Probably, at least in terms of minimizing the risk of blood clots, according to a new study called ESTHER, published in February in the journal Circulation. The French researchers looked at 271 women ages 45 to 70 with deep vein blood clots and 610 women without, and correlated their risk with whether they used oral forms of hormone therapy, types delivered through the skin, or none at all.
They found that oral hormone users had four-times the risk of blood clots compared with non-hormone users and with those using transdermal preparations.
“The study is important,” said Dr. JoAnn Manson, chief of the division of preventive medicine at Brigham and Women’s Hospital in Boston and author of “Hot Flashes, Hormones and Your Health.” It adds to the mounting evidence that the route of administration of estrogen matters.
This study did not address whether transdermal estrogen might offset other risks of oral hormone use, such as an increased risk of breast cancer or stroke.
(A different study that looked at hormone pills, not patches, published earlier this month, suggested that starting hormone therapy right at the beginning of menopause does not increase the risk of heart attacks.)
In general, estrogen taken orally passes first through the liver, where it can increase the synthesis of clotting proteins and inflammatory markers and have other effects. The advantage of medications delivered through the skin is that they do not pass through the liver en route to the bloodstream.
A new study called KEEPS is also comparing oral estrogen to the patch as well as evaluating progesterone (Prometrium) to determine the effects of the hormones on plaque in artery walls, memory and cognitive function, blood clotting factors, glucose and lipid levels and other variables. The study (www.keepstudy.org; 617-732-9870) is still recruiting patients who are within three years of the onset of menopause.