Friday, June 29, 2012

Physical fitness may reduce hypertension risk in people with family history

If your parents have a history of high blood pressure, you can significantly reduce your risk of developing the disease with moderate exercise and increased cardiovascular fitness, according to new research in the American Heart Association’s journal Hypertension.
In a study of more than 6,000 people, those who had a parent with high blood pressure but were highly fit had a 34 percent lower risk of developing high blood pressure themselves, compared to those with a low-fitness level who had the same parental history.
“Understanding the roles that family history and fitness play in chronic diseases is critically important,” said Robin P. Shook, M.S., study lead author and a doctoral graduate student in the Arnold School of Public Health at the University of South Carolina in Columbia. “The results of this study send a very practical message, which is that even a very realistic, moderate amount of exercise — which we define as brisk walking for 150 minutes per week — can provide a huge health benefit, particularly to people predisposed to hypertension because of their family history.”
Previous research indicates that parental history accounts for about 35 percent to 65 percent of the variability in blood pressure among offspring, with varying levels of risk based on which parent developed it and the age of onset.
Researchers followed a group of 6,278 predominantly Caucasian adults 20- to 80-years-old for an average 4.7 years. The participants were patients of the Cooper Clinic, a non-profit organization dedicated to preventive medicine, research and education in Dallas. Thirty-three percent of participants reported that a parent had hypertension.
When the study began, all participants were healthy, reported no physician diagnosis of hypertension, and achieved an exercise test score of at least 85 percent of their age-predicted maximal heart rate. Researchers determined participants’ cardiorespiratory fitness using a maximal treadmill exercise test.
During the study, 1,545 participants reported they had developed hypertension.
Researchers found that:
  • Combining those with and without a family history of high blood pressure, high levels of fitness were associated with a 42 percent lower risk of developing hypertension, and moderate levels of fitness with a 26 percent lower risk.
  • People with both a low level of fitness and a parent with hypertension had a 70 percent higher risk for developing hypertension compared with highly fit people with no parental history.
  • Those with a high level of fitness and a parent with hypertension experienced only a 16 percent higher risk of developing hypertension compared to those who were fit and had no parental history.
“The correlation between fitness levels, parental history and risk are impossible to ignore,” Shook said. “This awareness can serve the clinician and the patient, as they work together to find effective and reasonable ways to avoid the diseases that have affected their family members — in some cases, for generations.”
The research findings may not apply to all people because the majority of the study participants were relatively fit, well-educated, middle to upper class white men.
The findings support the American Heart Association’s recommendations of moderately intense physical activity, such as brisk walking, for 30 minutes or longer at least five days a week.
Co-authors are Duck-chul Lee, Ph.D.; Xumei Sui, M.D., M.P.H.; Vivek Prasad, M.B.B.S.; Steven P. Hooker, Ph.D.; Timothy S. Church, M.D., M.P.H., Ph.D. and Steven N. Blair, P.E.D. Author disclosures are on the manuscript.
The National Institutes of Health and an unrestricted research grant from The Coca-Cola Company funded the study.

Wednesday, June 27, 2012

Doctors sometimes over-treat blood pressure: study

A new study suggests veterans hospitals are following guidelines when it comes to treating patients with diabetes and high blood pressure -- but some diabetics with healthy readings may also be getting intensive blood pressure treatment that won't do them much good.
"Good control of blood pressure is important for decreasing bad outcomes for patients (with diabetes), such as heart attacks and kidney disease," said Dr. Eve Kerr, the study's lead author from the Department of Veterans Affairs Ann Arbor Healthcare System and the University of Michigan.
Doctors have gotten very good at making sure everyone at risk gets treated with blood pressure medications, she added. But some patients who needed blood pressure medications to begin with might end up not needing them later on.
"Sometimes when blood pressure gets too low, it's okay to back off," Kerr told Reuters Health.
Her team examined the medical records of close to one million diabetes patients treated at VA medical centers and outpatient clinics.
The vast majority of patients age 18 to 75 -- 94 percent -- either had normal blood pressure or were getting high blood pressure treated according to guidelines.
That means most diabetic veterans are getting the help they need when it comes to high blood pressure monitoring and treatment. But although under-treating blood pressure may not have been a big problem in the VA group, over-treatment seemed to be at least as common, if not more so, the researchers found.
More than one-third of patients treated at the VA with a blood pressure below 130/65 mm Hg were on at least three blood pressure lowering drugs, or were having their drug regimen increased. That was equal to eight percent of all diabetic veterans.
High blood pressure is considered to be 140/90 mm Hg or higher, according to the National Institutes of Health.
Depending on the hospital, between three and 20 percent of diabetic veterans were possibly being over-treated with blood pressure medications, Kerr and her colleagues reported Monday in the Archives of Internal Medicine.
Not only might those drugs be unnecessary, but they could cause problems for patients as well, researchers said.
"You don't want to put patients on medications unnecessarily, because there's risks with any medication -- whether it's a nuisance risk of a dry mouth or it could be potentially more serious, like making your blood pressure too low and having you more at risk for falls," said Eileen Handberg, a cardiology researcher from the University of Florida in Gainesville.
"You don't want to treat someone's blood pressure to the point that they're weak and dizzy because their blood pressure is too low," Handberg, who wrote a commentary published with the study, told Reuters Health.
She said guidelines don't currently set a lower limit for recommended blood pressure in diabetic patients -- and because of that, it's hard to say doctors in this study were doing anything wrong when they prescribed more blood pressure lowering drugs to people who might not have needed them.
Still, Handberg added, "There is a lot of conversation about, maybe lower isn't always better."
One limitation of the new study is that it can't show whether patients were actually harmed by their blood pressure getting too low, said Dr. Franz Messerli, director of the high blood pressure program at St. Luke's-Roosevelt Hospital in New York.
"We don't know whether over-treatment or under-treatment increased heart attack, stroke or death, and that's obviously the important issue," Messerli, who wasn't involved in the research, told Reuters Health.
Kerr said the new study can help inform future guideline-makers about how diabetic patients are currently being treated -- and how often too much blood pressure treatment might be a concern.
Researchers agreed that patients who find their blood pressure numbers dropping very low or who have side effects such as dizziness should talk with their doctors about their blood pressure and the possibility they can ease off aggressive treatment.

Monday, June 25, 2012

9 in 10 Blacks With High Blood Pressure Have Early Heart Disease

High blood pressure is strongly associated with heart disease in black Americans, new research shows.
In the study, published online May 31 in the Annals of Emergency Medicine, researchers looked at 161 people who came to a single emergency department. More than 93 percent of the patients were black. None had symptoms or a history of heart disease but 94 percent had a history of high blood pressure, or "hypertension."
Echocardiograms (an image of the heart) revealed that nearly 91 percent of the patients had the beginnings of heart disease despite the lack of symptoms. Most of the patients with heart disease had diastolic dysfunction, which means that the heart had a reduced ability to pump blood to the body, brain and lungs.
"These results present a tremendous opportunity to screen for heart disease before it becomes symptomatic, especially in a population with high rates of hypertension," lead author Dr. Phillip Levy, of the department of emergency medicine at Wayne State University in Detroit, said in a journal news release.
"If we can detect incipient [early] heart disease early, we have a better shot at treating it before it turns into a full-blown health emergency. Our study is also a strong reminder that emergency patients with chronic disease -- in this case, hypertension -- are generally a high-risk group," he noted.
Levy urged emergency physicians to address high blood pressure with patients. "Blood pressure readings are taken for every patient in the [emergency department]. By not just taking in new information but also acting on it, we can substantively contribute to . . . disease prevention efforts," he said.

Friday, June 22, 2012

Despite obesity rise, kids' blood pressure dipped

The rate of childhood obesity may have soared between the 1970s and 90s, but kids' blood pressure did not follow the same trend, a U.S. government study suggests.
Researchers at the Centers for Disease Control and Prevention (CDC) found that while the obesity rate among Louisiana children nearly tripled between 1974 and 1993, their blood pressure actually improved a bit.
Among nearly 11,500 children and teens assessed over those 20 years, the rate of obesity rose from 6 percent to 17 percent.
But their blood pressure, on average, remained fairly stable. And far fewer children than expected actually had high blood pressure by 1993: about 4 percent of boys and 6 percent of girls.
By comparison, those numbers were about 6 percent and 8 percent, respectively, in 1974.
None of that means that obesity is harmless to kids, said lead researcher David S. Freedman, of the CDC's division of nutrition, physical activity and obesity.
"Maybe the biggest problem is that obese children usually become obese adults," said Freedman. Past research, he noted, has found that about 75 percent of obese kids are obese as adults as well.
And at that point, obesity carries an increased risk of chronic conditions like type 2 diabetes, heart disease and arthritis.
Height related to blood pressure
In the U.S., obesity -- in adults and kids, alike -- had its biggest surge between the 1970s and 90s, Freedman said.
Since then, things have leveled off. Among teenagers, for example, the obesity rate hovered between 18 and 20 percent in the decade between 1999 and 2008, according to another recent CDC study.
Blood pressure does tend to rise along with body mass index (BMI) -- a measure of weight in relation to height.
But studies have had mixed findings on whether the rise in childhood obesity spurred any increase in kids' blood pressure.
A problem with some past research, according to Freedman, is that it failed to account for the fact that kids have also gotten taller over the years. Height, Freedman said, is a stronger influence over kids' blood pressure than is weight.
"I think the take-home from this study is that we should not necessarily assume that increases in childhood obesity will be associated with changes in every risk factor," Freedman said.
Better nutrition?
So why didn't blood pressure rise along with kids' weight?
This study, published in the journal Pediatrics, cannot show the reason, Freedman said. In theory, he noted, it could have to do something with improvements in early childhood nutrition -- including rising breastfeeding rates. But that's speculation for now.
One area where kids are not doing better is type 2 diabetes.
Last month, a CDC study found that among U.S. teenagers, the prevalence of type 2 diabetes and "pre-diabetes" -- a precursor to type 2 -- rose from 9 percent in 1999-2000, to 23 percent in 2007-2008.
Type 2 diabetes is closely associated with obesity. But the rise in teen diabetes came at a time when the obesity rate held steady. The CDC researchers were not sure of the reasons.
But they said the bottom line for parents and kids remains the same: Eat a balanced diet and get regular exercise.
The U.S. Preventive Services Task Force, a government-backed panel, recommends that children age 6 and older be screened for obesity. If a child is heavy, pediatricians should offer families behavioral counseling, or refer them to someone who can.

Wednesday, June 20, 2012

Soy supplement shows no blood pressure benefit

Soy-rich diets have been linked to lower rates of heart disease, but a small study suggests that soy supplements may not do anything for older women's blood pressure.
The findings, reported in the American Journal of Clinical Nutrition, add to the mixed evidence on the health benefits of soy isoflavones -- compounds that are thought to have weak estrogen-like effects in some body tissue.
Researchers have long known that Asian populations with soy-rich diets have lower rates of heart disease compared with people who eat "Western" diets.
But it has not been clear whether soy isoflavone supplements have cardiovascular benefits, like cutting blood pressure or cholesterol levels.
A number of studies have found that intravenous infusions of soy isoflavones may boost the body's production of nitric oxide and help blood vessels dilate.
"But we don't take soy by infusion," said William Wong, a nutrition researcher at Baylor College of Medicine in Houston who led the new study.
On top of that, he told Reuters Health, those studies looked at short-term effects on blood vessel function -- and not whether there are "sustained" benefits for blood pressure.
So for their study, Wong and his colleagues randomly assigned 24 menopausal women to take either soy isoflavones or placebo tablets for six weeks. The supplement gave a daily dose of 80 milligrams of isoflavones.
All of the women started the study with moderately elevated blood pressure.
After six weeks, Wong's team found, women on the soy supplement were faring no better than those on the placebo.
On average, systolic blood pressure was 136 mm/Hg in the placebo group, and 137 mm/Hg in the soy group. Systolic blood pressure is the first number in a blood-pressure reading; levels of 140 mm/Hg or above are considered high.
As for diastolic blood pressure, the average in both groups landed at about 80 mm/Hg -- the upper threshold of "normal."
Wong's team also did special blood tests to see whether the soy supplement affected the women's production of nitric oxide, a chemical that dilates blood vessels. They found no effect.
"It was disappointing," Wong said.
The study only lasted for six weeks. But according to Wong, that should have been long enough to detect blood pressure benefits if there are any.
"If we didn't see anything in six weeks, we doubt there would be effects (longer term)," Wong said.
"I think that if people are looking for a magic bullet against high blood pressure," he added, "this is not it."
That said, getting more soy foods in your diet -- especially starting at a young age -- could be a healthy move, according to Wong.
He speculated that the health benefits linked to soy in Asian populations may be the result of a lifetime of eating those foods. Taking supplements later in life, he said, may simply not cut it.
"Maybe it has to be long-term exposure to soy products," Wong said.
For now, the mainstream treatment for high blood pressure is to start by eating a healthy diet low in sodium and high in fruits and vegetables, and get regular exercise. If you're overweight, losing some pounds can lower your blood pressure.
Many people for whom lifestyle approaches aren't enough also take blood pressure medications.

Monday, June 18, 2012

Americans Becoming Lax About High Blood Pressure

In a surprising reversal of longtime health gains, fewer adult Americans are aware they have high blood pressure, fewer are getting effective therapy, and more are dying as a result, Federal health officials said here today in issuing new treatment guidelines for the ailment, which affects 50 million Americans.
Over the last 25 years, therapies to fight high blood pressure have led to significant declines in deaths from stroke and coronary heart disease. But the latest health statistics show a rise in severe kidney disease and heart failure, a slight rise in the rate of stroke, and a leveling in the death rate for Americans with coronary heart disease. These conditions often occur as complications of longstanding high blood pressure, which is also called hypertension.
The reason for the abrupt reversal is not known, Federal health officials and experts in high blood pressure said at a news conference. But they said contributing factors could be an increase in obesity, growing complacency among doctors and patients about high blood pressure, a large number of patients who stop drug therapy because of unwanted effects like decreased sexual interest and fatigue, and lack of effective communication to the public.
''We are very concerned to see this decline in awareness and control,'' said Dr. Claude Lenfant, the director of the National Heart, Lung, and Blood Institute, a Federal agency in Bethesda, Md. Dr. Lenfant and Dr. Edward J. Roccella, who is in charge of the Government's education program on high blood pressure, said the institute was developing new public announcements and a research program intended to improve compliance with therapy, which generally has to be lifelong.
The institute released data today from a national survey conducted from 1991 through 1994 by the Centers for Disease Control and Prevention showing that 68.4 percent of Americans with high blood pressure were aware they had the ailment, 53.6 percent were being treated for it, and 27.4 percent had it under adequate control. The target blood pressure level is less than 140/90 mm of mercury. All three figures were down from a similar survey conducted from 1988 to 1991, which showed 73 percent were aware, 55 percent were being treated, and 29 percent had their blood pressure adequately controlled.
Officials had expected the positive trend of the last 20 years to continue, and the reversal, though small, is a challenge to the Government's longstanding goal to control high blood pressure in 50 percent of affected Americans by 2000.
Dr. Roccella said that goal was still realistic, that the Government had met eight of its nine objectives in hypertension control in 1990 and that ''we're optimistic about meeting'' the 50 percent goal in 2000. But Dr. Michael H. Alderman, president of the American Society of Hypertension, said, ''We are failing to achieve our national objective in controlling high blood pressure.''
Millions of taxpayer dollars have been spent on controlling high blood pressure, Dr. Alderman said, and ''progress has stopped, and the report did not explore why that happened.'' Dr. Alderman heads the department of preventive medicine at Albert Einstein College of Medicine in the Bronx.
Dr. Alderman, was one of five experts who resigned for various reasons from the group of more than 100 experts who contributed to the report. Dr. Alderman left because he disagreed with the report's discussion of a class of drugs. This section was unrelated to the main conclusions of the report.
The new guidelines are the sixth in a series dating to 1972 from the heart institute. The latest were developed with the cooperation of 38 national professional, public, and voluntary health organizations and 6 other Federal agencies.
Untreated high blood pressure is a major contributor to heart disease, the leading cause of death among Americans, and strokes, the third leading cause of death. Federal officials have credited the earlier reports for helping to reduce the adverse impact of high blood pressure.
Dr. Sheldon G. Sheps, who headed a committee of experts that wrote the report for the institute said that two-thirds of the reduction in deaths from strokes among African American women in recent years and half the reduction in stroke deaths among white women was attributable to improved blood pressure control.
The new guidelines strongly encourage weight loss, exercise and changes in diet to prevent high blood pressure among all people. Such life style changes can work as the only therapy for some people with high blood pressure and an adjunct to other treatments for everyone with high blood pressure.
The guidelines say those with the mildest form of high blood pressure (140 to 149 systolic, or top number, and 90 to 99 diastolic, bottom number) could try changing life style without drug therapy for up to a year under vigilant blood pressure monitoring.
Such changes include weight reduction of at least 10 pounds; 30 to 45 minutes of aerobic activity on most days; intake of no more than a teaspoon of salt a day including that in processed foods; and increased potassium intake. But care must be taken by those with kidney disease because of potential dangers in the potassium intake.
For the first time, the guidelines endorse a specific diet. One rich in fruits, vegetables and low-fat dairy foods, and with reduced saturated and total fats, could significantly lower blood pressure for all Americans, the report said.
For first-line therapy for individuals with uncomplicated high blood pressure, the guidelines recommended drugs from the diuretic and beta-blocker classes. Different types of drugs may be indicated for those with certain conditions like diabetes or heart failure.
A major challenge is to improve adherence to therapy. Without providing specific figures, Dr. Rocella said that ''there are more people who have been in treatment for high blood pressure who have dropped out than who are on therapy.''

Saturday, June 16, 2012

How Grapefruit Juice Makes Some Pills More Powerful

FOR four years, the patient was one of Dr. Paul Pizarik's bigger problems: a 63-year-old Arizona man with heart, lung and kidney disease, and blood pressure that stayed dangerously high despite combinations of a half-dozen different advanced medications.
And then suddenly, to Dr. Pizarik's great surprise, the man's pressure dropped into perfect control. It had been magically reduced by nothing more complicated than a six-ounce glass of grapefruit juice that the patient had decided to add to his morning pills.
A few weeks later, his pressure plunged so low that his medication had to be changed all over again.
Researchers have known since 1989 that when some of the common blood-pressure pills called calcium-channel blockers were washed down with grapefruit juice, far more of the drugs reached the blood than when they were taken with a swallow of water instead. But it is a piece of information that has passed many doctors and patients by, even though the interaction has now been reproduced for other drugs. The effect may be so striking that some scientists are now calling for warning labels about the effects of grapefruit juice on pill bottles to prevent accidental drug overdoses. Others have hastened to patent the chemicals involved and are planning to incorporate them into new combination pills.
''We are harnessing the power of the grapefruit,'' said Dr. Paul B. Watkins, a professor of medicine at the University of Michigan in Ann Arbor, whose research recently clarified why grapefruit alone among citrus fruits appears to make some pills more powerful.
The handful of drugs now known to be involved include some common and potent ones, among them Plendil (felodipine) for high blood pressure and heart disease, Seldane (terfenadine) for allergies, Sandimmune (cyclosporine) to prevent rejection of transplanted organs, and Invirase (saquinavir) for treating AIDS.
What these diverse substances have in common is their fate after they pass through the stomach. Unlike other drugs that are absorbed directly from the intestine into the bloodstream, these are first extensively broken down by an enzyme in the wall of the small intestine.
In research published in The Journal of Clinical Investigation in May, Dr. Watkins and his colleagues showed that grapefruit juice appeared to remove large amounts of that enzyme from the intestinal wall. The result is that less of the drug is broken down, more remains in the intestine and more is then absorbed into the bloodstream over a longer period, just as if the patient had actually swallowed a higher drug dose. The specific causes appear to be chemicals in the juice called furanocoumarins or psoralens that function like ''little suicide bombers,'' attaching to the enzyme and damaging it so badly that the entire complex disappears from the cell.
But the amount of the enzyme in the intestinal wall varies greatly among people, Dr. Watkins said, which explains why the grapefruit juice effect may be serious for some people and unimportant for others. It probably makes very little difference if people with relatively low levels of the intestinal enzyme take their medicine with grapefruit juice or with water. But for others with a great deal of the enzyme, an unaccustomed glass of juice in the morning may send enzyme levels plummeting and drug levels soaring as much as ninefold.
Dr. J. David Spence at the Roberts Research Institute in London, Ontario, thinks this is what may have happened to a Michigan man who died in 1993 with toxic blood levels of Seldane after drinking two glasses of grapefruit juice. ''The problem is that juice is taken intermittently,'' he said. ''And grocers don't take a drug history when they sell it.''
Seldane blood levels are increased not only by grapefruit juice but also by many common prescription drugs, and serious heart problems may result. Although the drug is under new scrutiny by the Food and Drug Administration for its toxicity, it remains available by prescription in this country and is sold over the counter in Canada. In new prescribing information supplied to doctors only last month, Seldane's manufacturer, Hoechst-Marion-Roussel, added grapefruit juice to the list of substances that should not be taken with it.
Although information about grapefruit juice accompanies other affected drugs, it is printed in the tiny type reserved for doctors and pharmacists and seldom makes it out onto the patient's pill bottle. Many other drugs have never been specifically tested for grapefruit juice interactions.
The effect of a glass of grapefruit juice on drug levels lasts a day or more, and it increases over time, Dr. Spence cautioned. He favors a practice now routine in parts of Australia of affixing specific grapefruit juice warnings to pill bottles if an interaction is known or might be expected.
Other experts feel that chances of drug overdoses from a breakfast containing grapefruit are too small to warrant major public concern. ''These are generally safe drugs,'' Dr. Watkins said. ''I just tell patients, if you're used to taking your medicines with juice, keep doing it. If you're not, don't start.''
In fact, the danger of grapefruit juice impresses many scientists less than does its ability to augment drug effects cheaply and palatably without the need for larger doses.
Dr. Leslie Benet, chairman of the department of biopharmaceuticals at the University of California at San Francisco, has founded a corporation called Avmax to evaluate and market substances like those in grapefruit juice that inhibit intestinal enzymes, making drugs more available to the body with less person-to-person variability. His company has licensed one of the patented chemicals responsible for the effect in grapefruit, and is beginning studies combining it with several prescription drugs.
Other doctors just direct patients to the supermarket. Like many doctors who treat AIDS, Dr. Nereida Ferran, an internist at Beth Israel Hospital in New York, routinely advises her patients taking Invirase for H.I.V. infection to take it with grapefruit juice. ''The blood levels of the drug increase at least twofold,'' she said. ''Many of my patients are doing very, very well on what is supposed to be one of the weaker H.I.V. drugs.''
And Dr. Pizarik remains aware of grapefruit's double-edged potential. Over time, his patient's initially elevated blood pressure dropped so low with grapefruit juice that the man almost went into shock.
''He became pretty pale and pasty-looking,'' said Dr. Pizarik, who has not given grapefruit juice to any other patients. ''I don't know that I'd recommend it again until more studies are done.''