Weight Matters for Type 2 Diabetes Risk, But Not Equally
For type 2 diabetes risk, the mantra has been that weight gain increases your chances of developing the disease. However, a new study suggests all weight gain is not equally relevant when it comes to type 2 diabetes.
In fact, the findings of the study also prompted the authors to conclude that “type 2 diabetes is not a single disease entity, but rather a heterogeneous [composed of differing factors] disease with different pathophysiological pathways depending on the level and development of obesity.” In other words, while being overweight or obese is still a risk factor for type 2 diabetes, there are various ways weight gain has its impact on development of the disease.
The results of the new study, which was conducted by a team from the Steno Diabetes Center in Gentofte, Denmark, illustrates this idea. Here is how the team came to their conclusions.
Data from the Whitehall II cohort (white male and female civil servants in London) were analyzed to identify changes in body weight and other factors during the study period, which was from 1991 to 2009. At the start of the study, the 6,705 participants did not have diabetes.
At five-year intervals, all the subjects were tested for development of diabetes and an evaluation of body mass index (BMI) and other risk factors for type 2 diabetes was made. During the course of the study, 645 participants were diagnosed with type 2 diabetes.
The breakdown of those who developed type 2 diabetes was as follows:
- 606 of the patients had been overweight for many years (“stably overweight”) and showed little change in their BMI over the years before they were diagnosed
- 15 patients had been gaining weight continuously throughout the years before they were diagnosed
- 26 patients had been obese for as long as 18 years before they entered the study
Why this study is important
The authors noted that their findings question whether the idea that a recent amount of weight gain is a significant risk factor for development of type 2 diabetes. They also noted that they observed a substantial increase in insulin resistance (a common risk factor for diabetes) only in the individuals who had gained weight consistently during the years before they got their diagnosis.
Increased weight is still considered an important risk factor for the development of type 2 diabetes, but the exact impact of excess weight appears to be more complicated and dependent on several factors. Thus the authors suggested that it may be better to focus on encouraging everyone who is overweight to strive for small reductions in weight rather than “predominantly focusing on weight loss for high-risk individuals.”
Visitisen D et al. Patterns of obesity development before the diagnosis of type 2 diabetes: the Whitehall II cohort study. PLoS Medicine 2014; 11(2): e1001602