Published Date: Mar 2024


What is Ulcerative Colitis?

Ulcerative colitis is a type of inflammatory bowel disease that causes long-lasting inflammation and ulcers in the lining of the large intestine or colon. The exact cause of ulcerative colitis is unknown, but it is thought to be an autoimmune disorder where the body's immune system attacks healthy cells in the digestive tract. Some of the symptoms of ulcerative colitis include abdominal pain, rectal bleeding, diarrhea, weight loss and fatigue. The symptoms can range from mild to severe depending on the extent and severity of inflammation in the colon.

Rising Incidence Rates

Recent studies conducted in the United Kingdom have shown that the incidence rates of ulcerative colitis are continuing to rise over the past few decades. According to data from the Clinical Practice Research Datalink, the age-standardized incidence rate of ulcerative colitis increased from 8.5 per 100,000 person-years in the 1990s to 12.9 per 100,000 person-years in the late 2010s. This represents an increase of over 50% in incidence rates over the past 30 years in the UK.

The reasons for the rising incidence are still being investigated. Genetics are known to play a role, so improved diagnosis and changes in genetic susceptibility over time may be contributing factors. Environmental factors like the western diet, lack of breastfeeding, antibiotic overuse and reduced exposure to bacteria are also thought to influence disease development. The steady increase seen in the UK suggests that changes to these environmental exposures may be driving up ulcerative colitis cases.

Increased Risk in Younger Age Groups

Analysis of incidence data has shown the rise is most pronounced in younger age groups under 40 years of age. The incidence rate in those under 40 increased by 138% from 8.0 per 100,000 in the 1990s to 19.1 per 100,000 in the late 2010s. This is concerning as onset of disease at a younger age can lead to longer disease duration and increased need for medication and surgeries over the lifetime.

Doctors note more patients presenting with ulcerative colitis at 18-30 years of age compared to previous decades. The peak age of diagnosis which was previously 40-50 years has shifted to the late 20s. This raises speculation that environmental risk factors exposure during childhood and adolescence could be impacting disease risk.

Rising Rates in Women

In line with global trends, the prevalence of ulcerative colitis is higher in women than men in the UK. Analysis of epidemiological data reveals the increases in incidence are more significant among women compared to men. The age-standardized incidence rate in women jumped from 10.3 per 100,000 in the 1990s to 16.3 per 100,000 in recent years - a rise of over 58%. In contrast, incidence grew by 41% in men from 6.9 to 9.7 per 100,000 over the same time period.

Hormonal and immunological factors are thought to influence the female preponderance of ulcerative colitis. Changes to reproductive patterns like increasing use of oral contraceptives may be contributing to higher disease development in UK women in recent decades. However, more research is still required to fully understand the gender differences seen in prevalence trends.

Rising Hospital Admissions and Surgeries

In line with rising incidence, hospitalization rates for ulcerative colitis have also increased sharply over the past 20 years according to statistics from NHS Digital. Admissions to English hospitals for ulcerative colitis surged by 50% from 2001 to 2019 after adjusting for age and population changes. Similarly, the rate of colectomies or surgeries to remove all or part of the colon has climbed over the past decade.

This suggests more patients are experiencing severe flares requiring inpatient care. It also indicates the disease is impacting quality of life to a degree that surgery is now considered more often. The rising costs associated with hospital admissions and surgeries place a growing burden on the healthcare system in the UK dealing with inflammatory bowel disease. A multi-pronged approach is needed to better understand disease triggers and develop preventative strategies to curb the increasing prevalence.

Increased Awareness and Better Diagnosis

While changes to environmental risk factors do appear to be driving real increases in incidence rates over time, some studies note the rises may also be partially fueled by improved awareness and accurate diagnosis. In the past, milder or atypical presentations could have been misdiagnosed as irritable bowel syndrome for example. Today, clearer diagnostic criteria and widespread availability of investigative tests helps specialists more reliably distinguish ulcerative colitis from other intestinal conditions.

Additionally, public knowledge about inflammatory bowel disease has grown tremendously over the last two decades. More people recognizing common symptoms are likely seeking medical attention sooner rather than ignoring mild problems. This may make some of the seeming rise merely represent pre-existing cases being detected and then included in reported numbers sooner rather than indicating genuine new cases. However, evidence overwhelmingly indicates a true increase in disease incidence alongside these awareness and diagnostic factors.


In summary, multiple lines of evidence confirm the prevalence of ulcerative colitis is steadily rising in the United Kingdom. Younger individuals, women, and those living with more severe forms requiring hospitalization are disproportionately impacted by the increases. While genetic susceptibility remains important, changes to environmental exposures during development appear key to escalating disease risks seen over recent decades. Continued epidemiological monitoring coupled with research into modifiable risk factors is vital to curbing this worsening public health issue going forward.