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Studies on birth control pill’s benefits flawed

Federal officials backed away from the findings of two major studies on birth control pills, saying the research was flawed and that a new analysis shows there is no evidence that oral contraceptives cut the risk of heart disease.
/ Source: The Associated Press

A study concluding that birth control pills slightly lowered the risk of heart disease has now been called into question by federal officials who say it was flawed and wasn’t properly reviewed before it was presented at a major medical meeting in October.

Doctors from Wayne State University in Detroit had presented two studies at a reproductive medicine meeting in Philadelphia claiming that oral contraceptives lowered heart risks and did not increase the risk of breast cancer.

That got a lot of attention because the conclusions were opposite what previous studies had found. The new information also came from the largest women’s health study ever done in the United States.

But on Wednesday, Dr. Barbara Alving of the National Heart, Lung and Blood Institute, which funds and oversees the national study, said these particular analyses hadn’t been properly reviewed, and that a new analysis by senior statisticians had determined that the heart findings were flawed.

Once age and other factors were considered, they “could not find a relationship” between pill use and heart disease, Alving said.

The breast cancer findings also are suspect now, she said.

The research was from the Women’s Health Initiative, best known for its landmark finding in 2002 that taking hormones after menopause raised the risk of certain cancers and heart problems. But it is not the best kind of study for determining risks of oral contraceptives, Alving said.

That’s because it relies on women’s memories of what drugs they used in previous years rather than actual hospital or medical records.

Previous studies that were more scientifically sound have found that pill-users have a small increased risk of blood clots, heart attacks and stroke, she said. The Detroit researchers reported a small benefit — pill users reportedly had 8 percent less risk of cardiovascular disease and 7 percent less risk of developing any form of cancer.

But those findings were based on information women gave about whether they’d ever had heart problems or cancer, and were not verified with medical records as other WHI findings have been, Alving said.

“There is room for a lot of bias to be introduced,” she said.

Concerns about the studies were first raised in a story Sunday in the Seattle Times.

John Oliver, vice president for research at Wayne State, said the scientists were reviewing their work and would have no comment now.

“They want to look at the data. They’re in contact with the Women’s Health Initiative about how to proceed,” he said.

The university also issued a statement apologizing for any confusion caused by the studies, which it now calls preliminary, and pledged to publish full results when they are available.