Abstract 5315: Dietary intake and risk of lung cancer in non-smoking women: a hospital-based case-control study in Xuanwei and Fuyuan, China
Authors: Wong Jason Y. , Bassig Bryan A. , Hu Wei , Zhang Jinming , Seow Wei Jie , Caporaso Neil E. , Ji Bu-tian , Chapman Robert S. , Downward George S. , Li Jihua , He Jun , Yang Kaiyun , Huang Yunchao , Vermeulen Roel , Rothman Nathaniel , Lan Qing 
Published: July 2017

Xuanwei and Fuyuan are rural counties in China that have the highest lung cancer rates in the country among non-smoking women. This alarming public health burden has been attributed to the combustion of smoky (bituminous) coal for heating and cooking, which can produce carcinogenic emissions such as polycyclic aromatic hydrocarbons (PAHs). Previous studies found that green leafy vegetables could absorb PAHs through air and direct soil contamination. Further, oral ingestion of PAHs was found be to associated with pulmonary adenoma development in animal feeding studies. Therefore, we investigated the associations between lung cancer risk and dietary intake of specific green leafy vegetables and other foods in non-smoking women of this farming region.

We conducted a hospital-based case-control study of 1,074 female lung cancer patients and 977 frequency-matched controls from Xuanwei and Fuyuan, China in 2006-2013. Dietary intake was self-reported on questionnaires and categorized as never, several times/year, several times/month, several times/week, and every day. Unconditional logistic regression models were used to estimate the odds ratios (OR) and 95% confidence intervals (CI) of lung cancer in relation to intake of specific green leafy vegetables (i.e. lettuce, cabbage, fennel, spinach, hollow vegetables), corn, buckwheat, carrots, tomatoes, dried and fresh chili, pickled vegetables, bean curd, mushrooms, and preserved meats. Models were adjusted for age, county, first-degree relative with lung cancer, passive smoke exposure, education, lifetime smoky coal tonnage, respiratory disease history, time spent indoors, and menopausal status. Separate models were fitted for each dietary factor.

We found that increased consumption of several green leafy vegetables was associated with increased risk of lung cancer. Eating hollow vegetables every day was associated with 2.50 (95% CI: 1.18, 5.27) times the odds of lung cancer compared to never. Similarly, eating lettuce (OR=2.13, 95% CI: 1.41, 3.21) and cabbage (OR=1.82, 95% CI: 1.21, 2.69) every day was associated with increased risks compared to several times a year or less. Conversely, eating bean curd (OR=0.54, 95% CI: 0.40, 0.72) several times a week was associated with decreased risk compared to several times a year or less; while eating buckwheat (OR=0.59, 95% CI: 0.40, 0.89) several times a week was associated with decreased risk compared to never. No significant associations were found for fennel, spinach, and other foods.

Our findings suggest that increased consumption of a variety of green leafy vegetables may be related to elevated lung cancer risk in non-smoking women from Xuanwei and Fuyuan, China, independent of other risk factors. The increased risk may be due to environmental contamination of crops from coal combustion. Conversely, frequent consumption of bean curd and buckwheat was found to be protective.

Citation Format: Jason Y. Wong, Bryan A. Bassig, Wei Hu, Jinming Zhang, Wei Jie Seow, Neil E. Caporaso, Bu-tian Ji, Robert S. Chapman, George S. Downward, Jihua Li, Jun He, Kaiyun Yang, Yunchao Huang, Roel Vermeulen, Nathaniel Rothman, Qing Lan. Dietary intake and risk of lung cancer in non-smoking women: a hospital-based case-control study in Xuanwei and Fuyuan, China [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5315. doi:10.1158/1538-7445.AM2017-5315