People with diabetes who adhere to a healthy diet, exercise regularly, and follow other healthy lifestyle practices have a significantly lower risk of microvascular complications from the disease, such as diabetic neuropathy, retinopathy, and nephropathy, as well as foot disorders, than counterparts with diabetes who don’t, a prospective cohort study of more than 7,000 patients with type 2 diabetes has found.
Dr. Qi Sun
“We believe this is one of the first large-scale analyses among diabetes patients that specifically examined an overall healthy lifestyle in relation to the risk of developing microvascular complications,” senior study author Qi Sun, MD, ScD, said in an interview. “The results are not surprising that the healthy lifestyle is associated with lower risk of developing these complications and the enhanced adherence to the healthy lifestyle is associated with lower risk as well. And these findings bear lots of public health significance as they suggest the important role of living a healthy lifestyle in the prevention of diabetes complications, on top of the clinical treatment.”
Dr. Sun is an associate professor of nutrition and epidemiology at the Harvard T.H. Chan School of Public Health, Boston.
The study stated that the findings “lend support” for the American Diabetes Association guidelines for healthy lifestyle practices in people with diabetes.
The study used a cohort from two large prospective cohort studies, the Nurses’ Health Study (NHS) and the Health Professionals Follow-up Study (HPFS), comprising 4,982 women and 2,095 men who were diagnosed with type 2 diabetes during follow-up. They had no cardiovascular disease or cancer at the time of their diabetes diagnosis. Both NHS and HPFS used validated questionnaires to gather information on diet, lifestyle, medical history, and newly diagnosed diseases every 2-4 years. The latter study included NHS and HPFS participants who also completed supplementary questionnaires about their diabetes.
The latest study took into account five modifiable lifestyle-related factors: diet, body weight, smoking status, alcohol, and physical activity. For diet, both large studies used the 2010 Alternate Healthy Eating Index to assess diet quality; those in the upper 40th percentile of the study population were defined as healthy diet. Healthy body weight was defined at a body mass index of 18.5-25 kg/m2.
Among the latter study cohort, 2,878 incident cases of diabetic microvascular complications were documented during follow-up. Patients who adhered to a healthy lifestyle before their diabetes diagnosis, defined as having four or more low-risk lifestyle factors, had a 27% lower relative risk of developing any microvascular complication than counterparts with no low-risk lifestyle factors (relative risk, 0.73; 95% confidence interval, 0.35-1; P = .006).
The study found similar outcomes for those who adopted a healthy lifestyle after their diabetes diagnosis, with a 32% reduction in relative risk compared with those who didn’t adopt any healthy lifestyle practices (RR, 0.68; 95% CI, 0.55-0.83; P < .001).
Dr. Sun noted what was noteworthy about his group’s cohort study. “The unique design is truly the prospective follow-up over time so that we could examine the lifestyle at diabetes diagnosis as well as changes in lifestyle before and after diabetes in relation to the future risk of developing the complications,” he said.
A randomized trial would be a more rigorous way to evaluate the impact of a healthy lifestyle, he added, “although it’s much more expensive than a cohort study like what we did with this investigation.”
As for future research, Dr. Sun said, “It will be interesting to understand mechanisms underlying these observations. It’s also critical to understand why certain diabetes patients may not benefit from a healthy lifestyle, since some of them, even when living a healthy lifestyle, still develop the complications.”
Dr. Paul S. Jellinger
This trial shows in a new light the benefits of healthy lifestyle practices on microvascular complications of type 2 diabetes, Paul S. Jellinger, MD, of the Center for Diabetes and Endocrine Care in Hollywood, Fla., and a professor at the University of Miami, said in a comment. “These benefits have always been surmised and demonstrated in a limited way in previous trials, but not subject to the level of analysis seen in this prospective cohort trial.”
He called the study design “excellent,” adding, “ ‘Validated’ self-reported questionnaires were used widely, although minimal detail is provided about the validation process.” One limitation, he noted, was “the homogeneity of the participants; all were health professionals.”
The study “affirms” and “quantitates” the benefits of a healthy lifestyle in type 2 diabetes. “The issue is not unawareness but rather application,” Dr. Jellinger said. “Modifying long-held lifestyle habits is a real challenge. Perhaps by ‘quantitating’ the benefit, as shown in this trial and hopefully additional studies, impetus will be provided to refocus on this approach, which is too often simply given lip service.”
The National Institutes of Health provided funding for the study. Dr. Sun has no relevant disclosures. Dr. Jellinger disclosed relationships with Amgen and Esperion.