Study Finds Insomnia Raises Risk of Hemorrhoidal Disease

Perianal conditions such as hemorrhoids, anal fissures, and anal fistulas are among the most common anorectal disorders worldwide, though what causes them remains only partly understood. Hemorrhoids alone account for nearly 4 million outpatient visits a year in the United States, and fissures and fistulas place a substantial burden on patients physically and mentally. Diet, physical activity, and bowel habits have long been considered contributing factors, but whether sleep disturbances play a causal role has been unclear.

A new study from researchers at Peking University People's Hospital used large-scale genome-wide association study data from European populations and applied a bidirectional two-sample Mendelian randomization approach to separate causal relationships from confounding factors.

The analysis identified three sleep traits associated with increased hemorrhoid risk: insomnia, linked to a 23.3% higher risk; prolonged sleep duration, linked to a 16.2% higher risk; and daytime napping, linked to a 14.1% higher risk. The insomnia association held up even after stringent multiple-testing corrections. A reverse analysis found no significant causal effect running the other direction—from perianal disease to sleep traits—suggesting sleep disruption acts as a driver of hemorrhoidal disease rather than a result of it.

In the study published in Neuropsychiatric Research, the authors point to several plausible biological mechanisms. Disrupted circadian rhythms can impair gastrointestinal motility, leading to constipation, a known risk factor for hemorrhoids. Chronic sleep deprivation promotes systemic inflammation, which can worsen vascular congestion and swelling in the rectal venous plexus. Excessive daytime napping may also reduce physical activity and encourage venous stasis in the pelvic region.

The authors suggest that sleep hygiene interventions, including cognitive behavioral therapy for insomnia, consistent sleep schedules, and improved sleep environments, could be incorporated into the broader management of perianal conditions. Dietary changes that support both bowel regularity and sleep quality may offer additional benefit.

The authors note limitations, including the use of a less stringent SNP selection threshold and reliance on data from European-ancestry populations, and call for further research in more diverse populations to confirm and extend the findings. Overall, the study adds to evidence connecting sleep and gut health, suggesting that sleep quality may be a relevant factor in perianal disease risk alongside more established ones like diet and physical activity.