Effect of web-based messages on girls' knowledge and risk perceptions related to cigarette smoke and breast cancer: 6-month follow-up of a randomized controlled trial.

Compared with standard messages, targeted gender-sensitive, breast cancer-specific messages had a stronger influence on girls' knowledge and perceived risk of cigarette smoke exposure as a risk factor for breast cancer. Brief information-based interventions delivered over the Internet have the potential to provide effective health promotion that could be broadly disseminated and lead to long-term effects on girls' knowledge and risk perceptions about cigarette exposure and breast cancer.