Dementia
Dementia is a term used to describe a group of symptoms affecting memory, thinking and social abilities and is caused by damage to or loss of nerve cells and their connections in the brain. Alzheimer’s disease accounts for 50-75% of all cases of dementia. Other types include vascular dementia, dementia with Lewy bodies (abnormal deposits of protein inside nerve cells) and a group of diseases that contribute to frontotemporal dementia (degeneration of the frontal lobe of the brain).
Over 55 million people worldwide live with dementia, a number projected to reach 153 million by 2025. Despite its prevalence, approximately three out of four people living with dementia remain undiagnosed.
The link between Age, Diabetes and Dementia
Age is an important factor in both conditions. About 2 in every 100 people aged 65-69 live with dementia, and prevalence doubles approximately every five years. In Europe, about 60% of people living with diabetes are between 60–79 years old, compared to just 35% in the 40–59 age group. Despite aging being a risk factor, the 2019 World Alzheimer’s report found that 62% of health care professionals mistakenly believe dementia is a normal part of the ageing process.
Diabetes and dementia hold a bidirectional relationship. Diabetes increases the risk of developing dementia (1.5x for Alzheimer’s and 2.5x for vascular dementia). Conversely, dementia can impair a person’s ability to manage diabetes effectively. Both conditions are chronic, progressive and complex, requiring ongoing support.
How Diabetes Contributes to Dementia
For people living with T1D: Severe or repeated episodes of hypoglycaemia and hyperglycaemia increase dementia risk. Recurrent hypoglycaemia damages the hippocampus (the brain’s memory centre), while chronic hyperglycaemia contributes to vascular damage and inflammation. People with T1D have a 50% higher risk of dementia compared to those without T1D.
For people living with T2D: The key mechanism is insulin resistance. When the brain becomes insulin resistant:
- Amyloid plaques (a hallmark of Alzheimer’s) are less effectively cleared because insulin-degrading enzymes are preoccupied with excess insulin
- Chronic inflammation and impaired blood flow further damage brain cells.
Together, these processes significantly increase dementia risk.