Blood Pressure in Young Adulthood and the Risk of Type 2 Diabetes in Middle Age

OBJECTIVE: Hypertension is known to accompany type 2 diabetes in middle age, but it is unknown how early in life blood pressure (BP) begins to rise among individuals who later develop diabetes. The objective of this study was to evaluate elevated BP as a long-term predictor of type 2 diabetes. RESEARCH DESIGN AND METHODS: We conducted a prospective cohort study of 1,152 white male medical students in The Johns Hopkins Precursors Study to longitudinally assess systolic BP (SBP) and diastolic BP (DBP) from young adulthood through middle age in men who went on to develop diabetes. Incident diabetes was identified by self-report through mailed questionnaires verified by medical record review. RESULTS: During a median follow-up of 38 years, 77 cases of incident diabetes occurred. The mean age of diabetes diagnosis was 58 years. As early as age 30 years, mean SBP and DBP were significantly higher in men who developed diabetes during follow-up than in those who remained nondiabetic (SBP 122 vs. 119 mmHg, P = 0.009; DBP 78 vs. 75 mmHg, P = 0.0005). The rate of increase in SBP and DBP over time in men who developed diabetes was greater than the rate of increase in men who did not develop diabetes (SBP 0.49 vs. 0.27 mmHg/year, P < 0.00003; DBP 0.24 vs. 0.17 mmHg/year; P = 0.09). After adjustment for BMI and other risk factors for diabetes, SBP and DBP at age 30 years remained significantly higher in individuals who developed diabetes than in their nondiabetic counterparts; however, the difference in the rate of increase in SBP was no longer significant following multivariate adjustment. CONCLUSIONS: BP elevations precede the development of type 2 diabetes in middle age by 20-25 years. Higher BP in the prediabetic state might contribute to the presence of vascular disease at the time of diagnosis of type 2 diabetes.