The prevalence and risk factors of irritable bowel syndrome (PRIBS study) among adults in low- and middle-income countries: A multicenter cross-sectional study.

Ahmad Y. Arnaout : Conceptualization; data curation; formal analysis; investigation; methodology; project administration; supervision; validation; writing—original draft; writing—review & editing. Yaman Nerabani : Conceptualization; methodology; validation; writing—original draft; writing—review & editing. Zain Douba : Supervision. Luma Haj Kassem : Formal analysis; validation; writing—review & editing. khaled arnaout: data curation; formal analysis; validation. Muhammad B. Shabouk : Writing—original draft; Writing—review & editing. Hussein Zayat : Data curation; formal analysis. Wafik Mayo : Writing—original draft; writing—review & editing. Yamen Bezo : Writing—original draft; writing—review & editing. Ibrahim Arnaout : Data curation; writing—original draft. Ahmad Yousef : Supervision. Mohamed B. Zeina : Formal analysis; validation. Ziad Aljarad : Supervision; validation.

The international cross‐sectional study was conducted in 15 low‐ and middle‐income countries according to our previously published protocol NCT05340400 and the Strengthening the Reporting of Observational Studies in Epidemiology guidelines for cross‐sectional studies. 4 Participants were recruited in the period from April 22, 2022 to June 14, 2022. The inclusion criteria were adults willing to participate in this survey who were 18 years of age or older. Exclusion criteria were: any participant who was diagnosed with poorly controlled hyperthyroidism, poorly controlled hypothyroidism, poorly controlled hyperparathyroidism, paralysis, or parasitic diseases. Moreover, any presence (or suspicion) of liver disease, celiac disease, inflammatory bowel disease (Crohn's disease or Ulcerative colitis), lactose intolerance, or cancer or tumor in the digestive tract in their clinical history. No formal sample size was calculated for this study. The total number of participants in the study was 5506, from 15 low‐ and middle‐income countries. The number of participants from Syria was 2909, followed by Egypt (536), Sudan (536), Pakistan (380), Libya (222), Algeria (222), Jordan (176), Iraq (125), India (102), Yemen (72), Palestine (69), and the rest from Morocco, Serbia, Bangladesh, and Saudi Arabia. With the participation of 148 data collectors from different cities and institutions in the participating countries. The participants volunteered to participate by agreeing to the investigation and filling out their data. The data were collected using a validated, structured questionnaire. The first part collected sociodemographic characteristics such as age, gender, body mass index (BMI), educational level, work, and marital state. Participants were also categorized into five grades based on their health status using the American Society of Anesthesiologists physical status (ASA) classification. 5 Participants were also asked about their comorbidities. The diagnosis of IBS was made by identifying the presence of abdominal pain at least once a week in the last 3 months, in addition to at least two of the following: abdominal pain related to defecation, change in stool frequency, or shape. In addition to classifying patients according to their symptoms into IBS with constipation (IBS‐C), IBS with diarrhea (IBS‐D), or IBS with both (IBS‐M). 3 We determined the physical activity of the participants according to the Global Physical Activity Score of the World Health Organization (WHO). This score consists of three parts: the amount of effort spent at work (vigorous or moderate‐intensity activity), traveling from one place to another, and sports intensity (vigorous or moderate‐intensity activity) on a typical day. And then classified the participants according to whether physical activity is required or not. 6 Daily stress was evaluated with the Perceived Stress Scale (PSS), the most widely used measure of global perceived stress and a robust predictor of health and disease. The total score is calculated on the basis of the answers to a series of questions based on monthly stress and the participant's health status. PSS is a summary measure of 10 items (range 0–4 points for every item). It is classified into low (PSS 0–13), moderate (PSS 14–26), and high perceived stress (PSS 27–40). 7 Fatigue was measured using the Chalder Fatigue Scale (CFQ), a questionnaire for measuring the extent and severity of fatigue within both clinical and nonclinical epidemiological studies. 8 Diet and daily habits, including smoking and alcohol consumption, were evaluated. Participants were classified into four sections according to WHO's Smoking and Tobacco Use Policy. A daytime smoker is someone who smokes any tobacco product at least once a day, and an occasional smoker is someone who smokes but not every day. 9 Each question was explained to the participant separately by the collaborator. A large number of collaborators were chosen from different regions and institutions within each country to achieve diversity within the sample and reduce the probability of bias. We trained the collaborators with a course explaining each section of the questionnaire and how to present it to the participants. The tutorial videos were uploaded in Arabic and English on YouTube. We also translated the questionnaire into Arabic by two Arab doctors separately and simultaneously, and the translation underwent a peer‐review process. Data were analyzed using SPSS PC version 24.0 statistical software. Descriptive statistics (mean, standard deviation, frequencies, and percentages) were used to describe the quantitative and categorical variables. Moreover, the Chi‐square test was used for each variable only if the sample number exceeded 100 to observe the association between the categorical study and outcome variables. The quantitative variables such as age, body mass index, and drinking water in litters were divided into categories, and then we equated the chi‐square. We calculated the prevalence for each country if the country's participants exceeded 200. All the results of the statistical inference tests were interpreted to a 95% confidence level, that is, the significance level of 0.05 was used with two‐tailed hypothesis. The normal distribution suitability of the numerical variables was tested with the Shapiro–Wilk test. This study was performed in accordance with the ethical standards as laid down in the 1964 Declaration of Helsinki and its later amendments, and under ethical approval from the ethics committee at the Faculty of Medicine, University of Aleppo, Syria. Moreover, Ethical approval was obtained in each country independently by the national lead, and participants' information was kept anonymous and confidential. Informed consent was obtained from all patients before participating, and all forms were filled out after a personal interview with the participant to explain all the questions.

Most of the participants were of Caucasian ethnicity (85.3%), and the others were Asian (9.1%), Afro‐Caribbean (4.8%), and other ethnicities (0.8%). The mean age of the participants was 32.7, with a standard deviation of 14.5. 2% of participants were female (41.8% male). No missing data was found. The average prevalence of IBS was 25.2% (6.2%–44.2%), with a higher rate among the Afro‐Caribbean race at 31.5%. Most of the participants were of IBS‐M type (40.5%) and IBS‐C type (36.1%). The highest prevalence of IBS was in Sudan (29.2%) and Egypt (28.9%), and the lowest prevalence was in Algeria (18.5%). The prevalence of IBS and its sub‐types for each country and ethnicity are found in Table  1 . Prevalence of IBS according to the population based of the participants. Abbreviations: CI, confidence interval; IBS, irritable bowel syndrome; IBS‐C, irritable bowel syndrome‐constipation Type; IBS‐D, irritable bowel syndrome‐diarrhea type; IBS‐M, irritable bowel syndrome‐mixed type. For all study participants, even from countries with less than 200 participants. The prevalence of the IBS increased with age, especially the peak prevalence between 31 and 50 years (fourth decade 32.1% and fifth decade 31.1% p ‐value < 0.001). There was a tendency for the disease to be statistically greater among females than males (28.0% vs. 22.1%, p ‐value < 0.001). The prevalence of the disease was statistically lower in those with a body mass index within normal and increased if they were underweight, overweight, or obese (22.9 vs. 25.2%, 27.1%, and 33.8% consecutively, p ‐value < 0.001). IBS among healthy participants was lower than in participants with mild and severe systemic diseases (23.4% vs. 31.4% and 26.7% consecutively, p ‐value < 0.001). Rural participants were more likely to be patients than urban participants (29.6% vs. 24.8%, p ‐value < 0.001) (Table  2 ). Correlation of IBS according to the sociodemographic of the participants . Note : ASA I, healthy person; ASA II, mild systemic disease; ASA III, severe systemic disease; ASA IV, severe systemic disease that is a constant threat to life; ASA IV, a moribund person who is not expected to survive without the operation; ASA V, a declared brain‐dead person whose organs are being removed for donor purposes. Abbreviations: ASA, American Society of Anesthesiologists Classification; IBS, irritable bowel syndrome. 65.5% of the participants with IBS have reported that one of their first‐degree relatives has been diagnosed with IBS. The prevalence of IBS among patients with hypertension, diabetes, anemia, and allergies to certain substances is significantly higher (33.4%, 33.9%, 31.5%, and 28.8%, p ‐values < 0.05) than among non‐patients. There is an association between IBS and some other chronic digestive diseases such as EPS, PPDS, GERD, and functional dyspepsia ( p ‐value < 0.05). The prevalence of IBS among patients infected with COVID‐19 within a year is more significant than among others (27.4% vs. 24.1%, p ‐value < 0.001). There is a significant increase in prevalence in participants with severe fatigue (39.7%) compared with moderate (27.3%) and low (16.3%) fatigue ( p ‐value < 0.001). Also, there is a significant increase in prevalence in the participants with high stress (31.8%) compared with moderate (26.0%) and low (10.0%) fatigue ( p ‐value < 0.001) (Table  3 ). Correlation of IBS according to comorbidities . Abbreviations: COPD, chronic obstructive pulmonary disease; EPS, epigastric pain syndrome; GERD, gastro‐esophagus retardation disease; IBS, irritable bowel syndrome; PPDS, postprandial distress syndrome. There is a statistically significant increase in the prevalence of IBS in people who work, especially in the fields of agricultural projects and natural resources, civil engineering, informatics, technology or computer engineering, commercial companies and offices, home economics, industry, and teaching ( p ‐value < 0.05). But the prevalence of IBS among medical workers such as physicians and nurses is statistically less than others (23.6% and 22.7% vs. 25.8% and 25.6%, p ‐value < 0.001)  (Table  4 ). Correlation of IBS according to the field of work or profession of the participants . Abbreviation: IBS, irritable bowel syndrome. Participants who need to do physical activity are statistically more likely to be patients than those whose physical activity is acceptable (25.7% vs. 24.9%, p ‐value < 0.001). Also, those whose diet consists mainly of fats and proteins are statistically more likely to be patients than those who depend on high‐fiber foods and a diverse diet ( p ‐value < 0.001). There is also a statistical prevalence of those who eat intermittent meals between the main meals ( p ‐value < 0.001). IBS is statistically more prevalent among smokers than non‐smokers, even if they quit smoking or only smoke on occasion ( p ‐value < 0.001). There is a statistically lower prevalence of the disease in moderate drinkers, but there is not enough sample size in those heavy drinkers due to the religious nature of the participating countries, so we were unable to know the effect of heavy alcohol drinking on IBS. Participants who sleep 6–8 h were statistically less likely to be patients than those who slept more than 8 h or less than 6 h (24.9% vs. 27.5% and 25.8% consecutively, p ‐value < 0.001). The prevalence of the disease among those who drink stimulants like tea or coffee and its derivatives is statistically higher than its prevalence among those who drink other types of stimulants or who do not drink them ( p ‐value < 0.001). There appears to be an inverse correlation between the prevalence of disease and the amount of water drunk, but it is not statistically significant (Table  5 ). Correlation of IBS according to habits . Abbreviation: IBS, irritable bowel syndrome.

Our study included 5506 participants from 15 low‐ and middle‐income countries. The mean prevalence of IBS in our sample was 25.2%, with Sudan and Egypt having the highest percentages. The prevalence of IBS was higher among Africans than Caucasians, and it seems that environmental and genetic factors play a role in this, which should be investigated more in other studies. IBS prevalence in Pakistan was 21.6%, which is considered a dramatic increase from the 13.3% reported in the same country in 2006. 10 Furthermore, Egyptian IBS prevalence was 28.9%; a similar percentage (27.5%) was found by a cross‐sectional study done on Egyptian medical students in the year 2022. 11 Nonetheless, the Pakistani study used Rome II for diagnosis, and the Egyptian study included only 182 participants and used Rome III instead of Rome IV criteria. The pathophysiology of IBS is functional impairment of the GI tract in the absence of any obvious biological abnormalities. 12 This functional impairment is centered around three main principles: altered GI motility, GI hyperalgesia, and psychopathology. 13 The latter may justify the increased prevalence in stressed individuals, as well as in people who sleep less than 6 h. Several factors are associated with a higher probability of IBS. Some of these factors are non‐modifiable, such as the fourth and fifth decades of age and a positive family history of IBS. Some studies have found an association between some variations in the sucrase‐isomerase gene and increased risk of IBS, 14 , 15 a finding that might explain the increased prevalence in participants who have a positive family history of IBS in a first‐degree relative. The female gender was also a risk factor for IBS. This can be justified by the role of estrogen in regulating two of the three main principles of IBS, which are GI motility and visceral pain. 16 Non‐modifiable risk factors also include a personal history of allergies, a personal history of chronic diseases (especially hypertension and diabetes), and a history of COVID‐19 infection within the previous year. The predominant clinical features of the post‐COVID gastro‐intestinal syndrome include abdominal discomfort, diarrhea, constipation, and vomiting. A review has interpreted these long‐term digestive symptoms that are consistent with IBS as being caused by the infection itself or by various drugs used in the context of acute COVID, especially lopinavir and ritonavir. 17 Modifiable risk factors include an abnormal BMI (whether high or low), smoking, a protein‐ or fat‐rich diet, and drinking caffeine beverages. In our study, we found that acceptable physical activity is associated with a lower incidence of IBS. In the same context, a randomized controlled trial that included 102 IBS patients found that moderate to vigorous activity 3–5 days a week in these patients resulted in clinical improvement of the IBS symptoms. 18 A recent study described the association between heavy smoking (20 or more cigarettes per day) and the occurrence of IBS‐D. This can be explained by the direct effects of nicotine on colonic motor function, mediated by nicotine receptors on intrinsic and extrinsic colonic nerves. 19 , 20 Regarding diet, a Western diet high in fat has been associated with IBS in a large French cohort. 21 Several mechanistic hypotheses have been put forward to explain this association, including an enhanced colonic response to lipids. 22 Previous studies have also shown that the use of soluble fibers (e.g., oats and fruits) results in symptom improvement. 23 However, insoluble fibers (e.g., wheat bran) were not of significant and even caused abdominal bloating. 24 Living in a rural area and working in certain jobs are also modifiable risk factors for IBS. In our study, health workers were less likely to be patients than other professions. This could be due to doctors' and nurses' knowledge of the etiology and preventive ways of this disease; however, more studies are needed on this aspect. Here are some highlights of the clinical implications and potential strategies based on the findings from this cross‐sectional study on IBS prevalence and risk factors: Clinical implications: The high IBS prevalence (25.2%) demonstrates this is a major chronic digestive disease burden in developing countries that needs focused attention. Positive associations with modifiable factors like diet, smoking, activity levels, and so forth underscore the potential for lifestyle management. Protective effect seen in healthcare workers reinforces the value of patient education and awareness. The high IBS prevalence (25.2%) demonstrates this is a major chronic digestive disease burden in developing countries that needs focused attention. Positive associations with modifiable factors like diet, smoking, activity levels, and so forth underscore the potential for lifestyle management. Protective effect seen in healthcare workers reinforces the value of patient education and awareness. Potential strategies: Increaseing IBS awareness and screening practices in primary care in developing countries to improve early diagnosis. Lifestyle counseling by dieticians, social workers, and community health workers on diet, activity, and sleep hygiene. Smoking cessation programs and resources for patients with IBS where relevant. Self‐management workshops on stress reduction techniques like yoga, meditation, and cognitive behavioral therapies for IBS patients. Culturally appropriate educational campaigns on IBS using diverse platforms to reach rural areas. Policy efforts to promote physical activity through built environment changes in developing country urban areas. Increaseing IBS awareness and screening practices in primary care in developing countries to improve early diagnosis. Lifestyle counseling by dieticians, social workers, and community health workers on diet, activity, and sleep hygiene. Smoking cessation programs and resources for patients with IBS where relevant. Self‐management workshops on stress reduction techniques like yoga, meditation, and cognitive behavioral therapies for IBS patients. Culturally appropriate educational campaigns on IBS using diverse platforms to reach rural areas. Policy efforts to promote physical activity through built environment changes in developing country urban areas. In summary, the high disease burden calls for greater health system prioritization and lifestyle‐based management with tailored sociocultural approaches to curb preventable risk factors. Age —IBS prevalence increased with age. Age may confound associations between other factors and IBS. Gender —Females had a higher IBS prevalence. Gender differences could confound other observed relationships. Comorbidities —Chronic diseases like diabetes and hypertension were associated with higher IBS prevalence. These may confound other variables. Medications —Drugs used for comorbid conditions could influence IBS risk, confounding associations. Diet —Dietary patterns like high fat/protein diet were associated with IBS. Diet may be a confounder. Physical activity —Lack of adequate activity was linked to higher IBS prevalence. This could confound other observations, especially in the outcomes of certain jobs. Age —IBS prevalence increased with age. Age may confound associations between other factors and IBS. Gender —Females had a higher IBS prevalence. Gender differences could confound other observed relationships. Comorbidities —Chronic diseases like diabetes and hypertension were associated with higher IBS prevalence. These may confound other variables. Medications —Drugs used for comorbid conditions could influence IBS risk, confounding associations. Diet —Dietary patterns like high fat/protein diet were associated with IBS. Diet may be a confounder. Physical activity —Lack of adequate activity was linked to higher IBS prevalence. This could confound other observations, especially in the outcomes of certain jobs. Our study's importance comes from the fact that most of the included countries have not had sufficient data regarding IBS prevalence before. Nonetheless, there were some limitations. In terms of the population, despite the variety of nationalities included in the study, more than half of the participants were from Syria. We tried to overcome this by including participants from different geographical areas and different socioeconomic backgrounds. Also, most of the population was Caucasian; other ethnicities were represented by much fewer ratios. This is because Caucasians are the predominant ethnicity in the included countries. Furthermore, most of the included countries had a Muslim majority, so we could not clearly study the association between alcohol consumption and IBS. Finally, our study is cross‐sectional; we were able to study the association between several factors and IBS. However, a cohort study is still needed to further ascertain this association and examine its magnitude. This cross‐sectional study may reflect the prevalence and risk factors of IBS in low‐ and middle‐income countries. Individuals living in high‐income countries were not included in this study.

The prevalence of IBS appears to be higher in low‐ and middle‐income countries (mean = 25.2%, range [6.2%–44.2%]) than in high‐income countries, with a higher prevalence among Africans than Caucasians and Asians. In addition to the previously known risk factors for IBS, such as female sex, smoking, psychological stress, and chronic fatigue. Other risk factors were discovered, such as chronic diseases, including high blood pressure and diabetes, allergies to some substances, previous infection with COVID‐19, and first‐degree patients with IBS. There are also some other modifiable risk factors, such as an abnormal BMI (whether high or low), smoking, a protein‐ or fat‐rich diet, drinking caffeine‐containing beverages, and poor physical activity.

The spread of chronic digestive diseases in the world has led to a poor quality of life, especially in low and middle‐income countries. In those countries, many suffer from chronic digestive diseases, in particular irritable bowel syndrome (IBS). IBS is a chronic functional disorder of the gastrointestinal tract that is widespread and common all over the world. 1 In general, patients present to clinicians with different symptoms, but there are four that dominate overall: abdominal discomfort, pain, diarrhea, constipation, and bloating. However, patients may present with other symptoms such as postprandial upper abdominal discomfort, fullness, nausea, heartburn, and, less commonly, vomiting. Based on the idea of symptom diversity, IBS was classified into several subtypes according to the predominant stool pattern. 1 IBS prevalence ranges between 9% and 23% of the population across the world. 2 Since the 1980s, methods for diagnosing IBS have varied; since 2016, ROME IV criteria have been shown to be the standard methods for diagnosing IBS, in addition to excluding other digestive disorders. 3 Because of the plenty and abundance of risk factors and the expected increase in the prevalence of IBS in the world in general and in low and middle‐income countries in particular, our study was established with the aim of assessing and detecting latent potential and apparent risk factors, especially since risk factors and diagnostic criteria are constantly changing and evolving, in addition to updating the prevalence data in different societies and determining whether race has an effect.

The lead author Yaman Nerabani affirms that this manuscript is an honest, accurate, and transparent account of the study being reported; that no important aspects of the study have been omitted; and that any discrepancies from the study as planned (and, if relevant, registered) have been explained.

The authors declare no conflict of interest.