Diet, Exercise and Matters of the Heart

Lifestyle changes in diabetes patients may not add up to better heart outcomes

(RxWiki News) Diabetes patients who are overweight or obese are often advised to lose weight. Doing so may not only help them control diabetes, but can also protect the heart. But is that protection long-lasting?

A recent study suggested that healthy lifestyle changes, such as consuming fewer calories or exercising every week, did not lead to long-term heart protection for overweight or obese diabetes patients.

Though the results showed weight loss and better quality of life, not much of a difference was found in the number of negative heart-related outcomes between patients who did the lifestyle intervention and those who only received diabetes education.

"Talk to your doctor about lifestyle changes for diabetes control."

This study was conducted by Rena R. Wing, PhD, from the Warren Alpert Medical School of Brown University and Miriam Hospital in Providence, Rhode Island, and other researchers from institutions across the US.

The aim of this study, called the Look AHEAD study, was to examine what effects lifestyle changes for weight loss have on heart health in diabetes patients.

Intensive lifestyle changes are often recommended for overweight or obese diabetes patients to help them lose weight which, in turn, is believed to improve heart health and lower other health risks linked to diabetes.

According to the authors of this study, not many studies have looked at the long-term effects of such lifestyle changes on outcomes related to heart health.

This study was conducted across 16 centers in the US. The researchers recruited 5,145 overweight or obese type 2 diabetes patients between 45 and 75 years of age. These patients were randomly assigned to two groups.

The patients in the first group participated in intensive lifestyle interventions that called for eating fewer calories (1,200 to 1,800 kCal per day) and increased physical activity (at least 175 minutes per week) to try to reduce weight by at least 7 percent of body weight.

The second group of patients served as a comparison group. These patients received diabetes support and education.

The researchers then tracked the number of nonfatal heart attacks, hospitalizations for angina (chest pain when the heart doesn't get enough blood) and deaths due to heart-related causes. The study ended for patients if they experienced one of these events.

The participants continued either interventions or education and were observed for up to 13.5 years. The average period of follow-up for the entire group was 9.6 years.

The patients in the intervention group had significantly improved physical fitness, weight loss and reduction in waist size, compared to the education group. The average weight loss when compared to the beginning of the study was 6 percent in the intervention group and 3.5 percent in the education group.

After looking at the data, the researchers found that there had been 403 cardiovascular events (heart attack, hospitalization with angina or death) in the intervention group and 418 such events in the education group.

Overall, the study results suggested that, compared to diabetes education, intense lifestyle changes did not make a huge difference in negative heart-related outcomes among obese or overweight patients with type 2 diabetes.

These results may seem contrary to the advice commonly given to diabetes patients. But the researchers offered some possible explanations. 

One possible reason was that the weight loss was quicker in the diet and exercise group in the beginning, but towards the end the comparison group slowly caught up.

Secondly, the comparison group received tips to control their diabetes which could have motivated them to lose weight. They also used more cholesterol-lowering medications and blood pressure medications compared to the intervention group. This could have reduced the difference in outcomes between the two groups.

The authors also noted some limitations to their study. A different type of diet, such as the Mediterranean diet, instead of just reducing calories, might have led to different results. Also, since the patients who were recruited were already motivated to lose weight, these results may not apply to all type 2 diabetes patients.

This study highlighted the fact that there were other benefits from lifestyle changes that occurred in the intervention group, especially in the beginning of the study. These included better diabetes control, lower rates of loss of bladder control, sleep apnea, and depression as well as improvements in quality of life and mobility.

According to an editorial accompanying the study, clinicians can use this study's results to tell their patients that lifestyle changes can reduce weight, improve well-being and in some cases lead to better diabetes control. Lifestyle changes are unlikely to cause harm and may even provide a modest benefit.

"Even with no clear evidence of cardiovascular benefit, the Look AHEAD investigators have shown that attention to activity and diet can safely reduce the burden of diabetes and have reaffirmed the importance of lifestyle approaches as one of the foundations of modern diabetes care," the editorial concluded.

The results of this study were published July 11 in The New England Journal of Medicine.

The study was sponsored by the National Institutes of Health with additional funding from other federal partners, participating institutions and companies but according to the authors, none of the sponsors had any role in designing or conducting the study. No direct conflicts of interest were reported.

Review Date: 
July 10, 2013