healthy balanced diet, limiting alcohol intake, avoiding smoking, exercising regularly and keeping your blood pressure in check."