Devanarayana, Niranga M.*; Rajindrajith, Shaman†
Aerophagia is a recognised functional gastrointestinal disorder (FGD) in children. It is characterised by repetitive air swallowing, abdominal distension, belching, and excessive flatulence. It is thought to be common among children with learning difficulties (1,2), Rett syndrome (3), autism (4), and after fundoplication for gastroesophageal reflux (5). Although in the majority, aerophagia seems to be a benign condition, in severe cases it has led to grave complications such as spontaneous pneumoperitonium (6), volvulus of the colon (7), and intestinal perforation (8). So far, little is known about the aetiology, clinical profile, and epidemiology of aerophagia among children and adolescents.
In a previous survey conducted in a semiurban school, using the Rome III criteria, we demonstrated aerophagia in 6.3% of children ages 10 to 16 years (9). This is the only study that has assessed the community prevalence of aerophagia in children. Other studies based in health care institutions have reported varying prevalence. Uc et al (10) noted aerophagia in 2.4% of African American children in a primary care setting. A prospective study using the Rome III criteria has shown aerophagia in 15% of children evaluated for chronic abdominal pain in a secondary care centre (11). Analysing retrospective data from 1975 to 2003 in a tertiary care paediatric unit, Chitkara et al (12) found 44 patients with aerophagia. Furthermore, a case series has described characteristics of aerophagia in 9 children who had aerophagia in addition to constipation (13).
In the present study, we assessed the epidemiology of aerophagia among schoolchildren and adolescents, paying special attention to sex distribution, risk factors, and symptom characteristics.
This was a school-based, cross-sectional study conducted in Sri Lanka. Sri Lanka has 9 administrative provinces. The present study was conducted in 4 randomly selected provinces. Two schools were randomly selected (1 urban and 1 rural) from each province. From each school, 12 classes were randomly selected from academic years (grades) 6 to 11 (2 from each academic year). All of the children ages 10 to 16 years in the selected classes who were present on the day of the survey were included in the study.
Data were collected using a pretested questionnaire. The questionnaire was written in the native language (Sinhala) and questions were simple and easy to comprehend. It consisted of 2 parts. The first part included questions on sociodemographic and family characteristics and exposure to emotional stress. The second part was the Questionnaire on Pediatric Gastrointestinal Symptoms—Rome III version (14), translated into the Sinhala language. This questionnaire has been previously used to diagnose aerophagia in Sri Lankan children (9).
School administration, teachers, and parents were informed about the survey, and consent was obtained before collecting the data. In addition, consent was also obtained from each child who took part in the study. The questionnaire was administered in an examination setting to ensure confidentiality and privacy. Research assistants were present while participants were answering the questionnaire and explanations were given when the need arose. Because the questionnaire was collected on the same day, there were no nonresponders.
Aerophgia was defined using the Rome III criteria (15), which include at least 2 of the following features, once per week, for minimum of 2 months:
1. Air swallowing
2. Abdominal distention resulting from the presence of intraluminal air
3. Repetitive belching and/or increased flatus
Data were analysed using χ2 and the Fisher exact test using EpiInfo (EpiInfo 6, version 6.04, Centers for Disease Control and Prevention, Atlanta, GA, and World Health Organization, Geneva, Switzerland). P < 0.05 was noted as significant. Multiple logistic regression analysis was performed in variables that were found to have significant association with aerophagia. The present study protocol was approved by the ethical review committee of the Sri Lanka College of Paediatricians.
Aerophagia and Sociodemographic Characteristics
Among 2163 responders, 163 (7.5%) fulfilled the Rome III criteria for aerophagia in children. Of them, 97 (59.5%) were boys. Ages ranged from 10 to 16 years (mean 13.7 years, SD 1.8 years). There was no significant difference in the prevalence of aerophagia between girls and boys (P > 0.05, χ2 test). The prevalence of aerophagia was highest (10.5%) in children ages 15 years, but there was no definite correlation with age. Table 1 shows the sociodemographic and family characteristics of children with aerophagia and controls. The remaining 2000 children, without aerophagia, were considered to be controls.
Intestinal-related and Extraintestinal Symptoms
Figure 1 shows the intestinal-related symptoms and extraintestinal symptoms associated with aerophagia. All of the intestinal-related symptoms and extraintestinal symptoms assessed were significantly more prevalent among affected children, compared with controls (P < 0.05, χ2 test).
Effect of Symptoms on Daily Activities
Of 163 children with aerophagia, 18 (11%) had difficulty in sleeping and 31 (19.0%) had missed school because of symptoms. Both entities were significantly common among children with aerophagia than in controls (P < 0.05, χ2 test).
Association With Stressful Life Events
One hundred twenty (73.6%) children with aerophagia were found to be exposed to at least 1 school or family-related stressful life event during the previous 3 months. This is significantly higher compared with 733 (36.7%) in the control group (odds ratio [OR] 1.61, 95% confidence interval [CI] 1.11–2.35, P = 0.01). Individual stressful life events associated with aerophagia are shown in Table 2.
Following multiple logistic regression analysis, stressful events independently associated with aerophagia were loss of parent's job (OR 2.5, 95% CI 1.25–5.0, P = 0.01) and frequent punishment by parents (OR 2.89, 95% CI 1.62–5.0, P < 0.0001).
FGD Overlapping With Aerophagia
Thirty-nine (23.9%) of 163 children with aerophagia fulfilled the criteria for at least 1 other FGD. Irritable bowel syndrome was present in 16 (9.8%), functional abdominal pain in 10 (6.1%), constipation in 5 (3.1%), abdominal migraine in 5 (3.1%), and functional dyspepsia in 3 (1.8%).
To the best of our knowledge, this is the first study to describe epidemiological patterns of aerophagia in children and adolescents in a developing country. In the present study, prevalence of aerophagia was 7.5%. This condition showed no significant sex difference. Intestinal-related symptoms and extraintestinal symptoms were significantly more prevalent among affected children. Furthermore, a higher percentage of affected children were found to be exposed to stressful life events compared with controls.
The prevalence of aerophagia in the present study is slightly higher than that reported in our previous preliminary study (6.3%) in a semiurban school (9). No other community-based study in children with aerophagia has been published to enable comparison with our findings. Several previous hospital-based studies have reported a lower prevalence of aerophagia compared with the present study (9–12). Disturbance in daily activities is one of the main determinants of health care consultation (16). Only fewer than one-fifth of affected children in our study reported disturbances of activities such as missing school or sleeping difficulty because of symptoms. Therefore, the majority of affected children may not believe that the symptoms of aerophagia are significant enough to seek care. The difference in prevalence of aerophagia between this community-based study and previous hospital-based studies may result from the difference in health care consultation. Some community-based studies in adults have demonstrated a higher prevalence of aerophagia than in our study. A household survey conducted in the United States has shown symptoms related to air swallowing in 24% of adults (17).
The highest prevalence of aerophagia was seen in children ages 15 years, but there was no definite correlation with age. Furthermore, there was no significant sex difference in the prevalence of this condition. Sociodemographic and family factors including social class, maternal occupation, family size, birth order, and living area (urban vs rural) had no significant association with aerophagia. There are no published studies that have assessed the possible relation between these factors and areophagia. Therefore, we could not make a comparison.
In addition to the main symptoms included in the Rome III diagnostic criteria for aerophagia, other intestinal-related and extraintestinal symptoms were significantly more prevalent in affected children compared with controls. There are no previous community-based studies with which to compare our results, but a previous case series has shown a higher prevalence of abdominal pain, nausea, and vomiting among children with aerophagia than those with functional dyspepsia (12). The excess air, swallowed by affected individuals, probably accumulates in the stomach, causing abdominal distension and symptoms such as abdominal pain, nausea, and vomiting. The visceral hypersensitivity, which is regarded as one of the main pathophysiological mechanisms for functional gastrointestinal disorders, probably enhances pain perception in affected individuals. Furthermore, physiological studies are needed to identify the exact relation between symptoms and gastrointestinal air dynamics.
Disturbances in daily activities such as attending school and sleep disturbances were significantly associated with aerophagia. Abdominal discomfort caused by bloating could be the main reason for their periodic absence from school and for disturbed sleep. In addition, excessive flatulence may cause social embarrassment and rejection by peers. This factor may also play an important role in school absenteeism. Furthermore, in these children, flatulence also occurs during sleep (18) and may act as a triggering factor for sleep disturbances. It is also important to note that extraintestinal somatic symptoms such as headache, photophobia, lightheadedness, and limb pain were more prevalent in our study of children with aerophagia. These extraintestinal symptoms could also contribute to the disturbances in daily activities. Although the symptoms of aerophagia appear to be subtle and most clinicians tend to ignore them in general practice, we believe that these symptoms should not be overlooked because it could well be a cause for the significant disturbance in their lifestyle. Clinicians caring for children should look actively for diagnostic criteria with a view to making a positive diagnosis and to offer possible therapeutic options.
In the present study, we have shown that both family and school-related stressful life events were associated with aerophagia. The emotional stress generated by these events may lead to an alteration in the dialogue between the central nervous system and the gastrointestinal tract. Previous studies have shown enhanced visceral sensitivity and impaired gastrointestinal motility in individuals who are exposed to emotional stress (19). Abnormal propulsive movements in the stomach and the gastric antrum probably lead to altered physiology of gas handling in the gut. It is possible that emotional stress leads to abnormal gas handling in the stomach because of altered function of the brain-gut axis. This in turn predisposes the gastrointestinal tract to retain more gas in the bowel, which plays an important role in the pathogenesis of aerophagia. In addition, children may swallow air subconsciously during periods of stress, leading to the accumulation of air in the gastrointestinal tract. Hwang et al (20) have described videofluoroscopic abnormalities, such as paroxysmal opening of the upper oesophageal sphincter without the oropharyngeal swallowing motor sequences, in children with psychological stress after air swallowing.
In addition to aerophagia, abdominal bloating, excessive flatus, and burping are commonly seen in children with irritable bowel syndrome (21). In our study, approximately 10% of children with aerophagia also had irritable bowel syndrome. It was the most common FGD overlapping with aerophagia in our cohort of children. Functional abdominal pain, functional dyspepsia, abdominal migraine, and constipation were present in a small percentage. In this questionnaire-based study, we did not investigate children for organic diseases; however, organic diseases causing similar symptoms are uncommon in the paediatric population. In conditions with similar symptoms such as intestinal obstruction, children are too ill to come to school and unlikely to have been included in our sample. Even though celiac disease is common in Western children and is a differential diagnosis for bloating, it is extremely rare in Sri Lankan children. To date, only 1 case has been reported in this country (22). The rice-based staple diet in Sri Lanka (instead of the wheat-based diet of Western countries) and genetic differences may have contributed to this low prevalence. Lactose intolerance is considered a differential diagnosis for aerophagia. The majority of Sri Lankan children in this age group (59%) are deficient in lactase enzyme, compared with 5% in British children of the same age (23); however, in clinical practice, lactose intolerance rarely causes symptoms in Sri Lankans. In an adult study, even though the community prevalence of lactose intolerance was 66.2% to 78.8%, 65.5% of them did not have any symptoms related to milk ingestion (24). Furthermore, compared with Western countries, milk consumption is extremely low in Sri Lanka, especially in older children and adults. Therefore, symptoms seen in our patients are unlikely to be related to this condition.
In conclusion, aerophagia is a common problem in schoolchildren and adolescents. The prevalence was higher in older children and there was no sex difference noted. Comorbid intestinal-related and extraintestinal symptoms were more prevalent among affected children, and a higher percentage of affected children were found to be exposed to stressful life events when compared with controls.
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