Cohort profile: The Shanghai Child and Adolescent Health Cohort (SCAHC) - A prospective study of child growth and development in a megacity in China.

purposeChildren's health and well-being are cross-cutting indicators of sustainable development and underpin society's long-term development potential and productivity. The Shanghai Child and Adolescent Health Cohort (SCAHC) was established with a focus on the sociodemographic, environmental and biological determinants of children's growth and development.

participantsThe SCAHC adopted a two-stage random cluster sampling scheme stratified by economic development level to establish the cohort. A total of 13 primary schools from Pudong New Area were selected to recruit year 1 pupils and at least one of their parents. The SCAHC was initially designed to follow pupils from year 1 (aged 6-7) through to year 9 (aged 14-15), with a possible extension upon additional funding. Baseline data were collected in 2020 and included information on pupils (sociodemographic characteristics, health status, clinical conditions, personal medical history, sleep patterns, dietary consumption, lifestyles, environmental factors and laboratory test results on micronutrient status, lipid profile, thyroid function, renal function and metabolic status) and their parents (demographic characteristics, medical history, pregnancy status and lifestyle factors including smoking, alcohol consumption and physical activity). The primary growth and development outcomes include anthropometric measures (height, weight, waist circumference and hip circumference) and pubertal development (Tanner staging). Secondary outcomes include metabolic health, nutritional status, sleep quality and the prevalence of common childhood conditions (such as myopia, dental caries and asthma). Annual follow-up assessments with repeated measures were scheduled. All data were collected during baseline and follow-up periods through questionnaires, established instruments, standard physical examinations and routine laboratory tests. Sex differences in baseline data were evaluated using independent t-tests for continuous variables and χ2 or Fisher's exact tests for categorical variables where appropriate. FINDINGS TO DATE: The baseline child population included 1363 boys and 1132 girls (mean age 6.44 years). The mean body mass index of the children at baseline was 16.44 kg/m², and the mean waist-to-hip ratio was 0.81. Compared with girls, boys exhibited a higher prevalence of overweight and obesity (40.8% vs 31.4%, p<0.001) and higher rates of asthma (2.9% vs 1.1%, p=0.002) and attention-deficit hyperactivity disorder (5.9% vs 2.1%, p<0.001). Conversely, girls had higher rates of vitamin D deficiency (50.5% vs 40.1%, p<0.001) and abnormal urine findings (17.2% vs 0.4%, p<0.001). The overall prevalence of dental caries was high (60.2%), whereas the prevalence of myopia (12.6%) was lower than the national estimates. FUTURE PLANS: The SCAHC is an ongoing prospective cohort that provides rich information for identifying the multimodal determinants of children's growth and development. Findings from this cohort can inform targeted intervention strategies for major public health issues, such as obesity and sedentary lifestyles, as well as emerging challenges such as mental disorders in children and adolescents.