The difference between men and women is not inevitable and biological but something that can be altered

Dr Debbie Lawlor

Oestrogen is thought to improve cholesterol levels, and help to widen the walls of the arteries, putting less strain on the heart.

But this theory has been rejected by research published in the British Medical Journal, which studied trends in heart disease in many different countries over the last eight decades.

Researcher Dr Debbie Lawlor, of Bristol University, said it was more likely that the gender difference was due to environmental factors than human biology.

Saturated fat

She believes that men put themselves at risk by eating too much saturated fat in their diet.

Dr Lawlor said: "This is exciting because it means the difference between men and women is not inevitable and biological but something that can be altered.

"It may be possible to reduce deaths in men to levels similar to those found in women."

Levels of dietary fat eaten by men have been rising since the 1940s. The researchers found that over the same period there had been a marked increase in deaths from coronary heart disease among men.

Over the same period death rates among women have remained stable, or have declined.

Many factors

Belinda Linden, medical spokeswoman for the British Heart Foundation said there were many risk factors for coronary heart disease.

These include smoking, high blood pressure, high cholesterol levels and family history.

Ms Linden said: "It is rather ambitious for this study to draw specific conclusions about gender differences in coronary heart disease between men and women based on trends across 50 countries over 77 years - the study has many uncontrolled cultural, economic and dietary variations.

"In any long-term research we also need to understand more about other risk factors effecting different risk levels between individuals."