Self-reported insomnia symptoms, sleep duration, chronotype and the risk of acute myocardial infarction (AMI): a prospective study in the UK Biobank and the HUNT Study

Abstract

Insomnia and short/long sleep duration increase the risk of AMI, but their interaction with each other or with chronotype is not well known. We investigated the prospective joint associations of any two of these sleep traits on risk of AMI. We included 302 456 and 31 091 participants without past AMI episodes from UK Biobank (UKBB; 2006–10) and the Trøndelag Health Study (HUNT2; 1995–97), respectively. A total of 6 833 and 2 540 incident AMIs were identified during an average 11.7 and 21.0 years follow-up, in UKBB and HUNT2, respectively. Compared to those who reported normal sleep duration (7–8 h) without insomnia symptoms, the Cox proportional hazard ratios (HRs) for incident AMI in UKBB among participants who reported normal, short and long sleep duration with insomnia symptoms were 1.07 (95% CI 0.99, 1.15), 1.16 (95% CI 1.07, 1.25) and 1.40 (95% CI 1.21, 1.63), respectively. The corresponding HRs in HUNT2 were 1.09 (95% CI 0.95, 1.25), 1.17 (95% CI 0.87, 1.58) and 1.02 (95% CI 0.85, 1.23). The HRs for incident AMI in UKBB among evening chronotypes were 1.19 (95% CI 1.10, 1.29) for those who had insomnia symptoms, 1.18 (95% CI 1.08, 1.29) for those with short sleep duration, and 1.21 (95% CI 1.07, 1.37) for those with long sleep duration, compared to morning chronotypes without another sleep symptom. The relative excess risk for incident AMI in UKBB due to interaction between insomnia symptoms and long sleep duration was 0.25 (95% CI 0.01, 0.48). Insomnia symptoms with long sleep duration may contribute more than just an additive effect of these sleep traits on the risk of AMI.

Investigating the causal interplay between sleep traits and risk of acute myocardial infarction: a Mendelian randomization study

“…Nonetheless, our finding showing evidence of an adverse causal effect of insomnia symptoms and a weak adverse causal effect of short sleep on the risk of AMI is consistent with prior observational [9,10,12] and MR research [12,23,24]. Our finding yielding evidence of a protective causal effect of long sleep on the risk of AMI contradicts with prior observational studies [9,12], but aligns with a weak concordant effect shown by another MR study [23]. Long sleep may be an indicator of poor health status, being closely associated with depression, poor sleep quality, sedentary lifestyles and underlying comorbid conditions [47,48], and so residual confounding or reverse causation may have biased previous observational findings.…”

“…Nonetheless, our finding showing evidence of an adverse causal effect of insomnia symptoms and a weak adverse causal effect of short sleep on the risk of AMI is consistent with prior observational [9,10,12] and MR research [12,23,24]. Our finding yielding evidence of a protective causal effect of long sleep on the risk of AMI contradicts with prior observational studies [9,12], but aligns with a weak concordant effect shown by another MR study [23].…”

“…Sleep is a complex and multifaceted biological phenomenon which comprises several traits [8]. Previous observational studies have mainly focused on individual sleep traits as separate risk factors for CVDs [9][10][11][12][13]. Insomnia symptoms, short or long sleep duration, and evening chronotype have been identified as individual risk factors for acute myocardial infarction (AMI) [9,10,12,13].…”

“…Previous observational studies have mainly focused on individual sleep traits as separate risk factors for CVDs [9][10][11][12][13]. Insomnia symptoms, short or long sleep duration, and evening chronotype have been identified as individual risk factors for acute myocardial infarction (AMI) [9,10,12,13]. A few studies have investigated the joint effects of sleep traits and have found evidence that some of these sleep traits interact to increase the risk of cardiovascular outcomes [9,14,15].…”

“…Insomnia symptoms, short or long sleep duration, and evening chronotype have been identified as individual risk factors for acute myocardial infarction (AMI) [9,10,12,13]. A few studies have investigated the joint effects of sleep traits and have found evidence that some of these sleep traits interact to increase the risk of cardiovascular outcomes [9,14,15]. For instance, insomnia with short sleep considered the most biologically severe sleep disorder phenotype [16], has been found to be associated with increased cardiometabolic risk [14,17,18].…”