Abstract
Background: Chronic diseases such as type 2 diabetes, obesity, gout and cardiovascular disease have higher prevalence among Pacific Islanders than any other ethnicity in New Zealand. Increasing evidence has shown a link between increased fructose consumption and these diseases. However measuring dietary sugar intakes in these populations is difficult.
Objective: To test the relative validity and repeatability of a short Food Frequency Questionnaire developed to measure sugar intakes in Pacific Islanders living in South Auckland, New Zealand.
Design: A sample size of 68 participants were recruited from the Pukapuka Community Centre in Mangere, Auckland and through a Pacific Dietitian based in South Auckland. Participants completed two administrations of the FFQ approximately four weeks apart. Three interviewer administered 24h recalls were taken over the four weeks between questionnaires. Statistical analyses including Spearman’s correlation coefficients, cross classification agreement and Bland Altman tests of agreement were calculated to compare sugar intakes from the second administration of the FFQ with the mean 24h recall to assess the validity of the FFQ. Reproducibility was assessed by comparing repeated administrations of the FFQ using intraclass correlations.
Results: Spearman’s correlation coefficients ranged from 0.67 for fructose to 0.76 for total sugars derived from all sources. Correlations increased slightly for sugars derived from non-alcoholic beverages but decreased for sugars derived from fruits. On average, around 50% of participants were correctly classified into the same quartile for both sugars from all sources and non-alcoholic beverages, an only around 35% of participants for sugars from fruits, however less than 4% were grossly misclassified for all sugars from all sources. Bland-Altman statistics demonstrated that the FFQ had a strong level of agreement with the 24h recall for fructose, glucose and total sugars with values close to 100% and 95% confidence intervals including 100; however agreement was relatively poor for sucrose. The FFQ exhibited good reproducibility between administrations with intraclass correlations all greater than 0.7. Paired t-test analysis between the first and second administrations of the FFQ show there may have been an intervention effect with sugar intakes from the second FFQ administration significantly lower than from the first.
Conclusion: The FFQ showed good relative validity particularly for measuring total sugars and sugars from all sources and non-alcoholic beverages. High reproducibility was also seen between the first and second administrations of the FFQs. The results compare favourably with previous FFQs assessing sugar intakes. This is to our knowledge the first short FFQ measuring sugar intakes in Pacific Islanders living in New Zealand.