- Women in their early 40s with mild hypertension, elevated blood pressure, may be twice as likely as those with normal blood pressure to have a heart attack or unstable angina in their 50s, a new study suggests.
- While men are more likely than women to have hypertension in their early 40s, damage to arteries appears to begin at lower blood pressures in women.
- If confirmed, the findings imply that there should be a lower threshold for starting antihypertensive treatment in women.
In acute coronary syndromes, which include heart attacks and unstable angina, the flow of blood that normally supplies oxygen to the heart is impaired.
In recent decades, the overall incidence of acute coronary syndromes, and the mortality rates associated with these events, have decreased in Western countries.
However, these improvements do not appear to include younger women.
In some countries, the number of young and middle-aged women hospitalized with acute coronary syndromes has actually increased.
There is some evidence that the adverse effects of increasing blood pressure may be worse for women than men, but whether this applies to younger women remains uncertain.
A new study has found that women in their early 40s with mildly elevated blood pressure — defined as stage 1 hypertension in the United States — are twice as likely to have a heart attack or unstable angina in their 50s, compared with women who have normal blood pressure.
The research, led by scientists at the University of Bergen, in Norway, has been published in the European Journal of Preventive Cardiology.
“The results add to emerging evidence indicating that high blood pressure has particularly unfavorable effects on women’s hearts,” says lead study author Dr. Ester Kringeland.
Dr. Kringeland told Medical News Today:
“All adult women should be aware of their blood pressure and have their blood pressure measured at least every 5 years. If women have other risk factors for heart disease, such as obesity, diabetes, autoimmune disorders, [or] pregnancy complications, or if they have parents with high blood pressure, their blood pressure should be measured every 1–2 years.”
The researchers investigated possible links between mildly elevated blood pressure in middle age and acute coronary syndromes in 6,381 women and 5,948 men participating in Norway’s Hordaland Health Studies.
They defined mild, stage 1 hypertension as a systolic blood pressure of 130–139 millimeters of mercury (mm Hg) and a diastolic blood pressure of 80–89 mm Hg.
At the start of the study, when the average age of the participants was 41 years, 25% of the women and 35% of the men had stage 1 hypertension.
Over the next 16 years, 1.4% of the women and 5.7% of the men had been diagnosed with a heart attack or unstable angina.
To isolate the risk arising from hypertension, the researchers adjusted the figures to account for other risk factors, namely diabetes, smoking, body mass index, cholesterol levels, and physical activity levels.
After these adjustments, women with mild hypertension were 2.18 times as likely to have an acute coronary syndrome as women who had normal blood pressure at the start of the study.
In men, there was no statistically significant association between blood pressure and acute coronary syndromes.
The study authors speculate that sex-based differences in how small arteries respond to elevated blood pressure may explain the greater vulnerability of women at lower pressures.
At present, American and European clinical guidelines do not differentiate between males and females in terms of when clinicians should start treating hypertension.
MNT asked Dr. Kringeland whether there was now a case for lowering the threshold for treating hypertension females.
“Several studies have documented that women with hypertension are more prone to develop blood pressure-associated organ damage and that hypertension is a stronger risk factor for cardiovascular disease [CVD] in women than men,” she replied.
“Whether sex-specific thresholds for [the] definition of hypertension would improve CVD risk detection should be considered in future guidelines for hypertension management and CVD prevention,” Dr. Kringeland added.
However, she emphasized that there is a lack of evidence about whether treating mildly elevated blood pressure in women would reduce their risk of CVD.
Dr. Donna Arnett, dean of The University of Kentucky College of Public Health, in Lexington, and a past president of the American Heart Association (AHA), said that randomized clinical trials would be needed to accurately address this question.
She noted that the current study recorded who was receiving antihypertensive treatments at the start of the study, but not during the follow-up.
There remains a possibility, therefore, that differences in these treatments between males and females with mild hypertension could account for the apparent differences in their risk of acute coronary syndromes, Dr. Arnett told MNT.
“Perhaps the most balanced message given the state of evidence currently is to aggressively screen and treat hypertension in women and men,” she concluded.
MNT asked Joanne Whitmore, a senior cardiac nurse at the British Heart Foundation, to sum up what individuals can do to minimize their risk of developing hypertension.
“Simple everyday lifestyle choices can help lower your blood pressure. The national guidelines [in the UK] recommend 150 minutes of moderate exercise every week … The recommendations also suggest following a Mediterranean-style diet, which is low in fat and salt. And if you’re a smoker, then quitting is the single best thing you can do for your heart.”