Hygiene hypothesis in inflammatory bowel disease: A critical review of the literature

Abstract

The hygiene hypothesis is thought to be a significant contributor to the growing incidence of inflammatory bowel disease (IBD) around the world, although the evidence for specific factors that underlie the hygiene hypothesis in IBD is unclear. We aimed to systematically review the literature to determine which hygiene-related factors are associated with the development of IBD. Publications identified from a broad based MEDLINE and Current Contents search between 1966 and 2007 on key terms relevant to the 'hygiene hypothesis' and IBD including H pylori exposure, helminths, cold chain hypothesis, measles infection and vaccination, antibiotic use, breastfeeding, family size, sibship, urban upbringing, day care attendance and domestic hygiene were reviewed. The literature suggests that the hygiene hypothesis and its association with decreased microbial exposure in childhood probably plays an important role in the development of IBD, although the strength of the supporting data for each of the factors varies considerably. The most promising factors that may potentially be associated with development of IBD include H pylori exposure, helminths, breastfeeding and sibship. However, the vast majority of studies in this area are plagued by serious methodological shortcomings, particularly the reliance on retrospective recall of information making it difficult to truly ascertain the importance of a 'hygiene hypothesis' in IBD. The 'hygiene hypothesis' in IBD is an important area of research that may give clues to the aetiology of this disease. Directions for future research are recommended.

The paradoxical effects of vitamin D on type 1 mediated immunity

“…Changes in the normal bacterial flora and or the decreased incidence of intestinal parasites including worm infections are cited as the basis for the hygiene hypothesis in IBD (Khan et al 2002;Strober et al 2007;Koloski et al 2008). Experimental evidence shows that gastrointestinal worm infections can suppress IBD in experimental animals and humans (Khan et al 2002;Strober et al 2007;Koloski et al 2008). In addition, approaches that aim to alter the types of bacteria in the gastrointestinal track including the use of probiotics to replace the existing bacteria with "good" bacteria have been successful in some circumstances (Rolfe et al 2006).…”

Targeted Inhibition of Serotonin Type 7 (5-HT7) Receptor Function Modulates Immune Responses and Reduces the Severity of Intestinal Inflammation

“…The incidence and prevalence of human bowel diseases such as IBD have shown a dramatic increase in the last decades (11,12). Although the exact cause of IBD is unknown, studies have provided evidence that a dysregulated immune response, genetic factors, enteric flora, and environmental factors contribute to the pathogenesis of IBD (13)(14)(15)(16). Mucosal changes in IBD are characterized by ulcerative lesions accompanied by a prominent infiltrate of activated cells from both the innate and adaptive immune systems.…”

Mucosal immunity: aliment and ailments

“…27 Th is microbial-driven immune imbalance may contribute to the observed increase in prevalence of various organ-specifi c, immune-mediated infl ammatory diseases such as asthma, multiple sclerosis, 28 and, more direct for our discussion, infl ammatory bowel disease. 29 Th is theory, which stems from the " Hygiene Hypothesis " , 30,31 is supported by a few recent clinical and experimental data, through which the role of microfl ora in the modulation of immunemediated infl ammatory disorders was validated. Indeed, the administration of diff erent probiotic bacterial preparations inhibits intestinal infl ammation in patients who suff er from a certain clinical subset of ulcerative colitis.…”