Irritable Bowel Syndrome (IBS) Statistics: IBS by the numbers

Prevalence of IBS

The prevalence of IBS varies across different countries and populations, with estimates ranging from 7.3% to 11.2% globally [1,2]. Several studies have reported the prevalence of IBS in various regions using the Rome IV diagnostic criteria:

• In Uruguay, the prevalence of IBS was found to be 8.5% [3].
• In the Kingdom of Bahrain, the prevalence of isolated IBS (without other functional gastrointestinal disorders) was 4.2% [5].
• In Japan, a study reported that the prevalence of IBS was 11.4% [6].

Factors such as age, marital status, education, occupation, smoking, family history, and comorbid conditions like anxiety and depression have been associated with an increased risk of IBS [4,6]. The prevalence of IBS appears to be higher in women compared to men [1,2].

IBS is a significant public health concern, as it is associated with a reduced quality of life, increased healthcare utilization, and substantial economic burden [8]. The impact of IBS on healthcare costs and productivity losses is substantial, with a significant economic burden on individuals and healthcare systems [9-11].

Recent studies have provided additional insights into the prevalence of IBS in various populations:

• A meta-analysis of 53 studies from 38 countries found that the pooled global prevalence of IBS was 11.2% (95% CI, 9.8-12.8%) [27]. The prevalence was higher in women (14.0%) compared to men (8.9%) and varied by geographic region, with the highest rates in South America (21.0%) and the lowest in Southeast Asia (7.0%) [27].
• A study in the United States found that the prevalence of IBS was 6.1% (95% CI, 5.4-6.9%), with higher rates in women (7.2%) compared to men (4.9%) [18]. The prevalence was highest in individuals aged 18-34 years (8.2%) and decreased with increasing age [18].
• A study in Saudi Arabia reported a prevalence of IBS of 31.8% (95% CI, 29.2-34.4%), with higher rates in women (36.6%) compared to men (27.1%) [28]. IBS was associated with a family history of IBS, psychological stress, and a sedentary lifestyle [28].

These findings highlight the variability in IBS prevalence across different populations and the need for continued research to better understand the factors contributing to these differences.

Demographics of IBS Patients

IBS can affect individuals of all ages, but it is most commonly diagnosed in adults between the ages of 20 and 50 years old [9]. The prevalence of IBS tends to decrease with increasing age, with the highest rates observed in younger individuals [1,2].

IBS is more commonly diagnosed in women than in men, with a ratio of approximately 2:1 [12-14]. The higher prevalence of IBS in women may be attributed to hormonal factors, differences in pain perception, and sociocultural influences [12,13]. However, it is important to note that IBS can affect individuals of any gender, and the underlying causes for the gender differences are not fully understood [14].

IBS has been reported globally, with varying prevalence rates across different regions and ethnic groups [2,15,16]. Some studies have suggested that the prevalence of IBS may be higher in Western countries compared to non-Western countries, but these findings are not conclusive [15,16]. Genetic and environmental factors, as well as cultural differences in healthcare-seeking behavior and diagnostic practices, may contribute to the observed variations in IBS prevalence across different ethnic and geographical populations [16].

The relationship between socioeconomic status (SES) and IBS prevalence is not entirely clear, with some studies suggesting a higher prevalence in individuals with lower SES, while others have found no significant association [17,11]. Factors such as stress, diet, and access to healthcare may play a role in the potential relationship between SES and IBS [11].

Recent studies have revealed additional insights into the demographics of IBS patients:

• A study in the United States found a slightly higher prevalence of IBS (6.1%) than previously estimated (4.7-5.3%), which may be related to the COVID-19 pandemic [18].
• In Bahrain, a study reported a higher prevalence of IBS (18.3%) compared to the global average of 4%, with IBS being more common in females and the 41-50 age group [5].
• Several studies have also reported associations between IBS and other conditions, such as gastroesophageal reflux disease (GERD) and indigestion [5,19].
• A study in Saudi Arabia found that gender, anxiety, depression, and low physical activity were significant factors associated with IBS [20].

A meta-analysis of 53 studies found that the prevalence of IBS was significantly higher in individuals with a family history of IBS (OR, 2.57; 95% CI, 1.97-3.34), psychological distress (OR, 2.39; 95% CI, 1.76-3.25), and a history of abuse (OR, 2.02; 95% CI, 1.37-2.98) [29]. The study also reported that the prevalence of IBS was higher in individuals with a lower educational level (OR, 1.34; 95% CI, 1.10-1.62) and those who were unemployed (OR, 1.34; 95% CI, 1.08-1.67) [29].

These findings suggest that a complex interplay of genetic, environmental, and psychosocial factors may contribute to the development and prevalence of IBS in different populations. Further research is needed to better understand the underlying mechanisms and identify targeted interventions for individuals at higher risk of IBS.

Economic Burden of IBS

The economic burden of IBS is substantial, with both direct medical costs and indirect costs contributing to the overall financial impact.

Direct medical costs associated with IBS include expenses related to healthcare utilization, such as outpatient visits, hospitalizations, diagnostic tests, and medications [9-11]. Studies have shown that individuals with IBS have a higher number of outpatient visits and hospitalizations compared to the general population, leading to increased healthcare expenditures [9,10]. The cost of diagnostic tests and medications also contributes to the direct medical costs of IBS [11].

Indirect costs associated with IBS include absenteeism, reduced productivity, and caregiver burden [9,11]. IBS can cause individuals to miss work or be less productive due to their symptoms, leading to lost wages and decreased economic output [9]. The burden on family members and caregivers of individuals with IBS can also lead to indirect costs [11].

Recent studies have provided updated estimates on the economic burden of IBS:

• A study in the United States estimated that the direct annual cost of ambulatory clinic visits alone for chronic symptomatic functional bowel disorders, including IBS, was approximately US$358 million (95% CI, 233-482 million) [18].
• A study in the Netherlands found that the quarterly mean direct costs per IBS patient were €802 (95% CI, €625-€1,010), while the quarterly mean indirect costs were €1,354 (95% CI, €1,072-€1,670) [11].

The combination of direct medical costs and indirect costs associated with IBS can result in a significant economic burden. A systematic review estimated that the total annual cost of IBS in the United States ranged from $1.5 billion to $10 billion, with the higher end of the range accounting for both direct and indirect costs [11].

A recent systematic review and meta-analysis of 18 studies found that the annual direct healthcare costs for IBS patients ranged from $1,562 to $7,547 per patient, while the annual indirect costs ranged from $791 to $7,737 per patient [30]. The study also reported that the total annual cost of IBS in the United States was estimated to be $1.01 billion (95% CI, $0.75-1.27 billion) for direct costs and $0.2 billion (95% CI, $0.06-0.33 billion) for indirect costs [30].

Another study in the United Kingdom estimated that the total direct healthcare cost of IBS was £45.6 million (95% CI, £35.5-£55.7 million) per year, with an additional £72.3 million (95% CI, £46.5-£98.1 million) in indirect costs due to lost productivity [31]. The study also found that IBS patients had significantly higher healthcare utilization and costs compared to matched controls without IBS [31].

These findings highlight the substantial economic burden of IBS on both individuals and healthcare systems, emphasizing the need for cost-effective strategies for the prevention, diagnosis, and management of this condition.

IBS Subtypes and Their Prevalence

IBS can be classified into different subtypes based on the predominant bowel habit:

1. IBS with Constipation (IBS-C): Patients experience chronic constipation as the primary symptom, characterized by hard, dry stools and difficulty in bowel movements.
2. IBS with Diarrhea (IBS-D): Patients experience frequent, watery, and loose stools, along with urgency and a feeling of incomplete bowel movements.
3. IBS with Mixed Bowel Habits (IBS-M): Patients experience both constipation and diarrhea, alternating between hard, dry stools and loose, watery stools.
4. Unsubtyped IBS (IBS-U): Patients' bowel habits do not consistently lean towards constipation or diarrhea, and symptoms may be variable.

The prevalence of IBS subtypes varies across different studies and populations:

• IBS-C is estimated to account for 10-15% of all IBS cases [7].
• IBS-D is the most common subtype, accounting for 30-40% of IBS cases [7].
• IBS-M is estimated to account for 25-30% of IBS cases [7].
• IBS-U is relatively less common, accounting for 10-15% of IBS cases [7].

Recent studies have provided additional insights into the prevalence of IBS subtypes:

• A study in Uruguay found that IBS-C was the most frequent subtype at 35%, followed by IBS-D at 32% and IBS-M at 52% [3].
• A study in China reported that IBS-C was the most prevalent subtype at 40.7%, followed by IBS-M at 46.8% and IBS-D at 12.5% [7].
• A study in Colombia found that IBS-constipation was the most common subtype at 41.9%, followed by IBS-diarrhea at 16.7% and IBS-mixed at 58.3% [25].
• A study in Sri Lanka reported that constipation-predominant, diarrhea-predominant, and mixed-type IBS were almost equally distributed (27%-28%), while unsubtyped IBS had a lower prevalence at 17.8% [26].

These findings suggest that the distribution of IBS subtypes may vary across different populations and regions, potentially influenced by factors such as geographical location, cultural differences, and diagnostic criteria used in various studies.

A meta-analysis of 22 studies found that the pooled prevalence of IBS subtypes was 23.4% (95% CI, 19.4-27.8%) for IBS-C, 23.9% (95% CI, 19.5-28.8%) for IBS-D, 24.1% (95% CI, 19.8-29.0%) for IBS-M, and 27.0% (95% CI, 22.1-32.4%) for IBS-U [32]. The study also reported significant heterogeneity across studies, which may be attributed to differences in diagnostic criteria, study populations, and geographical regions [32].

Another study using data from the Rome Foundation Global Epidemiology Study found that the prevalence of IBS subtypes varied across different countries [33]. IBS-M was the most common subtype in the United States (45.1%), Canada (52.1%), and the United Kingdom (47.5%), while IBS-D was more prevalent in Mexico (47.1%), Italy (45.5%), and South Korea (41.1%) [33]. IBS-C was the most common subtype in China (38.7%) and Japan (37.5%) [33].

These findings highlight the variability in the prevalence of IBS subtypes across different populations and the need for further research to better understand the factors contributing to these differences. Identifying the predominant IBS subtype in a given population may have important implications for the development of targeted interventions and management strategies.

Global Distribution of IBS

IBS is a prevalent condition worldwide, with estimates suggesting that it affects between 9% to 23% of the global population [2]. However, the prevalence of IBS varies significantly across different regions and countries.

In North America, studies have reported the prevalence of IBS to be around 10-15% of the population [9]. In Europe, the prevalence ranges from 6% to 12%, with higher rates observed in Western European countries compared to Eastern Europe [1]. The prevalence of IBS in Asian countries is generally lower than in Western countries, ranging from 2.9% to 15.6% [15]. In Latin American countries, the prevalence is estimated to be between 6% to 12% of the population [16]. Limited data is available on the prevalence of IBS in African countries, but existing studies suggest a range of 4.2% to 11.5% [16].

Recent studies have provided additional insights into the global distribution of IBS:

• A study in Bahrain found the prevalence of isolated IBS to be 18.3%, with the majority (66.1%) having the mixed type (IBS-M) [5]. IBS was more common in females compared to males (22.6% vs. 11.9%), and the majority of cases (21%) were in the 41-50 age group. IBS was significantly associated with gastroesophageal reflux disease and indigestion [5].
• A study in Hainan Province, China, found the overall prevalence of functional gastrointestinal disorders (including IBS) to be 32.0%. Older age, poor sleep quality, anxiety, and the consumption of pickled food were identified as independent risk factors for the prevalence of these disorders [23].
• A study in Saudi Arabia found the prevalence of IBS to be 31.08%, with higher rates in females. IBS was associated with chronic diseases and higher anxiety levels [24].

Several factors have been associated with an increased risk of developing IBS, including gastrointestinal infections, stress and psychological factors, diet and nutrition, genetics, chronic pain conditions, and metabolic factors [9-11,21,22].

A meta-analysis of 83 studies from 41 countries found that the pooled global prevalence of IBS was 11.2% (95% CI, 9.8-12.8%), with significant heterogeneity across studies [34]. The prevalence was higher in women (14.0%; 95% CI, 11.9-16.4%) compared to men (8.9%; 95% CI, 7.3-10.8%) and varied by geographic region, with the highest rates in South America (21.0%; 95% CI, 15.9-27.3%) and the lowest in Southeast Asia (7.0%; 95% CI, 5.3-9.3%) [34]. The study also reported that the prevalence of IBS was higher in countries with a higher Human Development Index (HDI) and lower in countries with a lower HDI [34].

Another study using data from the Rome Foundation Global Epidemiology Study found that the prevalence of IBS varied across different countries, ranging from 4.7% in France to 21.0% in Mexico [33]. The study also reported that the prevalence of IBS was higher in women compared to men in all countries, with the female-to-male ratio ranging from 1.2:1 in Italy to 2.6:1 in South Korea [33].

These findings highlight the global burden of IBS and the need for continued research to better understand the factors contributing to the variability in IBS prevalence across different populations. Identifying high-risk populations and developing targeted interventions may help reduce the global burden of IBS and improve the quality of life for affected individuals.

Conclusion

Irritable Bowel Syndrome (IBS) is a prevalent and complex gastrointestinal disorder that affects millions of people worldwide. The prevalence of IBS varies across different countries and populations, with estimates ranging from 7.3% to 11.2% globally.

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