Prospective Cohort Study of Ginseng Consumption in Association with Cancer Risk: Shanghai Women's Health Study

Background: Ginseng has been commonly used in Asian countries to promote longevity and health for >2000 years. Recent in vitro and in vivo studies, coupled with limited epidemiologic studies, have suggested that regular ginseng consumption may be related to lower cancer risk.Objectives: We evaluated the association of ginseng consumption with risk of total and 15 site-specific cancers in a large cohort study conducted among Chinese women. Given the previous literature on ginseng consumption and cancer risk, we hypothesized that ginseng consumption might be associated with varying risks of cancer. Methods: This study included 65,732 female participants (mean age: 52.2 years) of the Shanghai Women's Health Study, an ongoing prospective cohort study. Baseline enrollment occurred between 1997 and 2000, and follow-up concluded on 31 December 2016. Ginseng use and covariates were assessed via an in-person interview conducted at the baseline recruitment. The cohort was followed for cancer incidence. Cox proportional hazard models were used to estimate HRs and 95% CIs for ginseng-cancer associations after adjusting for confounders.Results: During a mean 14.7 years of follow-up, 5067 incident cancer cases were identified. Overall, regular ginseng use was mostly not associated with risk of any site-specific cancer, or all cancers combined. Short-term (<3 years) ginseng use was found to be significantly associated with increased risk of liver cancer (HR = 1.71; 95% CI: 1.04, 2.79; P = 0.035), whereas long-term (>3 years) ginseng use was found to be associated with increased risk of thyroid cancer (HR = 1.40; 95% CI: 1.02, 1.91; P = 0.036). Long-term ginseng use was found to be significantly associated with decreased risk of lymphatic and hematopoietic tissue malignancy (HR = 0.67; 95% CI: 0.46, 0.98; P = 0.039) and non-Hodgkin's lymphoma (HR = 0.57; 95% CI: 0.34, 0.97; P = 0.039).Conclusions: This study provides suggestive evidence that ginseng consumption may be associated with risk of certain cancers.