Mon, Feb-27-06, 20:00
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Confusing studies don't alter health advice
Quote:
WASHINGTON - Forget the low-fat diet and toss out the calcium pills? Rethink estrogen in your 50s? Women might get that impression from a trio of confusing studies published this month. But look more closely: The research doesn't actually change current advice.
It just shows how hard it is to find simple, one-size-fits-all answers in medicine.
Indeed, scientists who led the massive study called the Women's Health Initiative meet near Washington this week to plan their next step: examining participants' genes, in a quest to better customize health recommendations for women over 50. Maybe there are genes that predict which women's hearts will most benefit from a strict diet, or predict who is most likely to have a stroke or other severe side effect when using estrogen to treat menopause's hot flashes.
"There may have been some disappointment" that the studies didn't always give clear answers, acknowledges Dr. Elizabeth Nabel, heart chief at the National Institutes of Health. "The findings are what they are. ... Now we're in a second wave of putting the findings into perspective."
The WHI tracked 161,000 women for 15 years to test different strategies for preventing heart disease, bone-thinning osteoporosis, and breast and colorectal cancer.
It is best known as the study that in 2002 overturned the dogma that hormone therapy after menopause was good for women's overall health. It found the opposite -- that long-term use of the hormones estrogen and progestin increased women's risk of breast cancer, strokes and heart attacks, even dementia. Estrogen-alone, offered only to women who have had hysterectomies, was risky, too.
The WHI's latest findings, published this month, also made startling headlines: A low-fat diet didn't seem to prevent cancer or heart disease. Taking calcium and vitamin D tablets to protect aging bones provided only limited benefit. And a second look at estrogen-only users suggested those who took it in their 50s may not face the heart risks of older hormone users.
But, the findings "may not be as surprising as they first appear," cautions Dr. Adriane Fugh-Berman of Georgetown University, who has closely monitored the work.
Each has some serious caveats:
Sorry, the diet study doesn't say fat is good, just that it's hard to avoid. Women were asked to cut daily fat consumption to 20 percent of calories, down from an average of 35 percent. But six years into the study, few had reached that goal. The dieters were eating only about 8 percent less fat than a comparison group, too modest a drop to expect any heart benefits, explains NIH's Nabel.
Complicating matters, other research made clear after WHI had already started that for the heart, the kind of fat you eat is crucial -- there are good kinds and bad kinds, and women in the new study didn't focus on cutting the bad fats.
Olive oil, fatty fish like salmon, and certain nuts contain so-called heart-healthy fats.
Heart-harming fats are saturated fats, from meats and other products containing animal fat, and trans fats -- found everywhere from french fries and fried chicken to cookies and crackers. Trans fats are formed when liquid oil turns into solid fat; only recently have food labels begun listing them so consumers can use the information to make healthier choices.
The study did find a slightly decreased rate of breast cancer among dieters, particularly those who cut fat consumption the most. The change wasn't big enough to know if it was due to chance; scientists will track the women for another five years to try to tell.
Taking calcium and vitamin D tablets for seven years didn't seem to protect against hip fractures, except for a small benefit among women over 60. But the study's ability to detect benefit suffered because many participants took extra calcium on their own both before and during the study; doctors widely recommend the pills because it's hard to get enough calcium from diet alone as women age.
Also, the study found a 17 percent increase in the risk of kidney stones with supplement use. That's actually a well-known effect of taking calcium between meals, said Fugh-Berman, a supplement specialist. Simply take the tablets with meals to lessen the risk, she advises.
Then there's estrogen. When the WHI first exposed hormones' risks, critics noted that the average participant was far older than the 50-something most likely to use estrogen to treat hot flashes. This month's reanalysis found the fraction of study participants that young who used estrogen alone had slightly fewer heart attacks -- but the difference was too small to be considered real.
Looking at just a subgroup of a big study is highly controversial, and Nabel cautions against false reassurance. The government's guideline remains: If you must use estrogen to treat hot flashes, take the smallest possible dose for the shortest amount of time.
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http://www.msnbc.msn.com/id/11594348/page/2/
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