Use of dietary supplements and over-the-counter products among adults with a self-reported history of cancer in Poland

Dietary supplement and over-the-counter product use is common among people with a history of cancer and may raise safety concerns, including treatment interactions. We assessed the frequency, patterns, temporal variation and correlates of dietary supplement and over-the-counter product use among adults with a self-reported history of cancer in Poland. We performed a repeated cross-sectional analysis of six annual waves (2020–2025) of a nationwide quota-based web survey in Poland. Among 1,271,102 respondents overall, 79,588 reported a history of cancer. Dietary supplement and over-the-counter product use in the previous 12 months was assessed by frequency and reported product category or purpose of use. Correlates of any dietary supplement and over-the-counter product use were examined using multivariable logistic regression. Any dietary supplement and over-the-counter product use was reported by 61.8% of respondents, including daily use in 26.9%, whereas 38.2% reported no use. The most frequently selected categories were multivitamins, digestive products, hair/skin products and sleep products. Men and older respondents had lower odds of dietary supplement and over-the-counter product use, whereas higher education and coexisting non-cancer comorbidities were associated with greater odds of use. Dietary supplement and over-the-counter product use was frequently reported among respondents and showed distinct sociodemographic and health-related patterns. Including these products in routine medication histories may help identify potential interactions and other clinically relevant issues.