Developing type 2 diabetes earlier may increase risk

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Type 2 diabetes may be linked to cognitive problems later in life. Katherine Monge/Stocksy
  • A new study by researchers at the Johns Hopkins Bloomberg School of Public Health in Baltimore has analyzed the association between prediabetes and dementia.
  • Their results did not show an overall association between prediabetes and dementia risk, but they did find that the development of type 2 diabetes was associated with dementia.
  • Additionally, scientists have learned that the earlier someone develops type 2 diabetes may increase the risk of dementia.

A study published in Diabetes shows a link between type 2 diabetes and dementia.

While the focus of the research was initially to determine if there was an association between prediabetes and dementia, scientists found that prediabetes alone is not associated with dementia.

Instead, they learned that what matters most in terms of dementia is whether a person progresses from prediabetes to type 2 diabetes and when the development of type 2 diabetes occurs.

With this knowledge, the medical community has yet another reason to focus on encouraging people to adapt to healthier lifestyles and not just reducing the burden of type 2 diabetes on the healthcare system, but also to reduce the number of people who develop dementia.

The authors used data from the Risk of atherosclerosis in communities (ARIC). The ARIC study focused on atherosclerosis, but because it tracked a lot of data (including cognitive functioning and glycated hemoglobin), the data is valuable for researchers conducting other studies.

The ARIC study is a prospective cohort study that followed participants for nearly 30 years.

The Diabetes Project researchers used data from 11,656 participants between the ages of 45 and 64 during initial recruitment. None of the participants had a diagnosis of type 2 diabetes at the start of the study, although 20% had prediabetes.

Throughout the participants’ follow-ups, some of the data that the ARIC study researchers tracked included blood sugar levels, medications, medical reports and cholesterol levels. Additionally, the researchers used questionnaires such as the Mini-Mental State Examination (MMSE) to check for cognitive functioning.

The diabetes study researchers divided the participants they included into four groups based on when they were diagnosed with type 2 diabetes: younger than 60, 60-69, 70-79 and 80 to 93 years old.

From there, the scientists looked at reports of when the loss of cognitive functioning occurred.

Throughout participant follow-up, 44.6% of those who entered the study with prediabetes developed type 2 diabetes. Of participants who did not have prediabetes, 22.5% eventually received a diagnosis of type 2 diabetes.

Additionally, 2,247 participants developed dementia over the years.

While scientists thought the link between prediabetes and dementia was key, they instead learned that the most important link was when a person had type 2 diabetes.

“The association of prediabetes and dementia was strongly attenuated and no longer statistically significant,” the authors write.

The earlier a person is diagnosed with type 2 diabetes, the higher their risk of developing dementia.

According to the authors, “the cumulative incidence of dementia was highest in those who developed diabetes at an earlier age.”

Participants who were diagnosed with type 2 diabetes before the age of 60 were three times more likely to develop dementia than other participants. As the age of the participants increased, the risk of dementia decreased.

People diagnosed with type 2 diabetes in the 60-69 age group had a 73% increased risk, and people in the 70-79 age group only had an increased risk 23% to develop dementia. People 80 and older did not have an increased risk of dementia.

These findings demonstrate the importance of not only preventing type 2 diabetes, but also working to reverse course when someone has prediabetes.

Before a person develops type 2 diabetes, they often develop prediabetes. According to Centers for Disaster Control and Prevention (CDC), “prediabetes is a serious health condition in which blood sugar levels are higher than normal, but not yet high enough to be diagnosed as type 2 diabetes”

Although there are no signs or symptoms associated with prediabetes, doctors can detect it with routine blood tests. When a person discovers they have prediabetes, they have the opportunity to make dietary and lifestyle changes to hopefully return to healthy blood sugar levels.

Prediabetes can progress to type 2 diabetes, a metabolic disorder that causes people to have high blood sugar levels since their body cannot properly process blood sugar.

THE CDC notes that about 37 million Americans have type 2 diabetes (about 10% of Americans).

People don’t always have symptoms when they first develop type 2 diabetes, but when they do symptoms may include the following:

  • increased thirst
  • frequent urination
  • fatigue
  • wounds that do not heal
  • tingling in the feet

People with type 2 diabetes may need to start insulin therapy to control their blood sugar. They can also make lifestyle changes, including changing their diet and getting more physical activity.

Dr. Zeeshan Afzal, health content advisor at online pharmacy and private health checkup service Welzo, who was not involved in the study, spoke with Medical News Today and explained how type 2 diabetes and dementia are related.

“The relationship between (type 2 diabetes and dementia) is complex and multifactorial. Some potential mechanisms that may contribute to this association include vascular damage, insulin resistance, chronic inflammation, and beta-amyloid plaque formation in the brain,” says Dr. Afzal.

Dr Afzal noted that type 2 diabetes is “characterized by high blood sugar levels resulting from insulin resistance or insufficient insulin production” and said it could damage the blood vessels and nerves.

“The brain depends on a constant supply of blood and oxygen, and any disruption in blood flow can affect its functioning and contribute to cognitive decline,” Dr. Afzal said.

Dr. Pouya Shafipour, board-certified family medicine and obesity physician at Providence Saint John’s Health Center in Santa Monica, Calif., also not involved in the research, discussed the study results and why dementia can occur with type 2 diabetes with DTM.

“Long-term higher hyperglycemic states lead to insulin resistance, prediabetes, and eventually diabetes,” Dr. Shafipour said.

“This study confirms this hypothesis which has been around for some time now,” noted Dr. Shafipour.

“This is most likely the result of a high state of insulin resistance, causing inflammation, microvascular damage, glycation of brain vessels and nerves resulting in dementia,” he explained.

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