But let’s have a reality check about what HRT, which is starting to look like a magic bullet, can really do. Low bone density is about a lot more than low estrogen—hip fracture rates rise well before menopause for Caucasian women, when their estrogen levels are still high. About half your lifetime bone loss occurs before menopause begins, and taking estrogen around menopause won’t do anything about that. Many, many of the more than a million fractures from low bone density that occur each year are in women who are taking estrogen. Up to 30 percent of women do not lose significant amounts of bone after menopause, and for them, the risks of HRT may outweigh the benefits. For women who do experience a dramatic drop in bone density, estrogen does slow bone loss, but the jury is still out about whether it can, on its own, do anything about increasing bone formation or even about limiting the slowdown in that arena. Your Z-score will eventually get back to normal—the level expected for someone of your age—but your T-score, the true measure of healthy bones, may never be reached using HRT alone. HRT can reverse the trend of bone loss, but it can’t replace what is already gone. And despite what HRT can do for your heart and how it can prevent strokes, we also know that smart diet, exercise, and lifestyle choices can do equally well—or better.
Then comes the biggest downside: an increase in cancer risk. Estrogen ups the risk of endometrial cancer by ten times when it is prescribed on its own. That’s why, for women who have a uterus, it should be taken together with a progestin. The combination of hormones puts the cancer risk back at normal, or is perhaps even protective.
The bigger (though less well documented) fear is of an increase in breast cancer risk. It isn’t hard to find alarmists who want to lay every case of breast cancer in this country at the feet of HRT and birth control pills (which are also estrogen based). Some valid controversy does surround the degree of risk involved. Some studies have shown a negligible difference on HRT, but some have shown an increase of up to 30 percent (in women taking hormones for at least five years before age 65—just what most experts generally recommend you do). And some evidence indicates that women who get breast cancer while taking hormones actually have a lower mortality rate than those who get it while not on HRT. If there is an increase in the rate of breast cancer, it is a small one. But with the lifetime risk of breast cancer already so high—one in nine women in this country, or over 11 percent, will have it—even a 1 percent change puts the rate up over 14 percent. That’s thirty-three more breast cancers detected per thousand women (on top of the 111 you’d already expect).
The key thing to remember—the fact most people overlook— is how much more common heart disease is in women than breast cancer. Breast cancer provokes a more visceral response, but the reality is that the average woman is much more likely to have serious heart disease than to have breast cancer, and far more likely to die from the former than the latter. One of every three women under 40 right now, and one in two women after menopause, will develop heart disease sometime in the future. That’s at least three times the commonly quoted one-in-nine risk for breast cancer.
More American women die from heart disease each year than anything else (conservative estimates put the numbers at 233,000 of them, vs. 43,000 for breast cancer and 65,000 for hip fracture). Of course, that means different things on a statistical and an individual level. If you are the one with breast cancer, the smaller likelihood of that happening means nothing to you. But since most of us can’t reasonably guess ahead of time if we are headed for breast cancer (setting aside those already known to be at high risk), the odds for large groups are the best we have to go on.
Even studies showing an increase in breast cancer in women taking estrogen do not show an increase in the death rate. In fact, women who take estrogen turn out to live longer on the whole, probably because of the many health benefits of being on HRT. Part of the confusion may arise from the fact that on HRT, breast cancer seems to appear earlier, but then have a lower recurrence rate. Estrogen may play a role, but probably promotes breast cancer that is already there rather than causing a new cancer itself. The most alarming studies were on estrogen alone, so it remains unclear if the addition of progestins mitigates or intensifies any increase in risk. At least one study suggests that your risk will return to normal (if it in fact increased) within five years of discontinuing estrogen use, and other studies show that the higher the lifetime dose of estrogen, the higher the breast cancer risk is.
You also have to throw into the mix the various potential side effects of HRT, which run the gamut from weight gain, nausea, vomiting, cramps, breast swelling and tenderness, hair loss, jaundice, irregular and uncontrollable vaginal bleeding, inability to wear contacts, yeast infections, dizziness, loss of sex drive, low blood sugar (making you crave sweets), bloating and headaches to increased risk of gallstones, higher risk of blood clots (which can lead to a stroke or heart attack), endometriosis, high blood pressure, fibrocystic breast disease, depression, liver problems, and fibroids. That’s a disheartening list, and on top of that is what progestins can do to you. Even if you experience only a couple of these items, they can make your life miserable. Altering the kind of estrogen you take, the dose you take, the schedule of dosing, or the combination with a progestin may alleviate the side effects, but it may also require a lengthy trial-and-error period. Of course, many women take estrogen with no symptoms whatsoever. Keep in mind that most studies have been done with conjugated estrogen, so other forms, like estradiol, may not have the same side effects.
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