Validation and reproducibility of an Australian caffeine food frequency questionnaire

Abstract

The aim of this study was to measure validity and reproducibility of a caffeine food frequency questionnaire (C-FFQ) developed for the Australian population. The C-FFQ was designed to assess average daily caffeine consumption using four categories of food and beverages including; energy drinks; soft drinks/soda; coffee and tea and chocolate (food and drink). Participants completed a seven-day food diary immediately followed by the C-FFQ on two consecutive days. The questionnaire was first piloted in 20 adults, and then, a validity/reproducibility study was conducted (n = 90 adults). The C-FFQ showed moderate correlations (r = .60), fair agreement (mean difference 63 mg) and reasonable quintile rankings indicating fair to moderate agreement with the seven-day food diary. To test reproducibility, the C-FFQ was compared to itself and showed strong correlations (r = .90), good quintile rankings and strong kappa values (κ = 0.65), indicating strong reproducibility. The C-FFQ shows adequate validity and reproducibility and will aid researchers in Australia to quantify caffeine consumption.

Keywords:

• Caffeine
• questionnaire
• nutrition assessment
• validation studies
• food frequency questionnaire
• reproducibility

Acknowledgments

We would like to thank all the participants and Lee Priestley and Stephanie Cheng, who helped make this research possible. We would further like to thank Associate Professor Jillian Dorrian for her statistical advice and Louise Massie for her valuable help.

Disclosure statement

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this article.

Funding

E. J. Watson was funded through a University of South Australia Post Graduate Award; otherwise this research received no specific grant from any funding agency, commercial or not-for-profit sectors.

Informed consent

Informed consent was obtained from all individual participants included in the study.

Ethical approval

All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. The study was approved by the University of South Australia’s Human Research Ethics Committee (#30885).