Is endometriosis associated with inflammatory bowel disease?
20 December 2011
In a nationwide Danish study published in the international journal ‘Gut’, researchers from Statens Serum Institut report that women who have been hospitalised with the gynaecological disease endometriosis more frequently than expected develop chronic inflammatory bowel disease. The specific cause is yet unknown, but perhaps the diseases share a common aetiology, or perhaps the increased prevalence of inflammatory bowel disease is caused by hormone therapy as treatment of endometriosis.
Previous studies indicate association between endometriosis and inflammatory bowel diseases
Endometriosis is a gynaecological disease, characterised by implantation of endometrium-like tissue in the abdominal cavity outside the uterus, resulting in periodic stomach ache. The mucous membrane lining the uterus is called the endometrium. Hence the name endometriosis, a disorder. The cause of endometriosis remains unknown, but the disease is suspected of being an autoimmune disease, i.e. a disease initiated by the body’s own immune system. Previous studies report that women with endometriosis seem to have a moderately increased prevalence of several other autoimmune diseases, but it is not yet known whether these women also are at increased risk of the two inflammatory bowel diseases Crohn’s disease (CD) and ulcerative colitis (UC), which are two of the most common autoimmune bowel diseases among young Danes.
Danish register-based study
In a Danish study from Statens Serum Institut based on data from the Danish National Hospital Register in the period 1977-2007, the researchers investigated whether women with endometriosis have an increased risk of inflammatory bowel diseases.
Women with endometriosis have a 50-80% increased risk of inflammatory bowel disease
The Danish study reports such increased risk. This remains the case when limiting analyses to women diagnosed with en-dometriosis in connection with ‘endocopic surgery’, which is the optimal way of diagnosing the disease. The risk of inflammatory bowel disease is still high more than 20 years after the endometriosis diagnosis which argues against erroneous, simultaneous registration of both diagnoses.
Does treatment of endometriosis result in development of inflammatory bowel disease?
The increased risk of inflammatory bowel diseases in women with endometriosis may be the result of common causes of the diseases in the body’s own immune system. However, the increased risk may also be associated with birth control pills used as treatment of endometriosis. Previous studies actually show that birth control pills may increase the risk of inflammatory bowel disease. The results from the Danish study should thus be followed by new studies to investigate whether common immunological features or treatment with birth control pills are responsible for the increased risk of inflammatory bowel disease in women with endometriosis.
Read the scientific article
Jess T, Frisch M, Jørgensen KT, Pedersen BV, Nielsen NM. Increased risk of inflammatory bowel disease in women with endometriosis: A nationwide Danish cohort study. Gut 2011. doi:10.1136/gutjnl-2011-301095