Smoking increases the risk of heart attack in all people, but much more so in young women, a new study shows.
British researchers examined data on more than 3 300 cases of acute ST segment elevation myocardial infarction (STEMI) that occurred in the Yorkshire region of England between January 2009 and July 2014.
Risk higher in women
STEMI is sometimes called a major heart attack and is caused by complete blockage of one of the main heart arteries. Previous research has linked smoking to nearly 50% of STEMI cases.
The percentage of patients in the study who were current smokers was 47.6% of men and 46.8% of women.
Smoking increased the risk of STEMI in all patients, regardless of age or gender, but the risk was higher in women than in men, the study found.
The largest risk difference between men and women smokers was among those aged 50 to 64, but the highest risk increase in both genders was among those aged 18 to 49.
Women in this age group who smoked had a more than 13 times higher risk of STEMI than those who didn't smoke. Men in this age group who smoked had an 8.6 times higher risk than non-smokers.
The findings were published in the Journal of the American College of Cardiology.
Men have larger heart arteries
There are several possible reasons why smoking leads to a much greater risk of STEMI in women than in men, according to the authors. One is that smoking may lower women's levels of oestrogen, which has been shown to protect against narrowing of the arteries.
Also, men have larger heart arteries than women, which means that chronic inflammation caused by smoking may result in greater narrowing of women's heart arteries.
The authors noted that while smoking increases the risk of STEMI, the risk is quickly lowered if you quit.
"Our study found that smoking cessation, regardless of age or gender, reduces STEMI risk to that of a never-smoker, possibly within a month," said study senior author Dr Ever Grech a consultant interventional cardiologist at South Yorkshire Cardiothoracic Center in Sheffield.
"Patients who smoke merit encouragement to give up their habit, and this study adds quantitative evidence to the massive benefits of doing so," Grech said in a journal news release.
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