Background: It has been debated whether smoking increases the risk of heart disease relatively more in women than in men. It is not known whether there are sex differences with regard to how many years prematurely smoking causes acute myocardial infarction (AMI) to occur. We aimed to determine how smoking affects the age of onset of first myocardial infarction in both the sexes.
Design: Clinical data were consecutively entered into a database and were analysed with a multivariate regression technique.
Methods: In the years 1998-2005, data on 1784 consecutive patients (38.3% women) who were discharged from or died in a district general hospital with a diagnosis of first myocardial infarction were included in the study. Age at first AMI was analysed.
Results: Unadjusted mean ages were 76.2 years for women and 69.8 years for men, a difference of 6.4 years (P<0.001). Mean age within the various groups was: women nonsmokers 80.7 years, women smokers 66.2 years, difference 14.4 years (P<0.001); men nonsmokers 72.2 years, men smokers 63.9 years, difference 8.3 years (P<0.001). After adjustment for risk factors (hypertension, cholesterol levels, diabetes) and patient characteristics (history of angina, history of stroke) 13.7 years of the age difference in women were attributed to smoking; the corresponding figure in men was 6.2 years (P<0.001).
Conclusion: First AMI occurred significantly more prematurely in women than in men smokers, implying that twice as many years were lost by women as by men smokers.