With treatment, most people achieve a healthy weight, and the mortality rate for the disease is relatively low. It can vary from being benign to very severe, and people with CD could experience just one episode or have continuous symptoms. It usually reoccurs, although some people can remain disease-free for years or decades. Up to 80% of people with Crohns disease are hospitalized at some point during the course of their disease, with the highest rate occurring in the first year after diagnosis. Most people with Crohns live a normal lifespan. However, Crohns disease is associated with a small increase in risk of small bowel and colorectal carcinoma (bowel cancer). Epidemiology
The percentage of people with Crohns disease has been determined in Norway and the United States and is similar at 6 to 7.1:100,000. The Crohns and Colitis Foundation of America cites this number as approx 149:100,000; NIH cites 28 to 199 per 100,000. Crohns disease is more common in northern countries, and with higher rates still in the northern areas of these countries. The incidence of Crohns disease is thought to be similar in Europe but lower in Asia and Africa. It also has a higher incidence in Ashkenazi Jews and smokers.Crohns disease begins most commonly in people in their teens and 20s, and people in their 50s through to their 70s. It is rarely diagnosed in early childhood. It usually affects female children more severely than males. However, only slightly more women than men have Crohns disease.
People with extensive small intestine disease may also have malabsorption of carbohydrates or lipids, which can further exacerbate weight loss. Extraintestinal
Crohns disease can affect many organ systems beyond the gastrointestinal tract. Visual
Inflammation of the interior portion of the eye, known as uveitis, can cause blurred vision and eye pain, especially when exposed to light (photophobia). Uveitis can lead to loss of vision if untreated.Inflammation may also involve the white part of the eye (sclera) or the overlying connective tissue (episclera), which causes conditions called scleritis and episcleritis, respectively.Other very rare ophthalmological manifestations include: conjunctivitis, glaucoma, and retinal vascular disease.Gallbladder and Liver
Crohns disease that affects the ileum may result in an increased risk of gallstones. This is due to a decrease in bile acid resorption in the ileum, and the bile gets excreted in the stool. As a result, the cholesterol/bile ratio increases in the gallbladder, resulting in an increased risk for gallstones. Although the association is greater in the context of ulcerative colitis, Crohns disease may also be associated with primary sclerosing cholangitis, a type of inflammation of the bile ducts.Liver involvement of Crohns disease can include cirrhosis and steatosis. Nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH) are relatively common and can slowly progress to end-stage liver disease.