Diabetes and dementia are both prevalent among older populations. Up until recently, the two were thought of as completely separate illnesses; however, new research has shown the two could be intrinsically linked.
That issue has been especially pronounced, given the rising rates of both diabetes and Alzheimer’s’ disease. The global prevalence of diabetes is expected to rise to 10.2% by 2030, impacting as many as 578 million people worldwide. For context, the population of the entire United States is about 330 million. It isn’t just the U.S. that is seeing issues with diabetes – in Vietnam, the disease is projected to be one of the top seven leading causes of death and disability by 2030.
The number of Alzheimer’s patients is growing too. Global dementia cases are expected to triple by 2050. The Alzheimer’s Association estimates that 6.5 million Americans over the age of 65 have that disease currently – that’s about one in nine people. Nearly two-thirds of them are women. The risk of it goes up the older people are, however; 73% of the 6.5 million Alzheimer’s sufferers in the U.S. are over the age of 75. Those medical costs are expected to cost the nation about $321 billion in 2022.
Rates of Overlap
The number of people with diabetes in the United States has been steadily rising, as has the number of people with diabetes. Certain factors could explain that – for instance, obesity rates in the U.S. have skyrocketed, putting people at a higher risk of developing diabetes; plus, people are living longer, raising the likelihood that they may develop dementia in their old age.
There are some overlaps in symptoms that scientists are now examining, too. For instance, diabetes can have an impact on the ability to retrieve memories, or on memory processes linked to retrieval. Diabetes has been shown to atrophy the brain and change synaptic communication abilities.
“Many recent studies have indicated that impaired hippocampus insulin signaling impairs the memory and other executive functions, attributing to the decline of insulin signaling and concurrent development of insulin resistance,” researchers wrote.
Although those trends are not necessarily linked, there has been an alarming degree of overlap between the diseases. Studies have found that patients with Type 2 diabetes are 50-65% more likely to also develop Alzheimer’s when compared to those without diabetes or with Type 1. There’s also evidence showing endocrine abnormalities such as (and especially) diabetes are common in Alzheimer’s patients.
Those researchers have also pointed out that both Alzheimer’s and Type 2 diabetes are chronic inflammatory diseases, which seem to damage cells, in the same way, causing an imbalance of oxygen reactive species in tissues, which the system is not able to properly detoxify. Further, scientists have discovered that Alzheimer’s patients experience insulin resistance in the brain’s nerve cells, along with resistance to another hormone that’s associated with prediabetes.
The researchers explained glucose is the main energy source for cells, including brain cells. If a person is not properly processing glucose because of their diabetes, the brain is starved of that energy. Some doctors now believe that lack of glucose access in the brain can lead to oxidative damage, resulting in Alzheimer’s.
Does Diabetes Lead to Dementia?
Increasing rates of obesity, coupled with a greater number of jobs that are largely inactive – requiring employees sit in front of a computer screen for long periods, rather than performing physical labor – have contributed to the rise in Type 2 Diabetes. Sedentary lifestyles and lack of exercise have also been proven as risk factors for dementia.
A study examining over 10,000 patients found the younger a person was when they developed diabetes, the more likely they were to develop dementia. The numbers were shocking, too – for every 1,000 people examined in the study, 8.9 of them who did not have diabetes were afflicted with dementia to some degree by age 70. For the study participants who did have diabetes, that number rose to 10.
Dementia set in earlier, too. And if a person got diabetes more than 10 years earlier than the average age the researchers recorded, the likelihood of them getting dementia rose to 18.3 per 1000 people.
“At age 70, every 5-year younger age at onset of type 2 diabetes was significantly associated with a [hazard ratio] of dementia of 1.24…in analyses adjusted for sociodemographic factors, health behaviors, and health-related measures,” the study shows.
That study accounted for other factors too, taking into consideration things like age, sex, race, tobacco use, alcohol consumption, exercise habits, diet of fruit and vegetables, blood pressure, body mass index, medication intake, and medical history for things like heart disease. The scientists also took into account whether the study participants had a gene called apolipoprotein E, which is considered an indicator that a person may have diabetes.
“Both diseases have been recognized to have multifactorial interactions involving both the environment and to a lesser degree, genetics. Yet, insulin insensitivity has been linked to memory deficits, cognitive decline, and many of the characteristic symptoms that have been displayed in [Alzheimer’s Disease],” researchers studying the link between diabetes and dementia found. “At the same time, type 2 diabetes has remained one of the most adjustable risk factors for the development of [Alzheimer’s Disease.]
Type 3 Diabetes
Some scientists are now proposing that Alzheimer’s could actually be a form of diabetes. Physicians and researchers who have adopted this theory have even started referring to Alzheimer’s Disease as Type 3 Diabetes.
The link is that poorly-controlled glucose levels in the blood seem to increase the risk of developing Alzheimer’s. When neurons in the brain can no longer respond to insulin and therefore are unable to complete basic tasks like memory recall, researchers think that leads to the cognitive decline we call Alzheimer’s. That process is what they’re now calling Type 3 diabetes.
The effects on the brain due to glucose levels are extremely pronounced. Brain insulin resistance can lead to neuronal stress that eventually leads to neurodegeneration. That’s hastened by an accumulation of neurotoxins that occurs when the brain is resistant to insulin. Insulin signaling processes being impaired because of diabetes is also a signal for dementia. Scientists are moving to define Type 3 diabetes as a metabolic syndrome.
There’s another clue in the gene known as APOE4. That gene is a major indicator that a person may develop diabetes; it’s present in about 20% of the general population but has been found in over half of people with Alzheimer’s. That gene interrupts how the brain processes insulin. Mice with the same gene demonstrated high rates of insulin impairment, especially as they aged.
Researchers were also able to prove that a high-fat diet leading to a greater body mass induced insulin resistance in the brain. High intakes of saturated fats in particular raised the risk of Alzheimer’s by nearly triple. In contrast, mice that were fed diets high in nutrients had fewer problems with memory. Human studies show diets high in antioxidants like Vitamin E could provide some protection against dementia.
A major notable difference between diabetes and dementia is the availability of treatment. Diabetes can be treated and controlled to the point where people with type 2 diabetes can reverse the impacts of the disease and go into remission. People with prediabetes can fend off diabetes onset. Alzheimer’s, in contrast, has no known cure and no effective treatment.
This link between diabetes and dementia could prove to be the answer, however. Clinical studies have shown that the use of insulin treatment or Peroxisome Proliferator-Activator Receptor antagonists (a medication used to fight diabetes) may be effective for treating Alzheimer’s. Those drugs stabilize blood glucose levels and lipids in the blood. Another type of antagonist drug, called fibrates, is also being investigated as a possible treatment option for Alzheimer’s Disease.
There are also ways to reduce your risk of developing diabetes, thereby reducing the likelihood that you may get dementia. A healthy diet of low-fat foods that are high in vitamins can be a major difference-maker in the fight against both of these diseases. Exercising is another big help, too – scientists say aerobic engagement 30 minutes a day, five days a week can go a long way in the fight against both of these diseases. Another bit of advice is to avoid smoking.
Treatment of other medical conditions that can serve as risk factors for diabetes is also important. Make sure to keep high blood pressure and high cholesterol in check by finding medications that work for you and checking in frequently with your doctor. Reducing stress is also important – relaxation, socialization, music, and trying to keep a positive outlook can all reduce stress.
If you do develop diabetes, treatment can be expensive. As we now know, letting diabetes run rampant is not only a problem for the symptoms and effects of that disease, but also raises the risk of dementia setting in each time glucose levels reach unhealthy levels. Buy Canadian Insulin can help. By making insulin more affordable for Americans, patients can help keep blood glucose measurements under control, which, in turn, can reduce the risk of developing Alzheimer’s.