BACKGROUND: Little is known about the role of genetic and environmental factors in irritable bowel syndrome. Various extra-intestinal manifestations are more prevalent in cases than in controls. Genetic effects may be important in the liability to develop functional bowel disorders. AIMS: To evaluate the associations of irritable bowel syndrome with several disorders co-morbid with the condition, using both a case-control design and a co-twin control design. METHODS:A sample of 850 Swedish twin pairs, aged 18-85 years, was contacted for a telephone interview. Through a diagnostic algorithm, 72 unrelated cases of irritable bowel syndrome and 216 age- and gender-matched controls were identified. Fifty-eight twin pairs discordant for irritable bowel syndrome were evaluated in co-twin analyses. RESULTS:Renal problems (odds ratio (OR)=3.3; confidence interval (CI), 1.3-8.2), obesity (OR=2.6; CI, 1.0-6.4), underweight in the past (OR=2.4; CI, 1.1-6.4), gluten intolerance (OR=9.0; CI, 1.4-60.1), rheumatoid arthritis (OR=3.2; CI, 1.1-9.4) and poor self-rated health (OR=1.8; CI, 1.0-3.2) were significantly associated with irritable bowel syndrome. In the co-twin analyses, the only factors maintaining significance were renal and recurrent urinary tract problems. CONCLUSIONS: The association between irritable bowel syndrome and renal and urinary tract problems does not reflect a genetic or familial mediation. Eating disorders in childhood represent a familial-environmental influence on irritable bowel syndrome, whereas the association with rheumatoid arthritis and perhaps gluten intolerance probably reflects genetic mediation.
RCT Entities:
BACKGROUND: Little is known about the role of genetic and environmental factors in irritable bowel syndrome. Various extra-intestinal manifestations are more prevalent in cases than in controls. Genetic effects may be important in the liability to develop functional bowel disorders. AIMS: To evaluate the associations of irritable bowel syndrome with several disorders co-morbid with the condition, using both a case-control design and a co-twin control design. METHODS: A sample of 850 Swedish twin pairs, aged 18-85 years, was contacted for a telephone interview. Through a diagnostic algorithm, 72 unrelated cases of irritable bowel syndrome and 216 age- and gender-matched controls were identified. Fifty-eight twin pairs discordant for irritable bowel syndrome were evaluated in co-twin analyses. RESULTS: Renal problems (odds ratio (OR)=3.3; confidence interval (CI), 1.3-8.2), obesity (OR=2.6; CI, 1.0-6.4), underweight in the past (OR=2.4; CI, 1.1-6.4), gluten intolerance (OR=9.0; CI, 1.4-60.1), rheumatoid arthritis (OR=3.2; CI, 1.1-9.4) and poor self-rated health (OR=1.8; CI, 1.0-3.2) were significantly associated with irritable bowel syndrome. In the co-twin analyses, the only factors maintaining significance were renal and recurrent urinary tract problems. CONCLUSIONS: The association between irritable bowel syndrome and renal and urinary tract problems does not reflect a genetic or familial mediation. Eating disorders in childhood represent a familial-environmental influence on irritable bowel syndrome, whereas the association with rheumatoid arthritis and perhaps gluten intolerance probably reflects genetic mediation.
Authors: Christine M Peat; Lu Huang; Laura M Thornton; Ann F Von Holle; Sara E Trace; Paul Lichtenstein; Nancy L Pedersen; D Wayne Overby; Cynthia M Bulik Journal: J Psychosom Res Date: 2013-08-27 Impact factor: 3.006