Who gets PSC?
PSC is a liver disease that anyone can get, at any age 22, but it is rare.
PSC is a rare disease
According to Rare Disease UK, a rare disease is a disease that affects less than 500 people per million (or less than 1 person in 2000).
How many people have PSC?
It is difficult to truly calculate how many people have PSC because of differences in health records and data collection from country to country. In the UK there could be as many as 10,500 people living with PSC but estimates vary.
The latest figures from the University of Birmingham show that PSC is indeed rare, affecting only around 80 people per million in the UK (prevalence of PSC) 23. Other studies suggest it is even lower at only 56 people per million 24.
There is a geographic pattern of PSC with numbers decreasing from Northern Europe towards Southern Europe 10. A study looking at a number of different countries reported varying numbers of people with PSC in each country ranging from 0 (no one affected) to 162 cases per million people 25.
Of course, it might also be the case that a number of individuals with colitis may also have as yet undetected PSC. In fact, studies have suggested that perhaps 8-14% of people with colitis and normal liver blood tests have changes in their bile ducts that are associated with PSC (when their bile ducts are closely examined) 3.
How many people are diagnosed with PSC each year?
The number of people diagnosed with PSC each year is called the incidence of PSC. It is reported that around seven people per million get diagnosed with PSC each year in the UK 23,24. The number of new cases each year is thought to be increasing, perhaps because PSC is being diagnosed at an earlier stage or because we’re becoming more exposed to environmental triggers (or that our exposure to protective factors is decreasing) 15.
PSC and smoking
Interestingly, people with PSC are usually non-smokers 1,10,24. In fact, studies looking back on people’s health records suggest that smoking could even have a protective effect against the development of PSC 26. However, cigarette smoking is harmful to your health, even at low levels of consumption 27,28 and one of the biggest causes of deaths in the UK 29 - you should not take up smoking.
PSC and alcohol
Getting PSC is not associated with drinking alcohol. A study investigating the relationship between possible environmental factors and risk of developing PSC found that people with PSC reported lower alcohol consumption both at the time asked and back when they were 18 years old 1. Having said that, most doctors suggest that if you have PSC you have no alcohol, or minimal alcohol, as any alcohol can accelerate pre-existing liver damage.
PSC and coffee
Some recent studies reported that people with PSC generally drink less coffee than control subjects, suggesting that coffee consumption may be associated with a reduced risk of developing PSC 26,30, as well as a slower progression of the disease 31. However, these data need further validation.
More men than women have PSC
PSC is diagnosed in up to twice as many men as women 23,32. However, some researchers are beginning to believe that PSC occurs as commonly in females as in males, but that there may be fewer signs or symptoms in females 2 so it may remain undiagnosed 3. The disease seems generally to have a milder course in female patients than in male 7.
PSC can affect people at any age
Most people with PSC are diagnosed between 25 and 40 years of age, although it can be diagnosed at any age, and is recognised as an important cause of chronic liver disease in children 22,23.
PSC and socioeconomic deprivation
No relationship between new cases of PSC and socioeconomic deprivation has been found. This is important to note because this does appear to be the case for another immune-mediated bile duct disease, PBC (primary biliary cholangitis). In PBC, certain aspects of socioeconomic deprivation may be involved in the development of the condition 33.
Will my children get PSC?
Many people with PSC worry that their children will ‘inherit’ PSC because genetic changes contribute to the development of PSC. First degree relatives of people with PSC are thought to have a 0.7% prevalence of PSC 34. So, while first degree relatives are slightly more likely to have PSC, it is worth noting that PSC is not subject to the classic Mendelian inheritance laws we learnt at school 17 and it is very rare to see PSC run in families. At the present time therefore, we do not suggest screening for PSC in family members with no symptoms.