Researchers from the Milken Institute School of Public Health found that maintaining a lifestyle of weight loss and physical activity reduces the long term likelihood of at-risk adults developing type 2 diabetes, according to a study published last month.

The study, published by the U.S. Diabetes Prevention Program, coordinated by the GW Biostatistics Center and co-chaired by Marinella Temprosa, an associate research professor at Milken, followed 3,195 adults diagnosed with prediabetes — a condition where blood sugar levels are higher than normal but not high enough to be diagnosed as diabetes — over 21 years. William Knowler, a consultant to Milken who worked on the study, said researchers created the study to compare the effectiveness of lifestyle changes and medication in preventing type 2 diabetes development before shifting to a long-term analysis of the effects of the two methods. 

Knowler said the study was “unusual” because few clinical studies have the ability to fund or follow people over such a long period of time. Knowler said it’s also difficult for research participants to maintain motivation to continue participating in the study, which makes the continued positive results from the study “important” for researchers to see.

“The remarkable thing that you know really came as a surprise is that there was still evidence of ongoing benefit, even after up to 21 years of follow up,” said Knowler. “And this is unusual, not just in the diabetes area, but in medical clinical trials.”

There were 38.4 million people diagnosed with diabetes in the U.S. in 2021, according to the Center for Disease Control. The most common form of diabetes in the U.S. is type 2 diabetes, a preventable disease which occurs due to lifestyle factors like obesity, diet and lack of physical exercise, followed by type 1 diabetes, an unpreventable autoimmune disease. 

Diabetes hinders the body’s ability to produce insulin — a hormone that absorbs glucose, a type of sugar — which prevents the kidneys from filtering out the glucose, causing symptoms like excessive urination, thirst and hunger.

Knowler said researchers randomly assigned the subjects to one of three treatment groups and were provided either placebo, diabetes medication, or lifestyle guidance — which included mandatory exercising and nutritional classes — for three years, after which all groups received the same treatment. Researchers initially found a 58 percent lower incident rate of type 2 diabetes in patients provided lifestyle guidance than in patients assigned the placebo. 

Researchers also found a 17 percent lower incident rate of type 2 diabetes in patients that were provided extensive lifestyle guidance compared to patients provided the prescription diabetes medication Metformin, indicating maintaining an intensive lifestyle may prevent type 2 diabetes more than taking medication.

Knowler said although the lifestyle group’s low rate of developing type 2 diabetes didn’t fully last over time — patients who received lifestyle guidance only had a 24 percent lower incident rate of type 2 diabetes than the placebo group by the end of the study —  they still have a lower incident rate of type 2 diabetes compared to groups initially provided with medication. 

“Those big treatment effects initially, even though on a year to year basis they did not continue, they did result in long term benefits for those who had received the initial favored treatments, still less diabetes in the long run,” Knowler said. 

Knowler said their team also started investigating a possible link between diabetes and cognitive diseases like Alzheimers in 2023, but funding for the study from the National Institute of Health was “abruptly” terminated amid ongoing cuts to federal research by President Donald Trump’s administration. Five federal grants from the NIH to GW researchers to study HIV were cancelled in March because of their alleged relation to diversity, equity and inclusion programs. 

Knowler said the cuts to the study are a “tragedy” because of the amount of time researchers and participants had dedicated to the study. The study, which received $50 million in funding from the NIH in 2023, had funds cut before it was planned to finish, preventing researchers from reaching a “definitive” conclusion.

“We’ll do the best we can to analyze them and report them,” Knowler said. “But the promise of having more definitive answers on these outcomes is unfortunately gone.”

Paddy Dempsey, a medical research scientist at the University of Cambridge, said physical activity reduces the risk of diabetes by making the body use excessive blood sugar. This prevents the body from developing insulin resistance, which occurs when the pancreas overproduces insulin to regulate blood sugar levels, making insulin less effective over time as the body builds resistance to it and causing an excess of glucose that triggers diabetes. 

“At a basic level, moving your body helps your muscles use blood sugar more effectively,” Dempsey said. “It also reduces inflammation and helps maintain a healthy weight, all of which play a role in preventing diabetes.”

Dempsey said research on the correlation between physical activity and diabetes development over time, like the GW study, shows that consistent exercise reduces the risk of developing diabetes. He said healthcare providers can use these findings to build better health habits for prediabetic patients, like incorporating regular physical activity into treatment plans.

“Staying active over the long term really pays off,” Dempsey said. “People who maintain regular movement have much lower risk of developing Type 2 diabetes, even years down the track.”

Reem Al-Dallal, an assistant professor of medicine at the University of Texas at Houston, said providing patients with personalized lifestyle guidance, like patients received in the study, reduces the risk of diabetes. She said communication between patients and their providers is “essential” to improving care and outcomes for patients with diabetes because it enables providers to continuously monitor glucose levels in patients and adjust treatment plans when necessary. 

“I believe counseling patients on lifestyle changes is a fundamental part of endocrine care — and of medicine as a whole,” Al-Dallal said in an email. “It’s about more than giving advice; it’s about building trust and working with patients to create individualized plans that fit their everyday lives, which makes lasting change more achievable.”

Al-Dallal also said some patients face challenges, like limited access to healthcare and exercise facilities or financial constraints, to maintaining an active lifestyle. Al-Dallal said these barriers prevent at-risk patients from reaching the healthcare and guidance they need, increasing the risk of developing type 2 diabetes.

“Socioeconomic factors can significantly affect the patients’ risk of developing diabetes,” Al-Dallal said. “Food insecurity, housing instability, and financial barriers are associated with a higher risk of developing type 2 diabetes primarily related to reduced access to fresh foods, healthcare and exercise facilities.”