Abstract 632: Associations of coffee and tea consumption with lung cancer risk: A pooled analysis of 17 cohort studies involving over 1.2 million participants
Authors: Zhu Jingjing , Zheng Wei , Sinha Rashimi , Smith-Warner Stephanie A. , Xiang Yong-Bing , Park Yikyung , Tsugane Shoichiro , White Emily , Koh Woon-Puay , Park Sue K. , Sawada Norie , Kanemura Seiki , Sugawara Yumi , Tsuji Ichiro , Robien Kim , Tomata Yasutake , Yoo Keun-Young , Kim Jeongseon , Yuan Jian-Min , Gao Yu-Tang , Takata Yumie , Saito Eiko , Blot William , Shu Xiao-Ou 
Published: August 2019

Abstract
Background
Epidemiological studies investigating the associations of coffee and tea intake with lung cancer risk have yielded inconsistent results. These previous studies included mostly lung cancer patients diagnosed among smokers. Because coffee and tea consumption are closely related to smoking behavior, these previous studies could suffer from biases due to residual confounding of smoking. To better characterize the relationship, a large study with a large number of lung cancer cases diagnosed among never smokers and detailed information on tea and coffee consumption, is needed. Using data from a large-scale pooled analysis that consists of over 1.2 million participants in the U.S. and Asia, we carried out a comprehensive evaluation on the association of coffee and tea intake with lung cancer risk.
Methods
Individual-level data from seven prospective cohort studies conducted in the U.S., and ten studies conducted in Asia, were included. Demographic, lifestyle, coffee and tea intake data were collected at the baseline survey for each study. Multivariable-adjusted Cox proportional hazard models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs). The first 2 years of follow-up time was excluded to minimize potential influence of reverse causality on study results. Subgroup analyses by smoking status, sex, race, histologic subtype and coffee type (caffeinated or decaffeinated) were also conducted to assess potential effect modification, as well as heterogeneity of the association.
Results
After a median follow-up of 8.6 years, 20,519 incident lung cancer cases were identified. Both coffee and tea consumption were associated with an increased risk of lung cancer. Comparing non-coffee and non-tea consumption, HRs for lung cancer associated with exclusive coffee drinkers (≥2 cups/day) among current, former and never smokers were 1.30 (95% CI, 1.15-1.47), 1.49 (1.27-1.74) and 1.41 (95% CI, 1.21-1.63), respectively. Similar positive associations were observed for caffeinated and decaffeinated coffee. The HRs associated with exclusive tea drinkers (&gt;2 cups/day) were 1.16 (95% CI, 1.02-1.32), 1.10 (0.92, 1.32) and 1.37 (95% CI, 1.17-1.60) for current, former and never smokers, respectively. These associations did not differ significantly by sex, race or histologic subtypes.
Conclusion
A high consumption of coffee or tea was both associated with an increased risk of lung cancer regardless of race or smoking status. Our study included a large number of never-smoker lung cancer patients, which minimized potential confounding effects due to smoking. The positive association observed for both caffeinated and decaffeinated coffee suggests that compounds other than caffeine may play a role in the etiology of lung cancer.
Citation Format: Jingjing Zhu, Wei Zheng, Rashimi Sinha, Stephanie A. Smith-Warner, Yong-Bing Xiang, Yikyung Park, Shoichiro Tsugane, Emily White, Woon-Puay Koh, Sue K. Park, Norie Sawada, Seiki Kanemura, Yumi Sugawara, Ichiro Tsuji, Kim Robien, Yasutake Tomata, Keun-Young Yoo, Jeongseon Kim, Jian-Min Yuan, Yu-Tang Gao, Yumie Takata, Eiko Saito, William Blot, Xiao-Ou Shu. Associations of coffee and tea consumption with lung cancer risk: A pooled analysis of 17 cohort studies involving over 1.2 million participants [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 632.