ASPO Abstracts
Prospective study of the association between garlic supplements with cancer incidence and mortality in the PLCO screening trial
Category: Lifestyles Behavior, Energy Balance & Chemoprevention
Conference Year: 2019
Abstract Body:
PURPOSE: To examine the association between garlic supplement use and risk of all cancerincidence and mortality and specific cancers in the Prostate, Lung, Colorectal, and Ovarian (PLCO)screening trial. METHODS: The PLCO study was a randomized controlled screening trial designed to assesswhether screening exams for prostate, lung, colorectal, and ovarian cancers reduced morality across tenstudy centers in the United States. Among 154,897 randomized participants aged 55-74 years old, 88,984 completed avalid dietary history questionnaire and reported garlic supplement use in both the intervention and controlarms. Garlic supplement users were defined as those who have taken garlic supplements at least 25 times in theirlifetime; non-users were those who had not. Hazard ratios (HRs) and 95% confidence intervals were calculated withCox proportional hazards model, adjusted for confounders including age, sex, study center, randomizationarm, and smoking. Follow-up time was calculated from the completion of the dietary questionnaire until theoccurrence of diagnosis of cancer, death, or the end of follow-up, whichever occurred first.RESULTS: After median follow-up of 12.4 years, there were 13,061 incident cancer cases and2,977 cancer deaths. Among all eligible participants, 14.42% were garlic supplement users and 85.58%were non-users. Garlic supplement users were more likely to be female (52.07% vs. 47.93%), drink less (9.73 g/day± 25.71 vs. 8.73 g/day ± 23.76) and smoke less (16.98 years ± 25.72 vs. 18.02 years ± 26.94). Garlicsupplement use was inversely associated with all cancer incidence (adjusted HR=0.93, 95% CI: 0.88, 0.98);however, the association with total cancer mortality showed a reduced but non-significant association (adj.HR=0.95, 95% CI: 0.86, 1.06). In analyses of site-specific incidence and mortality, there was an indication for reducedrisk of breast and prostate cancer; however, the results were no longer significant after adjustment (adj. HR=0.89,95% CI: 0.77, 1.02; adj. HR=0.93 95% CI: 0.85, 1.03, respectively).CONCLUSIONS: We observed a small significant decrease in risk of total cancer incidenceand reduced but non-significant decrease for total cancer mortality, associated with garlic supplements.
Keywords: chemoprevention,garlic, supplements