Epidemiology of hemorrhoidal disease

Hemorrhoids are vascular cushions that underlie the distal rectal mucosa and contribute approximately 15–20% of the resting anal pressure, ensuring complete closure of the anal canal. Hemorrhoids became symptomatic when enlarged, inflamed, thrombosed, or prolapsed, and the most common symptom is painless rectal bleeding, which is why hemorrhoids are one of the most frequent causes of severe acute lower gastrointestinal bleeding. Defining the term “hemorrhoids” and their epidemiology has always been controversial. Unfortunately, at present, even after years of articles, debates, and pathogenetic theories, we do not know the extent of this phenomenon. In this chapter, we will discuss the epidemiology of hemorrhoidal disease and compare the most important studies in the literature.