The National Institutes of Health recently announced study results showing that diet and exercise can lower the risk of diabetes by 58% for 10 million Americans on the cusp of developing this common but deadly illness. The results were so impressive that federal officials halted the study a year early. We know you have questions about what this means for you and your family. Some answers follow.
Question: Oh, boy, more people telling me to lose weight and get up off the couch. What's the big deal this time?
Answer: This study is one of the best demonstrations that a few simple changes in lifestyle can have a powerful impact on preventing disease in high-risk people. In this research, people on the brink of developing diabetes followed a lower-fat diet, walked or did some other form of moderate exercise about 30 minutes a day five days a week and lost around 10 to 15 pounds. These changes reduced their chances of getting Type 2 diabetes by almost 60%. Even better, this program worked in men and women, in young adults and seniors, and in all races. And the lifestyle changes were nearly twice as effective as the expensive medication to which it was compared.
Q: I know statistics can exaggerate the importance of a study. What were the chances of these people getting diabetes without any treatment? What were their chances if they made the changes?
A: Each year, 10% of the people in this study who got no treatment developed diabetes. Do the math over a period of years and you can see this group is at very high risk indeed. About 5% of those who followed the moderate diet and exercise program developed the disease each year. That's an impressive drop in risk--but it's not a perfect record. The lifestyle program does not appear to prevent the disease in everybody at risk, but it improves their odds significantly.
Q: Why are we so worried about diabetes all of a sudden? I thought heart disease and high blood pressure were the real killers.
A: Type 2 diabetes has reached epidemic proportions, and the number of people at risk for developing it increases every year. Some 16 million people have the disease and an estimated 800,000 Americans will be diagnosed this year. Type 2 diabetes is a chronic degenerative disease characterized by elevated blood sugar levels; it's the leading cause of kidney disease, limb amputations and acquired blindness in adults.
It also increases the risk of heart disease and stroke. (Rates of Type 2 diabetes have tripled in the last 30 years because of the rise in obesity and sedentary living. Worse, Type 2 diabetes is being diagnosed in people at increasingly younger ages--even in kids.
Q: How do I know if I'm enough like the people in this study to benefit from the lifestyle changes?
A: Most people in this study were overweight, sedentary adults. To be eligible, they also had to have "impaired glucose tolerance"--a pre-diabetic condition in which the body fails to process glucose efficiently, elevating blood sugar levels. (Over time, high blood sugar damages organs and blood vessels throughout the body, leading to kidney failure, blindness, amputations and heart disease.) An estimated 10 million Americans have this pre-diabetic condition, and most have lifestyles that put them at risk for developing it. Strictly speaking, benefits demonstrated in the study apply only to those who already have impaired glucose intolerance--but researchers believe similar interventions can reduce risk for others.
Q: How do I know if I'm "overweight"?
A: . You can start with body mass index, which considers height and weight. If you have a BMI of 30 or more--technically the cutoff for "obesity"--you're in the diabetes danger zone. At 5 feet 10 inches tall, that's 209 pounds; at 5-4, it's 174 pounds. (The Obesity Education Initiative can help you compute your BMI. Go to http://www.nhlbisupport.com/bmi/--you'll also find a link to a BMI chart.)
A BMI higher than 25 (128 for a five-footer, 164 for someone 5-8, 184 for a 6-footer) is considered "overweight" and is also associated with an increased risk for impaired glucose tolerance.
Q: Every time you guys write about the body mass index, people write in and say it's inaccurate, deeming even those who have muscular physiques "fat."
A: If you have a muscular physique and low body fat like the professional athletes cited by those letter writers, chances are you're not at risk for diabetes. We'll be politic and say that if your BMI is 30 or over, chances are pretty good that you are at increased risk.
If you prefer, measure your body fat instead--but it's hard to do accurately without professional help. Healthy ranges vary, but if you're a woman with a body fat number above 35% or a man whose number is over 24%, you should be worried. (Log on to http://www.shapeup.org/bodylab/frmst.htm for more information on body fat.)
Q: Are there other things aside from body mass or body fat that put me in a high-risk group?