Insomnia maybe a significant risk factor for heart attacks and strokes

A new study published this week says that persons who suffer from insomnia or sleep difficulties are more likely to suffer from heart disease or get a heart attack or a stroke. Researchers from Peking University in Beijing published their study titled, “Insomnia symptoms and risk of cardiovascular disease among 0.5 million adults: A 10-year cohort” in the latest issue of the journal Neurology.

Researchers explained that difficulty in sleep could an important but underestimated factor that contributed to heart disease and adverse cardiac events.

For this study the team of Chinese researchers looked at nearly half-million Chinese individuals and asked then three important questions;

• Do you have trouble falling asleep?
• Do you wake up too early in the morning and cannot go back to sleep?
• Do you have trouble staying focussed during the day because you did not get enough sleep the previous night?

The individuals were followed up for an average of around a decade (up to 2016) over which time their heart health was recorded. The cohort or participants of the study were included from the China Kadoorie Biobank. The data was gathered from 10 regions across China and a total of 487,200 adults aged between 30 and 79 years were chosen. These individuals had never had a stroke, coronary heart disease and cancer at the start of the study. They were asked if the above questions were true for them for three days a week or more.

During the period of follow up there were a total of 130,032 cases of cardiovascular disease. Insomnia symptoms were seen in 16.4 percent participants. The results revealed that those who had all the three symptoms of insomnia based on these questions, were 22 percent more likely to develop coronary artery disease and 10 percent more likely to develop stroke compared to those who did not have any symptoms of insomnia and slept well.

The authors wrote that persons who suffered from the three symptoms of insomnia were more likely to be, “older, more likely to be female, not married, and from rural area; had lower education level, household income, and BMI (Body Mass Index); we're more likely to report a history of diabetes mellitus; and had depression or anxiety symptoms.” These associated factors were thus seen among the insomniacs and researchers believed that these could be linked with both heart disease as well as insomnia.

The team adjusted for factors such as smoking, level of physical activity, alcohol consumption and other lifestyle choices and still noted that sleep problems could be linked to heart disease. They found that persons who only said that they had difficulty focussing during the day because of their lack of sleep the night before were 13 percent more likely to experience heart problems compared to those who did not have this complaint.

Further persons who had difficulty falling asleep and staying asleep only were also 9 percent more likely to get heart problems. Individuals who only woke up too early and failed to go back to sleep were similarly 7 percent more likely to develop cardiovascular problems. Those with the only difficulty in maintenance of sleep were the ones most significantly at risk of getting an acute myocardial infarction or acute heart attack. None of the three insomnia symptoms were associated with the risk of getting a hemorrhagic stroke the researchers found. The risk of ischemic stroke, however, was consistent.

The researchers wrote in conclusion, “Individual and coexisting insomnia symptoms are independent risk factors for CVD incidence, especially among young adults or adults who have not developed hypertension.”

Dr. Liming Li, of Peking University in Beijing, in a statement, said, “The link between insomnia symptoms and these diseases was even stronger in younger adults and people who did not have high blood pressure at the start of the study. So future research should look especially at early detection and interventions aimed at these groups.”

There have been studies that have found that poor sleep at night led to altered hormone activity and also changed the metabolism and inflammatory processes in the body. Each of these could contribute to factors that raise the risk of obesity, diabetes and heart attacks or stroke say, experts. The authors of the study said that the changes caused by insomnia may be too small to be detected immediately and thus the ten-year-old study over a large population cold help determine the cause-effect relationship of insomnia and heart disease.

This study was funded by the National Key Research and Development Program of China, the Chinese Ministry of Science and Technology, the National Natural Science Foundation of China and the follow up was supported by UK Wellcome Trust.

Journal reference:

Insomnia symptoms and risk of cardiovascular diseases among 0.5 million adults Bang Zheng, Canqing Yu, Jun Lv, Yu Guo, Zheng Bian, Mi Zhou, Ling Yang, Yiping Chen, Xiaojun Li, Ju Zou, Feng Ning, Junshi Chen, Zhengming Chen, Liming Li Neurology Nov 2019, DOI: 10.1212/WNL.0000000000008581, https://n.neurology.org/content/early/2019/11/06/WNL.0000000000008581.