Dietary Supplements Use among Adults with Cancer in the United States: A Population-Based Study.

To assess the patterns of use of dietary supplements among cancer survivors in the United States in a population-based setting. National Health and Nutrition Examination Survey (NHANES) datasets (1999-2016) were accessed, and adult respondents (≥ 20 years old) with a known status of cancer diagnosis and a known status of dietary supplements intake were included. Multivariable logistic regression analysis was then used to assess factors associated with dietary supplements intake. Moreover, and to evaluate the impact of dietary supplements on overall survival among respondents with cancer, multivariable Cox regression analysis was conducted. A total of 49,387 respondents were included in the current analysis, including a total of 4,575 respondents with cancer. Among respondents with cancer, 3,024 (66.1%) respondents have reported the use of dietary supplements; while 1,551 (33.9%) did not report the use of dietary supplements. Using multivariable logistic regression analysis, factors associated with the use of dietary supplements included older age (OR: 1.028; 95% CI: 1.027-1.030); white race (OR for black race vs. white race: 0.67; 95% CI: 0.63-0.72); female gender (OR for males vs. females: 0.56; 95% CI: 0.53-0.59), higher income (OR: 1.13; 95% CI: 1.11-1.14), higher educational level (0.59; 95% CI: 0.56-0.63), better self-reported health (OR: 1.36; 95% CI: 1.17-1.58), health insurance (OR: 1.35; 95% CI: 1.27-1.44), and history of cancer (OR: 1.20; 95% CI: 1.10-1.31). Using multivariable Cox regression analysis and within the subgroup of respondents with a history of cancer, the use of dietary supplements was not found to be associated with a difference in overall survival (HR: 1.13; 95% CI: 0.98-1.30). Dietary supplement use has increased in the past two decades among individuals with cancer in the United States, and this increase seems to be driven mainly by an increase in the use of vitamins. The use of dietary supplements was not associated with any improvement in overall survival for respondents with cancer in the current study cohort.