Abstract 4200: Association between reproductive factors with lung cancer incidence and mortality: A pooled analysis of over 308,000 females in the Asia Cohort Consortium
Authors: Yin Xin , Kishida Rie , Abe Sarah Krull , Islam Md. Rashedul , Rahman Md. Shafiur , Saito Eiko , Lan Qing , Bletcher Batel , Merritt Melissa , Choi Ji-Yeob , Shin Aesun , Katagiri Ryoko , Shu Xiao-Ou , Sawada Norie , Tamakoshi Akiko , Koh Woon-Puay , Tsuji Ichiro , Nagata Chisato , Park Sue K. , Kweon Sun-Seog , Gao Yu-Tang , Tsugane Shoichiro , Kimura Takashi , Yuan Jian-Min , Lu Yukai , Kanemura Seiki , Sugawara Yumi , Wada Keiko , Shin Min-Ho , Ahsan Habibul , Boffetta Paolo , Chia Kee Seng , Matsuo Keitaro , Qiao You-Lin , Rothman Nathaniel , Zheng Wei , Inoue Manami , Kang Daehee , Seow Wei Jie 
Published: April 2023

Abstract
Background: Previous studies have investigated the association between reproductive factors and lung cancer risk; however, findings have been inconsistent. This study aims to assess the association between reproductive factors with lung cancer incidence and mortality among Asian women.
Methods: A total of 308,949 female participants with a mean age of 55.13 from 11 prospective cohorts and four Asian countries (Japan, Korea, China, and Singapore) in the Asia Cohort Consortium (ACC) were included. Cox proportional hazards regression models were used to estimate the hazard ratios (HR) and 95% confidence intervals (CIs).
Results: A total of 3,119 primary lung cancer cases and 2,247 lung cancer deaths were identified with a mean follow-up of 16.4 years. Parous women had a lower risk of lung cancer incidence and mortality as compared with nulliparous women, with HRs of 0.82 (95% CI = 0.70 - 0.96) and 0.78 (95% CI = 0.65 - 0.94). Corresponding HRs were lowest among women with 1-2 children, with HRs of 0.78 (95% CI = 0.66 - 0.93) and 0.72 (95% CI = 0.59 - 0.87) for lung cancer incidence and mortality. The protective association of parity and lung cancer incidence was greater among ever-smokers (HR=0.66, 95% CI = 0.49 - 0.87) than in never-smokers (HR=0.90, 95% CI = 0.74 - 1.09) (P-interaction = 0.029). Compared with age at first delivery ≤20 years, older age at first delivery (≥26 years) was associated with a lower risk of lung cancer incidence and mortality. Compared with age at menopause &lt;45 years, older age at menopause (≥55 years) was associated with a decreased risk of lung cancer mortality (HR=0.75, 95% CI = 0.58 - 0.96). Women who ever used hormone replacements had a higher likelihood of developing non-small cell lung cancer (HR = 1.30, 95% CI = 1.01 - 1.67), compared to those who never used hormone replacements.
Conclusions: Distinct from Western women, Asian parous women, especially those who have 1-2 children had a lower risk of lung cancer incidence and mortality compared with nulliparous women. Future studies are needed to assess the underlying mechanisms, the relationships within these female reproductive factors, and the potential changes in smoking habits over time.
Citation Format: Xin Yin, Rie Kishida, Sarah Krull Abe, Md. Rashedul Islam, Md. Shafiur Rahman, Eiko Saito, Qing Lan, Batel Bletcher, Melissa Merritt, Ji-Yeob Choi, Aesun Shin, Ryoko Katagiri, Xiao-Ou Shu, Norie Sawada, Akiko Tamakoshi, Woon-Puay Koh, Ichiro Tsuji, Chisato Nagata, Sue K. Park, Sun-Seog Kweon, Yu-Tang Gao, Shoichiro Tsugane, Takashi Kimura, Jian-Min Yuan, Yukai Lu, Seiki Kanemura, Yumi Sugawara, Keiko Wada, Min-Ho Shin, Habibul Ahsan, Paolo Boffetta, Kee Seng Chia, Keitaro Matsuo, You-Lin Qiao, Nathaniel Rothman, Wei Zheng, Manami Inoue, Daehee Kang, Wei Jie Seow. Association between reproductive factors with lung cancer incidence and mortality: A pooled analysis of over 308,000 females in the Asia Cohort Consortium. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4200.