A provocative study presented at the AHA has found an association between long-term use of birth control pills and buildup of plaque in arteries in the neck and legs, which could be a sign of heart disease.
A provocative study has found an association between long-term use of birth control pills and buildup of plaque in arteries in the neck and legs, which could be a sign of heart disease. Even the researchers who did the study said their finding does not prove that taking the pill for years will raise the risk of heart attack years after a woman stops taking oral contraception.
But doctors said the study, is another reason for women to be vigilant about monitoring other heart disease risk factors such as smoking, cholesterol and blood pressure.
"We can’t confer cause and effect" because of the study, said Raymond Gibbons, a cardiologist and professor of medicine at the Mayo Clinic who was not associated with the research. "I don’t think people should stop taking the pill, but they need to be more aware about their heart disease risk factors."
The study involved ultrasound measurements on the carotid and femoral arteries of 1,301 women who were or had been taking oral contraceptives. The average age of the women was 46.
The researchers found that for every 10 years a woman took oral contraception, there was a 20% to 30% risk of troubling plaque on either the carotid or femoral arteries. For each year of contraceptive use, the plaque risk increased about 2%.
The study was designed to adjust for the effects of a variety of other risk factors such as smoking, cholesterol, blood pressure, diabetes, alcohol use, diet and exercise.
The researchers noted that more than 80% of women in the United States born between 1947 and 1967 have used the pill for at least one year, with a typical woman using the drug for about 13 years.
The birth control pill was introduced in the 1960s, and many of the first women to who have used it are now approaching 60, an age when heart disease becomes more of a risk, said lead author Ernst Rietzschel, a researcher with Ghent University in Belgium.
"If these data are replicated, we will have to change the way we look at oral contraception risk," he said. Rietzschel noted that newer and presumably safer generations of the pill have been developed over the years, and part of the concern might be with women who used the first generation of the pill.
Still, he said, all oral contraceptives have the ability to raise blood pressure by as much as five points. He said any drug that does that could have ill effects on the heart.
He said he decided to do the study after researchers in Belgium noticed very high levels of C-reactive protein, or CRP, in birth control pill users. CRP is a substance in the blood that indicates the presence of inflammation.
So far, he said, there has not been other evidence that long-term use of the pill increases heart disease risk if it is discontinued, but "it’s not really surprising that we haven’t seen anything yet. And maybe we will not see anything at all. "We might be at the foot of a wave, but the wave might be a ripple."
Rietzschel said that if the pill does cause the buildup of plaque in the arteries of the heart, it is not likely to go away by merely stopping use of the drug.
The study was observational and not a rigorous clinical trial, but the findings suggest that women who use the pill should be even more vigilant about controlling other known heart disease risk factors, said Gordon Tomaselli, a professor of medicine at Johns Hopkins University School of Medicine.
He said it has long been believed that any vascular risk associated with the pill went away after use was stopped. The Belgian study now is raising some concern that that belief might not be true, he said.
American Heart Association 2007 Scientific Sessions Nov, 2007