Stimulation of Skin Pigmentation with UVR Is a Risk Factor for Cholelithiasis

Long-term clinical experience suggested that skin fairness is one of the risk factors for developing cholelithiasis. However, it was unclear how to connect skin color with the development of gallstones. The discovery of reactive melanin precursors resulted in the hypothesis that some of these compounds could be excreted via bile and form the basis of gallstones. There are indications that the excretion of these compounds from melanocytes is higher in individuals with less pigmented skin who were irradiated by UV radiation. A clinical study revealed that people with fair skin who like sunbathing run a very high risk of developing cholelithiasis. We also present several studies that report a significant increase in cholelithiasis among psoriasis patients. Most gallstones remain asymptomatic. However, some patients may develop symptoms shortly after the gallstones are formed. We cite several investigations that found the highest frequency of cholecystectomies and cases of acute pancreatitis in the summer and the lowest in the winter. We propose that skin fairness should be considered a real risk factor for cholelithiasis, but only in combination with UV stimulation of cutaneous pigmentation. In this review, we discuss the laboratory and clinical work that can be connected to this hypothesis.