Blood pressure strongly predicts the development of type 2 diabetes in healthy middle-aged women, according to the results of a recent study .
Women with high-normal or high blood pressure, as well as those whose blood pressure climbs to those levels over time, are at substantially increased risk of developing type 2 diabetes. Their risk is elevated even if they are not overweight and have no other components of the metabolic syndrome, said Dr. David Conen of Brigham and Women's Hospital, Boston, and his associates in the Women's Health Study.
The study, a prospective randomized trial that assessed low-dose aspirin and vitamin E therapy in preventing cardiovascular disease and cancer, involved nearly 40,000 women health professionals aged 45 and older at baseline in 1993. Dr. Conen and his associates examined blood pressure and diabetes onset in the cohort.
A total of 1,672 subjects developed type 2 diabetes during a median follow-up of 10 years. The incidence of diabetes was 1.4% in women who had an optimal blood pressure measurement at baseline, 2.9% in those with normal blood pressure, 5.7% in those with high-normal blood pressure, and 9.4% in those with high blood pressure. “Women with baseline hypertension had a sevenfold increased risk of developing diabetes, compared with women with optimal blood pressure,” the investigators said (Eur. Heart J. 2007 Oct. 10 [Epub doi:10.1093/eurheartj/ehm400]).
These risks were attenuated but remained significant after the data were adjusted to account for multiple potentially confounding variables, so that healthy but hypertensive women still showed a threefold higher risk of developing diabetes than did those with optimal blood pressure.
Similarly, women whose blood pressure increased during follow-up were at increased risk of developing diabetes. Even those whose blood pressure rose but remained within normal limits had a hazard ratio of 1.26, compared with women whose blood pressure remained stable or decreased. Those whose blood pressure progressed to hypertension had a 64% higher risk of incident diabetes.
Blood pressure was a strong predictor of incident diabetes across all body mass index categories. “Although the absolute risk of developing type 2 diabetes was highest among overweight and obese women, we nonetheless observed a strong association between blood pressure and incident type 2 diabetes in women with normal weight,” Dr. Conen and his associates said. “Among women with no more than one out of three components of the metabolic syndrome excluding glucose or blood pressure, we found the same strong trend across blood pressure categories and very similar hazard ratio estimates compared with the entire study population.”
They concluded, “Taken together, our findings suggest that obesity or the metabolic syndrome do not explain the entire association between blood pressure and incident diabetes.
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