Abstract 7370: Evaluations of lifestyle factors with biliary tract cancer risk in cohort studies including 742,906 Asian adults

Abstract Biliary tract cancer (BTC) is a rare, aggressive malignancy and incidence has globally increased 76% from 1990 to 2017. BTC incidence is higher in Asia than Europe and North America, yet studies evaluating BTC risk in Asian populations are limited. Herein we evaluate tobacco smoking, alcohol consumption, BMI, physical activity, and dietary factors with BTC risk. We evaluated 742, 906 adults enrolled in 14 cohort studies as part of the Asia Cohort Consortium. Represented countries include China, Japan, Korea, Bangladesh, India, and Iran. Participants completed baseline surveys which collected demographics, lifestyle characteristics, and medical histories, and were followed to identify cancer diagnoses. Participants were removed due to data only on cancer death, a baseline history of cancer or stroke, among other reasons. Cox regression was used to estimate hazard ratios and 95% confidence intervals describing risk of first primary incident BTC in pooled cohort data. Models were adjusted for age, sex, education, cohort study, diabetes, and BMI, where applicable. Some evaluations were stratified by sex due to differing smoking and drinking behaviors. The analyzed cohort includes 451, 053 participants with a median age of 54 years, follow-up time of 15.0 years, and 1, 300 incident BTC cases. More men than women reported ever smoking or drinking (76.9% vs 7.0%, 63.3% vs 8.0%, respectively). Alcohol consumption was positively associated with BTC risk in men [HR (95% CI) comparing >=60 to 0 grams/day was 1.48 (0.99-2.20), p-trend=0.02]. In both sexes, duration of smoking was positively associated with BTC risk [comparing >40 to 0 years: 1.40 (0.81-2.43), p-trend=0.008] as was high BMI [comparing ≥27.5 to 18.5-22.9: 1.36 (1.11-1.66), p-trend=0.002]. Physical activity was not associated with BTC risk [comparing moderate to minimal activity: 1.00 (0.77-1.28), p-trend=0.76]. Given that our study suggests that obesity, alcohol, and smoking may play an important role in the etiology of BTC, mitigating these conditions could combat the rising incidence of this fatal malignancy. Future plans include dietary evaluations, study-specific estimates combined with meta-analysis, and sensitivity analysis studying BTC death. Citation Format: Valerie Gunchick, Wei Zheng. Evaluations of lifestyle factors with biliary tract cancer risk in cohort studies including 742, 906 Asian adults [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 7370.