Young women smokers at much higher risk of deadly heart attack

While smoking boosts the likelihood of heart attack in both men and women of all ages, it has a much more powerful effect in younger women, especially those under 50, a new study suggests.

For women smokers ages 18 to 49, the risk of a deadly type of heart attack was more than 13 times higher than it was for non-smoking counterparts, researchers reported in the Journal of the American College of Cardiology.

"This study sheds new light on the risk impact that smoking has in provoking major heart attacks, especially in younger and female smokers," said coauthor Dr. Ever Grech, an interventional cardiologist at the South Yorkshire Cardiothoracic Center at the Northern General Hospital in Sheffield, UK. "I hope (the study) will correct the perception by young smokers that heart attack risks only arise much later in life."

There was the hint of some good news in the new study. When women quit smoking, their risk of a major heart attack dropped back to that of non-smokers.

"This reversibility was a surprise, which I regard as a 'silver lining' within the dark cloud of smoking outcomes," Grech said in an email. "This will undoubtedly incentivise those smokers who may have genuine concerns regarding their longer term health and realise the massive benefits of abstaining."

Grech and his colleagues studied five years of data on patients who came to their hospital with a so-called ST elevation myocardial infarction (STEMI), which results from a complete blockage of a major coronary artery.

Grech and his colleagues compared the 3,343 STEMI patients with data on the entire population served by the South Yorkshire Cardiothoracic Centre using 3 years of information gathered on residents aged 18 or older by the Integrated Household Survey from the United Kingdom Office for National Statistics.

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After analysing all the data, the researchers determined that smoking was associated with a significantly greater increase in the STEMI risk for women than men. Compared to their nonsmoking counterparts, female smokers were 6.62 times more likely to have a major heart attack, while male smokers were 4.40 times more likely to have a major heart attack.

Younger women smokers, those under age 50, saw the highest increase in risk. They were 13.22 times more likely to experience a major heart attack compared to their nonsmoking counterparts. Male smokers in the same age group were 8.6 times more likely to experience a STEMI compared to nonsmoking counterparts.

The researchers also found the risk of a STEMI in women who had quit smoking for at least a month dropped back to that of nonsmokers. The caveat to that finding is that 38 per cent of ex-smokers did not have information in their records detailing the date they quit.

Grech suspects the reason for the increased risk of STEMI in younger women is tied to the impact of smoking on the hormone estrogen. "What is clear is that the protective effects of estrogen in young female smokers are overridden by the powerful impact of cigarette smoking," he said.

The researchers focused on STEMIs because this is the type of heart attack most likely to kill you, said Dr. Omar Ali, director of the cardiac catheterisation lab at the Detroit Medical Center's Heart Hospital.

"This is a very interesting study," Ali said. "They found that not only was smoking associated with an increased risk of this type of heart attack, but also that the increase in risk was much higher in women. This was not a surprise to me. But it sheds new light on the relationship between women and heart disease."

"A lot of people are showing interest in specialising in heart disease in women and this study certainly supports that," Ali said. "We need to learn more about how heart disease affects women and how the risk factors increase or decrease."