Heidi Ledford at Nature covers a recent presentation at the American Heart Association of data showing that oral contraceptive use increases the amount of plaques in women's arteries over years of use. This is part of several studies that have shown that the use of oral contraceptives may have some health consequences for women, particularly women in high risk groups.
However, I like this article because it emphasizes the reticence with which most women should take these findings. Results with oral contraceptives are ambiguous, and they are confounded by the fact that most of the studies were done on older forms of the contraceptives that used much higher doses than are commonly prescribed today. Money quote:
Why is it so hard to get a straight answer?
In addition to differences between populations of women, study results can be muddied by differences in the composition and concentration of hormones in the many different birth-control pills on the market, says Hayes. "You can't lump all oral contraceptives together."
Many studies were begun years or decades ago, when birth-control pills contained higher overall levels of hormones and the hormones were derived from different sources. "The drugs we're using now are very different," says Hayes.
"This is one of the problems we often face in medicine. We start a study only to have the treatment evolve radically between the beginning of the study and its end. You can get good results, but they're not necessarily clinically relevant."
And, Hayes notes, study designs are often less than ideal. "It would be very hard to randomize an oral-contraceptive trial," she says.
Read the whole thing.
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