HEART ATTACKS: The nine triggers

Top of the pile is cigarette smoking. Smoking 6 to 10 cigarettes a day doubles your risk, the risk quadruples if you smoke 20 a day, while those who smoke 40 or more a day have a nine-fold risk of an attack.

The other major marker was an abnormal ratio of apolipoprotein A to apolipoprotein B, which is considered a more sensitive indicator than high- and low-density lipoprotein. This, together with smoking, accounted for two-thirds of total risk.

Other factors include high blood pressure, diabetes, abdominal obesity, low daily fruit and vegetable consumption, a lack of exercise and stress.