Prediabetes is usually discussed as a warning sign for type 2 diabetes. But a new long-term study suggests the lifestyle changes often recommended at that stage may matter for more than blood sugar alone.
In an observational follow-up of a randomized clinical trial, researchers found that adults with prediabetes who had been assigned to an intensive lifestyle program had a lower long-term burden of multiple chronic conditions than those assigned to placebo. The study, published in JAMA, followed Medicare-enrolled participants from the Diabetes Prevention Program and its long-term outcomes study for up to 21 years.
The finding does not mean lifestyle changes can prevent aging-related disease or replace medication. Most participants eventually developed at least two chronic conditions, regardless of their original treatment group. But the results suggest that structured lifestyle support in people at high risk for diabetes may have lasting benefits that extend beyond whether someone develops diabetes itself.
The study looked at 1,173 adults who had prediabetes when they enrolled in the original Diabetes Prevention Program, a major U.S. clinical trial that began in the 1990s. Participants had originally been randomly assigned to one of three groups: an intensive lifestyle intervention, metformin or placebo.
The lifestyle program focused on reduced calories and fat, at least 150 minutes of physical activity per week and a goal of losing at least 7% of body weight. The metformin group was assigned the diabetes medication, while the placebo group received a matching inactive pill.
For this new analysis, researchers used Medicare data to examine multimorbidity, a medical term for having two or more chronic conditions. The study looked at 15 chronic conditions, including diabetes, hypertension, hyperlipidemia, chronic kidney disease, ischemic heart disease, depression, congestive heart failure, osteoporosis, asthma, some cancers, COPD, atrial fibrillation, stroke or transient ischemic attack and dementia or Alzheimer’s disease.
By the end of follow-up, chronic illness was common across all three groups. Overall, 85% of participants had developed at least two chronic conditions. That included 82% of those originally assigned to the lifestyle group, 85% of those assigned to metformin and 87% of those assigned to placebo.
After researchers adjusted for factors such as age, sex, race and ethnicity, smoking, alcohol use, body mass index and fasting glucose at the start of the study, the lifestyle group had a lower risk of multimorbidity than the placebo group. The metformin group did not show a statistically significant difference from placebo for this broader chronic disease outcome.
That distinction is important. Metformin has a well-established role in diabetes prevention and treatment for certain people. This study was not designed to tell anyone to stop taking it or to suggest medication is unnecessary. Instead, it points to a broader question: When people with prediabetes receive structured help with eating patterns, physical activity and weight management, could those changes influence overall health decades later?
The answer from this study is cautiously encouraging, but not absolute.
The lifestyle group also had lower rates of some individual conditions, including diabetes and hypertension, compared with placebo. When researchers excluded diabetes from the multimorbidity definition, the overall association between the lifestyle intervention and lower multimorbidity risk still remained. That suggests the findings were not driven only by diabetes prevention.
Still, the study has limits. This was a long-term observational follow-up of people who had participated in an earlier randomized clinical trial. The original intensive lifestyle program lasted about three years, and the intensity of lifestyle support was not maintained at the same level over the full follow-up period. Participants in all groups were later offered some lifestyle classes, and medication use changed over time. Medicare claims data can also miss or misclassify some health conditions.
The participants were also people who had volunteered for a major diabetes prevention trial, so the results may not apply perfectly to everyone with prediabetes.
For many people, prediabetes can feel like a single-number problem, focused mainly on A1C or fasting blood sugar. This study adds to the idea that metabolic health is connected to a bigger picture, including blood pressure, cholesterol, heart health and the way chronic conditions accumulate with age.
It also highlights something often missing from health advice: support matters. The lifestyle intervention in this trial was not simply a pamphlet telling people to try harder. It was a structured program with specific goals and ongoing guidance. That difference may be one reason the findings are meaningful.
For people with prediabetes, the best next step is not to make sudden changes based on one study. It’s to talk with a health care professional about personal risk, medication options when appropriate and realistic ways to improve eating and activity patterns. The most useful lifestyle plan is not the most extreme one. It’s the one a person can actually keep practicing over time.
The study was supported by multiple National Institutes of Health institutes, the Centers for Disease Control and Prevention, the American Diabetes Association, the Indian Health Service, the Department of Veterans Affairs and other public or nonprofit research support. Merck KGaA provided medication for the Diabetes Prevention Program Outcomes Study. The Diabetes Prevention Program and its outcomes study also received donated materials, equipment or medicines from several companies, including Bristol Myers Squibb, LifeScan Inc., Merck & Co., Nike Sports Marketing, SlimFast Foods and Quaker Oats. One author reported grants from Amgen and consulting fees from George Washington University during the study.
The study sponsor was represented on the steering committee and was involved in the study design, conduct and decision to submit the manuscript for publication.