Development and evaluation of a Diet Quality Index for preschool children in an Asian population: the GUSTO cohort

Background: diet quality indices (DQIs) are useful tools to measure diet quality as they compare dietary intakes against recommendations. A DQI for Asian preschool children is lacking.Objective: the aims of this study were to develop and evaluate a DQI for preschool children based on Singapore dietary recommendations and to examine diet quality in a cohort of 5-year-old children. An additional aim was to assess associations between sociodemographic characteristics and DQI-5 scores. Design: a secondary analysis was conducted using dietary intake of children from the Growing Up in Singapore Towards healthy Outcomes (GUSTO) mother-offspring cohort assessed in 2015- 2016 using a validated Food Frequency Questionnaire. The socio-demographic data was assessed at recruitment between June 2009 and September 2010. The DQI was evaluated using a construct validity approach, whereby nutritional parameters associated with diet quality were studied.Participants/setting: participants were 767 Singaporean children aged 5 years of Chinese, Malay or Indian ethnicity.Main outcome measures: the main outcome measures were the DQI-5 scores and the sociodemographic characteristics associated with diet quality. Statistical analyses performed: Kruskal-Wallis tests were used to evaluate differences in adherence to dietary recommendations across DQI-5 tertiles. Linear multiple regression analysis was performed to identify sociodemographic characteristics that were associated with diet quality in the children. Results: the DQI-5 consists of 12 food and nutrient components, with a minimum score of zero and a maximum score of 110 points. The higher scores indicate a healthier diet, the mean (SD) DQI-5 score for the children was 61.6 (13.2). DQI-5 components with low scores included wholegrains, vegetables and fatty acid ratio, while total rice and alternatives, milk and dairy products components were overconsumed by 18% and 24.4% of the children, respectively. Children with higher scores were more likely to meet dietary recommendations and had higher intake of nutrients such as dietary fibre, iron, vitamin A and beta carotene. Children whose mothers were of Malay ethnicity and whose mothers had low income, an education below university and shared primary caregiver responsibilities were more likely to have lower DQI-5 scores. Conclusions: the DQI-5 scores revealed diets to be low for several components and excessive for a few. The DQI-5 developed for preschool children in Singapore had adequate construct validity.