Dietary supplement use among adult cancer survivors: Results from a large cross-sectional study in Poland.

e13782 Background: Dietary supplement use is common among adults with a history of cancer and may reflect unmet needs and safety risks, including non-disclosure and potential interactions with anticancer and supportive therapies. We used a nationwide health survey in Poland to quantify the prevalence and patterns of supplement use among adults with self-reported cancer. Methods: We conducted a cross-sectional analysis of pooled data from six annual editions (2020–2025, n = 1,271,102 respondents) of a nationwide web-based survey (Medonet). The analysis was restricted to respondents with a self-reported history of cancer (N = 79,588; 6.3% of all respondents). Supplement use in the prior 12 months was captured by frequency and by declared type or purpose (multiple-choice). Data were presented as mean (standard deviations, SD), median (interquartile ranges IQR) or number (n, %), as appropriate; survey-wave differences were assessed with chi-squared tests. Predictors of any supplement use were analysed with multivariable logistic regression with p < 0.05 considered statistically significant. Results: Among 79,588 adult respondents with a self-reported history of cancer, 62.4% (n = 49,649) were women and the mean age was 62.05 years (SD 12.68). Any dietary supplement use in the prior 12 months was reported by 61.8% (n = 49,165), including daily use in 26.9% (n = 21,446) and use several times per week in 12.7% (n = 10,128); 38.2% (n = 30,423) reported no supplementation. The most frequently selected types or purposes (multiple answers; % of the total cohort, N = 79,588) were multivitamin preparations (32.5%, n = 25,827), digestive preparations (16.8%, n = 13,379), hair/skin preparations (13.2%, n = 10,467) and preparations facilitating sleep (9.8%, n = 7,765). Supplementation patterns differed across survey waves (p < 0.001), with no supplementation ranging from 33.1% (2021) to 42.3% (2025) and daily use from 30.2% (2021) to 26.2% (2025). In multivariable logistic regression, men had lower odds of any supplementation than women (adjusted odds ratio aOR 0.675; 95% confidence interval CI 0.654-0.698), odds decreased slightly with age (aOR 0.994 per year; 95% CI 0.992-0.996), higher education was strongly associated with use (vs primary: vocational aOR 1.128; 95% CI 1.018-1.250; secondary 1.637; 1.489-1.800; bachelor 2.117; 1.902-2.356; MSc 2.444; 2.218-2.693) and supplement use was more likely among respondents reporting non-cancer comorbidities (aOR 1.103; 95% CI 1.055-1.153). Conclusions: In this nationwide sample, dietary supplement use was common, including frequent daily intake and declined from 2021 to 2025. Use clustered by patient characteristics, being less likely in men and older respondents and more likely with higher education and non-cancer comorbidities. Routine assessment and counselling on supplement safety should be integrated into cancer care and follow-up.