body. The most common of these complications affect the skin and bones.3 These extraintestinal complications may be evident in the: • eyes (redness, pain, and itchiness) • mouth (sores) • joints (swelling and pain) • skin (tender bumps, painful ulcerations, and other sores/rashes) • bones (osteoporosis) • kidney (stones) • liver (primary sclerosing cholangitis, hepatitis, and cirrhosis)—occurs rarely Mortality Death due specifically to Crohn’s disease or its complications is uncommon. However, people with Crohn’s disease have a slightly higher overall mortality rate than the general healthy population. The increase in deaths is largely due to conditions such as cancer (particularly lung cancer), chronic obstructive pulmonary disease, gastrointestinal diseases, (both including and excluding Crohn’s disease), and diseases of the genital and urinary tracts.4 Death due to ulcerative colitis or its complications is also uncommon. Most people with ulcerative colitis do not have a higher risk of dying from any particular disease than the general population. However, those with extensive inflammation in the colon are at higher risk than the general population for dying from gastrointestinal and lung diseases (although not lung cancer).5 8 9 Genetics Scientific evidence clearly points to the role of heredity in IBD. Studies have shown that 5% to 20% of affected individuals have a first-degree relative (parent, child, or sibling) with one of the diseases.6 Children of parents with IBD are at greater risk than the general population for developing IBD.7 The risk is greater with Crohn’s disease than with ulcerative colitis. The risk is also substantially higher when both parents have IBD. One study found that 36% of people with both parents affected developed IBD.8 While genetics is clearly a factor, the association is not simple. It is likely that more than one gene is at work, and just having the genes associated with IBD does not absolutely predict the disease will occur. Instead, these are susceptibility genes, which increase the chances for getting the disease. It is clear that other factors, including environmental factors, must also come into play. Numerous genes and genetic mutations connected to IBD have been identified. The first one discovered was a mutation in the NOD2/CARD15 gene, which was found to be associated with developing Crohn’s disease.9 Up to 20% of IBD patients in North America and Europe may have a mutation in the NOD2/CARD15 gene. While genetic testing is possible, it is not currently a part of the diagnostic process for IBD. This is because many people who carry these genes will never develop IBD. So, at this time, genetic testing can identify a potential risk for IBD in an individual, but cannot predict whether or not they will develop it. IBD is a complex disease that results from the interaction of an individual’s genes with environmental factors and the immune system. Environmental Triggers The environmental factors that trigger IBD are not known, but several potential risk factors have been studied.10,11 More studies are needed to fully understand the risk factors for IBD. • Smoking: Active smokers are more than twice as likely as nonsmokers to develop Crohn’s disease.12 Surprisingly, the risk of developing ulcerative colitis is decreased in current smokers compared with people who have never smoked. The numerous potential harmful health effects of smoking (e.g., cancer, heart disease) largely outweigh any benefits of smoking for people with ulcerative colitis. • Antibiotics: May increase the risk for IBD. • Nonsteroidal anti-inflammatory drugs (aspirin, ibuprofen, naproxen): May increase the risk for getting IBD and may cause flares. • Appendicitis: Children who undergo an appendectomy (removal of the appendix) are less likely to develop ulcerative colitis later in life, but may be at a higher risk of developing Crohn’s disease. However, the benefits of appendectomy in patients with severe acute appendicitis certainly outweigh the risks. • Diet: IBD is not triggered by eating any one particular food. But for some people, certain foods can aggravate symptoms. The role of diet in Crohn’s disease and ulcerative colitis is an important subject, and more research is needed to better understand how diet