March 20, 2014
News Review From Harvard Medical School -- Middle-Age Diabetes Tied to Memory Issues
Having diabetes or high blood pressure in middle age may increase the risk of memory and thinking problems later, new research suggests. The study included more than 1,400 people. Their average age was 80. They had either normal brain function or mild cognitive impairment. This is a milder form of thinking and memory problems that can lead to dementia. People received MRI scans and tests of their memory and thinking skills. Researchers also looked at medical records. They noted who had been diagnosed with high blood pressure, diabetes or both during middle age (40 through 64). On average, people who developed diabetes in middle age were twice as likely to have mild cognitive impairment as those without the condition. Their brains were about 2.9% smaller. The hippocampus, a part of the brain important in memory, was 4% smaller. They were 85% more likely to have evidence of damage from tiny strokes. People who had high blood pressure in middle age were twice as likely to have past stroke damage in parts of the brain that are key to thinking and memory. The journal Neurology published the study online. HealthDay News wrote about it March 19.
By Robert H. Shmerling, M.D.
Harvard Medical School
What Is the Doctor's Reaction?
Diabetes and high blood pressure (hypertension) can have a profound impact on your health.
Both conditions raise the risk of heart attack and stroke. Diabetes also can threaten your vision, damage nerves and cause kidney failure. High blood pressure can cause heart failure. It is also a cause of kidney disease. And these are just some of the most common problems.
A new study links diabetes and high blood pressure with "mild cognitive impairment." This is a form of poor memory and impaired thinking. It often leads to dementia. The risk appears to be higher if diabetes and high blood pressure develop during middle age (ages 40 through 64) than if they develop later.
The study enrolled more than 1,400 elderly adults (average age: 80). They had either normal brain function or mild cognitive impairment. Each person had an MRI scan. Researchers also reviewed their medical records to determine if and when they had been diagnosed with high blood pressure or diabetes.
Here's what the study found:
- Those who developed diabetes during middle age had smaller brains (by nearly 3%) than those without diabetes. The hippocampus, a part of the brain involved in memory, was 4% smaller in those with diabetes.
- Problems with memory and thinking were twice as common in those who had developed diabetes during middle age.
- Those who had developed high blood pressure during middle age also doubled their risk of brain damage (as seen on their MRI scans).
- High blood pressure or diabetes diagnosed after age 65 seemed to have less of an impact on brain function or appearance.
These findings suggest that diabetes and high blood pressure may be even worse for brain health than we had recognized. And the impact can take decades to develop.
Unfortunately, this study did not examine the impact of treatment or changes in lifestyle on the risk of brain disease. It's possible that dietary changes, exercise and medicines could make a difference. They might offset the risk of brain damage for people diagnosed with high blood pressure, diabetes or both during middle age.
What Changes Can I Make Now?
These findings provide new reasons to avoid diabetes and high blood pressure if you are able.
You can make changes now that may reduce your risk:
- Maintain a healthy weight.
- Exercise regularly.
- Drink only moderate amounts of alcohol.
- Don't smoke.
- Eat less salt, especially if you have "prehypertension." People with this condition have blood pressure readings of 120/80 to 139/89 millimeters of mercury (mmHg). These readings are slightly high, but not high enough to meet the definition of high blood pressure.
- If you have prehypertension, take medicines to lower your blood pressure.
- If you have mildly high blood sugar levels (pre-diabetes), take medicines to lower your blood sugar.
For some people, it is not possible to prevent diabetes or high blood pressure. This is especially true when there is a strong family history of these conditions.
Once you are diagnosed with diabetes or high blood pressure, close monitoring and treatment are of vital importance. With regular visits, your health care professional can adjust your medicines, check for side effects, and detect and treat any related health problems that arise.
What Can I Expect Looking to the Future?
We are now in the midst of an epidemic of obesity. So it is likely that in the near future we will see more diabetes and high blood pressure. If the results of this new research are confirmed, we could also see even higher rates of dementia than are currently predicted.
Even so, I hope that in the future we will have better ways to prevent high blood pressure and diabetes. We should also know more about how these conditions affect brain function and, more importantly, whether treatment can prevent later problems with thinking and memory.