Blood Pressure May Predict Incident Type 2 Diabetes in Healthy Women

October 16, 2007 — Baseline blood pressure (BP) and progression of BP were strong and independent predictors of incident type 2 diabetes among initially healthy women, according to results from The Women's Health Study reported in the October 9 Online First issue of the European Heart Journal.
"Despite [the] close relationship between hypertension and type 2 diabetes, little information exists on the relationship of BP levels with the subsequent development of type 2 diabetes," write Dr. David Conen, from the Brigham and Women's Hospital and Harvard Medical School in Boston, Massachusetts, and colleagues. "Finding an independent association between BP or BP progression and new-onset diabetes may be important, as it could imply close surveillance of blood glucose levels in individuals with increasing BP levels. We therefore evaluated the relationship of BP and BP progression with incident type 2 diabetes in a large cohort of initially healthy women."
This prospective cohort study included 38,172 women who had no evidence of diabetes and cardiovascular disease at baseline. Women were categorized based on self-reported baseline BP (< 120/75 mm Hg, 120 - 129/75 - 84 mm Hg, 130 - 139/85 - 89 mm Hg, and hypertension), and they were further categorized based on progression to a higher category of BP during the first 48 months of follow-up. The primary endpoint was time to incident type 2 diabetes.
During 10.2 years of follow-up, type 2 diabetes was diagnosed in 1672 women. Multivariable adjusted hazard ratios (HRs) for incident diabetes across BP categories were 0.66 (95% confidence interval [CI], 0.55 - 0.80), 1.0 (referent), 1.45 (95% CI, 1.23 - 1.71), and 2.03 (95% CI, 1.77 - 2.32; P for trend =.0001). The pattern of findings was similar when women were stratified by body mass index (BMI).
Adjusted HRs for incident diabetes after 48 months in women who had no progression of BP, women with BP progression but whose BP remained normotensive, and women who developed hypertension during the first 48 months were 1.0, 1.26 (95% CI, 0.97 - 1.64), and 1.64 (95% CI, 1.33 - 2.02) vs 2.39 (95% CI, 1.95 - 2.93) in women with baseline hypertension (P value for trend = .0001).
"Baseline BP and BP progression are strong and independent predictors of incident type 2 diabetes among initially healthy women," the study authors write. "This effect was independent of BMI and other components of the metabolic syndrome."
Limitations of the study include the use of self-reported BP, use of BMI rather than waist circumference as an indicator of central obesity, study population in predominantly white women, and possible residual confounding.
"Our study provides strong evidence that baseline BP and BP progression are associated with an increased risk of incident type 2 diabetes," the study authors conclude. "Clinicians should be aware of these relationships to optimize the management of patients at increased risk for cardiovascular disease."
The National Heart, Lung, and Blood Institute and the National Cancer Institute supported this study. Dr. Conen has disclosed receiving grants from the Swiss National Science Foundation and the Janggen-Poehn Foundation in St. Gallen, Switzerland. The remaining study authors have disclosed no relevant financial relationships.
Eur Heart J. Published online October 9, 2007.