By Dr. Asnat Raziel, bariatric surgeon specializing in obesity treatment, metabolic health and healthy longevity; Director of the Multidisciplinary Center for Obesity Treatment, Assia Medical, Assuta Ramat HaChayal, Tel Aviv
Prediabetes and lifestyle: what did a 21-year study find?
Prediabetes and lifestyle are a pair that everyone over 40 should know about. A new study in the journal JAMA followed people with prediabetes for 21 years. In other words, the researchers looked not only at whether diabetes developed, but at how many chronic diseases piled up over the years. The result is clear: people who went through an intensive lifestyle program had fewer chronic diseases in later life. By contrast, metformin, the long-established diabetes drug, did not show a similar advantage.
Why is prediabetes an opportunity rather than a life sentence?
Prediabetes is a condition in which blood sugar levels are higher than normal, but still below the threshold for diabetes. Many people discover it by chance, in a routine blood test. Even so, this condition is far from harmless. According to the editorial that accompanied the study, about 115 million adults in the United States live with prediabetes. Worldwide, the number is approaching 720 million.
The good news is that this condition is largely reversible. Moreover, this is exactly the point in time when changing your habits has the greatest impact. I have written in detail about the link between weight and diabetes in my article on obesity and type 2 diabetes.
The DPP study: the trial that began in 1996
The US Diabetes Prevention Program (DPP) is one of the most important trials in preventive medicine. Between 1996 and 1999, researchers recruited 3,234 adults at high risk of diabetes at 27 medical centers. They then randomly assigned participants to three groups: an intensive lifestyle program, metformin or placebo.
The lifestyle program set two simple goals: losing at least 7% of body weight, and getting at least 150 minutes of physical activity a week. To get there, each participant received 16 one-on-one coaching sessions over six months, followed by booster sessions. The original results from 2002 were impressive: lifestyle cut the onset of diabetes by 58%, and metformin by 31%.
How did researchers track prediabetes and lifestyle over 21 years?
After the three years of the original trial, participants moved on to a follow-up study called DPPOS. At this stage, the researchers stopped the placebo, while metformin continued. The lifestyle group received booster workshops twice a year. In addition, the study invited all participants to quarterly lifestyle workshops until 2014.
The new study drew on a unique source of information: records from Medicare, the US government health insurance program. A total of 1,173 participants consented to the use of these records through the end of 2021. Their median age was 74, and 68% were women. The researchers looked at “multimorbidity,” that is, having at least two chronic diseases from a list of 15 common conditions.
The results: fewer chronic diseases in the lifestyle group
At an average age of 74, most participants were already living with several diseases. Overall, 85% had at least two, and the median was five diseases per person. Still, the difference between the groups was consistent. In the lifestyle group, 82% of participants reached multimorbidity. That figure was 85% in the metformin group and 87% in the placebo group.
After statistical adjustment, the risk of multimorbidity in the lifestyle group was 21% lower than with placebo (hazard ratio 0.79, 95% confidence interval: 0.68-0.93). What’s more, the researchers saw the same advantage even when they removed diabetes itself from the list of diseases. So lifestyle protected not only against diabetes, but also against other chronic diseases.
The most striking finding concerns the diseases that cost the health system the most. When the researchers looked only at pairs of especially costly diseases, the hazard ratio fell to 0.57 (95% confidence interval: 0.38-0.85). Put simply, that is a risk about 43% lower. In other words, the link between prediabetes and lifestyle stands out most in the serious diseases.
What about metformin?
Here comes the surprise. Metformin reduced the onset of diabetes in the original study, but it did not reduce multimorbidity over the years. Its hazard ratio compared with placebo was 0.91 (95% confidence interval: 0.78-1.07), which was not statistically significant. Therefore, the drug alone is no substitute for changing your habits. I have written about the role of newer drugs in diabetes prevention in my article on what Foundayo adds, and what a healthy lifestyle provides.
Prediabetes and lifestyle: what do the numbers mean for you?
It is easy to get lost in percentages. So here is a simple translation. Out of 100 people with prediabetes who did nothing, 87 had at least two chronic diseases by age 74. Out of 100 who went through a lifestyle program, 82 reached the same point. The difference looks small, but it adds up across millions of people and decades.
It is also important to note what the numbers do not say. A healthy lifestyle does not prevent aging, and most participants accumulated diseases anyway. However, it slows the buildup of disease and especially delays the serious, costly conditions. That is exactly the idea behind healthspan: the number of years we live in good health and good function. I expanded on this in my article on what longevity medicine offers today.
The debate in JAMA: why does personal coaching matter?
Following the study, JAMA published an interesting letter from researchers at UCLA. In their view, the secret of the original program was personal coaching: 16 one-hour individual sessions over six months, followed by regular follow-up sessions. However, when the US Centers for Disease Control and Prevention (CDC) took over running the program, it dropped the personal coaching for budget reasons. According to the letter writers, this meant giving up a core ingredient of its success.
In their reply, the study authors agreed that this is the central challenge: keeping the essential elements of the intervention, even while adapting it to real life. They added that even in the era of new medications, behavioral change in energy balance remains a fundamental principle. That is also my approach in the clinic, as I described in my article on a holistic obesity treatment program.
Limitations of the study
First, this is an observational follow-up study, not a controlled trial from start to finish. The disease analysis relied on insurance records rather than direct medical examination. Second, only about a third of the original participants made it into the analysis, and only those who reached Medicare age. In addition, the study participants were especially committed, and it is not certain the results would hold in the general population. Finally, the study tested prediabetes and lifestyle in a 1990s program, before the era of GLP-1 drugs.
Prediabetes and lifestyle: what should you actually do?
The study offers a practical recipe that has proven itself over two decades:
Moderate weight loss. The goal in the program was 7% of body weight. For a person who weighs 90 kg, that is only about 6 kg. You do not need to reach an “ideal” weight to benefit.
150 minutes of movement a week. For example, a 30-minute brisk walk, five times a week. It is also worth adding strength training, as I explained in my article on aerobic vs. strength training.
Professional support. This is the lesson from the JAMA debate. Changing habits on your own is hard. On the other hand, regular meetings with a dietitian, doctor or coach greatly increase your chances of success.
Persistence. The advantage in the study built up over 21 years. So the goal is not a three-month diet, but a routine you can live with.
Bottom line
Prediabetes is a window of opportunity. A 21-year study shows that a structured lifestyle program, with personal coaching, reduces the buildup of chronic diseases in later life. Metformin alone did not achieve a similar result. Therefore, even in the era of advanced medications, investing in your habits remains the best investment in your healthy years.
The information in this article is general only and is not personal medical advice. For any question, consult your treating physician.
Questions and answers on prediabetes and lifestyle
Can I skip metformin if I have prediabetes?
Not necessarily. The drug reduced the onset of diabetes by 31% in the original study. However, it did not reduce the number of chronic diseases over the years. The decision about drug treatment is personal, and you should make it together with your doctor.
How much weight do I need to lose?
The goal in the program was 7% of body weight. This is a moderate target that most people can reach with the right support.
Are the results relevant for people on weight loss injections?
The researchers conducted the study before the GLP-1 era. Even so, the study authors stress that changing habits remains a fundamental principle alongside medications. Medications and behavioral change complement each other.
References
Lifestyle and Metformin Interventions and Risk of Multimorbidity in Adults With Prediabetes
Reduction in the Incidence of Type 2 Diabetes with Lifestyle Intervention or Metformin
Lifestyle and Metformin Interventions and Risk of Multimorbidity in Individuals With Prediabetes
Addressing Multimorbidity Challenges in Diabetes – Lifestyle and Beyond
