London: The safety of hormone replacement therapy (HRT) has been questioned after research showed that stopping it reduced breast cancer risk among women.
Scientists found that a decrease in the number of menopausal women taking HRT has coincided with a 10 percent decrease in cancer rates.
Fears over the treatment`s safety were first raised in 2002 when a major US study linked it to breast cancer, heart disease and strokes.
It led to thousands of British women abandoning the pills, and within three years the numbers using it had halved to one million, reports the Daily Mail.
But its link to breast cancer has since been disputed and in 2007 another study found that the risks applied only to those in their 70s and 80s -- much older than women who usually take HRT.
Now Canadian researchers have found that the decline in use of HRT prompted by the health scares coincided with a 10 percent fall in breast cancer rates in their country.
They found the biggest decline in use of HRT was between 2002 and 2004, when the proportion of women taking it fell from 12.7 percent to just 4.9 percent.
Over the same period, the number of breast cancer diagnoses fell by 9.6 percent.
But the researchers also said that they did not think HRT actually caused breast cancer, it merely encouraged it to develop several years earlier.
So women who developed tumours while taking the treatment may well have got them anyway.
The study found that the cancer rates began to rise again in 2005, suggesting that women who did not have HRT had postponed breast cancer by two or three years.
Pritwish De, from the Canadian Cancer Society, said: "The nearly 10 percent drop in invasive breast cancer incidence rate coincided with the decline in the use of hormone replacement therapy reported among Canadian women aged 50-69 years.