Inflammatory bowel disease is best known for causing problems in the digestive system, but its effects do not always stop there.
A new study suggests that some people with these long-term bowel conditions also develop a serious lung problem. The connection appeared to be stronger in people with ulcerative colitis than in those with Crohn’s disease.
Inflammatory bowel disease, often shortened to IBD, includes two main conditions: ulcerative colitis and Crohn’s disease. Both involve ongoing inflammation caused by an immune system that does not behave normally. Ulcerative colitis affects the large intestine, while Crohn’s disease can occur anywhere from the mouth to the end of the digestive tract.
People with IBD can have stomach pain, diarrhea, bleeding, weight loss and extreme tiredness. The disease can also affect areas outside the gut, including the joints, skin and eyes. Researchers have increasingly become interested in whether the lungs can also be affected.
The new study focused on interstitial lung disease, or ILD. This name covers a group of lung conditions that cause inflammation and sometimes scarring in the tissue surrounding the tiny air sacs where oxygen enters the blood. If enough scarring develops, the lungs become stiffer and breathing can become difficult.
Common symptoms can include a dry cough, shortness of breath and tiredness. However, early lung disease may cause few obvious problems, which means it can be missed. This is important because some types of lung scarring cannot be reversed once they become severe.
Sneh Parekh, D.O., from the University of Florida College of Medicine in Jacksonville, and colleagues examined medical data from 8,865 people with IBD.
The patients had been treated at two large specialist health centers in the southeastern United States between 2012 and 2022. The team compared people with ulcerative colitis and Crohn’s disease and looked for cases of interstitial lung disease.
The researchers found that 4.6% of the patients had both IBD and ILD. Lung disease was significantly more common among people with ulcerative colitis than among those with Crohn’s disease. The basic demographic characteristics of patients with the two forms of IBD and lung disease were otherwise similar.
Patients who had both IBD and ILD were generally older than people who had bowel disease without the lung condition. They were also more likely to visit an emergency department or be admitted to hospital. This suggests that having both illnesses may create a greater health burden.
The study also found that people with both conditions were more likely to have used steroid medicines. Steroids reduce inflammation and are often used when IBD becomes more active, although long-term use can cause side effects. Patients with IBD and ILD were less likely to have been prescribed mesalamine, a medicine commonly used for ulcerative colitis.
The researchers also reported that other health conditions were more common among minority patients with IBD and ILD than among White patients. The study does not explain exactly why this difference occurred. Differences in access to care, underlying health, treatment and other factors could potentially contribute and need further study.
There are several possible reasons why bowel and lung disease might occur together. IBD involves abnormal immune activity throughout the body, so inflammation may sometimes affect organs far from the intestines. Medicines, infections, smoking and unrelated lung conditions can also complicate the picture.
The researchers said doctors should consider the possibility of ILD in people with inflammatory bowel disease, particularly when patients develop unexplained breathing problems. They suggested that earlier detection or screening may deserve consideration, with particular attention to ulcerative colitis when medical resources are limited.
The research was published online July 24 in Crohn’s & Colitis 360. The study adds useful evidence because it examined thousands of patients over a 10-year period in real health care settings. Its large sample also allowed the researchers to compare ulcerative colitis with Crohn’s disease.
However, the findings need to be interpreted carefully. This was an observational study based on patients treated at two major specialist centers, so the results may not represent every person with IBD. It can show that ILD and IBD occurred together, but it cannot prove that ulcerative colitis directly caused the lung disease.
The 4.6% figure also should not be taken to mean that every person with IBD has a high chance of serious lung damage. Specialist hospitals may see patients who are older or have more complicated illnesses than people treated elsewhere. Future studies involving different hospitals and populations could help determine how common this problem really is.
Still, the difference between ulcerative colitis and Crohn’s disease is worth further attention. If future research confirms the finding, doctors may be able to identify patients who would benefit most from closer lung monitoring.
For patients, the practical message is not to panic, but to mention persistent cough or unexplained shortness of breath rather than assuming these symptoms are unrelated to their bowel disease.
Source: University of Florida.
