People who suffer from insomnia are 69 per cent more likely to have a heart attack, a new paper finds.

This is especially the case for women.

The paper, led by a medical student from Alexandria University in Egypt, was presented last week at the American College of Cardiology’s Annual Scientific Session Together With the World Congress of Cardiology.

The authors have called for insomnia to be listed as a modifiable risk factor for myocardial infarction.

This comes at a time when the American Heart Association has recommended doctors include the sleep behaviours when assessing their patients’ risk for heart disease.

As we recently reported, the Australian Heart Foundation is developing a similar policy.

Other findings

Insomnia was diagnosed by the presence of any or all of these three symptoms. These were difficulty falling asleep, difficulty staying asleep or waking early and not being able to get back to sleep.

Sleep duration was used as an objective measure of insomnia (a somewhat loose way of going about it).

On that basis, the researchers found that “people who clocked five or fewer hours of sleep a night had the greatest risk of experiencing a heart attack”.

People with both diabetes and insomnia had a twofold likelihood of having a heart attack.

Going deeper, people who reported five or less hours of sleep a night “were 1.38 and 1.56 times more likely to experience a heart attack compared with those who slept six and seven to eight hours a night, respectively”.

There was no difference in the risk of heart attack between those getting five or less or nine or more hours of sleep a night – “which supports findings from previous studies that have shown that getting too little or too much sleep can be harmful to heart health”.

Overall, patients who slept six hours had a lower risk of heart attack compared with those who slept nine hours.

Trouble falling or staying asleep were also tied to a 13 per cent increased likelihood of heart attack.

The study

The paper is a systematic review of the literature that yielded 1226 studies, including studies originating from the US, United Kingdom, Norway, Germany, Taiwan and China.

Taken together, data for 1,184,256 adults (43 per cent of whom were women) was assessed. The average age was 52 years and 13 per cent (153,881) had insomnia.

People with obstructive sleep apnea were not included.

Most patients (96 per cent) did not have a prior history of heart attack. Heart attacks occurred in 2406 of those who had insomnia and 12,398 of those in the non-insomnia group.

The findings were confirmed after controlling for other factors such as age, gender, co-morbidities and smoking.

“Based on our pooled data, insomnia should be considered a risk factor for developing a heart attack,”  said Yomna E. Dean, lead author of the study.

She said “we need to do a better job of educating people” about how dangerous a lack of good sleep can be.