Secondhand smoke and breast health awareness among Vietnamese American families in California: A mixed methods study

Introduction: Tobacco exposure is a preventable breast cancer risk factor. High smoking rates among Vietnamese American (VA) men place VA women at elevated secondhand smoke exposure (SHSe) risk; yet research on the extent to which VA women are aware of SHSe and breast cancer risk is limited. Methods: This community-partnered, mixed-methods, cross-sectional study examined SHSe prevalences, knowledge, attitudes, and beliefs about SHSe as a breast cancer risk factor among VA women (aged 18-65 years) and explored multilevel factors contributing to SHSe within VA families in Southern California, December 2024 - January 2026. We recruited self-identifying VA women (n=179) via a community-based, snowball strategy for a 30 min survey, and then conducted 60 min one-on-one interviews with 22 VA individuals (11 family dyads). Results: Current SHSe prevalence was 43% (vs 25.2% nationally); 52.0% reported indoor SHSe during childhood. Only 63.7% had explicit home smoking rules, despite 99.4% believing SHSe affects children's health and 85.2% linking SHSe to increased breast cancer risk. A Rapid Group Analysis Process of the interview data revealed 3 themes, corroborating survey findings: 1) Religious/spiritual influences led participants to attribute health outcomes to fate or divine will, undermining preventive behaviors and beliefs, 2) A lack of available health information contributed to uncertain/diverging views on breast cancer causes; and 3) Non-smoker women expressing challenges navigating familial smoking-related tension while maintaining relational harmony. Conclusions: Our findings highlight the importance of family-centered communication while accounting for gender-related tension and family roles to promote cessation, breast cancer prevention and smoke-free spaces.