Abstract
Primary sclerosing cholangitis and nongenetic risk factors Little is known about nongenetic risk factors for primary sclerosing cholangitis (PSC) besides a suggested protective effect of smoking. We aimed to study co-morbidities, tobacco and coffee consumption and female reproductive health in PSC patients compared to healthy controls. Methods: A questionnaire was sent to our PSC registry patients and healthy individuals in the Norwegian Bone Marrow Donor Registry. We included 245 PSC patients (70% male) and 245 randomly selected gender and age matched controls. Results: At least one immune-mediated disease excluding IBD was reported by 26% of the PSC patients and 11% of the controls. Ever (former or current) daily smoking was reported by 22.5% of the PSC patients and 45,3% of the controls (p= 1,1 x 10-7). The proportion of PSC patients drinking coffee was lower than in the controls both currently (76% vs 86%, p=0.008) and at the age of 18 (37,1% vs. 49%, p=0.006). In addition, a smaller proportion of the PSC patients reported coffee consumption at all. In women, number of children (1.8 vs. 1.6 children) were similar. However, fewer PSC patients reported ever using hormonal contraception than controls (48% vs 85%, p=2,9x10-6). Interestingly, there was a strong linear relationship between number of children and age at PSC diagnosis (r=0.63, p<0.001). Conclusions: Coffee consumption may be added to cigarette smoking as an environmental exposure possibly protecting against PSC. The negative association with hormonal contraception, and correlation between pregnancies and disease onset may indicate that hormonal factors influence gender differences and disease phenotype in PSC