Antibiotics for Heart May Not Help in All Cases
A theory that looked good in the lab - that giving antibiotics to people with cardiac problems would reduce the risk of heart attack or stroke - has failed in real-life trials.
And heart patients who also had long-term infections with Chlamydia pneumoniae, a bacterium that causes respiratory illness, did no better when given regular doses of antibiotics than patients who did not get the medications, according to two studies reported in the New England Journal of Medicine. Chlamydia pneumoniae is different from the better-known Chlamydia that is one of the most common sexually transmitted infectious agents. Infection with C. pneumoniae, as it is formally called, is much more common, with more than 80 percent of Americans carrying antibodies to the bug, explains Dr. Christopher P. Cannon, a cardiologist at Brigham and Women's Hospital who helped conduct one of the studies. C. pneumoniae infection usually causes passing symptoms, similar to those of the common cold, but then the bacterium takes up permanent residence in the body, where it can harm arteries. "This is a foreign substance that the body reacts to," Dr. Cannon says. "It gets into the arteries and creates inflammation that can help plaque rupture." Arterial plaque is comprised of cholesterol-rich fatty deposits that can clog arteries. A heart attack, stroke, or other major cardiovascular event can occur when a plaque ruptures, blocking an artery. Experts have long theorized that medications that cut chronic infection might cut heart disease risks, too. The Brigham and Women's trial included nearly 4,200 people who had been hospitalized for such an event. Half of them were given regular doses of the antibiotic gatifloxacin for two years, and the other half received a placebo (inactive substance).
There was a slight reduction in deaths and severe cardiovascular events for those who got the antibiotic, but it was not even close to being statistically significant - 23.7 percent for the antibiotic group, 25.1 percent for the placebo group.
Maybe antibiotic treatment is just too little and too late for these people, Dr. Cannon notes. Persons hospitalized for heart conditions usually have a variety of risk factors, such as high cholesterol levels or high blood pressure, and perhaps "trying to treat one part of the problem doesn't have a big impact," he speculates. Another explanation is that a Chlamydia infection might help start the process of artery blockage, "but then 20 or 30 or 40 years later, it is too late to treat the problem," Dr. Cannon says. The second study, led by researchers at the University of Washington, used a different antibiotic, azithromycin, and had a different patient population, 4,012 people with stable coronary artery disease. Again, a four-year follow-up found no difference in the occurrence of coronary events such as heart attacks between those who got the drug and those who got a placebo. Dr. J. Thomas Grayston, an emeritus professor of epidemiology who led the study, was philosophical about the outcome. "The trials were not really designed to study whether Chlamydia pneumoniae was involved in heart disease," he says. "Instead, we jumped over to see if antibiotics worked. If they did, there would be a tremendous upside. If not, it was a trial that did no one harm." In explaining the results, "there are two possibilities," says Dr. Jeffrey L. Anderson, a professor of medicine at the University of Utah who wrote an accompanying editorial and has conducted lab studies of Chlamydia and heart disease. "One is that this whole idea of infection increasing the risk of heart disease and stroke is wrong," he says. "More likely, we've taken the wrong approach. Giving antibiotics to everyone isn't going to work." Studies in real life and the lab support the infection-heart disease link, Dr. Anderson says. Several papers have found an increased incidence of heart attack and stroke in the weeks after people have an infection. And animal studies done in Anderson's lab found that the process of artery blockage was accelerated in rabbits infected with Chlamydia who were fed a high-fat diet. "But maybe we just used the wrong antibiotics or the disease was so advanced that it was just too late" in the human trials, Dr. Anderson says. Or maybe Chlamydia hides so well in arterial plaque that the antibiotic cannot get to it, he says. In any case, it is back to the drawing board, Dr. Anderson says. "We have got to figure out how the risk occurs and how to reduce it," he notes. Maybe intervention has got to begin much earlier, Dr. Cannon says. "One intriguing idea is that if we had a vaccine that prevented infection in the first place, it might reduce the damage. But that is something that is not easily created or tested." Always consult your physician for more information.
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Seniors who follow a modified Mediterranean diet high in fish, fruit, and vegetables tend to live longer, according to a report in the British Medical Journal.
That is the conclusion of a major study involving almost 75,000 seniors in nine countries. The findings lend more support to a diet many experts consider one of the healthiest around.
"This is the largest study on the topic of the Mediterranean diet and health, and the results are the most generalizable concerning elderly people, since the study was undertaken in several European populations," says lead author Dr. Dimitrios Trichopoulos, of both the University of Athens Medical School and Harvard School of Public Health, Boston.
He adds that "there is not yet sufficient information about the effects of this diet on mortality among younger adults, but it is unlikely that the effects would differ by age."
Evidence has been gathering in support of the Mediterranean diet's health benefits, so the news is not particularly surprising to people in the field.
"All of the research that has been done on this type of diet has been extremely positive. This is nothing new," says Nancy Restuccia, a bariatric dietitian with the Center for Obesity Surgery at New York Presbyterian Hospital/Columbia University Medical Center in New York City.
"It's a very, very healthy diet," she says. "Unfortunately, even in some of the Mediterranean countries they're moving away from it as our fast foods move into the area."
The traditional Mediterranean diet emphasizes vegetables, legumes, fruits, nuts, cereals, and olive oil.
It goes light on saturated fats and involves a moderately high intake of fish, a low-to-moderate intake of dairy products, a low intake of meat and poultry, and a regular, albeit moderate, intake of alcohol, mostly in the form of wine at meals.
Most of the studies of the Mediterranean diet done thus far have involved only small numbers of people or only individuals from Greece.
The authors of this study wanted to see if the same positive results could be replicated in a more diverse group of people so they modified the diet, using unsaturated fats instead of monounsaturated fats.
Unsaturated fats are plant-based fats and include monounsaturated fats which are found in olive oil, seeds, and nuts.
They also widened the study population to include almost 75,000 healthy men and women aged 60 and over from nine European countries.
Participants followed the modified diet and their adherence to that diet was measured using a recognized 10-point scale.
Those who followed the diet more closely had a lower overall mortality, the researchers report.
A two-point increase on the scale corresponded to an 8 percent reduction in mortality, while a three- or four-point increase was associated with a reduction of 11 percent and 14 percent, respectively.
That means that a healthy 60-year-old man who followed the diet closely would live about one year longer than a man of the same age who did not adhere to the diet.
Always consult your physician for more information.
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