Increases in Waist Circumference and Weight May Predict Incident Diabetes
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May 28, 2010 — Increases in waist circumference and weight may predict incident diabetes, according to the results of a study reported online May 18 in Diabetes Care.
"Individuals with impaired fasting glucose (IFG) are at high risk for type 2 diabetes," write Alain Gautier, MD, from Center Hospitalier Universitaire de Rennes in France, and colleagues from the Data from an Epidemiological Study on the Insulin Resistance syndrome (D.E.S.I.R.) Study Group. "Although visceral adiposity and waist circumference are strong risk factors for type 2 diabetes, the consequence of an increase in waist circumference among individuals with IFG at baseline has not been fully investigated, in particular in those who are not overweight or obese at baseline. This report investigates the relative importance of increases in waist circumference and weight on progression to diabetes, in individuals with baseline IFG, according to baseline BMI [body mass index] strata."
Using the D.E.S.I.R. cohort, the investigators studied the 9-year incidence of diabetes in 979 men and women with baseline IFG. After adjustment for risk factors at baseline, increases in both waist circumference and weight were significantly associated with diabetes incidence. Standardized odds ratios (ORs) were 1.79 for waist circumference (95% confidence interval [CI], 1.45 - 2.21) and 1.86 for weight (95% CI, 1.51 - 2.30).
For patients with a BMI of less than 25 kg/m² at baseline, the effect of increase in waist circumference was greater (OR, 2.40; 95% CI, 1.63 - 3.52) vs patients with a BMI of 25 kg/m² or more at baseline (OR, 1.66; 95% CI, 1.28 - 2.16). Adjustment for concurrent changes in either insulinemia or the updated version of the homeostasis model assessment of insulin resistance (HOMA2-IR) index did not abolish the difference in effect based on initial BMI. The effect of weight change was similar in both BMI groups.
"In IFG individuals, it is important to monitor and prevent increases in waist circumference, in particular for those with BMI<25 kg/m²," the study authors write.
Limitations of this study include absence of gold-standard measures of insulin sensitivity, such as the euglycemic-hyperinsulinemic clamp.
"Impaired β-cell function is considered an important characteristic in individuals with IFG and reduced insulin secretion has been shown to be a prominent mechanism leading to diabetes in lean individuals," the study authors write. "We speculate that an increase in waist circumference may induce further alterations in insulin secretion beyond that inherent in a worsening insulin resistance. Potential mechanisms may involve β-cell lipotoxicity through enhanced free fatty acid release from adipose tissue."
The D.E.S.I.R. study has been supported by INSERM contracts with CNAMTS, Lilly, Novartis Pharma, and Sanofi-Aventis; by INSERM (Réseaux en Santé Publique, Interactions entre les déterminants de la santé, Cohortes Santé TGIR 2008), the Association Diabète Risque Vasculaire, the Fédération Française de Cardiologie, La Fondation de France, ALFEDIAM, ONIVINS, Ardix Medical, Bayer Diagnostics, Becton Dickinson, Cardionics, Merck Santé, Novo Nordisk, Pierre Fabre, Roche, and Topcon. The study authors have disclosed no relevant financial relationships.
Diabetes Care. Published online May 18, 2010. Abstract
Dysglycemia is a risk factor for the development of type 2 diabetes mellitus, and a previous meta-analysis by Gerstein and colleagues, which was published in the December 2007 issue of Diabetes Research and Clinical Practice, quantified this risk. Compared with normoglycemic individuals, the risk for incident diabetes was increased from 4.6 to 7.5 times among patients with IFG or impaired glucose tolerance. However, the presence of both forms of dysglycemia in the same individual increased the risk for diabetes more than 12-fold.
The current study examines how weight change and waist circumference can affect the risk for incident type 2 diabetes among patients with IFG.
- Study participants were drawn from the D.E.S.I.R. Study Group. All participants were between the ages of 30 to 64 years and had a fasting plasma glucose level between 5.6 and 6.9 mmol/L.
- Participants underwent screening examinations for diabetes 3 times annually. The planned follow-up period was 9 years.
- The main study outcome was the incidence of type 2 diabetes mellitus, which was defined as a fasting plasma glucose level of at least 7 mmol/L, or treated diabetes.
- In the current study, researchers focused on how weight change and waist circumference affected the risk for incident diabetes, particularly with regard to baseline BMI. This result was adjusted to account for demographic, disease, and lifestyle factors.
- 674 men and 305 women participated in the study.
- There were 142 cases of incident diabetes during follow-up.
- In adjusted models, each 1-SD increase in body weight and waist circumference was associated with ORs of 1.86 and 1.79 for diabetes, respectively. Both of these higher risks were statistically significant.
- When examining only participants with a baseline BMI of less than 25 kg/m2, an increase in body weight did not significantly elevate the risk for diabetes when accounting for baseline hyperinsulinemia and insulin resistance.
- However, the adjusted OR for diabetes associated with at least a 1-SD increase in waist circumference was 2.40 vs those with a baseline BMI of 25 kg/m2 or more (OR, 1.66). This risk remained significant in analyses adjusted for hyperinsulinemia and insulin resistance.
- In contrast, among participants with a baseline BMI of less than 25 kg/m2, increases in both body weight and waist circumference significantly increased the risk for diabetes.
- The effect of waist circumference in increasing the risk for diabetes appeared more profound among participants at normal weight.
- Age did not significantly interact with body weight and waist circumference increases in promoting higher rates of incident diabetes.
- A previous meta-analysis found that both IFG and impaired glucose tolerance increase the risk for incident diabetes by a similar degree, but the presence of both forms of dysglycemia was synergistic in promoting an even higher risk for diabetes.
- The current study demonstrates that although both body weight gain and increases in waist circumference can increase the risk for incident type 2 diabetes among overweight or obese adults with IFG, increase in waist circumference may be a more significant risk factor for diabetes among adults at normal weight with IFG.