Outcome Expectancies, Health Information Seeking, and Cancer Beliefs Associated with Multivitamin/Mineral Use in a National Sample, HINTS-FDA 2015.

Background: Dietary supplements, including multivitamins/minerals, are commonly reported by adults, yet little is known about multivitamin/mineral use in relation to information seeking, cancer-specific outcome expectancies, and cancer beliefs.

Objective: To examine the relationship of heath information seeking, beliefs about cancer, and outcome expectancies with multivitamin/mineral use within a national sample.

Design: A secondary analysis of data collected by The Health Information National Trends Survey (HINTS) and the US Food and Drug Administration (FDA) (HINTS-FDA 2015) was conducted. HINTS-FDA 2015 evaluated information seeking, beliefs about cancer, and health behaviors and was a self-administered, two-stage mail survey sent to a random sample of US postal addresses stratified by county smoking rates.

Participants: Adult household residents were invited to participate, resulting in a 33% response rate (n=3,738).

Main Outcome Measures: Participants self-reported use of multivitamin/mineral products.

Statistical Analyses: Adjusting for covariates (demographics, single-ingredient and herbal supplement use) weighted stepwise binary logistic regression was used to examine correlates of self-reported multivitamin/mineral use.

Results: Intake was associated with less than a high school education, having health insurance, and single-ingredient and herbal supplement use. Trust in health organizations (odds ratio [OR]=1.67, P<0.001) and the expectancy that cancer could be avoided with dietary supplements (OR=1.76, P<0.001) correlated with use. Agreement that supplements labeled as "anticarcinogenic" could treat (OR=3.07, P<0.001) or prevent cancer (OR=6.06, P<0.001) correlated with multivitamin/mineral use. Fatalistic beliefs (P<0.001) and negative information-seeking experiences (P<0.001) were associated with slightly lower odds of use.

Conclusions: Despite leading health organizations' discouragement of dietary supplements for cancer prevention, this study found that trust in health organizations and outcome expectancies were associated with multivitamin/mineral use. This divergence presents a need to explore how dietary supplement evidence based recommendations can be translated and disseminated for the public.