Aim: General nutrition knowledge has been frequently researched in athlete populations. However, the majority of studies have done so using poorly validated nutrition knowledge questionnaires. Validation is essential to guarantee the questionnaire can evaluate the knowledge construct systematically and consistently when used in different populations or the same population on repeated occasions. Only two nutrition knowledge questionnaires have been well validated for use in athlete populations in the past 20 years. There have been no studies evaluating the nutrition knowledge of athletes using a valid questionnaire in New Zealand over the past 20 years. Therefore, the aim of this study was to profile the general nutrition knowledge of young rugby players in New Zealand using a previously validated general nutrition knowledge questionnaire.
Method: Four population cohorts were invited to complete an internet-based survey between September and October 2012. The four cohorts included: rugby players from NZRU Academies (RP), student dietitians from the University of Otago (SDT), sports dietitians/nutritionists contracted as nutrition providers to the NZRU (NP) and an age- and gender-matched control cohort of employees from 17 Placemakers stores (C). All candidates from RP, SDT and NP were invited to participate in the survey via an email sent directly to them or through a third party. The questionnaire was initially promoted to the control cohort using a promotional poster placed in store at Placemakers. The internet-based survey consisted of a demographics component and a General Nutrition Knowledge Questionnaire (GNKQ (1–3)). This questionnaire consisted of four sections each covering a different domain of general nutrition knowledge: dietary recommendations (section A); sources of nutrients (section B); choosing everyday foods (section C); and diet-disease relationships (section D). Section scores were combined to provide a total nutrition knowledge score (TNKS) for both the GNKQ (1–3) and Revised-GNKQ (R-GNKQ (1)) scoring rubrics. Of the 255 potential participants from RP, SDT and NP, 181 respondents (RP; n=114; SDT: n=55; NP: n=8) completed the survey giving a pooled response rate of 71.0%. However, there was only one respondent in C from an unknown number of candidates. Therefore, this respondent’s data was removed from analysis. The scores for NP and SDT were not statistically different and were pooled to give the dietetically trained cohort (DT).
Results: DT scored significantly higher than RP in the unadjusted and adjusted TNKS for both the GNKQ (DT: 86.6 ± 5.1%; RP: 52.1 ± 11.2%) and R-GNKQ (DT: 91.7 ± 4.6; RP: 55.7 ± 13.3%) scoring rubrics (both p=0.000). There were two non-modifiable (age and gender) and five modifiable (education level, living arrangement, weight loss, weight loss methods and sources of nutrition information) demographic variables with significant associations to TNKS amongst all respondents. Good levels of internal consistency, measured using Cronbach’s α, (GNKQ: 0.97; R-GNKQ: 0.97) and test-retest reliability, measured using Spearman’s (rho) rank correlation (GNKQ: 0.80; R-GNKQ: 0.72) were demonstrated for TNKS.
Conclusion: The GNKQ (1–3) was confirmed as a valid and reliable tool for measuring the general nutrition knowledge of rugby players compared to dietetically trained individuals. The rugby players’ knowledge of dietary recommendations was adequate, however their knowledge of sources of nutrients and diet-disease relationships were poor in comparison to the dietetically trained cohort. Further research is needed using a validated general nutrition knowledge questionnaire to establish the relative knowledge of all rugby players compared to well-matched control cohorts.
