As the use of hormone replacement therapy (HRT) has fallen in recent years, so too has the incidence of heart attacks in older women, new research suggests.

In 2002, the Women's Health Initiative found that HRT use increased the risk of heart attacks and other heart disease "events" among healthy postmenopausal women, leading to a sharp decline in its use.

Dr. Kanaka Shetty from the RAND Corporation in Santa Monica, California, and colleagues exploited the "natural experiment" caused by the dramatic decline in HRT use following the 2002 report to examine the relationship between HRT use and cardiovascular outcomes.

They found that HRT usage rates among women aged 50 to 69 years remained fairly steady in the mid-1990s and then declined sharply in the 2000s, following the pivotal report on HRT, from over 30 percent of the population in 2001 to less than 15 percent in 2005.

Rates of heart attack, they found, declined steadily over this period with a sharper decline in the post 2001 period, especially among women aged 50 to 59 years.

The researchers calculate that the decreased use of HRT was associated with 25 fewer heart attacks per 10,000 persons per year.

Decreases in HRT use did not reduce the number of hospitalizations or deaths from stroke, the investigators report in the journal Medical Care.

But Dr. Nieca Goldberg, a cardiologist at Total Heart Care in New York City whose practice focuses primarily on women, suggests that there may be reasons other than the decline in HRT use for the decline in heart attack rates in women.

"The reduction in hormone therapy coincided with the American Heart Association's and National Heart, Lung, and Blood Institute's women and heart disease awareness campaigns," Goldberg told the Health Behavior News Service.

"It's premature to attribute the decline in heart attack rates to the decline in hormone therapy," she concludes.