Insomnia has been linked to various diseases such as obesity, diabetes, heart diseases and depression. But is insomnia a risk factor for myocardial infarction (MI)? A team of researchers from Egypt, India, Pakistan and the United States set out to decipher this question in a systematic review and meta-analysis published in the journal Clinical Cardiology.¹

Following a comprehensive literature search, 9 studies involving 1,184,256 adults were included in the meta-analysis. Of these, 153,881 (13%) had insomnia and 1,030,375 patients did not have insomnia. The average age of the participants was 52 years.

The association between insomnia and the incidence of MI was found to be robust compared with those who did not have insomnia. People with insomnia were 1.69 times more likely to suffer a heart attack with a relative risk (RR) of 1.69. Participants with sleep duration of ≤5 hours were at 1.56 times increased risk of developing a heart attack compared to those who slept for 7-8 hours daily with an RR of 1.56. No statistically significant difference was noted among those who slept for ≤5 hours or ≥9 hours suggesting that this group was also at risk. People who found it difficult to initiate and maintain sleep were also at greater risk (RR 1.13).

The risk of MI increased by 2-folds among individuals with insomnia who also had diabetes compared to those who did not have these conditions (RR 2.06). Similarly, the incidence of MI was also higher among patients with coexisting hypertension and hyperlipidemia with RR of 1.84 and 1.76, respectively. However, the association between MI and nonrestorative sleep and daytime dysfunction was non-significant.

People with insomnia are therefore at greater risk of developing MI compared to those who do not have insomnia. Those who slept for 5 hours or less were at the highest risk with no gender difference observed. Sleeping for longer hours was not protective. Presence of comorbid conditions further added to the risk. According to this study, insomnia is a risk factor for MI and therefore should be included in the guidelines on the prevention of MI, especially primary prevention of heart disease.

Reference

1. Dean YE, et al. Association between insomnia and the incidence of myocardial infarction: A systematic review and meta-analysis. Clin Cardiol. 2023 Feb 25. doi: 10.1002/clc.23984.