Of Mares, Menopause and Markets

A lifelong rider examines the newly documented risks of hormone-replacement therapy for herself, 10 million American osteoporosis sufferers and 70,000 North American horses.
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A lifelong rider examines the newly documented risks of hormone-replacement therapy for herself, 10 million American osteoporosis sufferers and 70,000 North American horses.

My doctor finally had to get gruff with me: "You have bone loss--osteopenia--and are heading for osteoporosis [brittle , porous bones]," she told me. "You have a choice: Deal with it now and get some calcium back in your bones, or you could break a hip and that will keep you off riding forever."

Study results could affect PMU mares |

Study results could affect PMU mares |

More than 40 years of near-daily riding, hauling hay bales and cleaning stalls had kept me lean and relatively fit, but they had done nothing for my bones, at least according to the bone-density scan my doctor was inspecting. I fit the susceptible body type: thin, fair, fine boned, Caucasian and postmenopausal. At least I didn't smoke, drink significantly or take steroids, which are among the factors that could potentially worsen my bone loss. I had enjoyed better-than-average health all my life, but this silent crumbling had already taken measurable millimeters off my spine. And my low-density lipoprotein (LDL) cholesterol -- the "bad" kind -- was suddenly headed upward as well. Weight lifting, walking and calcium supplements had not halted either problem.

I had to take action to keep my bones fit for riding. Yet supplementary estrogen, I argued, wasn't natural. My physician, June La Valleur, MD, associate professor in the University of Minnesota's women's health department, had heard these objections before. "Historically, many women died before they reached menopause," she points out. "If they lived past it, they got dowagers' humps, fractured hips and vertebrae and died of osteoporosis or stroke. That's what's natural."

Taking it seriously
The historical perspective made sense, and the threat of not being able to ride is something I take with absolute seriousness. I had already tried skin cream containing plant-derived, or phyto, estrogen and noticed no differences in the odd feelings and roller-coaster energy I was experiencing. And, La Valleur explained, plant-estrogen creams were not standardized nor have they been proven effective. Should I increase my dietary calcium? I was already a cheese fiend, yogurt lover and ice-cream glutton. Eat soy? I had switched from cow's milk to soymilk 25 years ago, and I like tofu. More weightlifting? My sisters own a gym five blocks from my house. Been there, ate that, done (some of) that, and still my bones were crumbling.

Your Odds for Bone Loss

Eighty percent of osteoporosis sufferers are female, and, because bone is built before age 35, prevention is the best strategy for a skeletal longevity. Throughout life, but especially after age 35, it's crucial to have a diet rich in calcium, adequate daily intake of vitamins A and D obtained through sunlight, food or supplements and regular weight-bearing exercise, such as walking, running or lifting weights. Women who exhibit some of the following characteristics are at increased risk for osteoporosis and need to take particular care in maintaining bone strength:

  • thin, fine-boned and weighing less than 127 pounds,
  • Caucasian or Asian,
  • postmenopausal or elderly,
  • have insufficient calcium intake,
  • smoke,
  • drink more than one alcoholic beverage daily,
  • take steroids, anticonvulsants and other medications,
  • have had their ovaries removed,
  • have a family history of the disease.

Medical strategies to prevent or counter bone loss are under study and development, including a synthetic estrogen, called estren, that was recently shown to have positive bone effects without stimulating undesirable effects in the reproductive organs.

A few options remained. There are calcium-retention and -building drugs, including Fosamax(r) and Evista(r), but La Valleur told me she believed that estrogen is not only best for bone but that it also has other potential benefits, including lowered risk of heart disease (the chief cause of death in American women), improved memory and skin condition and possible protection against Alzheimer's disease. Yet as a horsewoman, I didn't want to take anything including horse urine. It wasn't a matter of squeamishness: I grew up eating Jell-O, which contains gelatin derived from cows' hooves, I eat sushi, and I've been known to sample steak tartare. I draw my personal gastronomic line at species I love: dogs, cats, horses.

It's my empathy for horses that made me resist taking the HRT drug Premarin. I am ambivalent about the living conditions of mares used in the production of pregnant mare urine (PMU) from which the estrogen is derived, but I am also reluctant to put these mares out of work. And while I admire, even covet, many of the foals produced on PMU ranches, I also do not want to contribute to the phenomenon of surplus PMU foals and mares going to slaughter.

So I chose not to become one of the 20 million American women who take equine conjugated estrogen--Premarin, Prempro, Premelle or Premphase. What else could I take? My physician prescribed Cenestin, a soy- and yam-based estrogen, to be taken with progesterone. Unopposed estrogen is more likely to cause problems, she pointed out, and the progesterone would help me sleep, another blessing for the middle-aged.

Rising worries
That was in 2000, and for two years, I had no side effects but lived with constant suspicion -- and the occasional debate with friends who are taking equine-derived estrogens -- that we can't cheat nature. On July 9, 2002, I read the announcement that the Women's Health Initiative (WHI) was ending its 10-year study of the effects of Prempro (estrogen-progestin) on 27,000 women aged 50 to 79 because of unfavorable risk-benefit assessments that included a rise in breast cancer, stroke, blood clots and heart disease. The study of estrogen-only treatment was to continue. Then on July 17, the U.S. National Cancer Institute released results of a study of HRT use in 44,000 postmenopausal women, showing a notable increase in ovarian cancer.

My immediate reaction to the news was to wonder what would happen to PMU mares and foals. What if women taking urine-derived products stampede away to other choices? For horses, obsolescence or unemployment too often means a trip to a slaughter plant. My second thought was to question if all these risks applied to my own estrogen-replacement drug.

My doctor is the gynecological investigator at one of the 18 vanguard centers with women enrolled in the WHI studies on HRT. She quickly sent a "do not panic letter" to her patients and appeared in a public panel discussion on HRT developments. "I am counseling women differently about Prempro since we now have objective data," she said. "We don't know if this information applies to other estrogen, other doses of the same estrogens or other routes of delivery [transdermal or vaginal HRT]. Those weren't studied. It's a matter of testing to see which works best for the individual woman."

For the rest of this story, see EQUUS 303 (January 2003).