Cohort Profile: Chengdu Positive Child Development (CPCD) survey

Abstract

The Chengdu Positive Child Development (CPCD) survey is a Chinese multidisciplinary school-based cohort study investigating any associations between students’ sociodemographic, physical and psychological characteristics, family environment, lifestyle behaviours, academic performance and health status. We recruited 8825 students aged 6–16 from five primary and middle schools in Chengdu (the capital city of Sichuan Province) at baseline (between 23 December 2019 and 13 January 2020), and their caregivers and school principals were surveyed for students’ behaviours, the caregiver’s health status and information about the schools. At the first follow-up of 7985 students, completed between 16 June and 8 July 2020, COVID-19-related information was collected from both students and their caregivers; further follow-ups are planned. By providing an unbiased baseline in the pre-COVID era, the CPCD survey could be an important resource when studying the effect of epidemics on early-stage physical and mental development. Planned follow-up surveys would allow the effects of the epidemic on the life course of the ‘COVID-19 generation’ children to be examined. Researchers interested in collaboration should contact the principal investigator Professor Peng Jia. Childhood is a critical developmental stage affecting future health, competence and capacity. According to theories of child development (physical and behavioural development risk process theories), some preventable outcomes include chronic illness, mental illness, obesity, myopia, developmental injury, substance abuse, antisocial behaviour, social alienation and school failure.1,2 Positive Child Development (PCD) is a positive psychological approach which focuses on the growth, cultivation and nurturing of developmental assets, abilities and potentials in children.3,4 It focuses on each child’s unique talents, strengths, interests and potential. It aims to understand children and engage them in productive activities rather than correct or cure for maladaptive tendencies.5 It has been highlighted as potentially supporting better health and social outcomes throughout the life course.6–9 Many US development programmes have shown positive changes in children’s and adolescents’ behaviours (such as interpersonal skills and quality of peer and adult relationships) and significant improvements in problem behaviours (e.g. drug and alcohol use, school misbehaviour).10 Other studies have found similar findings where, for example, children with positive development were more satisfied with life and had fewer problem behaviours.11–14 There have been some efforts in tracking child development in China. For example, since 1985, the Chinese National Survey on Students Constitution and Health has conducted surveys every 5 years under a repeated cross-sectional study design (without follow-up data) into the physical health of children and adolescents aged 7–22 years.15 The China Education Panel Survey, followed up annually since 2013–14, focuses on influences of various factors (e.g. individual, family, school) on the quality of education among middle school students (aged 13–15 years).16 However, few large-sample and long-term (e.g. cohort) studies have looked at child development in mental health and social adaption. Moreover, most Chinese studies adopted a deficit perspective, focusing on children’s problem behaviours and unhealthy psychological states, and seeking their causes. The importance of promoting children’s holistic development has been largely overlooked.17–20 The Chengdu Positive Child Development (CPCD) survey is an ongoing school-based cohort study in the capital city of Sichuan Province, with support from Hong Kong Polytechnic University and Sichuan University. Chengdu, a western China mega-city, comprises 12 urban districts, three counties and five county-level cities. The total area is 14 335 km2 (about 6.6% built-up areas) with about 16.6 million permanent residents (74.4% urban). The baseline was established between 23 December 2019 and 13 January 2020. The CPCD is an integral component of the Tin Ka Ping Positive Adolescent Training through the Holistic Social Programs Project, a Jockey Club Youth Enhancement Scheme. The original aims of the CPCD are understanding the current state of positive development and psychosocial and behavioural problems in children, and evaluating the effects of the Positive Child Development programmes (such as school courses of health education and promotion) on facilitating positive development and remediating psychological and behavioural problems. The study protocol was approved by the Medical Ethics Committee of Sichuan University (K2020025). The CPCD adopted a cluster sampling method to select five primary and middle schools: one downtown, two suburban in the south and two suburban in the north of Chengdu. A total of 8968 questionnaires were sent out at the baseline survey, and a total of 8825 students at Grades 1–9 (aged 6–16) who attended school on the date of the survey have completed the questionnaire, with a response rate of 98.4% (Figure 1). Flowchart of implementation of the Chengdu Positive Child Development (CPCD) survey. Before participation, written informed consent was given by the students’ legal guardians. This included a project overview, survey procedures, potential benefits and risks and confidentiality agreement. All students provided written informed consent before participating. The first follow-up was planned for 1 year after the baseline survey. However, it was conducted 6 months ahead of schedule to capture the immediate impact of the coronavirus disease 2019 (COVID-19) epidemic, commencing in late January 2020. This followed immediately after the baseline survey of participants, who have all experienced social distancing (e.g. stay-at-home, school closure). As a result, 7985 students were followed up for the first time between 16 June and 8 July 2020 (6 months after the baseline survey). A total of 840 students were lost to follow-up, who were mainly middle school students with 84.4% (709 out of 840) at Grade 9. The follow-up was too close to the high school entrance examination (14–15 July 2020) for them to participate; the remainder were absent on the survey date, but are expected to participate in future follow-ups. Future follow-ups are planned to be both passive and active. In the passive mode, the students will be linked to the school database of physical examination to obtain data on anthropometric measurements and health outcomes. In the active mode, all students in the baseline survey will be invited to complete the baseline questionnaire every 1–2 years. All of those currently lost to follow-up are planned to be re-included to the cohort. Information collected through a self-administered questionnaire from the students and caregivers was linked to the students’ physical examination database to obtain anthropometric measurements (Table 1). Moreover, school information was collected by interviewing school principals. In addition, COVID-19 related information was collected from both students and their caregivers in the first follow-up. Summary of the measurements at the baseline of the Chengdu Positive Child Development (CPCD) survey between 23 December 2019 and 13 January 2020 Anthropometric measurements, conducted by trained health professionals during the annual school physical examination, included height, weight, blood pressure, vital capacity and naked eye vision. Naked eye vision was measured as the level at which one could see on a standard logarithmic visual acuity chart (GB 11 533–1989) at 5 m (test distance), without glasses and with one eye open alternately. Vital capacity (the maximum amount of air one can expel from the lungs after a maximum inhalation) was measured instrumentally. Sociodemographic characteristics were collected from both the students’ and caregivers’ questionnaires. These included age, sex, weekly pocket money, parents’ age, education level, and occupation, family living conditions and monthly income. Health problems (such as how often students had allergic diseases, asthma, headaches, rashes or other skin problems, stomach ache or stomach cramps, nausea, nervousness, constipation and obesity) were reported by students’ caregivers on a 3-point Likert-type scale. Depressive symptoms were measured by the Center for Epidemiological Studies-Depression Scale. This is a 20-item tool that asks students to rate how often they have experienced depression-related symptoms or feelings in the past week.21 Anxiety was measured by the Screen for Child Anxiety Related Disorders, a 41-item measure on a 3-point Likert-type scale.22 Post-traumatic stress disorders was measured by the Chinese version of the Children's Revised Impact of Event Scale, a 13-item tool measuring the frequency of symptoms for intrusion, avoidance and hyperarousal.23 PCD attributes were measured by the Chinese Positive Youth Development Scale, an 80-item self-report tool with 15 sub-scales. These include bonding, resilience, social competence, recognition of positive behaviours, emotional competence, cognitive competence, behavioural competence, moral competence, self-determination, self-efficacy, clear and positive identity, beliefs in the future, prosocial involvement, prosocial norms and spirituality.3,24 Satisfaction with life was measured by a Life Satisfaction Scale,25 the Chinese version of which has shown acceptable psychometric properties in assessing the global judgment of one’s quality of life.26 Materialism was measured by a Chinese Adolescent Materialism Scale.27 Egocentrism was measured by a Chinese Adolescent Egocentrism Scale.28 Empathy was measured using an 11-item scale with items such as ‘I try to understand others’ perspectives when making a decision’, which was developed specifically for this cohort’s data collection. Family dysfunction was measured by a Chinese Family Assessment Instrument with five sub-scales: mutuality, communication, conflict and harmony, parental concern and parental control.29 Three aspects of academic performance were measured by the instruments developed specifically for this cohort’s data collection. Academic intrinsic value was assessed by two questions: ‘Do you think doing school work is boring?’ and ‘Do you enjoy doing your school work?’. Academic utility value was assessed by three questions: ‘How useful do you think what you learned in school is now in your daily life?’, ‘How much of what you learn in school today do you think will be useful to you in your daily life in the future?’ and ‘How much do you think what you learned in school will help you become the person you want to be when you graduate?’. Academic anxiety was assessed by three questions: ‘How worried are you about falling behind in your studies?’, ‘How nervous are you when the teacher hands out the graded papers?’ and ‘How nervous are you going to be during the exam?’.30 In addition, the students’ most recent final exam results at the time of the survey were collected through the student management information systems. Internet addiction was measured by a Young Internet Addiction Test. The test scores responses from 1 to 5, with a score of 1 for ‘rarely’ and 5 for ‘always’. Summative scores ranging from 20 to 49 are considered to indicate ‘average’ online users. Scores from 50 to 79 are considered to indicate occasional to frequent problems related to internet use. Scores from 80 to 100 are considered to indicate significant problems related to internet use.31 Delinquent Behaviours were measured by 12 questions on how many times students had engaged in certain misconducts or showed poor performances over the previous year.32 Non-suicidal self-injuries were measured by the short version of the Deliberate Self-Harm Inventory.33 Suicidal behaviours were measured by three questions: ‘Have you ever seriously considered trying to suicide?’, ‘Have you made any specific plans for how you would suicide?’, and ‘How many times have you actually tried to suicide?’. In addition to the self-report questionnaire, students’ behaviours were also assessed by the primary caregiver, using a Child Behaviour Checklist which listed the students’ behaviours over the past 6 months.34,35 Caregivers’ depressive symptoms were measured by the Zung Self-rating Depression Scale which, based on the diagnostic criteria for depression, asked how they have felt in the past week. Caregivers rated each item on a 4-point Likert scale. Individual’s standard scores were calculated by summing the 20 scores and multiplying by 1.25. The severity of depression was defined by standard score as no depression (<53), mild depression (53–62), moderate depression (63–72) and severe depression (>72).36 Caregivers’ anxiety symptoms were measured by the Zung Self-Rating Anxiety Scale (SAS), comprising 20 items and based on the diagnostic criteria for anxiety. Similarly, the standard score was calculated for each caregiver and the severity of anxiety was defined as no anxiety (<50), mild anxiety (50–59), moderate anxiety (60–69) and severe anxiety (>69).37 In addition to the questions asked in the baseline survey, more questions were added to the first follow-up survey about the students’ and caregivers’ behaviours and perceptions which might have been affected by the COVID-19 lockdown. Behaviours included self-reported time spent on sleeping, in physical activity and at electronic screens (for purposes of both online classes and entertainment). Perceptions included awareness of COVID-19 and the extent to which it has affected aspects of their lives.38,39 At baseline, the students were aged from 6 to 16 (Table 2). There were slightly more boys than girls (51.6% vs 48.4%) and more primary than middle school students (62.7% vs 37.3%). More students lived in urban than rural areas (65.0% vs 35.0%). More than half of the students’ parents had at least high school education. On average, boys’ parents had a higher educational level than girls’ (p = 0.02 for fathers and p = 0.04 for mothers). Parents of primary school students had a higher educational level than those of middle school students (p <0.01 for both). On average, boys’ families had more monthly income than girls’ (9.8K yuan vs 9.5K yuan), but allocated less pocket money weekly (24.8 yuan vs 25.1 yuan). Eyesight of the middle school students was generally worse than that of the primary school students. Characteristics of the participants at the baseline of the Chengdu Positive Child Development (CPCD) survey between 23 December 2019 and 13 January 2020 SD, standard deviation. p-values tested the differences in each variable between sexes (boy and girl) and grades (primary and middle school), and were based on χ2 tests for categorical variables or t tests for continuous variables. Characteristics of the students lost to follow-up but remaining in the cohort are shown in Table 3. A summary of the information collected at the baseline and first follow-up survey showed that, in the follow-up survey, favourable declines were observed in the delinquent behaviour score (0.28 to 0.24, p <0.001), anxiety score (17.14 to 15.21, p <0.001), academic anxiety score (3.38 to 3.33, p = 0.007), family dysfunction score (1.96 to 1.93, p = 0.006) and child behaviour checklist score (24.82 to 19.82, p <0.001). Characteristics of the participants followed up and lost to follow-up between 16 June and 8 July 2020 SD, standard deviation; sch., school. The academic intrinsic value score, however, decreased (3.75 to 3.71, p = 0.009), whereas the materialism score (1.87 to 1.94, p <0.001) and suicidal behaviour score (0.17 to 0.21, p <0.001) increased, all considered unfavourable (Table 4). The positive youth development attributes and behaviours of the participants in the baseline (between 23 December 2019 and 13 January 2020) and first follow-up surveys (between 16 June and 8 July 2020) SSD, standard deviation. A higher score is considered favourable. A lower score is considered favourable. The t tests examined the differences in each variable between the baseline and first follow-up surveys. Whereas a decline in the use of electronic devices was self-reported, it was, in the caregivers’ opinion, reported to have increased. Awareness of COVID-19 and the extent to which COVID-19 has affected different aspects of life were reported by both students and caregivers (Table 5). Most families of the students (96.7%) were not infected by COVID-19. Most of the students considered COVID-19 to be very serious (69.5%) and the infection to be very dangerous (75.8%). Most reported that being infected was ‘impossible’ or ‘not quite possible’ (59.2%) and that they were ‘capable’ or ‘very capable’ of preventing the disease (79.4%). Most thought that the COVID-19 lockdown did not affect their dietary (77.3%), study (66.2%), social (61.3%) and physical activities (60.7%), by reporting ‘not at all’ or ‘a little bit ’. The COVID-19-related information among the participants in the first follow-up survey between 16 June and 8 July 2020 SD, standard deviation. The CPCD provides a unique opportunity to investigate the associations between students’ sociodemographic, physical and psychological characteristics (including PCD), family environment, lifestyle behaviours, academic performance and health status in China. More importantly, all students experienced the COVID-19 pandemic (prevalent locally during January and April) which has had an unknown impact on children’s short-term and long-term development.40 Baseline data were, coincidentally, collected before the outbreak of COVID-19. They provide an important resource for studying the effect of the epidemic on early-stage physical and mental development, by providing an unbiased baseline. Continuous follow-ups would further enable investigation of the life course effects of the epidemic on children of the ‘COVID-19 generation’. The first follow-up will provide a baseline in the post-COVID era. This could be an important reference for evaluating the effects of subsequent interventions and policies on improving children’s health. As epidemics might become more intensive and frequent in the 21st century,41 findings from our cohort could inform multiple stakeholders, including policy makers, clinical practitioners, school administrators and guardians (including parents) of potential changes in students’ psychological, behavioural and health statuses, facilitating better policy making, clinical practice and intervention at home and at school.42 There are also some weaknesses in the CPCD. First, in addition to the intrinsic limitations of the tools used to measure psychological and behavioural characteristics, most responses were self- or caregiver-reported, with limited measurements from students’ physical examination. Second, the Chinese Positive Youth Development Scale was validated for adolescents but not for primary school students (this does, however, create an opportunity to validate the suitability of this tool in measuring positive development quality among primary school students). The time spent on sleeping, physical activity and viewing electronic screens, as reported by caregivers, might not be accurate. Third, the considerable number of middle school students lost to follow-up might affect the representativeness of the remaining cohort of middle school students in Chengdu overall; moreover, the cohort was not randomly sampled and are not city-representative. To learn more about this cohort and explore potential collaborations, please contact the principal investigator Professor Peng Jia. The data underlying this article will be shared on reasonable request to the corresponding author. The International Institute of Spatial Lifecourse Epidemiology (ISLE) and Hong Kong Polytechnic University (19H0642) support this research. We thank all participants for providing their information. We also are grateful to the investigators of the West China School of Public Health and other participating schools for data collection. None declared.