Irritable bowel syndrome (IBS) among Lebanese adults: unidentified IBS and associated factors

A cross-sectional study was conducted in Lebanon between June and December 2022 by using the snowball sampling technique. The digital questionnaire was built using Google Forms and distributed online via social media platforms. The research team approached people they know, who were asked to forward the link to other friends, coworkers and family members they know. We included all Lebanese adults aged more than 18 years old and excluded participants with a previous physician-diagnosed of IBS and those who refused to participate by filling out the questionnaire.

Minimal Sample Size calculation was done using the G-Power software with a R² deviation from zero of 0.05, a type I error of 5%, a power of 80% and 15 predictors to be entered in the final model. The required minimal sample of participants was 371.

A validated, confidential, anonymous and self-reporting questionnaire in Arabic was used; it included validated scales and scoring systems and other questions covering sociodemographic details (age, sex, weight, height, marital status, education (dichotomized in secondary education or less and university education) cigarette smoking, water pipe smoking, alcohol consumption, and physical activity) as well as other questions about the house crowding index [35], and previous diagnosis of IBS by a physician. The following scales were used in our questionnaire:

The SPSS v.25 software was used for the statistical analysis. The Chi-square test was used to compare two categorical variables, whereas the Student t test was used to compare two means. A logistic regression, using the ENTER method and taking the presence vs absence of IBS according to the ROME IV criteria as the dependent variable, was conducted. All variables that showed a p < 0.25 in the bivariate analysis were taken as independent variables in the model. The interaction eating attitudes/insomnia severity by cigarette smoking was tested; a stratification analysis according to the smoking status was deemed necessary if the interaction(s) was significant. P < 0.05 was deemed statistically significant.

The results of the bivariate analysis are shown in Table 2. A higher percentage of females had possible IBS according to the ROME IV criteria compared to males. Moreover, higher mean eating attitudes, psychological distress and insomnia severity scores, as well as lower mean BMI, and physical activity were significantly found in participants who had possible IBS.

The result of a logistic regression taking the presence vs absence of IBS according to the ROME IV criteria as the dependent variable, showed that higher psychological distress (aOR = 1.07) and insomnia severity (aOR = 1.08) were significantly associated with higher odds of having possible IBS. Moreover, a higher household crowding index (aOR = 0.67) was significantly associated with lower odds of having possible IBS (Table 3).

The interaction eating attitudes by cigarette smoking (aOR = 1.33; p = 0.025; 95% CI 1.04; 1.70) and insomnia severity by cigarette smoking (aOR = 0.89; p = 0.023; 95% CI 0.80; 0.98) were significantly associated with the presence of possible IBS according to the ROME IV criteria. Consequently, a stratification analysis was according based on the smoking status. In nonsmokers, higher psychological distress (aOR = 1.07) and insomnia severity (aOR = 1.10) were significantly associated with higher odds of having possible IBS. In smokers, higher BMI (aOR = 0.78) was significantly associated with lower odds of having possible IBS, whereas higher eating attitudes scores (more inappropriate eating) (aOR = 1.40) were significantly associated with higher odds of having possible IBS (Table 4).

In this study, the rate of possible unidentified IBS was 46.8% using the Rome IV criteria. Previous studies conducted in Lebanon among bank employees and university students based on the Rome III criteria showed a significantly lower prevalence of IBS [5, 6]. Higher rates of possible unidentification of IBS were also reported in our study in comparison with other studies conducted in other countries. A population-based study conducted in the United States, Canada and the United Kingdom based on a self-assessment questionnaire using the Rome IV Diagnostic Questionnaire and Rome III irritable bowel syndrome (IBS), showed a prevalence of IBS ranging from 4.4% to 4.8% [57]. Another study conducted in Poland, among participants of the 2018 Woodstock Rock Festival using questionnaires based on the Rome IV criteria showed a rate of 11% of IBS [58]. A cross-sectional study conducted in Riadh in 3 out-patients clinics using self-assessment questionnaires distributed via social media and based on the Rome IV criteria showed a prevalence of 7.9% of IBS [59]. IBS prevalence was reported to be 7.4% according to a nationwide study conducted in the USA by using an online survey based on the Rome IV criteria during the peak of the coronavirus first wave [60]. The increasing prevalence of IBS among Lebanese adults may be due to psychiatric disorders like anxiety, depression and sleep disturbances. Lebanon has been going through a hard period due to socioeconomic and food insecurities as well as the political problems,but the majority of our participants have a university degree and live in a household with less than two persons per room which indicated that socioeconomic and food insecurities may not be associated with high rates of IBS in our study.

Psychiatric disorders and IBS diagnosis:

Our study reported that higher psychological distress was significantly associated with higher odds of having possible IBS. Previous published studies have shown a strong correlation between IBS and psychiatric disorders like depression and anxiety [37‐40]. It has been proven that psychiatric disorders can alter the gut’s motor functioning, sensory threshold and stress susceptibility; the other way around is also true where IBS can impact negative emotions like anxiety and depression [61]. A meta-analysis including case–control and prospective cohort studies concluded that anxiety and depression can double the risk of having IBS in the future [62]. A study conducted in the USA concluded that IBS can alter people’s everyday life, suffer from focusing, encounter difficulties in making arrangements, avoid sex, and leave the house [63].

Furthermore, higher insomnia severity was significantly associated with higher odds of having possible IBS, corroborating the findings of prior studies [26, 43, 44]. A study conducted in order to evaluate the relationship between sleep disruption and gastrointestinal symptoms in women with and without irritable bowel syndrome found data that supported the notion that poor sleep leads to worse gastrointestinal symptoms the next day in women with IBS [64]. A study reported the association between IBS symptoms like abdominal pain and difficulty falling asleep [65]. According to Ali et al. sleep disturbances can be caused by abnormal gastrointestinal immune mechanisms found in gastrointestinal diseases such as IBS [66].

Moreover, a significant moderating effect of smoking on IBS was found in our study. It was shown that in nonsmokers, higher psychological distress and insomnia severity were significantly associated with higher odds of having possible IBS. Many published studies supported our findings with a significant association between IBS and psychological distress and insomnia [26, 37‐40, 43, 44]. We speculate a relationship between the gut and the hypothalamic pituitary axis: the corticotropin-releasing hormone, a well-known modulator of stress has been linked with IBS by increasing intestinal permeability [67]. In addition, serotonin, which helps regulate emotions and behaviors such as depression and anxiety, has been implicated in the gut-brain function in functional gastrointestinal disorders such as IBS [67]. Moreover, studies have shown the relationship between the gut microbiota and circadian disturbances leading to insomnia [68].

In smokers, higher eating attitudes scores (more inappropriate eating) were significantly associated with higher odds of having possible IBS. Many studies showed significant association between IBS and eating disorders [45‐47]. A study showed that eating disorders were present before the onset of IBS for the vast majority of the participants suggesting that eating disorders are a risk factor for IBS [47]. Another study conducted among adolescents and young individuals reported that IBS participants are more prone to develop eating-associated symptoms that tend to be avoided by restricting the incriminating food [69]. Some types of food were reported to trigger symptoms related to IBS more frequently in participants suffering from IBS than in controls [29], this could be a major factor in the development of eating disorders among IBS patients. We hypothetize that smoking can exacerbate inappropropriate eating attitudes that can lead to higher rates of IBS. In addition, the constituents of cigarettes may exacerbate IBS symptoms by promoting mucosal cell death, limiting the cellular regeneration, reducing blood irrigation of the mucosal epithelium in the gastrointestinal tract and impeding with the mucosal immune response [70], leading to higher rates of inappropriate eating disorders. Moreover, smoking has been shown to be highly associated with eating disorders according to a meta-analysis [71]. A possible explanation can be related to the fact that smoking can control appetite and lead to weight control, women who smoke primarily to lose weight were found to have significantly higher levels of eating disorders than nonsmokers [72].

The great majority of literature reported an association between IBS and obesity. A prospective cohort study conducted in Norway showed that weight loss can alleviate IBS symptoms [73]. In addition, inflammatory processes have been linked to IBS, these processes can alter the gastrointestinal reflexes [74] and higher levels of inflammatory biomarkers were detected in obese patients with IBS in comparison with controls [75]. However, smokers with higher BMI in our study were significantly associated with lower odds of having possible IBS; this finding can be related to the hypothesized role of cigarette smoking in preventing the development of IBS by reducing the gut mucosal inflammation [76] and slowing the gastrointestinal tract motility [77].

The results of our study may serve as a first step toward implementing better awareness among the Lebanese population about IBS and the Lebanese physicians through helding conferences in schools and universities and distributing brochures in health clinics to increase the rate of diagnosis of IBS; treatment plans, methods of symptom management and appropriate diet program should be developed and spread among health care workers. We should also underline the importance of considering the presence of psychological distress, eating and sleeping disorders among patients diagnosed with IBS.

Some limitations should be taken into consideration while assessing the findings. Although this was a population-based cross-sectional study, the majority of responders were females in their twenties, which might have contributed to the high IBS rate; therefore, the rate of unidentified IBS cannot be generalized to the general population. Moreover, the study was conducted by using self-administered questionnaires only, without adopting neither colonoscopy tests to rule out the presence of intestine damage, or fecal occult blood test to eliminate the presence of blood in stools, or blood tests to eliminate a potential anemia nor a physician assessment of other signs and symptoms, therefore underestimation and exaggeration may occur. A selection bias cannot be eliminated since participants selection was based on the snowball technique, which relied on friends belonging to a certain age group may have affected the age and the socioeconomic class selected. A residual confounding bias might be present since not all factors associated with IBS were included in this study, such as family history of IBS, sexual, emotional or physical abuse and food intolerance.