Study Will Assess How Diet, Exercise May Extend Lifespan

People with cystic fibrosis (CF) generally are living longer and healthier lives than in the recent past. Now, researchers will conduct a five-year study to look into ways to further increase and improve the lifespan of people with the disease.

The idea behind the study comes from a collaborative effort between Emory University, the Medical College of Georgia (MCG) at Augusta University, and Georgia Institute of Technology. Together, they established the Georgia Cystic Fibrosis Research and Translation Core Center.

Fifty 50 patients ages 6 and older are being enrolled at the MCG location. Emory University is enrolling another 50 patients. People with CF interested in participating in the study should call research assistant Reva Crandall at 706–721–5483.

While CF traditionally has been considered a disease of the lungs, it may affect many other organs, such as the pancreas, liver, and intestines. To understand what this means for patients, the researchers are interested in looking deeper into the non-lung-related aspects of CF. Specifically, they want to address the link between clinical outcomes and lifestyle or behavioral choices such as diet, exercise, and sleep.

The lead researcher for the study, which is funded by the National Institutes of Health, is Ryan Harris, PhD, clinical exercise and vascular physiologist at the MCG Department of Georgia Prevention Institute. Kathleen McKie, MD, interim chief of the Division of Pediatric Pulmonology at the MCG Department of Pediatrics, and Caralee Forseen, MD, pulmonologist at the MCG Department of Medicine, will work with Harris on the new study.

“Patients are living longer and leading more normal lives,” Forseen, who also is director of the adult program of one of two Cystic Fibrosis Foundation-accredited care centers in Georgia, said in a news story on the MCG at Augusta University website.

“Now we are seeing people going to work who were never able to hold a job, getting advanced degrees, getting married, having children, they are living a normal life that they thought they could have,” Forseen added. “I think our goal now is to continue to improve that quality of life.”

Therapies targeting the malfunctioning, disease-causing protein made by a mutated CFTR gene are thought to be at the basis of the rise in lifespan among the CF population.

People who live longer, however, also are at increased risk of other diseases, such as heart disease, which tend to increase with age. In the particular case of heart disease, people with CF may be at even higher risk because of related problems such as exercise intolerance (decreased ability to perform physical exercise) and CF-related diabetes.

As such, maintaining healthy habits is becoming ever more important to people living with CF.

The new study intends to help determine diabetes risk in this population, and how an adequate diet and exercise regimen might help reduce the risk.

A preliminary study conducted at the MCG revealed that adults with CF have a low-quality, high-sugar diet, as measured by the U.S. Department of Agriculture’s Healthy Eating Index. Too much sugar is associated with fat accumulation and is a major risk factor for heart disease and CF-related diabetes.

As part of the study, patients will be asked to keep a food diary for three days, including one weekend day. This will allow the scientists to identify dietary habits and how they affect indicators of body composition and clinical outcomes. The researchers think that a better diet will mean a greater percentage of lean body mass, increased ability to force air out of the lungs, and a lower risk of CF-related diabetes.

“We know they have better lung outcomes if their BMI [body mass index, a measure of body fat] is at the target, which is the 50th percentile,” McKie said.

More physical activity will translate into better health, the team believes. However, the reason behind exercise intolerance in people with CF remains unclear.

“We are really trying to understand why patients with CF have exercise intolerance because it is not directly related to their lung health,” Harris said.

To study the ability of patients to perform physical activity, the researchers plan a series of tests, including a six-minute self-paced walk to see how far patients can go, a ride on a cycle ergometer (stationary bike) to see how much physical work the rider is doing, and a test to measure grip strength and lower body fitness. The investigators also plan to monitor clinical outcomes such as lung function, blood pressure, oxygen saturation in the blood, and arterial stiffness, a known risk factor for heart disease.

The participants also will wear an accelerometer to monitor movement during sleep. Sleep is crucial to overall health, so the researchers want to asess how much the coughing often linked with CF interferes with sleep quality.