January 16, 2014
News Review From Harvard Medical School -- Study: Heavier Diabetics Die Sooner
There's no "obesity paradox" related to death rates for people with diabetes, a new study concludes. Except for smokers, people who were heavier died earlier, the study found. Some small studies have suggested that people who are a little overweight might have a lower death risk. The new study included 11,000 adults with type 2 diabetes. Researchers kept track of them for about 16 years. A body mass index (BMI) of 18.5 to 24.9 is considered normal. In this study, the lowest BMI, 18.5 to 22.4, was linked with higher death rates than for all groups except the most obese (BMI of 35 or more). But people with a BMI on the higher side of "normal" (22.5 to 24.9) were less likely to die than all other groups. Then researchers looked at the numbers for people who had never smoked and for smokers and ex-smokers. Overweight and obese people who had never smoked were more likely to die as their BMI went up. But smokers were most likely to die if they were thin. The New England Journal of Medicine published the study. HealthDay News wrote about it January 15.
By Robert H. Shmerling, M.D.
Harvard Medical School
What Is the Doctor's Reaction?
I saw a patient several years ago who was 40 pounds overweight. When I suggested he lose weight, he was having none of it. He had read that being "a few pounds overweight" wasn't such a bad thing. In fact, he'd heard that it might help him live longer.
His view is not rare. And many believe he is right.
Some experts suggest that you can be "fat but fit." This view says that even if you are obese, as long as you are active and your metabolic tests (such as blood sugar and cholesterol) are normal, you may live longer than those who are thinner. It's called the "obesity paradox." Debate about whether it exists has been going on for years.
Some studies dispute the idea of an obesity paradox. Just last year, a widely publicized study found that obese people with normal cholesterol and blood sugar had a significantly higher risk of heart attack, stroke and death than those of ideal weight. The impact of being overweight (but not obese) was less clear.
This week's New England Journal of Medicine takes a look at the issue. Researchers report on more than 11,000 nurses and other health professionals who developed diabetes. They kept track of people for about 16 years. They found that the higher people's body mass index (BMI), the higher the risk of death. BMI is a measure of size that includes height and weight.
This study compared other weight groups with a BMI of 22.5 to 24.9. Compared with this "normal" group, death rates were:
- 12% higher for those who were mildly overweight (BMI of 25 to 27.4)
- 9% higher for those who were more significantly overweight (BMI of 27.5 to 29.9)
- 24% higher for those who were obese (BMI of 30.0 to 34.9)
- 33% higher for the most obese individuals (BMI of 35.0 or higher)
Interestingly, the death rate also was higher among those with the lowest BMI (18.5 to 22.4). This was particularly true among smokers.
These findings cast doubt on the notion that extra weight provides health benefits. However, this study was limited to people who developed diabetes. It also assessed only one thing -- the link between BMI and death rates. Studies of people without diabetes and tracking other outcomes (such as nonfatal stroke or heart attack) could have produced different results.
What Changes Can I Make Now?
When it comes to body weight, there is plenty of disagreement even among experts. My advice is not to focus on how much excess weight you can carry without it affecting your health. Rather, try to avoid obesity, which is more clearly risky for your health. Set reasonable and realistic goals for your weight. Then create a plan of action to achieve them.
These steps could help:
- Know your BMI and make a serious effort to avoid obesity (BMI of 30 or higher). Losing weight is often quite challenging. That means it's important to avoid excessive weight gain in the first place.
- Adopt an active lifestyle. If possible, walk more and drive less. Take the stairs. Exercise for at least 45 minutes, at a moderate intensity, most days of the week. Keep in mind that that exercise has been linked with enormous health benefits above and beyond weight loss.
- Know your blood lipid levels, including the total, HDL ("good") and LDL ("bad") cholesterol results. Work with your doctor to keep them in a healthy range.
- If you are already obese, don't rely on an "obesity paradox." Talk to your doctor about a diet and exercise program to lose weight. Modest changes in your diet and increased activity levels may be all you need. Just reducing portion size and "mindless eating" may have an impact. However, an organized weight-loss program such as Weight Watchers can be helpful.
- If you are very obese (a condition called morbid obesity), consider taking a weight-loss medicine approved by the U.S. Food and Drug Administration or having obesity surgery. Morbid obesity is defined as having a BMI of at least 40, or at least 35 if you also have an obesity-related health problem, such as diabetes.
- Ask your doctor if you should be tested for diabetes. This may be particularly important if you are obese, have a family history of diabetes or have symptoms that suggest diabetes. These include frequent urination and constant thirst.
What Can I Expect Looking to the Future?
You can expect the debate about the health impact of excess weight to continue. We may never have a definite answer to just how much extra weight is too much. But evidence is mounting that there is no such thing as an "obesity paradox."
We are in the midst of an obesity epidemic in the United States. The health consequences are huge. In the future, you can expect to hear much more about research studies, public health measures and even laws (such as banning or taxing large servings of high-calorie drinks) that address this important and common problem.