Patients recently diagnosed with anemia have a greater risk for developing Crohn's disease, based on an analysis of population data from South Korea's National Healthcare Insurance patient database in 2009, in which nearly 9.97 million people older than 20 years participated in the health screening program. Investigators found no additional risk for ulcerative colitis, a study published in PLOS ONE found. The risk is higher in men, and the chances of developing Crohn's had an inverse relationship with severity of anemia, according to researchers.