Authors: Mendall MA, Kumar D.

Institution: Mayday Hospital, Thornton Health, Surrey, UK.

Background: Antibiotics cause well defined short-lived disturbances in bowel habit. There is evidence to suggest that antibiotics may play a role in the pathogenesis of IBS. Atopy has been associated with small household size in childhood and could also play a role in IBS. We conducted a survey examining the relation of drug use and other epidemiological correlates of IBS.

Subjects and Methods: 421 subjects (46% male, mean age 47 years (range 18-80 years) attending a general practice health screening clinic were interviewed by a research nurse and completed a previously validated questionnaire. Symptoms of IBS were said to be present if abdominal pain with 2 or more Manning criteria symptoms occurred more than once per month over the previous 6 months.

Results: 48 subjects had symptoms of IBS. The following were strongly related to its presence: antibiotic use [adjusted OR 3.70 (1.80-7.60)], female sex and childhood living density < 1 person per room [OR 3.47 (1.57-7.64)], manual father's occupation [OR 0.35 (0.16-0.76)]. The use of NSAIDS, H2 antagonists or other types of medication was not greater in this group.

Conclusion: Antibiotic use is associated with IBS. The association with antibiotic use requires testing in prospective studies. Privileged childhood living conditions were also an important risk factor which is consistent with an allergic aetiology for IBS.

Study link: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=9512954&query_hl=84

Authors: Maxwell PR, Rink E, Kumar D, Mendall MA.

Institution: Department of General Practice and Primary Care, St George's Hospital Medical School, London, United Kingdom.

Objectives: Data suggest that subjects with irritable bowel syndrome are more likely to report a recent course of antibiotics. This study tests the hypothesis that a course of antibiotics is a risk factor for an increase in the number of functional bowel complaints over a 4-month period in a general population sample.

Methods: We initiated a prospective case-control study in three general practices in South London. Consecutive patients aged 16-49 attending their general practitioner with non-GI complaints and given a prescription for antibiotics were invited to participate. Comparison subjects who had not had antibiotics for 1 yr were identified from the practice records by age group, gender, and previous general practitioner visits. Fifty-eight antibiotic and 65 control patients agreed to participate. Questionnaires covering demographic, GI, and psychological data were sent at recruitment and at 4 months. Seventy-four percent of subjects completed the study. The number of symptoms at follow-up compared to that at recruitment.

Results: Twenty of 42 antibiotic subjects (48%) versus 11/49 control subjects (22%) demonstrated one or more additional functional bowel symptoms at 4 months (unadjusted odds ratio = 3.14 [1.27-7.75]) (chi2 = 6.4, p = 0.01). Ten of 42 antibiotic subjects (24%) versus 3/49 control subjects (6%) demonstrated two or more additional functional bowel symptoms at 4 months (unadjusted odds ratio = 4.79 [1.22-18.80]) (chi2 = 5.8, p = 0.02).

Conclusions: Functional bowel symptoms come and go, but subjects who are given a course of antibiotics are more than three times as likely to report more bowel symptoms 4 months later than controls.

Study link: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=11808932&query_hl=56