Glucosamine and chondroitin, typically taken to treat osteoarthritis and chronic joint pain, are among the most commonly used non-vitamin, non-mineral, specialty supplements in the United States. These supplements have been shown to exhibit anti-inflammatory and anti-cancer properties in vitro and in vivo. Inflammation is thought to play an important role in cancer etiology and progression at several anatomic sites, including the lung. Studies have reported inverse associations of non-steroidal anti-inflammatory drug (NSAID) use and lung cancer risk; however, none have examined long-term use of glucosamine and chondroitin with lung cancer risk.

The VITamins And Lifestyle (VITAL) study is a large, prospective cohort study designed to investigate the association of vitamin, mineral, and specialty supplements with cancer risk. Previously in this cohort, we found that glucosamine and chondroitin were inversely associated with lung cancer risk. We now evaluate these specific associations in more detail (by amount of use, histological subtypes of cancer) with an additional year of follow-up. Participants included 76,904 adults, 50-76 years, with no history of lung cancer, who were living in the region of western Washington State included in the Surveillance, Epidemiology, and End Results (SEER) cancer registry, and who completed a baseline questionnaire in 2000-2002. After 6 years of follow-up, 807 lung cancer cases were accrued. We characterized glucosamine and chondroitin use in the 10 years before baseline as non-use; low: <4 days/week or <4 years; high: ≥3 days/week and ≥4 years. We used multivariable-adjusted Cox regression to estimate hazard ratios (HR) and 95% confidence intervals (CI) for the association of glucosamine and chondroitin with lung cancer risk.

Compared to non-use, high use was associated with a linear 33% reduction in risk (HR 0.67, 95% CI: 0.56-1.07, P-trend=0.04). There was no clear trend with high chondroitin use (HR 0.96, 95% CI: 0.67-1.37, P-trend=0.21). When stratified by histologic type, high use of glucosamine (HR 0.49, 95% CI: 0.27-0.90, P-trend<0.01) or chondroitin (HR 0.69, 95% CI: 0.36-1.31, P-trend=0.03) was strongly and inversely associated with risk of adenocarcinoma but not small cell or other non-small cell lung cancers. Factors associated with inflammation, including smoking, chronic-obstructive pulmonary disease, osteoarthritis, and NSAID use, did not modify these associations.

The strength of the associations we observed is similar to those reported from studies of NSAIDs and lung cancer risk. Unlike NSAIDs, glucosamine and chondroitin carry few known adverse effects. Although confirmatory studies are needed, glucosamine and chondroitin may be potential lung cancer chemopreventive agents.

Supported by NCI grants R25-CA94880, R01-CA154512, and K05-CA154337

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1912. doi:10.1158/1538-7445.AM2011-1912