Who gets IBD and WHY???
In the United States, approximately 1 million people have some form of Inflammatory Bowel Disease. Each year, about 30,000 individuals in the USare newly diagnosed. So who are these people? (Besides most of you who visited this website...)
The EPIDEMIOLOGY of IBD….
(Epidemiology: The branch of medicine that deals with the causes, distribution, and control of disease in populations)
The majority of newly diagnosed individuals are between the ages of 15-30, with about 10% being under 18. Although IBD is more commonly diagnosed in young people, there is a small group of individuals diagnosed between the ages of 50-70.
IBD seems to affect men and women equally, although Ulcerative Colitis is slightly more common in men while Crohn’s Disease is slightly more common in women.
If you breakdown IBD incidence into racial and ethnic groups, the disease occurs most frequently in people of Caucasian and Ashkenazic descent. However, the gap between racial groups is continually closing, as disease incidence among African Americans and second generation south Asian immigrants continues to rise.
The ETIOLOGY of IBD….
(Etiology: The branch of medicine that deals with the causes or origins of disease.)
The truth is, NO ONE REALLY KNOWS what causes IBD, but theories of contributing factors can be separated into two categories: environmental and genetic.
ENVIRONMENTAL FACTORS
Growing up in a developed country
Inflammatory Bowel Disease is most prevalent in industrialized nations, including the United States and Western Europe. On a more local level, IBD seems to occur more often in urban areas than rural. Scientists believe this has to do with particular lifestyle factors, but have been unable to identify a direct cause.
Cleanliness
Opposite of what you might guess, poor hygiene actually may protect against IBD (warning: this is not an excuse to stop showering!... your friends wouldn’t be happy). Studies have shown that individuals raised in less sanitary conditions and in crowded households have a lower frequency of Crohn’s and Colitis. Alternatively, individuals from wealthier backgrounds with spacious living conditions have a higher frequency of IBD. This may be because in a “sterile” environment you have less opportunity to come into contact with good bacteria that protect your intestines.
Jobs
“White-collar” occupations, which involve sitting in an office for 8 hours a day, are actually correlated with a higher incidence of IBD. Alternatively, “blue-collar” jobs, like farming and other outdoors work, have been correlated with a lower incidence of IBD. This likely has less to do with occupation and more to do with the amount of physical activity people get, which protects you from all kinds of diseases!
Diet
Surprisingly, no particular diet has been found to cause IBD. There are some studies, however, that show excessive fast-food consumption may increase your risk, but that’s not a huge surprise…. did you see what happened to the guy in the movie “Super Size Me?”
Smoking
Don’t do it. If you do, quit. It is the single greatest risk factor for the development of IBD. In Crohn’s Disease, smoking can actually be directly responsible for a more severe disease course.
GENETIC FACTORS
Family
Susceptibility to Inflammatory Bowel Disease is inherited. However, the genetics of IBD are very complex and likely involve different combinations of multiple mutations.
If you have a sibling with Crohn’s Disease, your chances of developing the disease are only 4-12%. However, if you have an identical twin with Crohn’s, your chances of developing the disease are as high as 58%.
The IBD Genes
While many chromosomes are likely to play a role in the development of IBD, the most exciting one is Chromosome 16. Chromosome 16 contains the NOD2/CARD15 gene which, when mutated, has been directly linked to Inflammatory Bowel Disease. However, it is estimated that the mutation only accounts for 17-27% of Crohn’s Disease cases. NOD2 is not clearly understood, but scientists hypothesize that it activates targets which mediate inflammatory responses.
So what does all this mean???
Truthfully…. Not much. Most of the contributing factors were totally out of your control – you didn’t choose your parents, your birthplace, or your genetic code.
What’s important to know is that there’s nothing you or your family did or didn’t do to cause your disease. If you keep an eye on your disease, eat healthy, don’t smoke, try to manage stress, and stay active you’re doing everything you can!
Information adapted from: Hanauer SB. Inflammatory bowel disease: epidemiology, pathogenesis, and therapeutic opportunities. Inflamm Bowel Dis. 2006 Jan;12 Suppl 1:S3-9.