Sex hormones may not offer eternal youth, but they are promising robust old age. In 1995 as many as 16 percent of postmenopausal American women took estrogen in hopes of reducing risks of heart disease, osteoporosis, and even Alzheimer’s. Soon more may take it to protect themselves against colon cancer.
But there’s a dark cloud in this bright picture. In June researchers at Harvard Medical School reported that the incidence of breast cancer nearly doubled in women 60 to 65 years old who had been taking estrogen for more than five years.
The sex hormones estrogen and testosterone, like all hormones, are chemical messengers, substances produced in one part of the body that go on to tell other parts what to do. Both women and men produce both estrogen and testosterone, though in different quantities, and both sexes produce less as they age. That reduction can have a range of undesirable consequences--for example, women entering menopause can experience uncomfortable hot flashes and mood swings as their bodies adjust to the new low levels of hormone.
To counter such effects, doctors began prescribing estrogen supplements in the 1970s, and the treatment proved safe and successful. But it was usually short-term--on the order of just two years. More recently, as estrogen has been prescribed for an increasing number of ailments, the course of treatment has stretched out, and therein apparently lies the problem documented in the Harvard study.
Sustained exposure to estrogen can stimulate too much cell division in the breasts and thus increase the chance of cancerous mutations. Harvard researcher Graham Colditz points out that there is a known relationship between breast cancer and the age at which a woman starts menstruating, at which she has her first child, and at which she undergoes menopause (earlier puberty, later birth, and later menopause are associated with higher risk). All are mediated by estrogen, he says. If we’re not going to accept that estrogen relates to breast cancer, then we need to forget everything we know about the disease.
For some women, however, estrogen’s benefits might be worth the increased risk. Although breast cancer is the leading cancer among women, heart disease is the leading killer. In Colditz’s study, estrogen supplements nearly doubled the risk of contracting breast cancer--but the risk was still only 3 percent. For women who are at high risk for heart disease, estrogen’s demonstrated ability to reduce that greater risk may be more compelling than its threat. But for other women, Colditz says, dietary changes, calcium supplements, and frequent exercise can prevent bone loss and heart disease just as well as taking estrogen.
The effects of aging, of course, aren’t restricted to women, and the benefits of hormone supplements needn’t be, either. Joyce Tenover, a geriatrician at Emory University in Atlanta, points out that as men age, their sex drive wanes, they put on fat and lose muscle, and, like women, they gradually lose density in their bones. Men start with more bone and lose less, says Tenover. So we’re seeing osteoporosis in men now because they are living into their nineties. But the research is 20 years behind where we are in women.
One worry in giving testosterone supplements has been that the hormone will stimulate cell growth in the prostate gland, in effect creating a male version of the estrogen-breast cancer risk. This past year, however, a small-scale Chicago Medical School study found that a low dose of testosterone for two years seemed to cause no side effects. According to endocrinologist Fredrick Ellyin, who conducted the study, these men felt better and had denser bones, lower cholesterol, and more sexual appetite than men who weren’t receiving the hormone. With this minidose, says Ellyin, it may be that at age 70 they are thinking like people who are 50 or 55.
Although testosterone has been charged with such diverse effects as clogged arteries and bar brawls, a recent UCLA Harbor Medical Center study revealed the hormone’s gentler nature. Young and middle-aged men with abnormally low testosterone levels were given enough hormone to bring their levels to normal. Before treatment, the men felt irritable and depressed. Afterward, they didn’t feel more aggressive; they just were happier, lustier, and more outgoing.
Twelve percent of Americans are now over 65. Within 35 years, that figure will rise to 20 percent. Clearly, that shift will bring a higher incidence of age-related disorders. Can sex hormones minimize the debilitating frailty that besets an aging population? We cannot stop aging, says Ellyin, but we can delay it. I call that a success.