Female reproductive and hormonal factors and lung cancer mortality among never‐smokers: A prospective cohort study of 287 408 Chinese women

Abstract

There is growing, but inconsistent evidence suggesting oestrogen may play a key role in lung cancer development, especially among never-smoking women for whom lung cancer risk factors remain largely elusive. Using the China Kadoorie Biobank, a largescale prospective cohort with 302 510 women aged 30 to 79 years recruited from 10 regions in China during 2004 to 2008, we assessed the risk of lung cancer death among self-reported never-smoking women who were cancer-free at baseline, in relation to age at menarche, age at menopause, time since menopause, prior use of oral contraceptives (OCP), number of livebirths, breastfeeding and age at first livebirth. Women were followed up to December 31, 2016 with linkage to mortality data. Hazard ratios (HR) and 95% confidence intervals (CI) were estimated using Cox regression, adjusting for key confounders including several socio-demographic, environmental and lifestyle factors. Among 287 408 never-smoking women, 814 died from lung cancer with a median follow-up of 10.3 years. Women who had used OCP within 15 years prior to baseline had a significantly higher hazard of lung cancer death compared with never-users: HR = 1.85 (95% CI: 1.14-3.00) and risk increased by 6% with each additional year of use: HR = 1.06 (1.01-1.10). Among parous women, the hazard of lung cancer death increased by 13% with each single livebirth: HR = 1.13 (1.05-1.23); and among post-menopausal women, the risk increased by 2% with each year since menopause: HR = 1.02 (1.01-1.04). These results suggest that reproductive factors which were proxies for lower endogenous oestrogen level, for example, longer duration of OCP use, could play a role in lung cancer development.

Sexual quality of life between healthy women and women with gynecological cancer: Results of a hospital‐based case–control study in Türkiye

“…Women with gynecological cancer who smokers had worse sexual quality of life. Smoking was causing chronic diseases by disrupting the function of many systems, including the genital system 25 . Because gynecological cancers had a negative impact on women's sexual quality of life in our study and other chronic diseases associated with cancer worsen the quality of sexual life 22,23,26 .…”

Patient's experiences of coughing after lung cancer surgery: A multicenter qualitative study

“…A study in Barcelona found that females had higher rates of anxiety, depression, and poorer health than males 30 . This may be because females are more sensitive and pay more attention to body changes than males 31,32 . This suggests that medical staff should consider the sex differences between male and female patients when providing personalized nursing and psychological support for female patients to improve their overall health.…”

Reproductive factors and risk of lung cancer among 300,000 Chinese female never-smokers: evidence from the China Kadoorie Biobank study

“…These overall results were consistent with findings from a cohort of 107,171 postmenopausal nurses in the US [ 40 ], although the association was not statistically significant among our postmenopausal group, which might be due to its small size. A previous study on mortality among never-smokers in CKB ( n = 814 lung cancer deaths) reported a significant trend of lung cancer mortality associated with duration of OC use with users for ≥ 10 years had almost twice the risk of developing lung cancer (1.97, 1.24–3.13) compared to never-users [ 13 ]. However, the latter study was limited by the very small number of cases among OC users (< 100).…”

“…The sex differences in lung cancer risk and prognosis are well documented with studies suggesting a higher risk of lung cancer among females at any given tobacco smoke exposure compared to males [ 10 ]; hence, questions have been raised on the possible role of oestrogen and other hormonal factors in lung cancer development and survival [ 11 – 13 ]. Existing evidence on the association of reproductive factors (as proxies of endogenous oestrogen exposure) with the risk of lung cancer has been inconclusive [ 14 – 17 ].…”

“…Most previous studies on reproductive factors and the risk of lung cancer among Chinese females were limited by small sample sizes (< 1000 participants), short follow-up duration (< 5 years), restricted to a single geographical region in the country or focused only on mortality [ 13 , 28 – 30 ]. The present study utilised data from China Kadoorie Biobank (CKB), a population-based prospective cohort with > 300,000 Chinese females recruited from ten geographical regions in China, to assess the associations of reproductive characteristics with incident lung cancer risk among Chinese female never-smokers.…”