Most Australians are well aware of the risks posed by diabetes. There are the common early symptoms such as excessive thirst, lethargy and mood swings. And left untreated, diabetes puts you at risk of heart attack, stroke and kidney disease.
Now, research suggests there may be another consequence of type 2 diabetes: dementia.
The revelation comes in a study published in May in the clinical journal Diabetologia. Specifically, the research identifies a time-frame link. The data suggests that the younger you at the onset of diabetes, the greater your risk of developing dementia.
Interestingly, the original intent of the study’s authors was to see if there was a link between prediabetes and dementia. Prediabetes means you have higher than normal blood sugar levels. But not yet high enough to be considered type 2 diabetes.
What they found, though, was that the more important factor is whether someone progresses from prediabetes to type 2 diabetes. More specifically, they identified that earlier development of type 2 diabetes substantially increased the risk of developing dementia.
Diabetes and dementia – the study
The study was conducted by researchers from the Johns Hopkins Bloomberg School of Public Health in Baltimore. They used data compiled from a previous project called the Atherosclerosis Risk in Communities (ARIC) study.
Although the focus of the ARIC study was atherosclerosis, it incorporated rich data that made it valuable for other research. This included measures of cognitive functioning and glycated haemoglobin, both relevant to research into diabetes and dementia. What’s more, the ARIC study has tracked its participants for almost 30 years.
The researchers in the diabetes project used data from more than 11,000 participants, aged 45 to 64 when initially recruited. None of the participants had a type 2 diabetes diagnosis when the study began, but 20 per cent were identified as prediabetic.
Participants were categorised into one of four age groups, depending on when they received a type 2 diabetes diagnosis. The four age ranges were under 60, 60 to 69, 70 to 79, and 80 to 93 years.
Over the course of the study’s follow-ups, 44.6 per cent of those who started the study with prediabetes went on to develop type 2 diabetes. Of those who did not have prediabetes, 22.5 per cent eventually received a type 2 diabetes diagnosis.
In the long run, 2247 of participants developed dementia. And by breaking down that group by age, the researchers found their ‘smoking gun’.
Where they expected to find a potential link between prediabetes and dementia, they found none. “The association of prediabetes and dementia was strongly attenuated and was no longer statistically significant,” they concluded.
Instead, they found that “the cumulative incidence of dementia was highest among those who developed diabetes at an earlier age”.
In practical terms, what do these results tell us?
Dr Pouya Shafipour (not involved in the study), an obesity medicine physician from California, says hyperglycaemia is key factor. “Higher states of hyperglycaemia in the long term result in insulin resistance, prediabetes, and then eventually diabetes,” he said.
Associated with insulin resistance is inflammation, microvascular damage, and a chemical process glycation known as cerebrovascular glycation, linked to dementia.
In short, the research provides another reason to try to avoid developing diabetes. And perhaps more importantly, to warn the younger people in our lives of the long-term dangers of diabetes.
It’s not just their hearts and kidneys at risk, but also their brains.
Do you have family members at risk of diabetes? Are you likely to warn them of the dangers they face after reading this article? Let us know in the comments section below.
Also read: Simple test could help identify type 2 diabetes risk earlier
