1 Introduction

Hemorrhoidal disease is one of the oldest and most common proctologic diseases that has been described (Trompetto et al. 2015) and studied (Serra et al. 2016). In the United States, it is estimated that more than 50% of the population over 50 years of age has experienced hemorrhoid problems (Gencosmanoglu et al. 2002).

We can find traces of their description in both the Old Testament and Buddhist scriptures (Burkitt and Graham 1975; Hyams and Philpot 1970). Furthermore, Hippocrates (460 BC) was the first to use the term “hemorrhoid” (from the ancient Greek word “hema,” blood, and “rhoos,” flow) meaning flow of blood (Yang 2014). More recently, historical study shows signs of the presence of hemorrhoids even in battle. Everybody knows that 200 years ago (18 June 1815), Napoleon Bonaparte was defeated at Waterloo by the Duke of Wellington, who was joined by the Prussians and an invisible enemy, “hemorrhoids.”

Literature is poor in data on the current incidence and prevalence of hemorrhoidal disease in the general population, especially because most people have no symptoms and often hide this disease out of a sense of embarrassment.

Nevertheless, the number of terms used to define hemorrhoids when pathological has generated enormous confusion.

2 Epidemiology of Hemorrhoidal Disease

Over the years, several epidemiological investigations have demonstrated the influence of environmental factors in the development of hemorrhoidal disease.

Hyams and Philpot were among the first in the modern age to study the prevalence of hemorrhoids, just a few years before Burkitt’s theory (Hyams and Philpot 1970). They classified patients according to age, sex, socioeconomic status, race, religion, bowel habits, and pregnancy. The most important finding was that one in four individuals over 30 years had a certain degree of hemorrhoidal disease.

Following the theory of Burkitt in the early 1970s (Burkitt 1972, 1975; Burkitt and Graham 1975), according to which hemorrhoids were causally related to constipation, Johanson and Sonnenberg (1990a) performed an epidemiological investigation comparing the epidemiology of hemorrhoids with the epidemiology of constipation and failed to demonstrate any correlation.

In fact, constipation, in contrast to hemorrhoids, was more common with increasing age, among blacks and among those with low socioeconomic status and less education.

The results, which were similar regardless of sex, showed a prevalence rate of hemorrhoidal disease of 4.4% with a peak between 45 and 65 years old and a decline after age 65. Moreover, hemorrhoids were uncommon in patients under 20 years old. Conversely, whites were affected 1.5 times more frequently than blacks, and in England and Wales (but not in the United States), higher social class was linked with an increasing prevalence of hemorrhoids (1.8 times more common). According to the authors, this trend was due to the difference in social classification. In fact, in England and Wales social class was closely related with occupation.

Interestingly, a theory about the role of occupation on the etiopathogenesis of hemorrhoids was developed by Prasad et al. (1976). They noted that most of their patients (66%) with hemorrhoids had occupations involving prolonged sitting.

An earlier article by Johanson and Sonnenberg (1991) claimed that physician visits, hospital discharges, and surgical procedures for hemorrhoids in the USA had considerably decreased over the past 25–30 years. The authors used only statistics based on the International Classification of Disease (ICD) and consequently not based on patient self-diagnosis.

There may be many reasons for this decrease: increased use of conservative treatment, self-medications with over-the-counter preparations, and the increased use of stool softeners and fiber supplements.

The fact that the epidemiology of hemorrhoids has always been a topic of interest was demonstrated in a letter to the editor by Haas (1992) in response to the latter debated articles of Johanson and Sonnenberg.

Haas criticized the definition of hemorrhoids used by the authors [“a dilation of hemorrhoidal plexus that protrudes into the lumen of the anal canal” (Johanson and Sonnenberg 1990b)] and started his letter with the first sentence in paragraph two of the “Practice Parameters for the Treatment of Hemorrhoids” (1990): “haemorrhoids are normal components of human anatomy,” i.e., if hemorrhoids are a normal component of the human body, then their prevalence should be 100% without any provocation.

According to Haas, the criteria used by Johanson and Sonnenberg, which were based on the definition of hemorrhoids written in the ICD, in determining the prevalence and occurrence of hemorrhoids were wrong.

Therefore, how could the epidemiology of hemorrhoids be established without defining it properly?

The answer by Johanson and Sonnenberg (1992) was quick to come, and even to this day the term hemorrhoids continues to be used to describe a pathological rather than a normal anatomic entity.

A few years previous, Haas et al. (1983) reviewed the records of 835 patients seen in their clinic. They had performed routine rectal examinations consisting of inspection of the anal area, digital examination, anoscopy, and sigmoidoscopy. The examinations were performed by five surgeons who were not advised of the purpose of the study to prevent selection bias.

Hemorrhoidal disease was diagnosed in 720 patients (86%): 198 (198/241; 82%) among the asymptomatic group and 522 among the symptomatic group (522/594; 88%). There were no significant differences between men and women with respect to prevalence, and socioeconomic factors do not influence the incidence of hemorrhoids. Interestingly, women were more likely to be symptomatic than men.

In the twenty-first century, there was a reduction in epidemiological studies on the prevalence of hemorrhoidal disease. However, chronologically, four studies deserve to be mentioned.

In a mini-review published by Everhart and Ruhl (2009), hemorrhoidal disease was classified as the fourth leading outpatient digestive system diagnosis in the United States, with only gastroesophageal reflux disease, chronic constipation, and abdominal wall hernia being more common. There was an estimated 2 million ambulatory care visits with hemorrhoids as the first listed diagnosis and 3.3 million visits as a diagnosis listed at all. Visit rates were highest among patients older than 65 years and among whites. There were no differences between genders.

Riss et al. conducted an epidemiological cross-sectional study to determine the prevalence of hemorrhoids in adults that also tried to define associated risk factors (Riss et al. 2012).

The authors included in the study all patients between 2008 and 2009 consecutively who underwent colorectal cancer screening in four Austrian medical institutions.

They highlighted an overall prevalence of 39% (380/976) in the current adult population with only 17% of patients complaining of symptoms related to hemorrhoids, while the remaining 22% of patients reported they did not have any problems.

In a prospective, observational, national study conducted in France, Tournu et al. (2017) investigated the management of anal symptoms in general practice.

Among 1061 patients treated by 57 general practitioners, anal symptoms were found for 166, and hemorrhoids was the most frequent diagnosis (42 pts.; 25.8%). First-line treatment consisted of addressing constipation and dyschesia, supporting previous studies that sought to correlate hemorrhoids with constipation (Burkitt and Graham 1975; Johanson and Sonnenberg 1990a; Delco and Sonnenberg 1998; Riss et al. 2011; Johannsson et al. 2005).

Last, a prospective 1-year follow-up study was conducted investigating the relationship between habitual bidet toilet use and the incidence of hemorrhoids or urogenital infections (Kiuchi et al. 2017). Although this study was not designed purely for research on the epidemiology of hemorrhoids and given the degree of embarrassment associated with this disease, web-based questionnaires may be the best option in the future to better investigate the prevalence of hemorrhoids due to their anonymity and privacy of respondents’ feelings (van Gelder et al. 2010). In a univariate analysis, the authors failed to find any potential risk factors except for BMI, which showed a significant correlation with the risk of developing hemorrhoids (p = 0.0391).

The authors failed to demonstrate a correlation between hemorrhoids and a history of childbirth in women, even though symptomatic hemorrhoids are the most common disease during pregnancy (Brown and Lumley 1998; Thompson et al. 2002).

3 Hemorrhoids During Pregnancy

Hemorrhoidal disease during pregnancy is a separate chapter because the prevalence changes completely. Pregnant women represent a high-risk category for developing hemorrhoidal disease (Altomare and Giannini 2013).

In fact, hemorrhoids are present in 85% of woman during the second and third trimesters of pregnancy (Gojnic et al. 2005) with a thrombosed hemorrhoid rate of 7.9% in the last 3 months (Abramowitz et al. 2002).

Abramowitz identified constipation and late delivery (after 39.7 weeks of pregnancy) as independent risk factors for hemorrhoids during the third trimester of pregnancy and the puerperium.

A prospective observational cohort study tried to define the incidence of hemorrhoids, fissures, and other perianal diseases during pregnancy and the puerperium (Poskus et al. 2014). A total of 280 pregnant women were followed with physical examination and anoscopy through 1 month after delivery. In all, 123 (43.9%) developed perianal symptoms. Of these 123 women, 114 (92.7%) had a diagnosis of hemorrhoids and 7 (5.7%) had hemorrhoids and an anal fissure. Furthermore, 64 women (52.9%) were diagnosed with thrombosed hemorrhoids.

4 Conclusion

Even though hemorrhoidal disease is one of the most common diseases in the world, its true epidemiology is unknown. In addition to the confusion generated by the use of the term hemorrhoids to describe both a pathological and physiological state as well as false positives on colonoscopy, another source of bias is definitely related to the embarrassment that patients feel that leads them to self-medicate instead of presenting to their physician.

There is no doubt that hemorrhoids are more frequent in industrialized countries. In fact, the changes and improvements in hygiene and diet that have led to a decrease in mortality from infectious diseases and better growth in children have, at the same time, been associated with increases in several diseases such as hemorrhoids, gallstones, and ischemic heart disease (Barker 1989).