Perianal diseases—including hemorrhoids, anal fissures, and anal fistulas—are among the most common anorectal conditions worldwide, yet their multifactorial etiology remains poorly understood. Hemorrhoids alone account for nearly 4 million annual outpatient visits in the United States, while anal fissures and fistulas impose a substantial burden on patients’ physical and mental well-being. Although lifestyle factors such as diet, physical activity, and bowel habits have long been implicated, the causal role of sleep disturbances in perianal disease development has remained unclear—until now.

A groundbreaking study titled “The Interplay Between Sleep Patterns and Perianal Diseases: Sleep as a Risk Factor and Disease as a Consequence”, authored by Cuicui Pang, Yingshuo Wang, and Yanlin Wang from Peking University People’s Hospital, was recently published in Neuropsychiatric Research. Leveraging large-scale genome-wide association study data from European populations, the team employed a bidirectional two-sample Mendelian randomization approach to disentangle causal relationships from confounding factors.

The findings are striking. The analysis identified three sleep traits that significantly increase the risk of hemorrhoidal disease:

Insomnia was associated with a 23.3% increase in risk (OR: 1.2332; P = 0.0002);

Prolonged sleep duration conferred a 16.2% higher risk (OR: 1.1618; P = 0.0102);

Daytime napping was linked to a 14.1% elevation in risk (OR: 1.1413; P = 0.0124).

Notably, the causal association for insomnia remained robust even after stringent multiple-testing corrections, underscoring the strength of the evidence. Importantly, reverse Mendelian randomization analysis revealed no significant causal effect of perianal diseases on sleep traits, suggesting that sleep disruption acts primarily as a driver—rather than a consequence—of hemorrhoidal pathology.

The underlying biological mechanisms are plausible and well-supported. Circadian rhythm disruption can impair gastrointestinal motility, leading to constipation—a major risk factor for hemorrhoid formation. Chronic sleep deprivation fuels systemic inflammation, which exacerbates vascular congestion and edema in the rectal venous plexus. Excessive daytime napping, meanwhile, may reduce physical activity and promote venous stasis in the pelvic region, further predisposing individuals to hemorrhoidal disease.

These results carry important clinical implications. The authors advocate for integrating sleep hygiene interventions—such as cognitive behavioral therapy for insomnia, consistent sleep schedules, and optimized sleep environments—into the comprehensive management of perianal conditions. Dietary modifications that support both bowel regularity and sleep quality may offer additional synergistic benefits.

While the study provides robust causal evidence, the authors acknowledge certain limitations, including the use of a less stringent SNP selection threshold and the reliance on European-ancestry populations. Future research in diverse ethnic groups will be essential to validate and extend these findings.

Nevertheless, this work represents a significant step forward in understanding the brain–gut axis and highlights the often-overlooked connection between sleep and perianal health. For clinicians and patients alike, the message is clear: a good night’s sleep may be more than restorative—it could be protective.
doi:10.2738/NPR.2026.0006