An association between cholelithiasis and prostate cancer has been reported sporadically in previous case-control and experimental studies, suggesting that cholesterol may play a promotional role in prostate cancer development and progression. However, this relationship remains poorly understood, and population evidence based on a strict study design is needed. The authors examined the history of cholelithiasis and the development of prostate cancer in the Ohsaki cohort followed from 1995 to 2003, in which 230 new cases of prostate cancer were ascertained among 22,458 Japanese men. Baseline information, including history of cholelithiasis, was collected using a self-administered questionnaire. The Cox proportional hazards regression model was used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs). The results showed that patients with a history of cholelithiasis had a higher risk of prostate cancer with a multivariate adjusted HR of 1.72 (95% CI: 1.12-2.66), and especially for advanced prostate cancer, the corresponding value was 2.29 (95% CI: 1.21-4.35). The associations were robust after adjustment for different potential confounders. This population-based prospective cohort study indicates that a history of cholelithiasis is associated with an increased incidence of prostate cancer.The incidence and mortality of prostate cancer has been increasing rapidly and is one of the major cancers affecting men, both in Japan and worldwide.1-4 However, its etiology and pathogenesis remain poorly understood.5 Previous studies have suggested that cholesterol may play a signal transduction role that promotes tumor cell growth during the development and progression of prostate cancer, 6 and that use of statin is associated with a decreased risk of advanced prostate cancer. 7 As cholelithiasis (gallstone disease) is related to cholesterol metabolism, it may further impact the carcinogenesis of prostate cells. Regarding the association between cholelithiasis and prostate cancer, one ecological study and one case-control study have been reported. 8,9 Both studies suggested such an association, but it needs to be further verified using a prospective designed study. Therefore, we examined the association between history of cholelithiasis and the risk of prostate cancer to further clarify this association using data from a population-based cohort study conducted in Japan.
Material and Methods
Study populationThe Ohsaki National Health Insurance (NHI) cohort study was a population-based prospective study conducted in Miyagi Prefecture, northeastern Japan. A detailed description of the design and methods is available elsewhere. [10][11][12] Briefly, all NHI beneficiaries aged 40-79 years living in the catchment area of the Ohsaki Public Health Center were involved in 1995, when baseline characteristics (such as basic information, history of cholelithiasis, and health-related lifestyle factors) were collected through a self-administered questionnaire. The Ohsaki Public Health Center, a local government agency, provi...