Development And Evaluation Of Diet Quality Assessment Methods For Preschool Children And Study On Influencing Factors Of Preschoolers’ Diet Quality

BackgroundDietary intake during preschool stage is related to the growth and development in childhood,and also has impact on their long-term health in adulthood.In recent years,China has been experiencing double burden of childhood malnutrition and overweight and obesity.Accurate and efficient quantitative estimates of children’s dietary intake,as well as objective assessment of overall diet quality,are the basis for conducting effective nutrition education and intervention and improving children’s health.Compared with general population,preschoolers have more meals in a day and more caregivers.Methodological limitations of traditional self-reported dietary assessment instruments may lead to bias in estimates of dietary intake in preschoolers.Among the innovative new tools developed in recent years,Remote Food Photography Method has been used widely.However,this method has only been applied in few populations in China,and its feasibility and efficiency in the one-day dietary survey of preschool children need to be examined.Additionally,dietary indices,which are used to evaluate overall diet quality,have been used among preschoolers abroad.And the development and evaluation of a dietary index measuring the diet quality of Chinese preschoolers needs to be further studied.Moreover,the research on the influencing factors of diet quality of preschool children is limited in China due to the lack of accurate dietary intake assessment and diet quality evaluation methods.ObjectiveFirstly,the objective of this study is to design and establish a new dietary assessment instrument for Chinese preschoolers,i.e.diet photography method,and to evaluate its efficiency.Secondly,we aimed to establish a dietary index for preschoolers,i.e.Chinese Preschooler Dietary Index(CPDI),and then evaluate its validity and reliability.Finally,we aimed to explore the influencing factors of diet quality of preschool children in urban areas of Chengdu city using Structural Equation Modeling.MethodsForty children aged 4-5 years and their parents in the First kindergarten of Sichuan University were recruited.Dietary intake of children on the same day was collected by weighed dietary record(WD),diet photography method(DP)and 24-hour dietary recall(HR),respectively.Taken the WD as the "gold standard",the agreement between the intakes of foods and nutrients obtained from the DP,HR,and WD were assessed by estimations of mean differences,Spearman’s correlation coefficients and Bland-Altman plots.Based on the current Chinese dietary intake recommendations,i.e.Chinese Dietary Guidelines(2016)and Chinese Dietary Reference Intakes(2013),as well as the evidence of diet-health relationships of children,the CPDI was developed to measure diet quality in Chinese preschoolers.Using data from 1806 children aged2-5 years from the 2004-2011 China Health and Nutrition Survey(CHNS),the diet quality of preschoolers was evaluated with the CPDI.Additionally,the validity and reliability of CPDI were evaluated by Spearman correlation analysis,logistic regression,principal component analysis,and Cronbach’s α coefficient.Furthermore,671 urban preschoolers were recruited from Chengdu city by stratified cluster sampling method.Dietary intakes at home and in school were collected by diet photography method and weighed dietary record,respectively.Preschoolers’ diet quality was assessed using the CPDI based on the 2-day dietary intake information.Finally,influencing factors of preschoolers’ diet quality were explored using univariate analysis,multiple stepwise regression analysis and Structural Equation Modeling(SEM).Results1.The efficiency of diet photography method in preschool childrenAmong the 10 categories and 61 kinds of foods involved in this study,except for livestock,the correlation coefficients between DP and WD(0.70-0.96)were higher than that of HR and WD(0.55-0.90).Except for livestock,eggs and milk,the differences between DP and WD were smaller than that of HR and WD.As expected,the rates of under-reporting and false-reporting of DP were lower than that of HR,respectively.For total energy and nutrients intake,except for calcium,the correlation coefficients between DP and WD were higher than that of HR and WD.And the difference between DP and WD were smaller than that of HR and WD,except for dietary fat,cholesterol,and vitamin PP.Moreover,compared with HR,the average differences between energy and 7 common nutrients obtained by DP and WD were closer to 0,and the data distributions were more concentrated,indicating that DP is more consistent with WD.2.Development and application of the CPDIThe CPDI consists of 13 components,including 6 adequacy components(i.e.vegetables,fruits,dairy and its products,soybeans and its products,vitamin A,and iron),4 moderation components(i.e.grains,meats,eggs,fish and shrimps),and 3limitation components(i.e.oil,salt,and added sugar).Each component contributed 0to 10 points,thus,the total CPDI ranged from 0 to 130 points.A higher CPDI score indicated a better diet quality.The mean CPDI of the 1806 CHNS preschoolers was 61.9±16.1,ranging from28.2 to 113.9.More than 60% of the children had a CPDI score between 50 and 80 points.Diet quality of preschoolers aged 2-3 years was lower than that of preschoolers aged 4-5 years(P<0.0001).No significant difference of diet quality was observed between boys and girls(P=0.63).In addition,children with older age,living in urban area,and those from families with higher parents’ education levels and higher family income,had better diet quality(P<0.0001).3.Evaluation of reliability and validity of the CPDIThe CPDI scored nearly perfect for the exemplary menus for preschool children aged3-5 years(127.3 points of 130 points).Low correlations of the CPDI total score and13 component scores with energy intake indicated that the CPDI measured diet quality independently of dietary intake quantity.Principal component analysis showed that the 13 components of CPDI could form at least 4 different dietary patterns,which indicated that the CPDI could reflect the diversity and complexity of diet.Moreover,the CPDI was able to distinguish the differences of diet quality between preschoolers living in urban and rural areas,and those with different parental educational levels(P<0.05).Logistic regression analysis showed that children with higher diet quality had 73%-82% lower risk of stunting and 66%-70%lower risk of underweight compared with those with lower diet quality.The standard and nonstandard Cronbach’s α coefficient of the CPDI was 0.40 and 0.43,respectively.4.Assessment of diet quality of preschool children in Chengdu City and analysis of influencing factors of diet qualityThe average CPDI score of preschool children in urban areas of Chengdu was 82.6±11.6.The CPDI scores of children aged 4-5 years and 5-6 years were significantly higher than that of children aged 3-4 years.Children who were only child,whose father and mother had higher educational level,tended to have higher diet quality(P=0.06,0.053 and 0.055,respectively).The results of multiple stepwise regression analysis showed that children with higher educational level of father,exclusive breastfeeding for 6 months,only child,mother as the main cook,and those who often helped with meal preparation,had better diet quality.The results of SEM showed that parental socioeconomic characteristics(standardized regression coefficient: 0.18,P=0.01)and preschoolers’ eating behaviors(standardized regression coefficient: 0.18,P=0.059)are the influencing factors of preschoolers’ diet quality.However,the mediation effect of preschoolers’ individual eating behaviors on the relationship between parental socioeconomic characteristics and preschoolers’ diet quality was not observed.ConclusionThe diet photography method seems to be more suitable for preschool children compared with traditional self-reported dietary assessment instruments.The Chinese Preschooler Dietary Index can be used to rank-order diet quality of Chinese preschoolers,and has acceptable validity and reliability.The diet quality of preschool children in urban areas of Chengdu City needs to be improved,and children with lower socioeconomic status should be payed more attention.Mothers’ participation in cooking and children’s helping with meal preparation may promote improved diet quality of preschoolers.