The Māori Kai semi-quantitative food frequency questionnaire: relative validity and reliability for assessing usual sugar intakes in New Zealand East Coast Māori

Abstract

Background: The rising prevalence of non-communicable diseases (NCDs) such as obesity, diabetes, cardiovascular disease and gout is contributing to global socioeconomic burden. In order to address this issue, the risk factors associated with NCDs need to be identified. Free dietary sugars, and in particular fructose, have been linked to unfavourable metabolic changes associated with these diseases. As New Zealand (NZ) Māori have higher rates of NCDs versus non-Māori, it is of interest to investigate the extent to which dietary sugars intakes might be an explanatory factor. To determine whether sugars intakes influence NCD risk amongst Māori there is a need to develop a culturally-appropriate dietary assessment tool for assessing sugars intakes that is both valid and reliable.

Objective: To assess the relative validity and reliability of a culturally appropriate, semi-quantitative food frequency questionnaire (FFQ) intended to measure usual intakes of fructose, glucose, sucrose and total sugars in a Māori adult population. Design: A 33-item FFQ, designed and pretested in Māori adults residing in Gisborne, NZ was used to determine usual sugar intakes over a one month period. FFQ items comprised of important sugary food and drink sources consumed in the target population. The FFQ was validated by comparison with dietary intake data collected through repeat-24 hour recalls (n=3) and reliability measured through re-administration of the tool at a one month interval. 72 Māori adults (24 men and 48 women) provided three 24-hour diet records and completed two administrations of the FFQ and were included in the analyses. Reliability of the FFQ was assessed by cross-classification agreement with weighted Kappa scores, and Spearman correlation coefficients. Mean sugars intakes were evaluated as group means using paired-t tests, and the strength of agreement between the two dietary assessment methods was assessed by the Bland-Altman method. Reliability of the FFQ was assessed by intraclass correlation coefficients. Results: 95% to 97% of participants were classified in the same or adjacent quartiles for all sugars intakes with weighted Kappa scores indicating excellent ability for the FFQ to rank individuals. Cross-classification agreement was even stronger for sugars intakes from non-alcoholic beverages. Mean sugars intakes corresponded well between the FFQ and repeat-24 hour recalls for fructose, glucose and total sugars, but sucrose was significantly different (P<0.05). Bland-Altman analyses showed good agreement between the tools for all sugars except sucrose which was overestimated by 12-51% by the FFQ. Intraclass correlation coefficients from re-administration of the FFQ showed excellent reproducibility for total sugars and sucrose (>0.75). Conclusion: Overall, the Māori Kai FFQ provided repeatable measurements of sugars intakes with good validity, and was able to correctly rank individuals by intake quartiles. Advantages of our FFQ lie in its relatively low response burden, ease of administration, cost effectiveness and cultural appropriateness for use on Māori in epidemiological research. Prospective validation of the FFQ with anthropometric and biochemical markers will provide a means for exploring the diet-disease relationship of sugar.