Factors related to the use of dietary supplements by cancer survivors

Estimates of the use of complementary and alternative medicine (CAM) among cancer survivors vary widely. Dietary supplements are an important CAM therapy to examine because of their potential to interact with conventional cancer therapies. We estimated the prevalence of dietary supplement use in a population-based sample of cancer survivors of the 10 most common cancers and examined potential correlates of use.

This cross-sectional analysis included participants from the American Cancer Society's longitudinal Study of Cancer Survivors-I recruited in Connecticut who completed self-administered baseline and supplemental questionnaires. Using univariate and multivariate logistic regression, we examined demographic, clinical, and psychosocial predictors of dietary supplement use after cancer diagnosis.

Of the 827 cancer survivors, 573 (69.3%) reported using dietary supplements after their cancer diagnosis. Female gender [odds ratio (OR) = 1.72, 95% confidence interval (CI) = 1.25-2.36] and higher-education levels (OR = 5.44, 95% CI = 2.98-9.93) were significantly associated with supplement use. Common reasons for using dietary supplements included "something they could do to help themselves" (56.2%) and "to boost their immune system" (51.1%). Most survivors (82.4%) informed their physician of their supplement use. Patients obtained information from a variety of sources including physicians, friends or family, and magazines or books.

Use of dietary supplements after cancer diagnosis was quite common among this population-based sample of cancer survivors. Although gender and education were associated with use, it is important that clinicians discuss supplement use with all cancer survivors.