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Slightly raised blood pressure, pre-hypertension linked to stroke risk
While high blood pressure is considered the most important risk factor for strokes, new findings target even slightly high blood pressure as a danger.
People whose blood pressure was above normal - known as pre-hypertension - were 55% more likely to have a stroke compared to people with normal blood pressure, according to an analysis of 518,520 adults involved in 12 studies on blood pressure and stroke occurrence. The report was published Wednesday online in Neurology. One in three adults in the USA has pre-hypertension.
The authors suggest treatments more aggressive than altering lifestyle might be necessary if future studies support the findings. Current treatments for pre-hypertension, defined by a systolic blood pressure (when the heart is pumping) between 120-139 and diastolic blood pressure (when the heart is at rest) between 80-89, include lowering it by losing weight, exercising, reducing salt intake and stopping smoking. Physicians might recommend drug therapy for patients with with pre-hypertension plus other diseases, including prediabetes and diabetes.
The findings are leading to discussions about starting earlier drug interventions to lower blood pressure, according to a doctor not associated with the study. Most often, medicine for lowering blood pressure isn't recommended until blood pressure is 140/50 or higher .
"It could be similar to what happened with cholesterol numbers," says Seemant Chaturvedi , director of the stroke program at Wayne State University and a fellow of the American Academy of Neurology. "Everyone knows those have been racheted down."
Pre-hypertension was classified in 2003 by a team of medical experts, flagging it as a precursor to hypertension but not a risk factor for stroke and calling for more studies on the condition. The studies reported on were all completed after 2003.
Other findings:
·People below the age of 65 with pre-hypertension were nearly 68% more likely to have a stroke compared to those with normal blood pressure.
·The risk for people whose blood pressure was in the lower pre-hypertension range (120-129) was 22% higher compared with normal blood pressure, but for the 130-139 level the risk was 79% higher.
"Pre-hypertension is very controversial,'' says the study's lead author Bruce Ovbiagele, director of stroke prevention program at the University of California, San Diego. "When it was first classified, people accused the experts of creating a fake class of people all needing to be on drugs.''
Physician Karen Furie, who is not associated with study, says pre-hypertension is a "very plausible risk factor for stroke," adding it does often lead to hypertension, which can damage and weaken artery walls.
"The significance of this paper is that it represents the synthesis of roughly a half million subjects,'' says Furie, a fellow of the American Academy of Neurology. "The conclusions appropriately call for additional studies.
"Confounders [variables] such as insulin resistance (pre-diabetes), sedentary lifestyle, obesity, alcohol consumption, and dietary factors, all related to stroke risk, could not be adequately addressed'' in this analysis.
Presence of baseline prehypertension and risk of incident stroke
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