The effect of body mass index and fasting glucose on the relationship between blood pressure and incident diabetes mellitus: a 5-year follow-up study

There is no consensus on the relationship between high blood pressure (BP) and incident diabetes mellitus (DM). Therefore, the aim of the current study was to investigate the independent association between BP and incident DM and identify the metabolic components that influence incident DM in Korean subjects. The current study included 14 054 non-diabetic subjects (mean age of 41 years) at the start of the study who were followed for an average of 5 years. We measured the risk for incident DM according to the subjects' baseline BP. Subjects were separated into three groups as follows: normotensive (<120/80 mm Hg), pre-hypertensive (120/80 mm Hg ⩽BP <140/90 mm Hg) and hypertensive (⩾140/90 mm Hg). The overall incidence of DM was 1.8% (246 subjects), comprising 0.9% of the normotensive group, 1.9% of the pre-hypertensive group and 4.0% of the hypertensive group (P<0.01). Within the hypertensive group, subjects with high body mass index (BMI) and high fasting-glucose levels were 40 times more likely to develop DM compared with those with low BMI and low glucose levels (0.3 vs. 13.2%, P=0.001). The risk for incident DM was significantly higher in the hypertensive group compared with that in the normotensive group (OR 3.41 vs. 1.00, P<0.0001). However, the significance disappeared after making adjustments for the baseline BMI and fasting glucose levels (OR 1.18 vs. 1.00, P=0.83). We found that the significance of high BP in predicting incident DM was influenced by the baseline BMI and fasting glucose levels of the subjects.