Coffee and cigarettes may protect against liver disease, study says
Coffee and cigarette smoking may protect against the rare liver disease Primary Sclerosing Cholangitis (PSC), study shows.
In a new study from Norway published in Clinical Gastroenterology and Hepatology, both coffee consumption and cigarette smoking are shown to potentially protect against primary sclerosing cholangitis (PSC). This is a chronic liver disease caused by chronic inflammation of the bile ducts.
The findings are of great interest against a backdrop of increasing knowledge on coffee as a possible protective agent in other liver diseases.
The cross-sectional study was conducted by researchers at the Norwegian PSC Research Center based at Oslo University Hospital and the University of Oslo.
The study was conducted using a questionnaire about environmental exposures, and included 240 PSC patients and 245 controls.
The study shows showed that the PSC patients had lower coffee consumption both currently and in the early adulthood, suggesting that coffee consumption could protect against the development of the disease. PSC patients who drank coffee, however, had lower levels of liver enzymes in the blood, thus suggesting a beneficial effect in the liver.
Regarding cigarette smoking, only 20% of the patients reported ever daily cigarette smoking, compared with 43% of the healthy controls. In addition, cigarette smokers acquired the disease on average 10 years later than non-smokers. Taken together, these observations confirm and strengthen previous observations of smoking as a possible protective factor in PSC.
While PSC is not a common disease, it is a severe condition affecting mostly young adults (30-40 years), and with a high risk of associated cancer of the bile ducts.
Few treatment options are available and PSC is one of the most important reasons for liver transplantation. While the possible protective effect of smoking against PSC seems rather unique to this particular liver disease, coffee consumption has been shown to protect against multiple other liver conditions including liver cirrhosis and liver cancer – and now for the first time also against PSC.
Background & Aims
Little is known about nongenetic risk factors for primary sclerosing cholangitis (PSC), except a possible protective effect of smoking. We investigated the relationship between environmental risk factors and susceptibility to PSC.
A questionnaire was distributed to patients with PSC, recruited from Oslo University Hospital Rikshospitalet in Norway through 2011, and randomly chosen individuals from the Norwegian Bone Marrow Donor Registry (control subjects). Data were analyzed from 240 patients with PSC and 245 control subjects, matched for gender and age.
A lower proportion of patients with PSC were daily coffee drinkers than control subjects, both currently (76% vs 86%; odds ratio [OR], 0.52; 95% confidence interval [CI], 0.32–0.82; P = .006) and at the age of 18 years (35% vs 49%; OR, 0.58; 95% CI, 0.40–0.83; P = .003). The associations were mainly attributed to differences observed in men. Twenty percent of the patients were ever (current or former) daily smokers compared with 43% of control subjects (OR, 0.33; 95% CI, 0.22–0.50; P < .001). Ever daily smoking before PSC diagnosis was associated with older age at diagnosis (42 years vs 32 years; P < .001). Ever daily smoking (P < .001) and being a coffee drinker at the age of 18 years (P = .048) were independently and negatively associated with PSC. Fewer female patients with PSC than control subjects reported ever use of hormonal contraception (51% vs 85%; P < .001). Among female patients, there was a strong correlation between increasing number of children before the diagnosis of PSC and increasing age at diagnosis (r = 0.63; P < .001).
Coffee consumption and smoking might protect against development of PSC. In women, the disease might be influenced by hormonal factors.