clinicaltrials.gov Identifier: NCT00848900.

This research examined factors associated with Internet addiction in adolescence using a population-based cross-sectional survey with self-reported questionnaires. Participants were recruited from high school students, ages 13 to 18 years, registered on the secondary school registry in Guangzhou city using a stratified random sampling technique. Internet addiction was assessed using the Internet Addiction Test (IAT). Information was also collected on demographics, health behaviors, and perception of personal condition. Depression was assessed by the Zung Self-Rating Depression Scale. The majority of respondents were classified as normal users of the Internet (n = 1,392, 89.2%), with 158 (10.2%) moderately and 10 (0.6%) severely addicted to the Internet. Results from the multivariate logistic regression analyses suggested a 50% increased odds for males to be addicted to the Internet (OR = 1.5, 95% CI = 1.1-2.2) when compared to females. Other potential risk factors included drinking behavior (OR = 1.7, 95% CI = 1.1-2.8), family dissatisfaction (OR = 2.4, 95% CI = 1.3-4.3), and experience of recent stressful events (OR = 10.0, 95% CI = 6.5-12.2). Stress-related variables were associated with Internet addiction among adolescents as they are also related to other addictions. Clinicians need to be aware of potential comorbidities of other problems such as stress and family dissatisfaction among adolescent Internet addiction patients.

Purpose To estimate the prevalence of myopia among primary and middle schoolaged students in Guangzhou and to explore the potentially contributing factors to myopia. Methods This cross-sectional study was based on a sample of students in grades 1-6 and grades 7-9. Data were collected from refractive error measurements and a structured questionnaire. Results A total of 3055 participants were involved in this analysis, and the overall prevalence of myopia was 47.4% (95% confidence interval (CI) = 45.6-49.2%). The prevalence of myopia in students increased along with the growth of grade level; the prevalence of myopia in students in grade 1 was only 0.2%, as it increased to 38.8% in students in grade 3, and the rate was the highest (68.4%) in students in grade 9. Girls were at a higher risk of myopia than boys (adjusted odds ratio = 1.22, 95% CI = 1.04-1.44). Both male and female students whose distance of reading was longer than 25 cm were less likely to have myopia and who have one or two myopic parents were at a higher risk of myopia. In addition, reading for pleasure more than 2 h per day (adjusted odds ratio = 1.84, 95% CI = 1.09-3.12) was only positively associated with myopia in boys and spending time watching television per week was only positively associated with myopia in girls. Conclusion Myopia in students is a significant public health problem in Guangzhou. Female gender, higher grade, longer time spent for near work, shorter distance of near work, and parental myopia were shown to be associated with the increasing risk of myopia in children.

SIB is common in adolescence in the study population in China. Addiction to the internet is detrimental to mental health and increases the risk of self-injury among adolescents. Clinicians need to be aware of potential co-morbidities of other addictions among adolescent self-injured patients.

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Background and aimsThe aim of this study is to estimate the longitudinal associations between online social networking addiction (OSNA) and depression, whether OSNA predicts development of depression, and reversely, whether depression predicts development of OSNA.MethodsA total of 5,365 students from nine secondary schools in Guangzhou, Southern China were surveyed at baseline in March 2014, and followed up 9 months later. Level of OSNA and depression were measured using the validated OSNA scale and CES-D, respectively. Multilevel logistic regression models were applied to estimate the longitudinal associations between OSNA and depression.ResultsAdolescents who were depressed but free of OSNA at baseline had 1.48 times more likely to develop OSNA at follow-up compared with those non-depressed at baseline [adjusted OR (AOR): 1.48, 95% confidence interval (CI): 1.14–1.93]. In addition, compared with those who were not depressed during the follow-up period, adolescents who were persistently depressed or emerging depressed during the follow-up period had increased risk of developing OSNA at follow-up (AOR: 3.45, 95% CI: 2.51–4.75 for persistent depression; AOR: 4.47, 95% CI: 3.33–5.99 for emerging depression). Reversely, among those without depression at baseline, adolescents who were classified as persistent OSNA or emerging OSNA had higher risk of developing depression compared with those who were no OSNA (AOR: 1.65, 95% CI: 1.01–2.69 for persistent OSNA; AOR: 4.29; 95% CI: 3.17–5.81 for emerging OSNA).ConclusionThe findings indicate a bidirectional association between OSNA and depression, meaning that addictive online social networking use is accompanied by increased level of depressive symptoms.

BackgroundEvidence linking caries in primary dentition and children’s anthropometric measures is contradictory. We aimed to evaluate the prevalence of primary dental caries and its relationship with body mass index (BMI) among 7-9 years old school children in urban Guangzhou, China.MethodsThis cross-sectional study enrolled 32,461 pupils (14,778 girls and 17,683 boys) aged 7-9 years from 65 elementary schools in Guangzhou. Dental caries was detected according to criteria recommended by the World Health Organization (WHO). The total mean decayed, missing or filled teeth (dmft) of primary dentition were assessed. Weight and height were measured and BMI was calculated. Children were classified into underweight, normal weight, overweight and obesity groups by BMI based on Chinese criteria. Z-score of BMI-for-age (BAZ) was calculated by WHO standardized procedure. Multivariable odds ratios (ORs) and 95 % confidence intervals (CIs) were calculated using logistic regression. Restricted cubic spline regression was applied to evaluate the shape of the relationship between BAZ and primary dental caries.ResultsThe prevalence of primary dental caries was 30.7 % in total sample. Regarding dmft values, the mean ± standard deviation (SD) in the combined sample were 1.03 ± 2.05 in boys and 0.93 ± 1.92 in girls. Both indices decreased by age. Compared with normal BMI group, children in overweight and obesity groups have 27 % (OR = 0.73, 95 % CI: 0.66-0.81, P < 0.0001) and 34 % (OR = 0.66, 95 % CI: 0.59-0.74, P < 0.0001) lower odds for the presence of primary dental caries after adjustment for age and gender, respectively. Although in general, increased BAZ was associated with decreased risk of dental caries, full-range BAZ was associated with dental caries in an A-shaped manner with a zenith at around -1.4.ConclusionHigher BMI was associated with lower odds of caries; overweight and obese children were more likely to be primary dental caries free among 7-9 years in Guangzhou, China.Electronic supplementary materialThe online version of this article (doi:10.1186/s12889-016-3295-3) contains supplementary material, which is available to authorized users.

Constraint therapy plus electrical stimulation is likely to be best in improving hand performance in children with hemiplegic cerebral palsy.