Does smoking cause breast cancer?
Smoking and using tobacco products are linked to an increased risk of developing several types of cancer, including breast cancer risk, particularly with long-term or heavy exposure. There is no safe level of tobacco use.
While there is currently no definitive clinical proof that vaping directly causes or increases breast cancer risk, early studies suggest that vaping causes cellular damage and promotes tumor growth, potentially helping breast cancer cells spread.
Sources:
National Cancer Institute
National Institutes of Health