Background: Use of the dietary supplement glucosamine has been associated with reduced risk of colorectal cancer; however, it remains unclear if the association varies by screening status, time, and other factors.
Methods: We therefore evaluated these questions in UK Biobank. Multivariable-adjusted HRs and 95% confidence intervals (95% CI) were estimated using Cox proportional hazards regression.
Results: No association was observed between use of glucosamine and risk of colorectal cancer overall (HR = 0.94; 95% CI, 0.85-1.04). However, the association varied by screening status (Pinteraction = 0.05), with an inverse association observed only among never-screened individuals (HR = 0.86; 95% CI, 0.76-0.98). When stratified by study time, an inverse association was observed in early follow-up among those entering the cohort in early years (2006-2008; HR = 0.80; 95% CI, 0.67-0.95). No heterogeneity was observed by age, sex, body mass index, smoking status, or use of nonsteroidal anti-inflammatory drugs.
Conclusions: While there was no association between glucosamine use and colorectal cancer overall, the inverse association among never-screened individuals mirrors our observations in prior exploratory analyses of U.S. cohorts. The National Health Service Bowel Cancer Screening Program started in 2006 in England and was more widely implemented across the UK by 2009/2010. In line with this, we observed an inverse association limited to early follow-up in those surveyed from 2006 to 2008, before screening was widely implemented.
Impact: These data suggest that unscreened individuals may benefit from use of glucosamine; however, further studies are needed to confirm the interplay of screening and timing.
©2022 American Association for Cancer Research.