Healthy Habits Can Delay Diabetes 10 Years

By Robert Shmerling, M.D.
Content provided by the Faculty of the Harvard Medical School

Healthy habits and weight loss can delay diabetes for 10 years in high-risk people, a new study has found. The new study was a follow-up. The first study included 3,234 overweight people. Their blood sugar was above normal, but not as high as in diabetes. They were divided at random into groups. One group took the diabetes drug metformin. Another got placebo pills. The third group got coaching on diet, exercise and weight loss. The third group had the lowest diabetes rates after an average of three years. Then everyone was given access to coaching on diet, exercise and weight loss. The people in the study were followed for 10 years. In that time, differences between groups narrowed. But overall the group first assigned to diet and exercise had a 34% lower risk of diabetes. The metformin group had an 18% lower risk. Researchers said the group that received coaching delayed diabetes by about four years and the metformin group by about two years. The journal Lancet published the study. The New York Times News Service wrote about it October 29.

What Is the Doctor's Reaction?

If you've ever known someone who had health problems caused by diabetes, you can probably appreciate the importance of preventing the disease. Damage to the eyes, kidneys and nerves and other organs causes enormous suffering. And these conditions often respond poorly to treatment.

Tight control of blood sugar may reduce the rate of such health problems. But tight control requires frequent tests and treatments that many find difficult. And you also can lower blood sugar too much. This can cause nausea, dizziness, fainting or even seizures. And many people develop these health problems despite tight control.

For these reasons, preventing diabetes should be a priority. Important research during the last decade has studied how to prevent diabetes among those at high risk. Studies have focused on the impact of making healthy lifestyle changes and taking diabetes medicines.

In one recent study, people at high risk for type 2 diabetes (the type linked to obesity) lowered their risk of developing diabetes by 58% over 3 years. They did this by making lifestyle changes, such as losing weight and exercising. Among those who took a diabetes medicine (called metformin), the risk fell by 31%.

That's good news, but what about the long-term? A newly published study followed more than 2,700 research subjects from the original study for a total of 10 years. Lifestyle changes were encouraged for all of them. Only one-third of them took metformin. Here's what happened:

  • People didn't lose a lot of weight, but kept it off. The average person lost about 4½ pounds.

  • The rate of new diabetes cases was reduced by 34% among those who made lifestyle changes.

  • The rate of new diabetes cases was reduced by 18% among those taking metformin.

  • The actual rate of newly diagnosed diabetes dropped from 11 cases per 100 people per year to 5 or 6 cases per 100 people per year.

These are impressive results. Not only was the rate of new diabetes cases markedly reduced, but this reduction was maintained for 10 years. It's likely that people also had fewer health problems caused by diabetes and lived longer. However, this study was not designed to evaluate these other outcomes.

What Changes Can I Make Now?

Know the factors that increase the risk of diabetes. In this new research, study subjects were considered high-risk because of:

  • A high body mass index (BMI)

  • A mildly high blood sugar level while fasting

  • An abnormal glucose tolerance test (a high blood sugar two hours after drinking a sweetened beverage).

Other factors that increase risk include:

  • Family history of diabetes

  • Having diabetes during pregnancy

  • Excess body fat around the waist

  • Lack of exercise

Some of these risk factors can be altered. As noted in this new study, a change in diet and modest weight loss were linked to much lower rates of diabetes. People in this latest study were encouraged to lose 7% of body weight. They were urged to exercise, with moderate intensity, for at least 2½ hours each week. Such exercise might include:

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