Risk Factors for Hemorrhoids
While many factors are commonly believed to cause hemorrhoids, rigorous scientific proof is surprisingly lacking for most of them, with constipation being the only consistently demonstrated risk factor. 1
Established Risk Factors
Age
- Peak prevalence occurs between 45 and 65 years of age, with community-wide prevalence in the United States reported at 4.4%. 1
- Approximately half of individuals older than 50 years experience symptomatic hemorrhoids. 2
Constipation
- Constipation is the most rigorously proven risk factor, associated with a 43% increased risk (OR 1.43,95% CI 1.11-1.86). 3
- Chronic straining at stool is widely believed by clinicians to contribute, though the American Gastroenterological Association emphasizes that rigorous proof is lacking. 1
Pregnancy
- Hemorrhoids occur in approximately 80% of pregnant persons, more commonly during the third trimester due to compression of the rectum by the gravid uterus. 4
- However, only 0.2% of pregnant women require urgent hemorrhoidectomy for incarcerated prolapsed hemorrhoids. 1
- Interestingly, when comparing gravid and nulligravida women in a large colonoscopy study, no significant association was found (OR 0.93,95% CI 0.62-1.40). 3
- A 2024 study found that only previous history of HD—not pregnancy-related factors like constipation or straining—was significantly correlated with symptom onset during pregnancy (OR 5.2, p < 0.001). 5
Family History
- Family history of hemorrhoids is significantly associated with higher occurrence of symptoms (p < 0.05). 6
- 44% of participants in one study reported a family history of hemorrhoids. 6
Commonly Cited but Unproven Risk Factors
Dietary Fiber
- The American Gastroenterological Association explicitly states that inadequate fiber intake lacks rigorous proof as a risk factor, despite widespread clinical belief. 1
- Paradoxically, high grain fiber intake was associated with a reduced risk (OR 0.78,95% CI 0.62-0.98) in a large colonoscopy study. 3
Prolonged Sitting on the Toilet
- No rigorous proof exists for this commonly believed risk factor, according to the American Gastroenterological Association. 1
Physical Activity and Sedentary Behavior
- Sedentary behavior was associated with a reduced risk (OR 0.80,95% CI 0.65-0.98), contradicting conventional wisdom. 3
- Physical activity showed no significant association (OR 0.83,95% CI 0.66-1.03). 3
- However, lack of regular physical activity was identified as a common factor (83%) in a Saudi Arabian population study. 6
Obesity
- Neither being overweight nor obese was associated with hemorrhoids (OR 0.89 and 0.86 respectively). 3
Diarrhea
- Proposed as a contributing factor but never rigorously proven. 1
Special Populations
Spinal Cord Injury
- Hemorrhoids are frequently seen in patients with spinal cord injury. 1
Higher Socioeconomic Status
- Increased prevalence rates are associated with higher socioeconomic status, though this may reflect differences in health-seeking behavior rather than true prevalence. 1
Pathophysiologic Considerations
Elevated Anal Resting Pressure
- Multiple studies have shown elevated anal resting pressure in patients with hemorrhoids compared to controls, though whether this is causative or consequential remains unknown. 1
- Resting tone normalizes after hemorrhoidectomy. 1
Critical Clinical Pitfalls
- Never assume all anorectal symptoms are due to hemorrhoids—up to 20% of patients with hemorrhoids have concomitant anal fissures. 7
- The American Gastroenterological Association warns that when hemorrhoids are simply assumed to be the cause, other pathology is too often overlooked. 1
- Symptoms commonly attributed to hemorrhoids (bleeding, pain, pruritus, fecal seepage, prolapse, mucus discharge) were equally reported by patients with and without hemorrhoids in research studies. 8