AUTHOR=Jiang Zongze , Chen Huilin , Li Ming , Wang Wei , Long Feiwu , Fan Chuanwen 

TITLE=Garlic consumption and colorectal cancer risk in US adults: a large prospective cohort study

JOURNAL=Frontiers in Nutrition

VOLUME=10

YEAR=2023

URL=https://www.frontiersin.org/journals/nutrition/articles/10.3389/fnut.2023.1300330

DOI=10.3389/fnut.2023.1300330

ISSN=2296-861X

ABSTRACT=<sec><title>Objective</title><p>To clarify the inconsistent findings of epidemiological studies on the association between dietary garlic consumption and colorectal cancer (CRC) incidence, by prospectively assessing the association in a large US population.</p></sec><sec><title>Methods</title><p>Data of 58,508 participants (aged 55–74) from the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial were analyzed. Dietary data were collected using a validated questionnaire. Multivariable Cox regression analysis determined hazard ratio (HR) and 95% confidence interval (CI). Restricted cubic spline regression was used to investigate the non-linear relationship, and subgroup analysis was conducted to examine potential effect modifiers.</p></sec><sec><title>Results</title><p>During a median follow-up of 12.05 years, 782 CRC cases were documented, including 456 proximal colon cancer cases, 322 distal CRC cases, and 4 CRC cases with an unknown site. Moderate dietary garlic consumption was significantly associated with a reduced risk of overall CRC (HR<sub><italic>quintile</italic> 3<italic>vs</italic>. 1</sub>: 0.70, 95% CI: 0.54 to 0.91, <italic>p</italic> = 0.007, <italic>P</italic> for trend: 0.434), exhibiting a U-shaped dose-response pattern, and also with overall CRC in males in the stratified Cox regression model (Model 2: HR<sub><italic>quintile</italic> 3<italic>vs</italic>. 1</sub>: 0.57, 95% CI: 0.40 to 0.81, <italic>p</italic> = 0.002), but not in females. The protective association was more pronounced in men, Caucasian, and those with lower alcohol consumption. Notably, these protective effects were observed for overall distal CRC (HR<sub><italic>quintile</italic> 3<italic>vs</italic>. 1</sub>: 0.62, 95% CI: 0.42 to 0.93, <italic>p</italic> = 0.021; and HR<sub><italic>quintile</italic> 4<italic>vs</italic>. 1</sub>: 0.63, 95% CI: 0.43 to 0.92, <italic>p</italic> = 0.018, <italic>P</italic> for trend: 0.208); and for distal CRC in males (HR<sub><italic>quintile</italic> 3<italic>vs</italic>. 1</sub>: 0.40, 95% CI: 0.22 to 0.71, <italic>p</italic> = 0.002, <italic>P</italic> for trend: 0.696), but not for proximal CRC.</p></sec><sec><title>Conclusion</title><p>Moderate consumption of dietary garlic is associated with a decreased CRC risk in the US population, with variations based on CRC anatomic subsites. Further in-depth prospective studies are needed to validate these findings in different populations and to explore subsites-specific associations.</p></sec>