From the Guidelines
The exact cause of ulcerative colitis remains unknown, but it is likely the result of a complex interaction between genetic predisposition and environmental influences that trigger an inappropriate immune response in susceptible individuals. The disease is characterized by a lifelong interaction between genetic and environmental factors, observed predominantly in developed countries 1. Several factors contribute to its development, including:
- Genetic factors, as having a family member with the condition increases the risk 1
- Environmental triggers, such as certain medications (like NSAIDs) 1, diet choices, stress, and smoking cessation 1
- Gut microbiome imbalances, as patients with ulcerative colitis often show altered bacterial populations in their intestines
- Age, with most diagnoses occurring before age 30
It is also important to note that a family history of ulcerative colitis or Crohn’s disease increases the risk for developing ulcerative colitis, with the risk being greatest in first-degree relatives 1. Additionally, smoking cessation may predispose to ulcerative colitis, with ex-smokers having approximately a 70% higher risk of developing the disease 1. The most recent study on the topic, published in 2024, highlights the importance of considering patient-centric aspects of the disease, including improvements in quality of life, symptoms, and inflammatory biomarkers, in defining comprehensive disease control 1. However, this study does not provide new insights into the causes of ulcerative colitis, and therefore, the 2017 study remains the most relevant for this question 1.
The factors that contribute to ulcerative colitis development can be summarized as follows:
- Genetic predisposition
- Environmental triggers
- Gut microbiome imbalances
- Age
- Family history of ulcerative colitis or Crohn’s disease
- Smoking cessation
Overall, the causes of ulcerative colitis are complex and multifactorial, and further research is needed to fully understand the underlying mechanisms of the disease.
From the Research
Causes of Ulcerative Colitis
The causes of ulcerative colitis (UC) are complex and multifactorial. Some of the key risk factors include:
- Genetics: UC has a strong genetic component, with certain genetic mutations increasing the risk of developing the disease 2
- Environmental factors: Diet, lifestyle, and exposure to certain medications or toxins may contribute to the development of UC 3
- Autoimmunity: UC is characterized by an abnormal immune response, with the immune system attacking the lining of the colon 2
- Gut microbiota: An imbalance of the gut microbiome may play a role in the development and progression of UC 2, 3
Other Potential Causes
Other potential causes of UC include:
- Western diet: A diet high in processed foods and low in fiber may increase the risk of developing UC 3
- Medications: Certain medications, such as antibiotics and non-steroidal anti-inflammatory drugs (NSAIDs), may trigger the onset of UC 3
- Lifestyle factors: Stress, smoking, and lack of exercise may also contribute to the development of UC 3
Current Understanding
While the exact causes of UC are not yet fully understood, research continues to uncover new insights into the disease. Studies have identified multiple genetic and environmental factors that contribute to the development of UC, and ongoing research aims to clarify the relationships between these factors and the disease 2, 3, 4, 5, 6