Instrument Development
The development of the Chinese Parental Health Literacy Questionnaire comprised two stages as illustrated in Fig. 1.
Stage 1: conceptual framework and indicators generation
The CPHLQ was based on the conceptual framework developed by Sorenson et al. in 2012, operationalized with a 3×4 matrix, including three health domains (health care, disease prevention, and health promotion) and four factors of information processing (accessing, understanding, appraising, and applying) for each domain [13].
Indicators were generated through three steps. Firstly, 10 key topics about children’s physical development in three health domains were extracted from literature review and confirmed by a 20-expert consultation (Table 1). The 20 experts were selected purposively. They are experts in child health care or health education, including researchers, pediatricians and child health care doctors. Pneumonia and diarrhea, the two leading infectious causes of childhood morbidity and mortality, were suggested to represent childhood common diseases in the health care domain. Secondly, several indicators were developed based on the 10 key topics and the four factors of information processing. Thirdly, 14 of the 20 experts completed a two-round Delphi consultation for confirming content representativeness, health literacy relevance, feasibility and significance of these indicators. At the results of these three steps, 34 parental health literacy indicators were identified by consensus [14].
Table 1. Key topics about children’s physical development in three health domains
Domain
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Key topics
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Health care
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Pneumonia and diarrhea; antibiotic use; health examination
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Disease prevention
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Vaccination; obesity and malnutrition; vitamin D and iron deficiency; oral and visual health care
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Health promotion
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Infant and child feeding; unintentional injury prevention; scientific parental care
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Stage 2: questionnaire development
Questions were designed based on the 34 indicators. Among them, 29 indicators were directly transformed into 29 questions; for the remaining five indicators, one indicator was converted into two to four questions. As the result, a 41-question CPHLQ were constructed. Each question, reflecting the factors of information processing of “accessing”, “appraising”, or “applying”, was rated with a 4-point Likert scale [15]. Meanwhile, questions relevant to information processing of “understanding” were mainly in the form of true/false questions or multiple choices with four options, designed to test the knowledge level among caregivers. For true/false questions, the correct answer would score 4 points. For multiple choice questions there were 4 options in a question, each option was a true/false question, and one correct choice would score 1 point. Each question also had an option of “Don’t know” which would get a ‘zero’ score. Therefore, each question had a score ranging from 0 to 4. Examples of the questions in the CPHLQ are showed in Table 2.
The original version of the 41-question CPHLQ was reviewed by one researcher, two child care doctors and two nurses to assess whether the questions were consistent to the indicators. The doctors and nurses came from the department of child health care of a Community Health Center (CHC) in Shanghai, whose main duties were providing medical consultation and health education for caregivers of children. The original version of the questionnaire was piloted with 10 parents to identify any ambiguous or unclear questions and to revise the wording. Minor changes were made to enhance clarity and comprehension.
Table 2. Examples of the Chinese Parental Health Literacy Questionnaire
Indicators
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Questions
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Accessing
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Get information about children's health checkup
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How easy is it for you to get information about your children's health checkup? ①very difficult ②fairly difficult ③fairly easy ④easy ⑤don’t know
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Understanding
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Know about the common manifestations of iron and vitamin D deficiency in children
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(1) What are the common symptoms/signs when children have iron deficiency? ①the child looks pale (especially lips, fingernail) ②loss of appetite ③upset ④fatigued ⑤don’t know
(2) What are the common symptoms/signs when children have vitamin D deficiency? ①easy to wake up and sweaty at night ②pillow bald patch ③muscle weakness ④in serious cases, knock knees and bow legs ⑤don’t know
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Understand the harm of dental caries in children
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“If tooth decay occurs in baby teeth, it does not require treatment, because tooth decay will go away after replacing with the permanent teeth.” Is it true? ①true ②false ③don’t know
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Appraising
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Pay attention to children and find the early signs of some common diseases in time
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Can you recognize the signs of some common diseases (such as pneumonia, diarrhea) from your child's physical conditions (such as alertness, body temperature, loose motions)? ①very difficult ②fairly difficult ③fairly easy ④easy ⑤don’t know
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Applying
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Ensure children vaccinated according to the local immunization program
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Can you always take your baby to scheduled vaccinations as doctor advised?
①always ②in most cases ③sometimes I fail ④rarely do ⑤don’t know
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Validation of CPHLQ
Participants and data collection
The study used a methodological design with a convenience sampling scheme. Usually for a validation study, the recommended sample size for each question is between 2 and 20 subjects; and the total sample of 500 participants is considered as good, 1000 or more as excellent [21]. Eight of the sixteen districts in Shanghai were willing to participate in the study, including three urban districts, three suburban districts and two outer suburban districts. Considering the sample size recommendations and the feasibility, minimum 100 participants from each district (at least 800 participants in total) were required. The target participants were the primary caregivers (including parents, grandparents and other caregivers, like nanny) of children under three years old. In Shanghai, the routine child health care is provided by CHCs. Therefore, in each participating district, three CHCs were selected as the study sites, representing high, medium and low social economic status (based on local economic indicators and child health care management rates). A cross-sectional survey was conducted in 24 CHCs from eight districts in Shanghai. Before the survey, two child health care doctors in each selected CHC were invited as co-investigators and were trained about how to recruit participants and complete the self-administered questionnaire.
Caregivers coming to these CHCs between March and April 2017 and meeting the inclusion criteria were invited to join in the survey by the trained doctors. The inclusion criteria were as follows: a) above grade three primary educations, b) able to communicate verbally or literally with the investigators; c) willing to participate in the study. In total 1090 caregivers were approached, and 807 (74.0%) caregivers completed the questionnaire. In order to evaluate test-retest reliability, each study site invited four or five participants to complete the questionnaire again two weeks later. Finally, 101 participants completed the questionnaire for the retest. Responses in the first survey by this sample of 101 participants were also used for item analysis.
Data on demographics were also collected from the participants, including caregiver’s relationship with the child, education level, family income, child’s age, gender, and Hukou (the Chinese official residency registration by location, which is directly linked to social costs, social benefits and administration). During the survey, the primary spoken language of the study participants was Mandarin, and the questionnaire was administered in Chinese.
Item Analysis
Based on Classical Test Theory, item analysis was conducted to screen each question’s performance and to ensure the appropriate questions were preserved [16]. The question performance is determined by item difficulty and item discrimination. Item difficulty is calculated as the average score of a particular question divided by the full score of the question, in our study the full score was 4; and for each question the higher this value is the easier the question will be [17]. Item discrimination is examined using the question-total correlation [18]. A question should be deleted, when: a) item difficulty lower than 0.2 or higher than 0.8 [19, 20]; and b) the coefficient of question-total correlation lower than 0.3 [18].
The results were shown in Additional file 1. Based on the above described analysis, three questions were identified to be deleted, “See the doctor in time when suspecting the child has pneumonia”, “Recognize possible risk factors of malnutrition in children”, and “Ensure children fully vaccinated according to the local immunization program”. However, considering the importance of immunization for children, the third question was remained and other two questions were deleted. The 39-question questionnaire across 3×4 sub-domains was finalized. The final CPHLQ was organized into three subscales: 12-question for health care health literacy (HC-HL), 16-question for disease prevention health literacy (DP-HL), and 11-question from health promotion health literacy (HP-HL).
Reliability and Validity Tests
Several psychometric properties of the 39-question CPHLQ and the three subscales were assessed.
The internal consistency was measured with Cronbach’s α [22]. Spilt-half reliability was measured with Spearman-Brown coefficient between odd questions and even questions [22]. Test-retest reliability was measured with the Pearson correlation coefficient between the CPHLQ results completed by the 101 caregivers with a two-week interval [22]. In addition, the reliability analysis of the three subscales was also performed. For the whole scale, values greater than 0.70 indicated acceptable reliability [23, 24]. For each of the subscales, values greater than 0.6 were considered as acceptable reliability [25]. The floor or ceiling effects were assessed by the proportion of respondents who received the lowest or the highest score [26].
Given that hypothesized constructs were identified with a priori model, confirmatory factor analysis (CFA) was used to verify the construct validity [27]. The analysis was conducted separately for the three subscales for HC-HL, DP-HL and HP-HL, in which questions were loaded into four factors related to the four information-processing domains of accessing, understanding, appraising and applying. The model fit was considered ‘relatively good’ if the following criteria were met: root mean square error of approximation (RMSEA) lower than 0.08; goodness-of-fit index (GFI) greater than 0.90; adjusted goodness-of-fit index (AGFI) greater than 0.90; comparative fit index (CFI) greater than 0.90; and due to the large sample, c2/df lower than 5 [28, 29]. The content validity was confirmed by the expert panel.
Statistical Analysis
When calculating the scores for parental health literacy, the weight of each indicator was based on the significance assessed during Delphi consultation, and was equally allocated to the questions related to the indicator. The total score was transformed to percentage grading system, with the full score of 100. The scores of the three subscales and the four competences were also calculated and standardized from 0 to 100. The mean and standard deviation (SD) of CPHLQ scores were calculated. A higher score indicated that the caregiver had higher health literacy. Additionally, descriptive statistics of the participants’ characteristics were tabulated. The relationships between scores and demographic characteristics were assessed with either a t-test or a one-way ANOVA.
CFA was conducted with maximum likelihood estimation by using AMOS 21.0. Internal consistency, spilt-half reliability, test-retest reliability and other parametric tests were computed by using SPSS 20.0. The significance level was set at P < 0.05.