By Don Rauf
About eight in 10 people with type 2 diabetes are overweight or obese. While weight is related to the condition, putting on pounds over a few years may not signal increased risk.
A new study found that most people who were diagnosed with diabetes were “stably overweight,” meaning they maintained the same amount of excess weight for years prior to being diagnosed with diabetes.
The researchers stressed weight loss as a way to reduce diabetes risk among most individuals.
Dorte Vistisen, PhD, Kristine Færch, PhD, from the Steno Diabetes Center in Gentofte, Denmark, and colleagues reviewed data on 6,705 diabetes-free individuals who were followed for 18 years to find out how body weight changed in people in the years before they were diagnosed with diabetes. The subjects were all British white men and women.
With type 2 diabetes, the body's cells are not responding appropriately to insulin, a hormone produced by beta cells in the pancreas. Insulin helps blood sugar (glucose) to be transported into the cells to be used as energy. When someone is overweight or obese, increased fat can make it more difficult for the body to correctly use insulin.
Every five years, participants in this study were tested for diabetes. Over the course of the follow-up, healthcare providers identified 645 people who had developed the condition.
The biggest group, with 606 people, was considered “stably overweight.” Their body mass index (BMI) changed very little from the start of the study. This group had an average weight gain of 2.3 BMI units during 18 years of follow-up. From five years prior to diagnosis onward, participants in this group had minor decline of beta cell function and insulin sensitivity (or how sensitive the body is to insulin).
Only 15 participants progressively gained weight in the years leading up to their diagnosis. They had an average gain of 8.6 BMI units prior to diagnosis. A few years prior to diagnosis, as these patients gained weight, they also experienced a linear rise in blood pressure and an increase in insulin resistance.
The 26 remaining subjects were labeled as persistently obese. They were obese throughout the entire investigation, and some were obese for 18 years prior to their diagnosis. As the patients in this group approached diagnosis, they experienced beta cell compensation (increasing the production of insulin) followed by loss of beta cell function. Their insulin sensitivity remained relatively stable.
Overweight and obesity for this study were defined by World Health Organization (WHO) standards. BMI is the ratio of a person's weight to height. A BMI measure greater than or equal to 25 is considered overweight. A BMI greater than or equal to 30 is obesity.
Overweight and obesity are the fifth leading risk for deaths around the world, according to the WHO. At least 2.8 million adults die each year as a result of being overweight or obese.
"Strategies focusing on small weight reductions for the entire population may be more beneficial than predominantly focusing on weight loss for high-risk individuals," the authors of this study concluded.
The study was published February 11 in PLoS Medicine.
Funding was provided by UK Medical Research Council, UK Economic and Social Research Council, British Heart Foundation, UK Health and Safety Executive, UK Department of Health, US National Heart, Lung and Blood Institute, US National Institute on Aging, US Agency for Health Care Policy Research and John D and Catherine T MacArthur Foundation.