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Purpose: To examine whether the detrimental smoking-related association with pancreatic cancer (PC) is the same for women as for men. Methods: We analyzed data from 192,035 participants aged 45–75 years, enrolled in the Multiethnic Cohort study (MEC) in 1993–1996. We identified PC cases via linkage to the Hawaii and California Surveillance, Epidemiology, and End Results Program cancer registries through December 2017. Results: During a mean follow-up of 19.2 years, we identified 1,936 incident PC cases. Women smokers smoked on average less than men smokers. In multivariate Cox regression models, as compared with sex-specific never smokers, current smokers had a similar elevated risk of PC for women, hazard ratio (HR) 1.49 (95% CI 1.24, 1.79) and as for men, HR 1.48 (95% CI 1.22, 1.79) (pheterogeneity: 0.79). Former smokers showed a decrease in risk of PC for men within 5 years, HR 0.74 (95% CI 0.57, 0.97) and for women within 10 years after quitting, HR 0.70 (95% CI 0.50, 0.96), compared with their sex-specific current smokers. Both sexes showed a consistent, strong, positive dose–response association with PC for the four measures (age at initiation, duration, number of cigarettes per day, number of pack-years) of smoking exposure among current smokers and an inverse association for years of quitting and age at smoking cessation among former smokers (all ptrend's < 0.001). Conclusion: Although MEC women smoke on average less than their men counterparts, the smoking-related increase in PC risk and the benefits of cessation seem to be of similar magnitudes for women as for men. [ABSTRACT FROM AUTHOR]

Background: The purpose of this study was to examine if the smoking-related higher breast cancer risk was similar for the five race/ethnicity groups in the Multiethnic Cohort (MEC) study and by oestrogen (ER) and progesterone (PR) receptor status.Methods: From 1993 to 2013, we followed 67 313 women who were enrolled in the MEC study at 45-75 years of age. We identified breast cancer cases and tumour receptor status via linkage to the Hawaii and California Surveillance, Epidemiology and End Results Program cancer registries through December 2013. We used Cox proportional hazards regression to estimate multivariable-adjusted hazard ratios with 95% confidence intervals (CI).Results: During a mean follow-up of 16.7 years, we identified 4230 incident, invasive breast cancer cases. Compared with parous never smokers, parous ever smokers who had smoked more than 5 years before their first live childbirth had a higher risk of breast cancer overall of 31% (95% CI: 1.14-1.51). This higher risk was 51% (95% CI: 1.05-2.16) for African Americans, 66% (95% CI: 1.10-2.50) for Native Hawaiians, 42% (95% CI: 1.13-1.78) for Whites, 37% (95% CI: 1.17-1.61) for ER-positive (ER+) tumours and 33% (95% CI: 1.11-1.59) for PR+ tumours. No difference was suggested by racial/ethnic groups (Pheterogeneity = 0.15) or tumour receptor status (Pheterogeneity = 0.60 by ER status and 0.95 by PR status).Conclusions: We find that the higher breast cancer risk related to smoking is similar across racial/ethnic groups and by ER and PR status, indicating that breast cancer should be considered as a smoking-related cancer. [ABSTRACT FROM AUTHOR]

We prospectively examined the association between smoking and the risk of breast cancer in a racially/ethnically diverse population comprising mainly women who did not drink alcohol. From 1993 to 2010, we followed 83,300 women who were enrolled in the Multiethnic Cohort Study at 45-75 years of age. We identified cancer cases via linkage to the Surveillance, Epidemiology, and End Results Program cancer registries that covered the states of Hawaii and California through December 2010. We used Cox proportional hazards models to estimate hazard ratios and 95% confidence intervals while adjusting for confounders that were decided a priori. During a mean follow-up of 15 years, 4,484 women developed invasive breast cancer. Compared with parous never smokers, women who had smoked for more than 20 pack-years and initiated smoking more than 5 years before their first childbirth had an overall risk of breast cancer that was 35% higher (hazard ratio = 1.35, 95% confidence interval: 1.13, 1.63). Among women who did not drink alcohol, the risk was 40% higher (hazard ratio = 1.40, 95% confidence interval: 1.08,1.81). This higher riskdid not significantly differ among racial/ethnic groups (Pinteraction = 0.82). We found that various measures of smoking exposure were associated with a higher risk of breast cancer, especially smoking initiated many years before first childbirth, and that risk did not differ by alcohol consumption (yes vs. no) or racial/ethnic group. [ABSTRACT FROM AUTHOR]