Stalking the Silent Killer
By D.R. Bartlette
Hypertension is a virtually symptom-less condition. Blood pressure normally varies with activity levels, stress and even posture. But in America, nearly 50 million people have hypertension, or high blood pressure. Left untreated, hypertension can lead to strokes, heart attacks, kidney failure and disability.
“It is the number one killer of women over 50,” said Heidi Kluess, an assistant professor of kinesiology at the University of Arkansas. “It kills more women than men.”
According to the American Heart Association, nearly half of all hypertension occurs in women. Last year, the association released a study showing that in every state, women had higher rates of uncontrolled hypertension than men, and the numbers keep climbing.
Gender apparently plays a role not only in risk factors, but also in treatment and control of the disease. In the five-year National Health and Nutrition Examination Study, researchers found that women had higher rates of central obesity (“belly fat”), high overall cholesterol and higher LDL (“bad”) cholesterol – all high-risk factors for hypertension.
In a 2005 study, researchers found that among patients with hypertension, women were less likely than men to meet their blood-pressure control targets or to receive medications such as aspirin, beta-blockers or statins. Less than 21 percent of women, versus almost 47 percent of men, received the recommended therapy at all.
Last year, Kluess, who has been studying vascular disease for over a decade, was awarded an $82,000 pilot grant from the National Institute on Aging to study the causes of hypertension in women. Specifically, she is looking at what role the sympathetic nervous system plays in women’s hypertension as they age.
“Our research is in the preliminary stages,” Kluess said. “We’re asking whether women’s response to aging is really different [than men’s].”
Kluess said that little previous research has focused on the biological differences between men and women in this regard.
“Women are severely understudied,” Kluess said. “It is a common problem in women, particularly after menopause.”
Researchers at the Mayo Clinic have found both biological and environmental factors that put women at a greater risk for heart disease in general. Stress and depression affect women’s hearts more than men’s, and smoking is much worse on women’s vascular systems. On the biological side, metabolic syndrome – a combination of increased blood pressure, elevated blood glucose and triglycerides — has a greater impact on women than men.
Asked if she thinks the causes for hypertension in women are predominately biological or environmental, Kluess said it’s hard to say.
“We don’t really know why women are different than men.”
She said researchers are investigating the effects of the hormone estrogen on hypertension, but there hasn’t been that much research. So far, researchers have found that lower levels of estrogen increase a woman’s risk of hypertension.
Both genders experience age-related changes, she said, but women experience a greater magnitude increase in sympathetic nerve activity and blood pressure.
The sympathetic nervous system controls many unconscious functions in the body, including digestion, pupil dilation and blood pressure.
“It’s part of the ‘fight or flight’ response, and we use it every day,” Kluess said. “It becomes more active as we age, particularly in women.”
Although hypertension typically doesn’t show any symptoms, it significantly increases a person’s risk of many other health problems, like stroke, heart attack and kidney failure, which is why it’s often referred to as “the silent killer.” But even before the trip to the emergency room, hypertension takes its toll.
“It’s a very serious disease; it hurts your heart, kidneys and brain to have high blood pressure,” Kluess said.
The American Heart Association also found that high blood pressure significantly increases the risk of disability later in life, such as the inability to lift objects, walk up or down stairs or bathe oneself. The study showed that women with hypertension have a higher risk of disability than hypertensive men.
Kluess said she will be using the grant to pay for one doctoral student and one undergraduate student to help in the lab. “It’s very important – you need to have people working for you in the lab. It’s very labor intensive.”
Previously, Kluess had been conducting research with a smaller grant from the Arkansas Biosciences Institute.
The pilot grant will allow Kluess to collect preliminary data to support a larger grant proposal for further research. Her research involves examining the role played by adenosine triphosphate, or ATP, the compound that transports energy within cells for metabolism. Kluess said this will be the first time a new ATP sensor will be applied to blood vessels.
Kluess said she hopes her research will someday help reduce women’s susceptibility to high blood pressure.
“It’s a topic that’s near and dear to my heart,” Kluess said. “As a woman, I want to know about these health issues. Hopefully down the road we can work with a pharmaceutical company to develop something for women’s unique systems.”
Are you at risk?
Controllable risk factors:
• Obesity — People with a body mass index (BMI) of 30.0 or higher are more likely to develop high blood pressure.
• Eating too much salt — A high sodium intake increases blood pressure in some people.
• Drinking too much alcohol — Heavy and regular use of alcohol can increase blood pressure dramatically.
• Lack of physical activity — An inactive lifestyle makes it easier to become overweight and increases the chance of high blood pressure.
• Stress — This is often mentioned as a risk factor, but stress levels are hard to measure, and responses to stress vary from person to person.
Uncontrollable risk factors:
• Race — African Americans develop high blood pressure more often than whites, and it tends to occur earlier and be more severe.
• Heredity — If your parents or other close blood relatives have high blood pressure, you’re more likely to develop it.
• Age — In general, the older you get, the greater your chance of developing high blood pressure. It occurs most often in people over age 35. Men seem to develop it most often between age 35 and 55. Women are more likely to develop it after menopause.
– source: American Heart Association
There is no way to tell if you have hypertension other than by having your blood pressure checked. A reading of 140/90 or higher indicates hypertension (the higher number is called the systolic blood pressure and represents the pressure when the heart is beating. The lower number is the diastolic blood pressure and represents the pressure when the heart is resting between beats).
Currently, there is no cure for high blood pressure. However, it can often be controlled with simple, common-sense approaches:
• Eat a diet composed mainly of whole grains, leafy vegetables, poultry and fish. Limit your intake of sodium, red meat, processed starches, caffeine, alcohol and sugars.
• Increase your activity levels and maintain a healthy weight.
• If you smoke, quit.
Not all hypertension can be controlled with diet and exercise alone, but even with medication, lifestyle changes are part of the prescription.
-source: Annals of Internal Medicine