Increased Risk of Diabetes Linked to Prehypertension

Prehypertension increases the risk of diabetes, researchers say in a published report. Much of the risk is explained by disorders related to insulin resistance, they add. 

In their report, Dr. David R. Mullican and colleagues from the University of Texas Health Science Center in San Antonio, note that prehypertension — systolic blood pressure (SBP) between 120 to 139 mm Hg and/or diastolic blood pressure (DBP) between 80 to 89 mm Hg — is known to be linked with increased cardiovascular risk and insulin resistance.

To study the relationship between prehypertension and Type 2 diabetes, the investigators analyzed data from 2,767 Mexican American and non-Hispanic white individuals between the ages of 25 and 65 in the longitudinal San Antonio Heart Study. All subjects were nondiabetic and normotensive at baseline. Slightly more than 30%, however, had prehypertension.

During a median follow-up of 7.8 years, there were 213 (7.7%) new cases of diabetes, with 12.4% of new cases occurring in subjects with prehypertension at baseline and 5.6% in subjects with normal blood pressure.

Compared to individuals with normal blood pressure, the odds of incident diabetes were 2.21-fold greater among those with prehypertension after adjusting for age, sex, and ethnicity. After further adjustment for body mass index, impaired glucose tolerance, family history of diabetes, and homeostasis model assessment of insulin resistance (HOMA-IR) and beta-cell function (HOMA-betaC), the risk of diabetes remained significant for SBP 130 to 139 mm HG and/or DBP 85 to 89 mm Hg (odds ratio, 1.69) but not for lower pressures.

Also, the research team points out, prehypertension was associated with increased diabetes risk in subjects between the ages of 25 to 49 years but not in those between 50 and 65 years of age.

Noting that they lacked information on waist circumference, chronic inflammation, and level of physical activity, the authors conclude, “Our study shows that subjects with prehypertension had greater risk of converting to diabetes than those with normal blood pressure. Further study is needed regarding mechanisms of this phenomenon.”