- Vidar Hjellvik: Norwegian Institute of Public Health, Oslo, Norway.
BACKGROUND: Obesity, hypertension, and hypertriglyceridemia are important risk factors for type 2 diabetes (T2D). We wanted to assess the risk associated with these three factors alone and in combination, and the relative importance of these and several other risk factors (eg, nonfasting glucose) as predictors of T2D.
METHODS: Risk factors in a Norwegian population (n = 109,796) aged 40-45 years were measured in health studies in 1995-1999. Blood glucose-lowering drugs dispensed in 2004-2009 were used to estimate the incidence of T2D. Groups based on combinations of body mass index (BMI), diastolic blood pressure, and triglycerides were defined by using the 50% and 90% quantiles for each variable for men and women. The relative importance of BMI, triglycerides, total cholesterol, high-density lipoprotein cholesterol, glucose, blood pressure, and year of birth for predicting T2D was assessed using deviance from univariate and multivariate logistic regression models. Height, weight, and blood pressure were measured. All biomarkers were measured in nonfasting blood samples.
RESULTS: In the various groups of BMI, triglycerides, and diastolic blood pressure, the incidence of T2D ranged from 0.5% to 19.7% in men and from 0.15% to 21.8% in women. BMI was the strongest predictor of incident T2D, followed by triglyceride levels in women and glucose levels in men. The inclusion of risk factors other than BMI, glucose, triglycerides, and blood pressure in multivariate models only marginally improved the prediction.
CONCLUSION: BMI was the strongest predictor of type 2 diabetes. At defined levels of BMI, the incidence of T2D varied substantially with triglyceride levels and blood pressure. Thus, controlling triglycerides and blood pressure in middle-aged individuals should be targeted to prevent later onset of T2D.