• Healthy Sleep Pattern Lowers Risk of Certain Cardiac Arrhythmias: Wide-Scale UK Registry Study

    A healthy sleep pattern lowers the risk of atrial fibrillation/flutter (AF) and bradyarrhythmia, independent of traditional risk factors, according to new UK registry findings in more than 400,000 participants.

    The association between sleep patterns and AF risk was also found to be greater in those with a lower genetic risk for AF, the researchers, led by Xiang Li, MD, PhD, from Tulane University, New Orleans, said.

    The findings were based on data in the UK Biobank, a large prospective cohort study containing in-depth genetic and health information from around half a million UK participants between 2006 and 2010. They were published Monday online ahead of the Sept. 21 issue of the Journal of the American College of Cardiology.

    Cardiac arrhythmias are a “burgeoning health threat” as established risk factors of morbidity and mortality, the researchers noted, adding that the most common form is AF, which in turn increases stroke, heart failure and death risk. Because AF is often asymptomatic, it is also commonly undetected, so associated risk could be “substantially underestimated,” they said.

    As a whole, cardiac arrhythmias may lead to life-threatening complications if left untreated, they stressed, adding that their prevention is, therefore, “an urgent public health priority.”

    Besides previously identified factors such as alcohol intake, smoking, extreme physical activity and obesity, emerging evidence links several sleep behaviors – excessive daytime sleepiness, sleep quality, sleep duration and insomnia – with arrhythmias, the researchers noted.

    Therefore, the current study was launched to evaluate overall sleep patterns that could be risk factors. Instead of focusing only on individual sleep factors like the majority of previous studies, the researchers generated their definition of a “healthy sleep pattern” incorporating five sleep behaviors recorded in the UK Biobank: chronotype (the body’s inclination to sleep at a certain time), sleep duration, insomnia, snoring and excessive daytime sleepiness.

    After excluding the 9,295 participants with existing AF, ventricular arrhythmias, or bradyarrhythmia at baseline, and the 98,810 with missing information on sleep behavior, the current analysis was left with 403,187 participants for the main cohort and 358,600 European-descent participants with complete genotyping data for the genetic susceptibility analysis.

    Healthy sleep factors – assessed by self-reported questionnaires – were defined as early chronotypes (those who define themselves as a “morning person” or “more a morning person than evening person”), sleeping 7 to 8 hours per day, those who reported they never, rarely or sometimes had insomnia symptoms, those with no self-reported snoring and those with no excessive daytime sleepiness. The sleep factors were each coded 1 if meeting the healthy criterion, and 0 if not, with higher scores therefore indicating healthier sleep patterns.

    The scores were then categorized as “healthy sleep pattern,” defined as a score of 4 or more, “‘intermediate sleep pattern” as a score of 2 to 3, and “poor sleep pattern”’ for scores below 1.

    The researchers documented a total of 11,724 incident AFs in the study population, 1,725 incident ventricular arrhythmias and 4,349 incident bradyarrhythmias during a median of 11 years of follow-up. A total of 86,483 (21.4%) participants had a healthy sleep score equal to 5, with women and non-smokers more likely to have healthier sleep patterns.

    “Participants with healthier sleep patterns also appeared to be less materially deprived; have a lower BMI; be more physically active; be less sedentary; and be less likely to have hypertension, type 2 diabetes, or high cholesterol,” the researchers said.

    Healthy sleep patterns were significantly associated with lowered risk for both AF (hazard ratio [HR] comparing extreme categories: 0.71; 95% confidence interval [CI]: 0.64-0.80; P < 0.001) and bradyarrhythmia (HR: 0.65; 95% CI: 0.54-0.77; P < 0.001) after adjustment for demographic, lifestyle and genetic risk factors.

    “Compared with individuals with a healthy sleep score of 0-1 (poor sleep group), those with a healthy sleep score of 5 had a 29% and 35% lower risk of developing AF and bradyarrhythmia, respectively.”

    However, they were not significantly associated with ventricular arrhythmias.

    The researchers also found that genetic predisposition to AF significantly modified the association of the healthy sleep pattern with the risk of AF (P-interaction = 0.017), with healthy sleep patterns’ ability to lower AF risk appearing to be strongest among those with lower genetic risk of AF.

    Compared with participants with a poor sleep pattern and a high genetic risk of AF, those with a low genetic risk of AF and a healthy sleep pattern had a nearly 50% lower risk of AF (HR: 0.54; 95% CI: 0.42-0.69).

    “Because cardiac arrhythmias are an ‘early stage’ risk factor for cardiovascular diseases and potentially reversible, our findings highlight the particular importance of improving cardiac arrhythmias by adherence to a healthy sleep pattern in the primary prevention of cardiovascular diseases,” the researchers concluded.

    Nevertheless, they stressed key limitations to the study, including that sleep behaviors were assessed via self-reported questionnaire.

    In an accompanying editorial, Alan Kadish, MD, and Jason Jacobson, MD, from New York Medical College, also lamented that: “Although the authors used a relatively sophisticated approach to the analysis of sleep, a major limitation is that arrhythmia diagnoses were obtained from diagnostic codes. Unlike other diseases, the diagnosis of arrhythmias such as AF, BA, and VA are subject to wide variability in clinical settings.”

    They suggested it would have been “more helpful” to know the type and duration of AF, the extent, timing, and significance of bradyarrhythmias, and the type of ventricular arrhythmias. “In the absence of this information, the results must be treated as somewhat tentative,” they said.

    Nevertheless, the editorialists branded the results “intriguing” as an addition to the growing body of data to suggest that the quality and quantity of sleep can affect AF and bradyarrhythmias.

    “These results must be taken as preliminary and hypothesis-generating, rather than findings that are ready to affect clinical practice,” they concluded.

    The researchers finished by calling for long-term studies to assess the impact of adherence to a healthy sleep pattern on other cardiovascular outcomes.

    Sources:

    Li X, Zhou T, Ma H, et al. Healthy Sleep Patterns and Risk of Incident Arrhythmias. J Am Coll Cardiol 2021;78:1197-1207.

    Kadish A, Jacobson J. Sleep Patterns and Arrhythmias: Should This Keep Us Awake at Night? J Am Coll Cardiol 2021;78:1208-1209.

    Image Credit: tab62 – stock.adobe.com

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