Why Being Overweight with Diabetes May Be Good News
Let's be clear: being overweight or obese generally is a health risk for many serious medical problems. However, a new study found that normal weight adults with type 2 diabetes are at greater risk of dying than are overweight or obese adults with the same disease. But why?
Weight is a factor for everyone with diabetes
It's well known that overweight and obesity are risk factors for type 2 diabetes, and in fact the majority of people--about 80%-- who have the disease are overweight. Therefore, people of normal weight are often overlooked when it comes to screening for diabetes or they typically don't worry about getting the disease. That does not mean, however, they cannot develop diabetes.
According to a new study from Northwestern University Feinberg School of Medicine, not only do normal weight people develop type 2 diabetes, but they are at significantly greater risk of dying from cardiovascular causes and from non-cardiovascular conditions than are individuals with diabetes who are overweight or obese.
To arrive at this finding, Mercedes R. Carnethon, associate professor of medicine at Northwestern, and her colleagues evaluated data from five studies that included 2,625 adults older than 40 who either already knew they had diabetes or who were diagnosed during one of the studies. Here's what they found:
- The average number of adults of normal weight at the time they were diagnosed with type 2 diabetes was 12% (range, 9-21%)
- During follow-up (range, 9-28 years, depending on the study), 449 study participants died: 178 from cardiovascular causes and 253 from non-cardiovascular causes (18 deaths were not classified)
- Rates of deaths from total, cardiovascular, and non-cardiovascular causes were higher among people of normal weight than among those who were overweight or obese, even after making adjustments for blood pressure, lipid levels, smoking, and waist circumference
- The authors concluded that "adults who were normal weight at the time of incident diabetes had higher mortality than adults who are overweight or obese."
Why is this so? Carnethon explained that genetics could be a factor in normal weight individuals who develop type 2 diabetes. In addition, "many times physicians don't expect that normal-weight people have diabetes when it is quite possible that they do and could be at a high risk of mortality." Thus undiagnosed diabetes may place these individuals at greater risk of dying because they don't know they have the disease.
Other risk factors for type 2 diabetes
It's important for everyone to remember that being overweight or obese is not the only risk factor for type 2 diabetes. Other risk factors include the following:
- Age older than 45 years
- Family history of diabetes
- Being African American, Hispanic American, Asian American, or Native American
- Having given birth to an infant weighing more than 9 pounds
- High-density lipoprotein (HDL) cholesterol less than 35 mg/dL
- High triglyceride level (250 mg/dL or greater)
- High blood pressure (140/90 mmHg or greater)
- Presence of polycystic ovarian syndrome
- Presence of metabolic syndrome
- Impaired glucose tolerance
- Sedentary (exercising less than 3 times a week)
Although the results of this study highlight an increased risk of dying among normal weight people who develop type 2 diabetes, this does not mean diabetics who are overweight or obese should not worry about their health. At least 65% of people with diabetes die from heart disease or stroke, according to the National Institutes of Diabetes and Digestive and Kidney Diseases, so this is a major concern.
In addition, having type 2 diabetes is associated with major complications ranging from blindness to neuropathy, skin infections, gum disease, kidney failure, erectile dysfunction, and hearing loss, among others.
The bottom line appears to be, no one is immune from developing type 2 diabetes. Carnethon recommended that "If you are of a normal weight and have new-onset diabetes, talk to your doctor about controlling your health risks, including cardiovascular risk factors." Having diabetes and being overweight or obese is not good news--but being normal weight with the disease can present a significant health risk.
Carnethon MR et al. Association of weight status with mortality in adults with incident diabetes. Journal of the American Medical Association 2012 Aug; 308(6): 581-90
National Institute of Diabetes and Digestive and Kidney Diseases