Irregular sleep patterns may increase risk for heart attack, stroke

Key takeaways:

• Irregular sleep markedly increased risk for major adverse cardiovascular events (MACE).
• Higher Sleep Regularity Index scores decreased risk for MACE.

Irregular sleep cycles corresponded with increased risk for major adverse cardiovascular events like stroke or myocardial infarction, results from a population-based cohort study published in Journal of Epidemiology & Community Health suggested.

This increased risk remained even in irregular sleepers who met the recommended hours of sleep, the researchers added.

Irregular sleep has been connected to a wide variety of health and behavioral issues, ranging from worse grades in school among adolescents to the development of diabetes.

“However, it is unknown whether healthy sleep duration can mitigate or even eliminate the adverse effects of irregular sleep patterns on cardiovascular health,” Jean-Philippe Chaput, PhD, MSc, a researcher at the Children’s Hospital of Eastern Ontario (CHEO) Research Institute, and colleagues wrote.

In the study, the researchers assessed the effects of irregular sleep on major adverse CV events (MACE) in a cohort of 72,269 people aged 40 to 79 years from the UK Biobank who had worn an activity tracker for several days. MACE comprised any fatal CV events, or occurrence of nonfatal ST-elevated or non-ST-elevated MI, or stroke or heart failure.

Chaput and colleagues used data accumulated from the activity trackers to determine Sleep Regularity Index (SRI) scores.

Researchers defined those with SRI scores more than 87, less than 72 or between 72 and 87 as sleepers with regular, irregular or moderately irregular sleep patterns, respectively.

The study followed participants — who did not have a history of MACE — for almost 8 years.

Irregular sleepers had a 26% greater risk for MACE compared with regular sleepers (HR = 1.26; 95% CI, 1.16-1.37), whereas moderately irregular had an 8% increased risk (HR = 1.08; 95% CI 1.01-1.7).

Dose-response analyses showed a near-linear association between SRI and risk for MACE, according to the researchers, with a greater risk reduction seen at higher SRI scores, whereas the median SRI score of 80.8 corresponded with a 18% risk reduction for MACE (HR = 0.82; 95% CI, 0.71-0.94).

They also found that meeting the recommended sleep duration — 7 to 9 hours in those aged 18 to 64 years and 7 to 8 hours in those aged 65 years or older — offset the risk for MACE in moderately irregular sleepers (HR = 1.07, 95% CI, 0.96-1.18) but not in irregular sleepers (HR = 1.19; 95% CI, 1.06-1.35).

Potential mechanisms driving the association between adverse CV health and irregular sleep “include disruptions in circadian rhythms, hormonal regulation, meal timing, inflammation and immune function,” researchers wrote.

“The intricate interplay of these mechanisms underscores the importance of maintaining regular sleep-wake patterns for overall cardiometabolic health,” they added.

Study investigators identified several study limitations, such as a low response rate among participants and an inability to determine cause and effect due to the analysis’ observational design.

The results “suggest that more attention needs to be paid to sleep regularity in public health guidelines and clinical practice due to its potential role in cardiovascular health,” Chaput and colleagues wrote.

References:

• Chaput JP, et al. J Epidemiol Community Health. 2024;doi:10.1136/jech-2024-222795.
• Irregular sleep-wake cycle linked to heightened risk of major cardiovascular events. Available at: https://bmjgroup.com/irregular-sleep-wake-cycle-linked-to-heightened-risk-of-major-cardiovascular-events/ . Published Nov. 26, 2024. Accessed Dec. 4, 2024.