AIM: To survey irritable bowel syndrome (IBS) using Rome III criteria among Malays from the north-eastern region of Peninsular Malaysia.

METHODS: A previously validated Malay language Rome III IBS diagnostic questionnaire was used in the current study. A prospective sample of 232 Malay subjects (80% power) was initially screened. Using a stratified random sampling strategy, a total of 221 Malay subjects (112 subjects in a “full time job” and 109 subjects in “no full time job”) were recruited. Subjects were visitors (friends and relatives) within the hospital compound and were representative of the local community. Red flags and psychosocial alarm symptoms were also assessed in the current study using previously translated and validated questionnaires. Subjects with IBS were sub-typed into constipation-predominant, diarrhea-predominant, mixed type and un-subtyped. Univariable and multivariable analyses were used to test for association between socioeconomic factors and presence of red flags and psychosocial alarm features among the Malays with IBS.

RESULTS: IBS was present in 10.9% (24/221), red flags in 22.2% (49/221) and psychosocial alarm features in 9.0% (20/221). Red flags were more commonly reported in subjects with IBS (83.3%) than psychosocial alarm features (20.8%, P < 0.001). Subjects with IBS were older (mean age 41.4 years vs 36.9 years, P = 0.08), but no difference in gender was noted (P = 0.4). Using univariable analysis, IBS was significantly associated with a tertiary education, high individual income above RM1000, married status, ex-smoker and the presence of red flags (all P < 0.05). In multiple logistic regression analysis, only the presence of red flags was significantly associated with IBS (odds ratio: 0.02, 95%CI: 0.004-0.1, P < 0.001). The commonest IBS sub-type was mixed type (58.3%), followed by constipation-predominant (20.8%), diarrhea-predominant (16.7%) and un-subtyped (4.2%). Four of 13 Malay females (30.8%) with IBS also had menstrual pain. Most subjects with IBS had at least one red flag (70.8%), 12.5% had two red flags and 16.7% with no red flags. The commonest red flag was a bowel habit change in subjects > 50 years old and this was reported by 16.7% of subjects with IBS.

CONCLUSION: Using the Rome III criteria, IBS was common among ethnic Malays from the north-eastern region of Peninsular Malaysia.

In the West, irritable bowel syndrome (IBS) is a major gastroenterological condition seen in daily clinical practice, with a prevalence of 10%-20%[1-5]. The prevalence of IBS in the East is reportedly lower. Previous studies from Thailand and Singapore reported a prevalence of less than 5%[6,7]. Recent studies from Hong Kong, Beijing and India also reported a similar low prevalence, although the rate may differ depending on the criteria used[8-11].

One of the earlier studies from Malaysia reported a prevalence of 15.8% among a group of young multi-ethnic medical students using Rome I criteria in central Peninsular Malaysia[12]. A later study by Rajendra et al[13] reported a rate of 15.5% using Rome II criteria in a mixed urban and rural multi-ethnic population in the north-western region of Peninsular Malaysia. The prevalence rates of IBS reported among the ethnic Malays (12.4%-15.8%) from both studies were higher than that reported by a recent study from Singapore (6.8%-10.3%)[14].

The north-eastern region of Peninsular Malaysia is more economically deprived and less developed compared with western and central parts of Peninsular Malaysia, and most of its population consists of ethnic Malays. We aimed to assess the prevalence of IBS among the Malay population in this region recruited within a hospital setting using a validated Malay language Rome III IBS Diagnostic Questionnaire. In addition, we also aimed to assess and compare the rates of red flags (alarm symptoms which may suggest the presence of organic diseases), psychosocial alarm features and other socioeconomic markers in IBS vs non-IBS in this population.

Among the 221 surveyed Malay subjects, 10.9% (24/221) had features of IBS according to the Rome III criteria. The mean age of recruited subjects was 37.7 years (15.7 years) and although subjects with IBS were slightly older (mean age 41.4 years) this was not statistically significant (P = 0.08). There was no difference in the prevalence rate of IBS between genders among Malay subjects (P = 0.4) (Table 1). Red flag symptoms were present in 83.3% (20/24) of subjects with IBS and 22.2% (49/221) of the total subjects recruited (P < 0.001) (Table 1). Psychosocial alarm features were present in 20.8 (5/24) of subjects with IBS and 9.0% (20/221) of the total subjects recruited (P = 0.4) (Table 1).

With univariable analysis, tertiary education, high individual income (> RM1000), married status, ex-smoker and presence of red flag symptoms were significantly associated with IBS among Malays (Table 1). With multiple logistic regression analysis, only the presence of red flags remained significantly associated with IBS (OR: 0.02, 95%CI: 0.004-0.1, P < 0.001).

The commonest IBS sub-type was of mixed type, IBS-M (58.3%), followed by IBS-C (20.8%), IBS-D (16.7%), and IBS-U (4.2%). Four of 13 (30.8%) female subjects with IBS also complained of menstrual pain. Most subjects with IBS had at least one red flag (70.8%), 12.5% had 2 red flags and 16.7% had no red flags. A bowel habit change for those above 50 years old was reported in 16.7% of subjects with IBS.

In the current study, the reported IBS rate of 10.9% among ethnic Malays was very similar to the study from Singapore (prevalence of 10.3% using Rome I criteria)[14] (Table 2). The reported IBS rate among ethnic Malays in the current study was relatively low compared with that in the study by Rajendra et al[13] (rate of 12.4% using Rome II criteria) and Tan et al[12] (rate of 15.8% using Rome I criteria) (Table 2).

These differences in prevalence rates between studies may be explained by differences in population demographic and socioeconomic backgrounds between different regions of Peninsular Malaysia. In the study by Tan et al[12], the studied population consisted of highly educated and healthy young Malaysians (mean age 22 ± 1.8 years) in the Klang Valley, a well-developed economic region in the central belt of the Peninsula. It is known that IBS is more common in a younger and more educated population[9,18]. In the study by Rajendra et al[13], the population from the north-western region of Peninsular Malaysia was a mix of urban and rural communities, was older (mean age 33.6 ± 13 years) and was recruited based on race-stratified disproportionate random sampling to ensure sufficient representation of all ethnic minorities. The economy in this region of Malaysia is less developed than the Klang Valley but is more developed than the north-eastern region of Peninsular Malaysia. The older population and the mixture of a rural community might explain the lower prevalence of IBS reported in the study by Rajendra et al[13] as compared with the study by Tan et al[12]. Our current study recruited only ethnic Malays (mean age 37.7 ± 15.7 years) who were visitors (friends and relatives) within a hospital setting. To ensure a homogenous representation of the general population, a random stratified sampling strategy based on occupation was used. An older population, a lower socioeconomic background compared with the other regions of the Peninsula and less education may have explained the prevalence seen in our current study. The similarity in prevalence rates between the Malays in our study and the study from Singapore somewhat validates our findings.

The diagnostic Rome criteria used was different across different studies from Malaysia and this can partially influence the reported prevalence rates[19]. The current study did not compare different Rome diagnostic criteria which is a limitation. The total sampling size was also different between studies but if the sample calculation on just the ethnic Malays was taken into account then it was not much different (221 subjects in the current study, 278 subjects in Tan et al[12], 314 subjects in Rajendra et al[13] and 263 subjects in Gwee et al[14]).

There was no gender difference among the Malays with or without IBS in the current study. This was in contrast with the studies of Rajendra et al[13] and Tan et al[12] which reported a female preponderance in subjects with IBS. While the cause is unknown, it is possible that in their studies, the women are more educated and have greater health-seeking behavior in the more developed west coast of Peninsular Malaysia. Alternatively, it could be an ethnic-specific phenomenon with more Chinese or Indian women reporting more IBS symptoms than the Malay women. Another possibility is that more women in their study may have misconstrued menstrual cramp as an IBS symptom. We have noticed that a third of the Malay women with IBS in the current study also complained of menstruation-related pain. It is also possible that males in our study seek more medical attention than the females, similar to what has been reported by hospital-based studies from India and Sri Lanka[11,20,21].

The current study also included assessment for red flags and psychosocial alarm symptoms since they were commonly reported from previous studies but their association with IBS is unknown[12,17]. Of all surveyed subjects, 9% (20/221) with red flag signs might have gastrointestinal symptoms from various diseases. While the question on the change in bowel habit is present in both the red flag questionnaire and the Rome III IBS diagnostic questionnaire, the question on age is not included in the IBS diagnostic questionnaire. We have noticed a significant percentage of subjects over 50 years old with symptoms of IBS who also reported a change in their bowel habit. This is important since elderly subjects above 50 years old have a higher risk for other organic diseases especially colorectal cancer.

Psychosocial alarm features were not commonly reported in the Malay population, either in the IBS or non-IBS sub-group, and if they were present, they were often dismissed as not being serious. This is in contrast with the Western populations where psychological disturbances were fairly common in those subjects with IBS especially in females[22]. One of the reasons for this discrepancy is the questionnaire itself, which may not have identified the idioms of psychological distress in this population[23]. Secondly, the socio-cultural stigmata attached to psychological and mental disturbance in this largely traditional Malay population may have resulted in the under-reporting of symptoms. Finally, high levels of family support, religious beliefs and other unknown cultural factors may have protected them against psychological distress[24].

The commonest sub-type of IBS reported in the current study was of mixed type followed by the constipation type which was similar to the study from Singapore[14]. This distribution was however different from the study by Rajendra et al[13] where constipation-predominant was the commonest subtype followed by the mixed type and diarrheal type. Many subjects with mixed type IBS often have features of constipation rather than diarrhea, and therefore the distinction of mixed or constipation type needs further clarification on their symptoms. This is important since treatment targeted against serotonin receptors can have contrasting effects on constipation or diarrhea.

There were limitations worth noting in the current study. It could be argued that recruiting subjects within the hospital compound might have led to sampling bias but this was unlikely. The recruited subjects involved all layers of the Malay community (from the poor to the rich) within a region of stable population dynamics and similar socio-cultural backgrounds. Furthermore, only native Malays were included in the current study and a proper stratified random sampling strategy was carried out. The sample size in the current study might have been relatively small but the study only involved ethnic Malays, and it was calculated with a good power. The current study did not report on results of investigations performed to rule out organic diseases in those subjects with red flags as this was not our research objective. However previous studies have shown that investigating these subjects very often has a low yield[25,26]. The current study did not compare the prevalence using different types of diagnostic criteria (Rome I, II and Manning criteria) for IBS. However this is the first study on IBS among ethnic Malays using a locally translated and validated Rome III IBS diagnostic questionnaire.

In conclusion, using the Rome III criteria, IBS was found to be prevalent among ethnic Malays from the north-eastern region of Peninsular Malaysia.

We thank the volunteers who agreed to participate in the study. A special thanks to the research assistant who has helped us in recruiting the volunteers.