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Accepted for/Published in: Journal of Medical Internet Research

Date Submitted: Oct 26, 2020
Open Peer Review Period: Oct 23, 2020 - Dec 18, 2020
Date Accepted: Feb 4, 2021
Date Submitted to PubMed: Apr 22, 2021
(closed for review but you can still tweet)

The final, peer-reviewed published version of this preprint can be found here:

Determinants of Knowledge About Dietary Supplements Among Polish Internet Users: Nationwide Cross-sectional Study

Karbownik MS, Horne R, Paul E, Kowalczyk E, Szemraj J

Determinants of Knowledge About Dietary Supplements Among Polish Internet Users: Nationwide Cross-sectional Study

J Med Internet Res 2021;23(4):e25228

DOI: 10.2196/25228

PMID: 33658173

PMCID: 8100877

Warning: This is an author submission that is not peer-reviewed or edited. Preprints - unless they show as "accepted" - should not be relied on to guide clinical practice or health-related behavior and should not be reported in news media as established information.

Determinants of knowledge about dietary supplements among Polish Internet users with no medical education: a nation-wide cross-sectional study

  • Michał Seweryn Karbownik; 
  • Rob Horne; 
  • Ewelina Paul; 
  • Edward Kowalczyk; 
  • Janusz Szemraj

ABSTRACT

Background:

Having true beliefs about dietary supplements is a prerequisite for informed decision regarding their intake. However, there is a need for studies of the public understanding of dietary supplements based on validated research tools.

Objective:

To assess knowledge about dietary supplements in Polish Internet users with no medical education, to identify its determinants and design an appropriate predictive model.

Methods:

Study protocol with statistical analysis plan was prospectively registered. Polish users of an online health service and a social networking service were administered a survey consisting of the recently-developed Questionnaire on Knowledge about Dietary Supplements, Questionnaire on Trust in Advertising Dietary Supplements, Beliefs about Medicines Questionnaire, as well as several other health related single-item measures and sociodemographic questions. The results were subjected to general linear modeling.

Results:

In total, 6273 participants were included. Out of 17 yes/no questions in the Questionnaire of Knowledge about Dietary Supplements, the mean number of correct responses was 9.0 (95% CI: 8.9 to 9.1). Health service users performed worse than social networking ones by 2.3 (95% CI: 2.1 to 2.5) points in an analysis adjusted for potential confounders. Internet users had less true beliefs about dietary supplements if they presented higher trust in their advertising (adjusted β: -.37, 95% CI: -.39 to -.34), used dietary supplements (adjusted β: -.14, 95% CI: -.17 to -.12), experienced their positive effect (adjusted β: -.16, 95% CI: -.18 to -.13), were older or younger than 35 (adjusted β: -.14, 95% CI: -.17 to -.12), interested in the topic of dietary supplements (adjusted β: -.10, 95% CI: -.13 to -.08), reported getting information about the products from friends (adjusted β: -.13, 95% CI: -.15 to -.11), believed that medicines are harmful (adjusted β: -.12, 95% CI: -.15 to -.10). The proposed 5-predictor model could explain 31.2% of variance in knowledge about dietary supplements. The model appeared resistant to overfitting and was able to forecast the majority of the observed associations.

Conclusions:

Polish Internet users with no medical education exhibit some false beliefs regarding dietary supplements. Trusting in advertising dietary supplements appears in conflict with having knowledge about them. There is an urgent need for effective online educational campaigns about dietary supplements and promotion of advertising literacy. The proposed predictive model, after being externally validated, may help identify the least informed target audience. Clinical Trial: Open Science Framework, https://osf.io/5e92d/


 Citation

Please cite as:

Karbownik MS, Horne R, Paul E, Kowalczyk E, Szemraj J

Determinants of Knowledge About Dietary Supplements Among Polish Internet Users: Nationwide Cross-sectional Study

J Med Internet Res 2021;23(4):e25228

DOI: 10.2196/25228

PMID: 33658173

PMCID: 8100877

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