Hormone replacement therapy could help to ward off heart disease in middle aged women, a new study has shown.
Scientists say that starting oestrogen steroid therapy within six years of the onset of menopause could help prevent clogged arteries and reduce cholesterol.
Researchers in the US found the hormone oestradiol helped avoid atherosclerosis - a potentially serious condition where arteries become clogged with fatty substances called plaques.
Oestradiol is a female sex hormone and a form of oestrogen often prescribed to treat the symptoms of menopause and to prevent osteoporosis.
Women who took the hormone showed healthier arteries and were less at risk of cardiovascular problems.
Study lead author Dr Roksana Karim from the University of Southern California in Los Angeles said: "Atherosclerosis is a major cause of heart disease, and cholesterol accumulation in the arterial wall is the predominant characteristic of atherosclerosis.
"Our results show that oestradiol initiated earlier in menopause reduces atherosclerosis and appears to do so by directly reducing cholesterol accumulation in the arterial wall."
Scientists studied more than 600 healthy postmenopausal women who were divided into four groups.
Two groups received 1mg daily of oestradiol or a placebo pill within six years after the onset of menopause. The other two groups were prescribed the hormone more than a decade after menopause. All participants took the pills daily for an average of five years.
Initial findings indicated women starting hormone therapy earlier in menopause experienced less progression of artery wall thickening than those who started it later, or who received the placebo.
Scientists also found the rate of atherosclerosis progression among early oestradiol users was less than half compared to the women taking the placebo who had gone through menopause within the last six years.
Oestradiol did not have this benefit among the women who started hormone therapy 10 years or more after the onset of menopause.
Results were similar for both the placebo group and those who started therapy a decade after menopause.
Dr Karim said: "Our results show that starting oestradiol soon after the onset of menopause may result in fewer cholesterol deposits in the arteries, compared to women starting estradiol much later."
But the American Heart Association (AAH) warns against the use of hormone replacement therapy in menopausal women to prevent heart disease.
Dr Suzanne Steinbaum, volunteer expert at the AAH, attending cardiologist and director of Women's Heart Health of Northwell Lenox Hill Hospital and senior faculty at Mount Sinai Hospital in New York City, said: "The American Heart Association does not recommend hormone replacement therapy after the onset of menopause to prevent heart disease.
"Although some studies, like this one, show benefits, we are still seeing other trials with different outcomes.
"Because of that, oestrogen replacement therapy should be used only to alleviate the symptoms of menopause."
The average age of the menopause in the UK is 51, with most women going through it between the ages of 49 and 52, according to charity Wellbeing of Women.
It is estimated there are 13 million women who are currently menopausal in the UK - equal to one third of the entire UK female population. Symptoms include menstrual cycle changes, hot flushes, mood swings, vaginal dryness and weight gain.
The findings were due to be presented at the AAH's Epidemiology and Prevention Lifestyle and Cardiometabolic Health Scientific Sessions 2020 in Phoenix, Arizona.