WEDNESDAY, Jan. 8, 2003 (HealthDayNews) -- After a spate of bad news about hormone therapy, new research offers a bit of good news: It reduces the risk of diabetes in postmenopausal women who have heart disease.
But no one, including the study's authors, are suggesting that hormone replacement therapy (HRT) be prescribed to reduce that risk. Rather, the report, which appears in this week's issue of the Annals of Internal Medicine, should trigger additional research, experts say.
In the study, Dr. Alka Kanaya, an assistant professor of medicine at the University of California at San Francisco School of Medicine, and her colleagues found that HRT, including estrogen and progestin, reduced the incidence of diabetes by 35 percent during the four-year follow-up in women who had undergone natural menopause and who already had heart disease.
About 16 million Americans have Type II diabetes, in which the body fails to make enough insulin or to use it properly, according to the American Diabetes Association (ADA).
In the new study, Kanaya and her co-researchers zeroed in on a subset of women from the trial known as HERS (Heart and Estrogen/progestin Replacement Study), in which 2,763 women with documented heart disease were assigned to take HRT or a placebo. The main HERS conclusion, that HRT did not help prevent second heart attacks, was released in 1998.
In the newer study, Kanaya and her colleagues focused on the 2,029 women in the HERS trial who were free of diabetes at the outset. These women took either HRT or a placebo each day.
After four years, 160 of the women developed diabetes -- 62, or 6.2 percent, of those on HRT and 98, or 9.5 percent, of those on a placebo.
"We found that in [these] women with coronary disease, HRT reduces the incidence of diabetes by 35 percent," says Kanaya. The reduction held, she says, after controlling for such risk factors as obesity, which boosts the chances of getting Type II diabetes.
The study is definitely not a reason to consider HRT to reduce diabetes risk, Kanaya says, however. "The conclusion is that this is a scientifically interesting finding that needs to be confirmed, and that the risk of hormone therapy outweighs the benefits and that it's premature to recommend the use of hormone therapy to prevent diabetes," she adds.
Last summer, a national trial evaluating the benefits of HRT in healthy women was halted after experts determined women taking HRT were at increased risk for strokes and heart attacks but decreased risk for osteoporosis and colon cancer.
"Clinically, it should not change practice in any way," Kanaya says. The HERS trial was funded by Wyeth-Ayerst, which makes HRT.
This latest study is not the first to suggest that HRT helps reduce diabetes risk, Kanaya adds. "A lot of small studies have looked at the effect of hormone therapy on glucose levels," she says. "The data is extremely mixed."
"Our feeling is that HRT has a direct effect on the liver, and how the liver processes glucose," Kanaya says. "It's almost a protection against having too much glucose produced by the liver."
Even so, the researchers note in the report that the findings may not apply to all postmenopausal women; those in the study all had heart disease and all had undergone natural (not surgical) menopause.
In an editorial accompanying the study, another expert agrees that the finding should not change clinical practice and that further studies are needed to zero in on the effect of HRT on the processing of glucose.
"Future studies of HRT should investigate its effect on glucose metabolism more thoroughly," writes Dr. Peter W. F. Wilson, a professor of medicine at the Boston University School of Medicine.
To reduce the risk of Type II diabetes, the ADA suggests keeping weight under control and getting regular exercise. Diabetes increases the risk for heart problems, stroke and complications related to poor circulation.
What To Do
For more information on Type II diabetes, see the American Diabetes Association. For more on the hormone therapy trial that was halted, see the Women's Health Initiative.
