There is no question that primary biliary cholangitis (PBC) overwhelmingly affects women, but no explanation for this has yet been found. PBC is an autoimmune liver disease that attacks the bile ducts that run through the liver, eventually destroying them. Bile then builds up in the liver, leading to chronic inflammation and permanent scarring of the liver, also known as cirrhosis. This damages liver function and may eventually result in liver failure.
While most people with PBC are asymptomatic at diagnosis, the most common symptoms are fatigue and pruritus (itchy skin). Jaundice can also occur in severe cases. These symptoms can take a heavy toll on a patient’s quality of life, leading to sleep disturbances, depression and self-isolation.
Gender as a risk factor
The cause of PBC is still unknown, but what is clear is that it is not caused by alcohol or drug use and that about 90% of people with PBC are women. Age is also a factor, as diagnosis occurs mostly in women aged 40-60 years.
Learn more about PBC causes and risk factors
Autoimmune diseases are chronic disorders in which the immune system attacks itself. They have been found to have a greater prevalence in women, at a rate of two to one. This has been attributed to the presence of two X chromosomes, and therefore a greater number of genes, which predispose women to autoimmunity. Other autoimmune diseases more commonly found in women and that often occur as comorbidities of PBC are Sjogren’s syndrome and autoimmune thyroiditis.
PBC is thought to develop as a result of genetic and environmental risk factors. One of these genetic factors concerns first-degree relatives of people with PBC, in particular mother-daughter pairs or sister-sisters. Clusters have also been found to exist, normally in mother-sister-daughter groups, or in four out of six sisters in one family.
While PBC is rarely found in males, some reports of male relatives with the disease have been confirmed.
PBC in pregnancy
Despite the average age of diagnosis of 40 years and over, some studies have also identified cases where pregnancy has triggered PBC. This rare diagnosis during pregnancy, most commonly found in women in their early thirties is thought to occur as a result of the drastic changes in female hormones, such as greater levels of bile acid levels and changes in the immune response. Symptoms are most commonly fatigue, pruritus and jaundice. While pregnancy is well-tolerated in women with PBC, risk is greater for miscarriage or preterm birth.
Overall, in pregnant women with PBC, maternal and neonatal outcomes are primarily good.
