Would you be willing to change one aspect of your life -- such as eating healthier or exercising more -- if you knew it would reduce your likelihood of developing diabetes? Would you make two, three or five lifestyle changes to bring down those chances even more?
Every little bit helps, a new government study suggests. Meeting just one of five key health goals reduces your odds of developing diabetes in middle age by roughly one-third, the study estimates, and the more goals you meet, the lower your risk falls, even if you have a family history of diabetes.
Doctors, of course, have long known that bad habits such as smoking, drinking too much, or eating unhealthy foods increase the likelihood of developing an array of chronic diseases, including type 2 diabetes. But the new study -- the largest of its kind to date -- is among the first to explore how several healthy habits combine to affect diabetes risk.
"The question we were trying to raise is whether there are added benefits to each individual lifestyle improvement you make, and it looks like that answer is definitely yes," says Jared Reis, Ph.D., the lead author of the study and an epidemiologist with the National Heart, Lung, and Blood Institute, in Bethesda, Md. "The strength of the association was really very dramatic and quite surprising."
Reis and his colleagues analyzed data from more than 200,000 men and women in eight states who are part of a long-running study on diet and health led by the National Cancer Institute. In the mid-1990s, when they ranged in age from 50 to 71 and showed no signs of serious illness, the study participants answered detailed questionnaires about their diet, lifestyle, medical history, physical characteristics, and demographic profile.
Ten years later, roughly 9 percent of the men and women had developed diabetes. Those who were least likely to receive a diabetes diagnosis shared five key health attributes:
- Normal weight. They were not overweight or obese, and maintained a body mass index below 25 (a threshold equivalent to 155 pounds for a 5-foot, 6-inch woman).
- Nonsmoking. They had never been regular smokers, or they'd been smoke free for at least 10 years.
- Physically active. They got at least 20 minutes of heart-pounding, sweat-inducing exercise three or more times per week.
- Healthy diet. They consumed a diet with lots of fiber, little trans fat, few refined or sugary carbohydrates, and a high ratio of good (polyunsaturated) to bad (saturated) fats.
- Light drinking. They used alcohol in moderation, if at all -- two drinks or less a day for men, and one drink or less for women.
Each additional attribute was associated, on average, with 31 percent and 39 percent lower odds of developing diabetes among men and women, respectively. People who met all five standards had roughly 80 percent lower odds of a diabetes diagnosis than demographically similar people who led less healthy lifestyles, according to the study, which was published in the Annals of Internal Medicine.
Of all five lifestyle factors, being overweight was linked most strongly to diabetes risk. But having healthy marks for the other four factors still made a difference in overall risk, regardless of whether a person was normal weight, overweight, or obese.
"It isn't always an easy thing to lose weight and to maintain that weight loss over the long term," Reis says. "So this is good news for those individuals who have a tough time losing weight: You can still lower your risk with these other lifestyle changes."
With questionnaire-based studies like this one, there's always a chance that the participants don't accurately report their behavior, or that the results are skewed by health and lifestyle factors that the researchers haven't taken into account.
But in this case the study's large, real-world population -- as opposed to the smaller, strictly monitored groups typically found in clinical trials -- may actually be a strength, says Robert Henry, M.D., the president of medicine and science at the American Diabetes Association, an advocacy organization based in Alexandria, Va.
"This study looked at factors we know can be easily modifiable, and the conditions that people actually live with in real life," says Henry, who is also a professor of endocrinology and metabolism at the University of California–San Diego. "And it does that better than some of the diligently done clinical trials that may not be applicable to a normal lifestyle situation."
The study also found that maintaining the five lifestyle factors lowers diabetes risk regardless of family history, suggesting that people with a genetic predisposition can still prevent or at least delay the onset of the disease.
"Some people will say, 'I'm too overweight for this to have any value,' or 'I'm doomed because diabetes runs in my family,' but we see here that's not true," says Henry, who was not involved in the study. "Even if you're obese, even if you have family history, this shows that there are real benefits to living a healthy lifestyle."