Researchers studied 229 adults with type 2 diabetes to understand why some develop memory and thinking problems. They found that 93% of participants showed signs of cognitive impairment—difficulty with memory, attention, or problem-solving. The longer someone had diabetes, the higher their risk. People who had diabetes for more than 8.5 years were especially likely to experience these thinking problems. The study suggests that doctors should regularly check the brain health of diabetes patients, especially those who’ve had the disease for many years, to catch problems early and help prevent them from getting worse.

The Quick Take

  • What they studied: Does having type 2 diabetes for a long time increase the chances of developing memory and thinking problems?
  • Who participated: 229 adults with type 2 diabetes (101 men and 128 women), average age 63 years old, who had diabetes for about 11 years on average
  • Key finding: 93% of the diabetes patients showed signs of cognitive impairment. For every extra year someone had diabetes, their risk of memory problems increased by 18%. People who had diabetes for more than 8.5 years had the highest risk.
  • What it means for you: If you have type 2 diabetes, especially for many years, it’s important to have your memory and thinking skills checked regularly by a doctor. Early detection can help prevent problems from getting worse. However, this study shows a connection but doesn’t prove diabetes causes the memory problems.

The Research Details

This was a cross-sectional study, which means researchers took a snapshot in time of 229 adults with type 2 diabetes and compared those with memory problems to those without. They gathered information about each person’s age, weight, medical history, and blood test results. They also gave everyone a standard memory test called the Montreal Cognitive Assessment (MoCA) to measure thinking and memory skills. A score below 26 on this test indicated cognitive impairment.

The researchers looked at many different factors that might explain why some people had memory problems and others didn’t. They examined things like how long someone had diabetes, their cholesterol levels, blood sugar control, and other health measurements. They used statistical analysis to figure out which factors were most strongly connected to memory problems.

This type of study is useful for identifying patterns and risk factors, but it’s like taking a photograph rather than watching a movie. It shows what’s happening at one moment in time, so researchers can’t be completely certain about cause-and-effect relationships.

Understanding which diabetes patients are at highest risk for memory problems helps doctors know who needs extra monitoring and care. If doctors can catch thinking problems early, they might be able to prevent them from getting worse through better diabetes management, lifestyle changes, or other treatments. This research helps identify that diabetes duration is a key warning sign.

The study included a reasonable number of participants (229 people) and used a standard, validated test to measure cognitive function (the MoCA). However, because this is a cross-sectional study, it only shows a snapshot in time—we can’t be sure if diabetes caused the memory problems or if other factors were involved. The very high rate of cognitive impairment (93%) is notable and suggests this particular group may have had more advanced diabetes or other risk factors. The study excluded people with serious brain or neurological disorders, which is appropriate but means results may not apply to everyone with diabetes.

What the Results Show

The most striking finding was that 213 out of 229 participants (93%) showed signs of cognitive impairment based on their test scores. This is a very high percentage and suggests that memory and thinking problems are common in people with long-standing type 2 diabetes.

The research identified diabetes duration as the strongest predictor of memory problems. The optimal cutoff point was 8.5 years—people who had diabetes for longer than this were significantly more likely to have cognitive impairment. For every additional year someone had diabetes, their risk of developing memory problems increased by 18%. This means that someone who had diabetes for 20 years would have much higher risk than someone who had it for 5 years.

LDL cholesterol (the “bad” cholesterol) levels also showed a connection to cognitive impairment, though this was weaker than the diabetes duration effect. Interestingly, most other factors researchers looked at—like age, weight, blood pressure, and blood sugar control—didn’t show significant differences between those with and without memory problems.

The study suggests that the longer diabetes goes on, the more it may affect the brain’s ability to think clearly and remember things. This relationship was consistent and statistically significant, meaning it’s unlikely to be due to chance.

LDL cholesterol levels were higher in people with cognitive impairment, suggesting that cholesterol management might play a role in brain health. However, this finding was not as strong as the diabetes duration effect. The study did not find significant differences in blood sugar control (measured by HbA1c), blood pressure, or body weight between those with and without cognitive problems, which was somewhat surprising and suggests that other mechanisms beyond these traditional risk factors may be involved.

Previous research has suggested that diabetes can affect brain health, but this study provides clearer evidence that the length of time someone has had diabetes is particularly important. Other studies have shown connections between diabetes and memory problems, but this research specifically identifies 8.5 years as a critical threshold. The finding that 93% of participants had cognitive impairment is higher than some previous studies reported, which may reflect the characteristics of this particular group or the sensitivity of the testing method used.

This study has several important limitations. First, it only looked at one moment in time, so we can’t prove that diabetes caused the memory problems—only that they occur together. Second, the very high rate of cognitive impairment (93%) is unusual and may not represent all diabetes patients. The study excluded people with serious brain disorders, which means results may not apply to everyone. Third, the study didn’t measure many lifestyle factors like exercise, diet, sleep, or stress, which could also affect memory. Finally, we don’t know if the memory problems got worse over time or if they stayed the same, because the researchers only tested people once.

The Bottom Line

If you have type 2 diabetes, especially if you’ve had it for more than 8 years, ask your doctor about getting your memory and thinking skills checked regularly. This is a moderate-confidence recommendation based on this research. Work with your doctor to keep your blood sugar, cholesterol, and blood pressure well-controlled, as these may help protect brain health. Consider lifestyle changes like regular exercise, a healthy diet, good sleep, and stress management, which benefit both diabetes control and brain health. However, remember that this study shows a connection, not proof of cause-and-effect.

This research is most relevant to people with type 2 diabetes, especially those who have had it for many years. It’s also important for family members and caregivers of people with diabetes. Healthcare providers should use this information to decide when to screen diabetes patients for memory problems. People without diabetes or those with type 1 diabetes should note that this study specifically looked at type 2 diabetes, so the findings may not apply to them in the same way.

Memory and thinking problems typically develop gradually over years, not weeks or months. If you make changes to your diabetes management or lifestyle, you might notice improvements in focus and memory within weeks to months, but significant changes usually take several months to a year. The key is consistent, long-term management of your diabetes and overall health.

Want to Apply This Research?

  • Track your diabetes duration and set a reminder for cognitive screening if you’ve had diabetes for more than 8.5 years. Log any memory or concentration changes you notice (difficulty remembering names, forgetting why you entered a room, trouble focusing on tasks) along with your blood sugar readings to identify patterns.
  • Use the app to set reminders for regular doctor visits focused on brain health screening. Create a checklist for diabetes management tasks (blood sugar monitoring, medication adherence, exercise, healthy eating) that help protect both metabolic and cognitive health. Set a goal to discuss cognitive screening with your doctor at your next appointment.
  • Track diabetes duration as a key metric. Monitor blood sugar control (HbA1c levels) and cholesterol levels as secondary indicators. Set quarterly reminders to assess and log any changes in memory, concentration, or thinking speed. Share this information with your healthcare provider to identify trends over time.

This research shows a connection between long-standing type 2 diabetes and memory problems, but it does not prove that diabetes directly causes cognitive impairment. This study is informational and should not replace professional medical advice. If you have concerns about your memory or thinking skills, consult with your healthcare provider for proper evaluation and diagnosis. Do not make changes to your diabetes treatment based solely on this research. Always work with your doctor before starting new treatments or making significant lifestyle changes. This information is not a substitute for medical diagnosis or treatment.