Spinal cord injury and obesity

Dec 26 2004

After living with a spinal cord injury for 10 years, Mark Pascoe knows he needs to work hard to keep his weight down.

“I continue to gain weight and have to be careful with my diet. I was very active and strong before the injury and now it’s limited those abilities,” says Pascoe, 46, who broke his neck when he fell off a jet ski and hit a rock in the water.

Pascoe is not alone in his weight worries. As the nation fights a growing obesity epidemic, the problem is even more dramatic for people with spinal cord injury.

Researchers at the University of Michigan Health System are looking at how people with spinal cord injury burn calories and how that is affected by their muscle mass and body weight. The goal is to make better recommendations to people with spinal cord injury, but the research will also translate into greater understanding of obesity in the general population as well.

“Individuals with spinal cord injury have significantly less bone mass and muscle mass. As a result, their body weight is comprised of much more fat and less muscle or bone than you would see in an able-bodied individual,” says David Gater, M.D., Ph.D., director of Spinal Cord Injury Medicine at UMHS and director of the Spinal Cord Injury Research Center at the VA Ann Arbor Healthcare System.

Muscle burns calories even when the body is at rest. For someone with a spinal cord injury – who has less muscle mass – resting metabolism can be as low as half that of a person without a spinal cord injury. And that means even when people with spinal cord injury exercise, they burn significantly fewer calories.

Burning calories at a reduced rate, combined with limitations on physical activity, contribute not just to obesity, but to all the associated health problems: high cholesterol, coronary artery disease, diabetes and cancer.

“Cardiovascular disease has recently become the greatest risk for mortality for somebody with a spinal cord injury,” Gater says. “We realize that related issues – pre-diabetes, diabetes and high cholesterol levels – are contributing factors. All of those things essentially contribute to an accelerated aging process for the person with a spinal cord injury. Subsequently, their expected lifespan is going to be shorter and the quality of life may be reduced, depending upon how those secondary factors impact them.”

Gater’s team is looking at glucose tolerance, body composition and cardiovascular risk factors in people with spinal cord injury. A key question is how this group burns calories during different types of activities – from rolling their wheelchair to playing basketball. In his Spinal Cord Injury Exercise Lab at the VA, Gater has a device that measures oxygen consumption, which helps determine how many calories are burned. Another piece of equipment, called the “Bod Pod,” is used to measure a person’s body density and help determine how much fat and how much muscle is in the person’s body.

“This research will allow us to develop a table or compendium of physical activity energy expenditures so a person with spinal cord injury can take a look at the table and figure out how many calories they’re going to burn doing this activity for a certain period of time,” Gater says. “Ultimately, our research will allow us to know how to better test and how to better prescribe exercise for people so they can burn more calories out in the community.”

James Minton, a 55-year-old who was injured in 1968 by a sniper in Vietnam, hopes Gater’s research will help reverse the weight gain he’s noticed recently in his own body. That’s why he signed on as a research volunteer.

“I’ve been in a wheelchair for 36 years and recently, I’d say in the past three or four years, I’ve noticed a muscle breakdown in my tissue,” he says. “Before, I was really strong and didn’t have a weight problem, didn’t have to worry about a diet or any of that. Now I do. Muscle’s gone and it’s replaced with body fat.”

While Gater and his patients hope this research will lead to advances in spinal cord injury care, there’s also potential for it to help with the overall obesity problem.

“Because of the unique impact of spinal cord injury on not just muscle mass but also whole body physiology, our research will have tremendous implications in able-bodied research, particularly as it relates to obesity and insulin sensitivity,” Gater says.

About spinal cord injury

• About 250,000 Americans are living with a spinal cord injury – roughly two times the capacity of the U-M football stadium.
• Men account for 82 percent of spinal cord injuries.
• The leading causes of injury are motor vehicle accidents, violence, falls and sports injuries.
• About 60 percent of people with spinal cord injuries are overweight or obese.