The family food environment questionnaire for Chinese school-age children
The study firstly developed and validated the Family Food Environment Questionnaire for Chinese School-age Children (FFEQ-SC). The conceptual framework and dimensions of FFEQ-SC were preliminarily constructed based on literature review and evaluated by food and nutrition experts in the study steering group.
The framework for the Analysis Grid for Elements Linked to Obesity (ANGELO) process was first developed as a practical tool to categorize and scan the environment for potential environmental barriers to healthy eating and physical activities . The basic framework was a 2x4 grid which divided obesogenic environments into two sizes of environment – micro and macro, and four types of environment – physical, economic, policy and sociocultural. Referring to ANGELO framework and other assessment instruments, the FFEQ-SC was desighed with six dimensions: 1) Family sociodemographic characteristics, including family structure (member number), family economic status, caregivers and their educational level and so on. The family economic status was assessed using adjusted “The Family Affluence Scale (FAS)”, which was a six-item scale used in Health Behavior in School-aged Children (HBSC), a WHO collaborative cross-national study. Considering the Chinese family situation, three items were remained, namely “How many cars, van or truck do your family have?”; “Does your child have its own bedroom?”; “How many times did your family travel for a holiday/vacation last year?”. 2) Caregiver’s food and nutrition literacy, including nutritional knowledge and skills (food and nutrients, dietary guideline, food labeling and food portion), modeling and encouragement practices, discussing nutrition information with children, and so on. 3) Family feeding patterns, including permission (I permit my child to eat what he/she wants.), restriction (I have to be sure that my child does not eat too many foods high in sugar, fat and salt.), enforcement patterns (If my child says “I am not hungry” I try to get him/her to eat anyway.) and so on. 4) Family eating rules, including focusing on dinner (No meals while watching TV/DVDs), food limitation (Limited sweet or fried snacks.) and food preparation (My child must help prepare food and do the dishes). 5) Family meal practices, including location, length, frequency and members present of family meals. 6) Family food availability, including healthy foods (fruits and vegetables, dairy products and whole grain) and unhealthy foods high in sugar, fat and salt.
Secondly, a cross-sectional survey was conducted in 599 Chinese school-age (7-13 years) children’s parents, to analyze the reliability and validity of FFEQ-SC. The preliminary questionnaire had 54 items. Finally, 47 items were determinded by the exclusion criteria as item discrimination less than 0.1, coefficient of difficulty more than 0.15 and less than 0.85, factor loads less than 0.4, and factor loading coefficients were similar in 2 or more than 2 factors. The overall FFEQ-SC questionnaire had acceptable internal consistency (Cronbach’s α =0.78, split-half reliability =0.84). The exploratory factor analysis extracted 15 factors which were included in the conceptual framework, and cumulative contribution of variance accounted to 62.33%. The Pearson correlation coefficients between dimensions and total questionnaire were from 0.33 to 0.76. The results of construct validity were χ2/df = 1.97, goodness of fit index (GFI) = 0.88, adjusted goodness of fit (AGFI) = 0.85, normed fit index (NFI) = 0.86, incremental fit index (IFI) = 0.92, comparative fit index (CFI) = 0.92, root mean square residual (RMR) = 0.03, and root mean square error of approximation (RMSEA) = 0.04 (P>0.05). The results showed the FFEQ-SC had good reliability, and it could potentially be a useful instrument to assess FFE for Chinese school-age children（The FFEQ-SC was shown at Additional file 1.）
The food and nutrition literacy questionnaire for Chinese school-age children
Literatures retrieval showed there were some FNL assessment instruments developed for adult population in different contexts. In comparison the assessment instrument for children was rare, and existing instruments were designed in Iran, Danish and American contexts, which were not suitable to be adjusted for use in Chinese children as huge differences of dietary patterns exist between China and these countries. Considering the difference of cognition and eating behaviors, the FNL questionnaire should be different for children in different ages. Based on these, we developed and validated a new FNL assessment questionnaire for Chinese school-age children, the Food and Nutrition Literacy Questionnaire for Chinese School-age Children (FNLQ-SC).
The conceptual framework and dimensions of FNLQ-SC were preliminarily constructed based on literature review and experts interview, within the cognitive level and dietary behavior problems in school-age children taken into consideration. In this study FNL is defined as “collection of inter-related knowledge, skills and behaviors required to plan, manage, select, prepare,and eat foods to meet needs, and determine food intake”. A two-stage electronically distributed Delphi consultation study was conducted to determine the dimension and core components of FNLQ-SC. Finally, 19 core components of FNLQ-SC were determined, including five dimensions of food and nutrition-related knowledge and understanding (cognitive domain), the ability of access, selection, preparing of food and healthy eating (skill domain), as well as three levels of functional, interactive and critical literacy. The final questionnaire set 50 questions.
Secondly, a cross-sectional survey was conducted in 2452 Chinese children aged 10-15 years, to analyze the reliability and validity of FNLQ-SC. The results showed the overall FNLQ-SC questionnaire had acceptable internal consistency (Cronbach’s α = 0.698). Regarding the five dimensions (knowledge and understanding, access and planning of food, selecting food, preparing food, eating), Cronbach’s α coefficient was 0.452, 0.300, 0.244, 0.148, and 0.436, respectively. The Kaiser–Meyer–Olkin (KMO) test showed sampling adequacy (KMO = 0.738), and Bartlett’s test confirmed factor analysis was appropriate (P<0.001). The exploratory factor analysis (EFA) of skill components extracted 5 factors (selecting and eating, access and preparation, food label and measurement, picky eating, snacks) with eigenvalue more than 1, and cumulative contribution of variance accounted to 50.60%. The commonality was more than 0.20 for all components. The Pearson correlation coefficients among different dimensions ranged 0.152-0.400, and correlation coefficients between dimensions and total questionnaire were from 0.370 to 0.877, especially the dimension of knowledge and understanding, selecting food, and eating, whose coefficients were more than 0.6, showed strong correlation with the total questionnaire. The results showed the FNLQ-SC had acceptable reliability, and it could potentially be a useful instrument for assessing FNL for Chinese school-age children（The FNLQ-SC was shown at Additional file 2.）.
Participants and data collection
A cross-sectional survey was conducted in a primary school in Beijing of China using convenient sampling during April 2019. The investigators explained the study protocol to all students from Grade 1 to 5 (aged 7-13 years) and their parents or other caregivers at parent-teacher meeting. Finally, written informed consent was obtained from 605 children and their guardians, with a response rate of 99.2%.
For all participant children (n=605), the FFE was assessed by developed self-administered FFEQ-SC, which was filled out by children’s caregiver.
Considering the differences of cognition, reading and writing literacy between junior and senior students, the FNL should be assessed by different instruments. Based on these, just for the senior children of Grade 3 to 5 (n=260), the FNL was assessed by self-administered FFEQ-SC, which was developed and validated for students of Grade 3-9, not for junior primary students (Grade 1-2).
The children’s anthropometric data (height, weight) were derived from “Beijing health information management for primary and secondary schools”, which was measured in April 2019. The permission of school, the children and their parents was obtained under the help of school administrative staff and sensitive and irrelevant information was filtrated. The children’s BMI (kg/m2) was calculated and defined according to Chinese standards of “Screening for overweight and obesity among school-age children and adolescents (WS/T 586-2018)” and “Screening standard for malnutrition of school-age children and adolescents (WS/T 456-2014)”.
The study protocol was approved by the Peking University Institutional Review Board (Beijing, China), and conducted according to the Declaration of Helsinki and ethical guidelines. The privacy of participant students and the confidentiality of their personal information would be protected.
In the FFEQ-SC, the relations of some items (such as family structure, children’s caregiver) with children’s FNL, eating behaviors and even health outcome remained bidirectional and inconsistent, which could not be scored. Besides these items, the total score of FFEQ-SC was 94, including family sociodemographic characteristics (18), caregiver’s FNL (20), family feeding patterns (14), family eating rules (18), family meal practices (8), and family food availability (16). Considering the scores were positively related with better/healthier performance theoretically, so the six dimensions were reclassified into two levels, high/good/healthy (≥P60 of total score) and low/poor/unhealthy (<P60 of total score). It was noteworthy that higher score of family feeding patterns was associated with more freedom of children’s food choice, and then different feeding patterns were defined as permission (≥P60 of total score), restriction (P40-P60) and enforcement (<P40) patterns.
The total scores of FNLQ-SC were 92 in Grade 3-4 and 98 in Grade 5 respectively, which were converted in a centesimal measure for further statistical analysis. And the dimensions of knowledge and understanding, access to and planning for food, selecting food, preparing food and eating included 7, 2, 10 (8 at grade 3-4), 5, 25 (22 at grade 3-4) questions respectively. A receiver operating characteristic (ROC) analysis was always used to determine the optimal FNL cut-off score , which compared the performance of the FNL score against the ‘gold standard’ measure of overall dietary quality like healthy eating index (HEI), to identify the cut-off point of FNL scale. Unfortunately, the dietary intake was not investigated in our study, so the cut points of FNL could not been identified, and the FNL score was analyzed as continuous variable.
The relations of FFE with FNL of children were analyzed to compare the FNL difference among different FFE groups by t-test, F test and least significant difference (LSD) methods. Also correlation coefficient was calculated between different dimensions of FFE scores and FNL scores. Multivariate linear regression analysis was employed to explore the related factors of FNL and overweight risk in children. The statistical significance is P<0.05.