Women face unique risks for developing hypertension and special challenges in keeping their high blood pressure under control, according to new research published in a special issue of Hypertension: Journal of the American Heart Association.

The issue featured more than 45 studies and editorials related to women and hypertension. The publication commemorated the fifth anniversary of the launch of the American Heart Association's Go Red For Women movement, which raises awareness of heart disease risks for women.

"Our goals were to help convey the importance of prevention and treatment of hypertension and cardiovascular disease in women, to emphasize that hypertension is a critical cardiovascular risk factor in women, and to publish the newest and best research related to hypertension in women," said John E. Hall, Ph.D., Hypertension Editor-in-Chief, and Arthur C. Guyton, Professor and Chair and Associate Vice Chancellor of Research, University of Mississippi Medical Center, Jackson, Miss.

Data from the American Heart Association Heart Disease and Stroke Statistics – 2008 Update shows that high blood pressure kills significantly more women than men and is two to three times more common in women who take oral contraceptives than in women who don't.

In his preface to the journal, Hall cited previous studies that show only about 60 percent of hypertensive women are treated, and among those treated, only about a third had their bloodpressure controlled at optimum levels. "Thus, inadequate control of high blood pressure continues to be the most important, and potentially treatable, cause of cardiovascular disease and stroke in women," he said.

"Through Go Red For Women the American Heart Association provides education and resources to help women live heart-healthy lives. More importantly, our movement puts a face on heart disease – the No. 1 killer of women," said Dr. Nieca Goldberg, Go Red For Women spokesperson, author and medical director of the New York University Women's Heart Program. "Our cause is based on science, such as the studies and perspectives we have gathered in this issue of Hypertension and the ongoing scientific research supported by the American Heart Association. This research is the foundation for the medical care doctors deliver in their offices. What we learn from this important body of science could one day save the life of someone's mother, wife, sister or daughter."

Here are highlights from the themed issue:

Dietary Calcium, Not Supplements, May Have a Role in Preventing Hypertension

In a study of 28,888 non-hypertensive American women, age 45 or older, researchers found that the risk of hypertension:

• decreased with a higher intake of low-fat dietary calcium and dietary vitamin D,
• did not change with calcium or vitamin D supplements, and
• increased with high-fat dairy product intake.

Researchers tracked the intake of dairy products, calcium and vitamin D based on a 131-item food frequency questionnaire and conducted annual follow-up over a 10-year period. (Nine possible responses ranging from "never or less than once per month" to "6+ per day" were recorded.) During that time, 8,710 cases of hypertension were identified.

Hypertension Poses Numerous Risks for Pregnancy

In a brief review accompanying several pregnancy-related studies in the issue, researchers note that hypertension is the most common medical disorder of pregnancy, complicating one in 10 pregnancies. They emphasize the importance of diagnosis in differentiating between pre-existing (chronic) hypertension from pregnancy-induced (gestational) hypertension and preeclampsia. They also support that pregnant women and those planning to become pregnant should avoid ACE inhibitors and angiotensin receptor blockers. Acceptable alternatives may include methyldopa, labetalol and nifedipine, in standard doses to manage hypertension in pregnancy.

In a prospective study of 822 women with chronic hypertension, researchers in London identified 180 cases of preeclampsia (22 percent), with early onset preeclampsia accounting for nearly half of those. Of those women with preeclampsia, nearly half (48 percent) delivered small birthweightbabies, while 51 percent of them delivered preterm, compared to 21 percent of women without preeclampsia having smaller babies and 15 percent of those women delivering preterm. According to the researchers, women with chronic hypertension should take special precautions before getting pregnant, including knowing their blood pressure, knowing of any family history of blood pressure problems during pregnancies, reducing their body mass index if it is elevated, quitting smoking and identifying any presence of renal disease.

Researchers in the United Kingdom found that, while cigarette smoking in preeclamptic pregnancies further increases already present risks, stopping smoking can decrease the risks. A multicenter, cohort study of 1001 white Western European women and their babies found that, compared to those who never smoke, the women who currently smoked in this study were more likely to deliver before 34 weeks, more likely to deliver lower birthweight babies or have babies with an adverse outcome (i.e., admission to a specialty unit, death), and were more likely to develop eclampsia. Women who had previously smoked and stopped prior to or during their pregnancy also significantly decreased their risks.

Of current smokers:

• 34.8 percent delivered before 34 weeks (compared to 26.8 percent of former smokers and 21.3 percent of non-smokers),
• 46.1 percent had low birthweight babies (compared to 37.5 percent of former smokers and 27.9 percent of non-smokers) and
• 65.6 percent had babies who experienced adverse outcomes (compared to 60 percent of former smokers and 50.4 percent of non-smokers).

Gender Plays a Role in Risk Factors, Treatment and Control of Hypertension

Two separate studies in the United States found persistent gender disparities in blood pressure control and cardiovascular disease management.

From the 1999-2004 National Health and Nutrition Examination Study, researchers analyzed data on 3,475 people, age 18 or older, diagnosed with hypertension. While blood pressure control in women and men was comparable (55.9 percent uncontrolled in women and 50.8 percent in men), the prevalence of central obesity, elevated total cholesterol level and low high-density lipoprotein-cholesterol were found to be significantly higher in women than in men. Those age adjusted risk factors included:

• central obesity (79 percent women vs. 63.9 percent men),
• elevated total cholesterol level (61.3 percent women vs. 48 percent men) and
• low high-density lipoprotein (LDL or "bad") cholesterol (39.7 women vs. 35.6 men.)

Using data from the 2005 National Ambulatory Medical Care Survey and the National Hospital Ambulatory Medical Care Survey, researchers analyzed data from 12,064 patient visits (7,786 female, 4,275 male). They found that among patients with hypertension, women were less likely than men to:

• meet blood pressure control targets (54 percent vs. 58.7 percent),
• receive aspirin (20.7 percent vs. 35.5 percent),
• receive beta blockers (31.9 percent vs. 44.5 percent) or
• receive statins (28.5 percent vs. 35.3 percent) for secondary prevention of cardiovascular disease.

Less than half (20.7 percent of women, 46.6 percent of men) of all patients received recommended therapy across all conditions considered.

"This issue of Hypertension features the latest research from basic, clinical and population scientists," Hall said. "We hope it is helpful to clinicians and researchers, and that it helps to increase awareness of healthcare professionals and the public to the greatest threat to the health of women – hypertension and cardiovascular disease."

To view this issue of Hypertension, visit http://hyper.ahajournals.org. To learn more about Go Red for Women, visit www.GoRedForWomen.org.

For more information on the American Heart Association visit www.americanheart.org.