People who suffer from insomnia are 69 per cent more likely to have a heart attack, we have reported previously.
This is especially the case for women, the research presented by the American College of Cardiology’s Annual Scientific Session Together With the World Congress of Cardiology, detailed.
The authors called for insomnia to be listed as a modifiable risk factor for myocardial infarction.
This came at a time when the American Heart Association recommended doctors include sleep behaviours when assessing their patients’ risk for heart disease.
As we’d recently reported, the Australian Heart Foundation is developing a similar policy.
New research suggests that “people who have insomnia symptoms such as trouble falling asleep, staying asleep and waking up too early, may be more likely to have a stroke”.
The researchers, from the Virginia Commonwealth University, found the risk was much higher in people under 50 years old.
What this means: if you’re under 50 and suffer from irregular and broken sleep, you’re much more likely to develop a stroke down the track.
This association between broken sleep and stroke was further increased for people with diabetes, hypertension, heart disease and depression.
Hardening of the arteries
If a lack of sleep raises the risk of a muscle-killing blockage to the heart, why not the brain?
In February, US researchers found sleep irregularity, particularly sleep-duration irregularity, was associated with several measures of subclinical (read: ‘lurking’) atherosclerosis.
This is the condition where sticky plaque builds up inside your arteries. It’s a leading cause of death via heart attack or stroke.
It’s old news that modifiable risk factors include high cholesterol and triglyceride levels, high blood pressure, smoking, diabetes, obesity, physical activity, and eating saturated fats. All these things you can change, thus bring down the risk.
As mentioned above, the evidence for sleep quality as a modifiable risk factor has grown to the extent that the Heart Foundation and other organisations promoting cardiovascular health now take it as read.
The new study
The new study involved 31,126 people with an average age of 61.
Participants had no history of stroke at the beginning of the study.
They were asked four questions about how often they had trouble falling asleep, trouble with waking up during the night, trouble with waking up too early and not being able to return to sleep, and how often they felt rested in the morning.
Response options included “most of the time”, “sometimes” or “rarely or never.”
Scores ranged from zero to eight, with a higher number meaning more severe symptoms.
The participants were then followed for an average of nine years. During that time, there were 2,101 cases of stroke.
After adjusting for other factors that could affect the risk of stroke, including alcohol use, smoking and level of physical activity, researchers found that:
- People with one to four symptoms had a 16 per cent increased risk of stroke compared to people with no symptoms. Of the 19,149 people with one to four symptoms, 1,300 had a stroke
- People with five to eight symptoms of insomnia had a 51 per cent increased risk. Of the 5,695 people with five to eight symptoms, 436 had a stroke
- Of the 6,282 people with no symptoms, 365 had a stroke.
The link between insomnia symptoms and stroke was stronger in participants under 50, with those who experienced five to eight symptoms having nearly four times the risk of stroke compared to people with no symptoms.
People age 50 or older with the same number of symptoms had a 38 per cent increased risk of stroke. Of the 654 people aged 50 and over with five to eight symptoms, 33 had a stroke.
What do these numbers mean?
Insomnia appears to be more of a risk factor for people under 50 than for people over 50.
The reason is simple: As we age, we become prone to a greater number of risk factors. These include blood pressure and diabetes. So for older people, insomnia is just one of many more potential triggers for stroke.
Co-author of the study, Dr Wendemi Sawadogo, a researcher at Virginia Commonwealth, puts it this way: “This difference in risk between these two age groups may be explained by the higher occurrence of stroke at an older age.”
Helpful take-away?
“This striking difference suggests that managing insomnia symptoms at a younger age may be an effective strategy for stroke prevention.”
In other words: Sort out your sleeping issues, and the risk of stroke will drop.
These associations are striking. But the study, relying on observational and self-reported data, can’t be said to prove that bad sleep causes stroke.
Nevertheless, doctors are being urged to discuss sleep quality with their patients when assessing overall health.
To read our story on insomnia and heart attack, click here.
