Factors Associated with Long-Term Dietary Supplement Use among Korean Breast Cancer Survivors: A Cross-Sectional Study

Purpose: The factors associated with the dietary supplement (DS) use of Asian breast cancer survivors in consideration of the duration of use and types of DS have not been well established. Methods: We recruited 693 Korean female breast cancer survivors at two university-affiliated hospitals and collected study data through a self-administered questionnaire and a review of medical records. A multiple logistic regression analysis was conducted to evaluate the multivariable-adjusted association between DS use and study variables. Results: The prevalence of any (>= 2 weeks) and long-term (>= 6 months) DS use among study participants was 48.2% and 12.0%, respectively. Education level, alcohol use, adequate physical activity (>= 150 min/week), and time lapse after cancer diagnosis were positively associated with any DS use. Among DS users, as compared with short-term (>= 2 weeks and <6 months) users, long-term users were more likely to have a higher cancer stage, more diverse cancer treatment modalities, a shorter time since cancer diagnosis, and lower fear of cancer recurrence. When we repeated the analysis for each DS type, time lapse after cancer diagnosis showed a consistently inverse association with long-term use of the most frequently consumed DS (multivitamins, followed by vitamin D/calcium, vitamin C, and omega-3). The number of cancer treatment modalities was positively associated with the long-term use of multivitamins and vitamin D/calcium. Alcohol consumption and low bone mineral density were positively associated with long-term vitamin D/calcium use. Conclusions: The factors associated with DS use differed by the duration of DS use and specific DS type. Long-term DS use was more frequently associated with cancer-related factors.