Mengjie Li1, Qiuyin Cai1, Yu-Tang Gao2, Adrian A Franke3, Xianglan Zhang4, Yingya Zhao1, Wanqing Wen1, Qing Lan5, Nathaniel Rothman5, Yu Shyr6, Xiao-Ou Shu1, Wei Zheng1, Gong Yang1. 1. Division of Epidemiology, Department of Medicine, Vanderbilt University Medical Center and Vanderbilt-Ingram Cancer Center, Nashville, TN, USA. 2. Shanghai Cancer Institute, Renji Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China. 3. University of Hawaii Cancer Center, University of Hawaii at Manoa, Honolulu, HI, USA. 4. Tennessee Department of Health, Nashville, TN, USA. 5. Division of Cancer Epidemiology and Genetics, Occupational and Environmental Epidemiology Branch, National Cancer Institute, Bethesda, MD, USA. 6. Department of Biostatistics, Vanderbilt University Medical Center, Nashville, TN, USA.
Abstract
BACKGROUND: Since several lines of evidence suggest that estrogens may be involved in lung carcinogenesis, it has been hypothesized that intake of phytoestrogens, similar in molecular structure to mammalian estrogens, may be associated with lung cancer development. OBJECTIVE: The aim was to prospectively evaluate the association between phytoestrogen exposure and lung cancer risk in never-smoking women. METHODS: We conducted a nested case-control study within a population-based prospective cohort study of women. A total of 478 incident lung cancer cases and their individually matched controls were identified among never-smoking women after a mean follow-up of 15.6 years. Habitual intake of and internal exposure to phytoestrogens were assessed by repeated dietary surveys and urinary biomarkers, respectively. ORs and 95% CIs for lung cancer were estimated in conditional logistic regression models. RESULTS: After adjustment for potential confounders, a moderate intake of dietary isoflavones was inversely associated with lung cancer risk in never-smoking women, with the OR for the second quartile vs. the lowest quartile of intake being 0.52 (95% CI: 0.35, 0.76). Further increasing intake did not convey additional benefits, with ORs (95% CI) for the third and fourth quartiles of 0.53 (0.36, 0.78) and 0.47 (0.31, 0.72), respectively (P-overall < 0.001 and P-nonlinearity = 0.006). A similar association was seen when exposure to isoflavones was assessed by urinary biomarkers. ORs (95% CI) for the second, third, and fourth quartiles compared with the lowest quartile of urinary isoflavone excretion were 0.57 (0.39, 0.83), 0.64 (0.44, 0.92), and 0.60 (0.41, 0.86), respectively. The inverse association reached a plateau beyond the second quartile, with P-overall = 0.04 and P-nonlinearity = 0.15. Urinary excretion of gut-microbiota-derived metabolites of lignans was not related to lung cancer risk. CONCLUSIONS: This study suggests that moderately increasing intake of isoflavone-rich foods is associated with lower risk of lung cancer in never-smoking women.
BACKGROUND: Since several lines of evidence suggest that estrogens may be involved in lung carcinogenesis, it has been hypothesized that intake of phytoestrogens, similar in molecular structure to mammalian estrogens, may be associated with lung cancer development. OBJECTIVE: The aim was to prospectively evaluate the association between phytoestrogen exposure and lung cancer risk in never-smoking women. METHODS: We conducted a nested case-control study within a population-based prospective cohort study of women. A total of 478 incident lung cancer cases and their individually matched controls were identified among never-smoking women after a mean follow-up of 15.6 years. Habitual intake of and internal exposure to phytoestrogens were assessed by repeated dietary surveys and urinary biomarkers, respectively. ORs and 95% CIs for lung cancer were estimated in conditional logistic regression models. RESULTS: After adjustment for potential confounders, a moderate intake of dietary isoflavones was inversely associated with lung cancer risk in never-smoking women, with the OR for the second quartile vs. the lowest quartile of intake being 0.52 (95% CI: 0.35, 0.76). Further increasing intake did not convey additional benefits, with ORs (95% CI) for the third and fourth quartiles of 0.53 (0.36, 0.78) and 0.47 (0.31, 0.72), respectively (P-overall < 0.001 and P-nonlinearity = 0.006). A similar association was seen when exposure to isoflavones was assessed by urinary biomarkers. ORs (95% CI) for the second, third, and fourth quartiles compared with the lowest quartile of urinary isoflavone excretion were 0.57 (0.39, 0.83), 0.64 (0.44, 0.92), and 0.60 (0.41, 0.86), respectively. The inverse association reached a plateau beyond the second quartile, with P-overall = 0.04 and P-nonlinearity = 0.15. Urinary excretion of gut-microbiota-derived metabolites of lignans was not related to lung cancer risk. CONCLUSIONS: This study suggests that moderately increasing intake of isoflavone-rich foods is associated with lower risk of lung cancer in never-smoking women.
Authors: Olga K Weinberg; Diana C Marquez-Garban; Michael C Fishbein; Lee Goodglick; Hermes J Garban; Steven M Dubinett; Richard J Pietras Journal: Cancer Res Date: 2005-12-15 Impact factor: 12.701
Authors: Gretchen J Cutler; Jennifer A Nettleton; Julie A Ross; Lisa J Harnack; David R Jacobs; Carolyn G Scrafford; Leila M Barraj; Pamela J Mink; Kim Robien Journal: Int J Cancer Date: 2008-08-01 Impact factor: 7.396