Metabolic syndrome and its associated early-life factors in children and adolescents: a cross-sectional study in Guangzhou, China.

OBJECTIVE: The present study aimed to investigate the prevalence of metabolic syndrome (MetS) in 7- to 17-year-old children and adolescents in China and to examine the relationship between MetS and its associated early-life factors. DESIGN: Data were collected using a standard parent/guardian questionnaire in a face-to-face interview. Each participant underwent a complete anthropometric evaluation. MetS was defined according to the criteria of the International Diabetes Federation (IDF; 2007) for children and adolescents. SETTING: Guangzhou, a large city in South China, September 2013. SUBJECTS: A total of 1770 children and adolescents were enrolled in the study, including 913 girls (51·6%) and 857 boys (48·4%). RESULTS: The overall prevalence of MetS in children and adolescents was 1·1% (n 19), which was higher in boys (1·4%) than in girls (0·8%). Multivariate analysis indicated that high birth weight was significantly associated with abdominal obesity (OR=2·86; 95% CI 1·62, 5·06) and MetS (OR=3·61; 95% CI 1·33, 9·82). Furthermore, >6 months of maternal breast-feeding was inversely associated with MetS (OR=0·39; 95% CI 0·16, 0·98). CONCLUSION: Based on IDF criteria, the prevalence of MetS among southern Chinese children was significantly lower than that in other populations. High birth weight was significantly associated with abdominal obesity and MetS, and breast-feeding for longer than 6 months was inversely associated with MetS in South China.

Dental caries is negatively correlated with body mass index among 7-9 years old children in Guangzhou, China.

BACKGROUND: Evidence 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. METHODS: This 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. RESULTS: The 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. CONCLUSION: Higher 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.

Relationship of BMI to the incidence of hypertension: a 4 years' cohort study among children in Guangzhou, 2007-2011.

BACKGROUND: In China, there has been a dramatic increase in overweight and obesity among children and adolescents in recent decades. However, little longitudinal studies reported BMI in relation to the risk for hypertension among children in China. We examined the longitudinal relations between BMI and hypertension in Chinese schoolchildren via a retrospective cohort study. METHODS: The cohort study was carried out in 7203 children (3821 boys and 3382 girls) in Guangzhou aged 6-8 years, with a continuous 4 years of follow-up. The participants, evaluated by body mass index (BMI), were categorized as thinness, normal weight, overweight, and obesity groups. The age and gender-specific BMI cutoffs newly developed by the Working Group on Obesity in China (WGOC) were used to define overweight and obesity. The thinness was defined by the international age- and gender-specific cut-off points for BMI for thinness grade 1. Hypertension was defined by using percentiles of systolic and diastolic values on the basis of height percentile, age, and gender. The Cox proportional hazards model was used to estimate the single or joint effect of BMI on the risk of hypertension. This study was approved by The Ethical Committee of School of Public Health, Sun Yat-sen University. RESULTS: During a follow-up of 4 years, a shocking high cumulative incidence of hypertension was found in Chinese overweight (50.1 %) and obesity (70 %) schoolchildren. The incidence of children hypertension were markedly higher among overweight and obesity group than normal weight and thinness group (24.3 %, 18.5 % vs 11.1 %, 7.4 %). Compared with the children in the normal weight group, the adjusted HRs and 95 % CIs of developing hypertension in thinness, overweight, and obesity group were 0.972 (0.851, 1.110), 1.313 (1.179, 1.461), and 1.816 (1.634, 2.081), respectively. Additionally, the protective effect of thinness on hypertension was observed in boys 0.808 (0.666, 0.981), but not in girls 1.158 (0.966, 1.389). CONCLUSIONS: The 4-year longitudinal study indicated that the overweight and obesity can predict the higher risk of hypertension in Chinese children, whereas, the thinness predict the lower risk of hypertension only in boys.

Effect of Time Spent Outdoors at School on the Development of Myopia Among Children in China: A Randomized Clinical Trial.

IMPORTANCE: Myopia has reached epidemic levels in parts of East and Southeast Asia. However, there is no effective intervention to prevent the development of myopia. OBJECTIVE: To assess the efficacy of increasing time spent outdoors at school in preventing incident myopia. DESIGN, SETTING, AND PARTICIPANTS: Cluster randomized trial of children in grade 1 from 12 primary schools in Guangzhou, China, conducted between October 2010 and October 2013. INTERVENTIONS: For 6 intervention schools (n = 952 students), 1 additional 40-minute class of outdoor activities was added to each school day, and parents were encouraged to engage their children in outdoor activities after school hours, especially during weekends and holidays. Children and parents in the 6 control schools (n = 951 students) continued their usual pattern of activity. MAIN OUTCOMES AND MEASURES: The primary outcome measure was the 3-year cumulative incidence rate of myopia (defined using the Refractive Error Study in Children spherical equivalent refractive error standard of ≤-0.5 diopters [D]) among the students without established myopia at baseline. Secondary outcome measures were changes in spherical equivalent refraction and axial length among all students, analyzed using mixed linear models and intention-to-treat principles. Data from the right eyes were used for the analysis. RESULTS: There were 952 children in the intervention group and 951 in the control group with a mean (SD) age of 6.6 (0.34) years. The cumulative incidence rate of myopia was 30.4% in the intervention group (259 incident cases among 853 eligible participants) and 39.5% (287 incident cases among 726 eligible participants) in the control group (difference of -9.1% [95% CI, -14.1% to -4.1%]; P < .001). There was also a significant difference in the 3-year change in spherical equivalent refraction for the intervention group (-1.42 D) compared with the control group (-1.59 D) (difference of 0.17 D [95% CI, 0.01 to 0.33 D]; P = .04). Elongation of axial length was not significantly different between the intervention group (0.95 mm) and the control group (0.98 mm) (difference of -0.03 mm [95% CI, -0.07 to 0.003 mm]; P = .07). CONCLUSIONS AND RELEVANCE: Among 6-year-old children in Guangzhou, China, the addition of 40 minutes of outdoor activity at school compared with usual activity resulted in a reduced incidence rate of myopia over the next 3 years. Further studies are needed to assess long-term follow-up of these children and the generalizability of these findings. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00848900.

Empirical change in the prevalence of overweight and obesity in adolescents from 2007 to 2011 in Guangzhou, China.

UNLABELLED: There is a strong evidence of an increasing secular trend in obesity in adolescents in most of the world over the past 10 years. However, no studies have been reported on this trend in Guangzhou, one of the most urbanized areas in China. This study assessed the empirical changes in body mass index (BMI) and the prevalence of overweight and obesity of adolescents in Guangzhou from 2007 to 2011. The data were derived from the surveys on students' constitution and health carried out by government in 2007, 2009, and 2011 in Guangzhou. Randomly, 17,157 students in 2007, 26,381 students in 2009, and 36,328 students in 2011, aged 12 to 18, from schools in the four urban districts were examined. Anthropometric parameters were measured in all students. Adiposity status was estimated using BMI according to the Working Group on Obesity in China criteria. The total prevalence of overweight and obesity increased from 8.1 % and 3.1 % in 2007 to 10.0 % and 4.2 % in 2011, respectively (P < 0.05). However, the total prevalence of obesity decreased significantly from 4.5 % in 2009 to 4.2 % in 2011 (P < 0.05). The prevalence of overweight and obesity in males was significantly higher than that in females in each year among the 4 years (P < 0.05). CONCLUSION: Although the prevalence of adolescent overweight and obesity in Guangzhou in 2011 is still lower than the average values of Chinese large coastal cities, a significant increase was still found in their prevalence from 2007 to 2011. However, the adolescent obesity, but not the overweight prevalence, starts to decrease from 2009 to 2011.

[Secular trends of overweight and obesity prevalence between 2007 and 2011 in children and adolescents in Guangzhou].

OBJECTIVE: This study aimed to explore the secular trends of overweight and obesity prevalence between 2007 and 2011 in children and adolescents in Guangzhou. METHODS: The data of physical examination was collected from the routine measurements carried out by the Health Care Facilities of Primary and Secondary schools between 2007 and 2011. Random stratified cluster sampling was conducted, all the students aged 5-18 years old form 19 primary and secondary schools from 4 districts (Tianhe district, Yuexiu district, Baiyun district and Haizhu district) were included in this survey, including 27 944 students in 2007 and 38 284 students in 2011. Body mass index reference norm established by Working Group on Obesity in China (WGOC) and the WHO cut-off criteria were employed for overweight and obesity screening, and the trend was analyzed. RESULTS: Prevalence of obesity in children and adolescents (7-18 years old) significantly increased from 5.96% (1 553/26 055) in 2007 to 6.56% (2 339/35 664) in 2011, and the difference showed statistical significance (χ(2) = 9.195, P < 0.05). Overweight and obesity was more common in boys (overweight: 13.25% (1 766/13 329) in 2007 and 13.87% (2 559/18 451) in 2011; obesity: 7.82% (1 042/13 329) in 2007 and 8.63% (1 592/18 451) in 2011) than in girls (overweight: 7.43% (946/12 726) in 2007 and 8.17% (1 406/17 213) in 2011; obesity: 4.11% (523/12 726) in 2007 and 4.48% (771/17 213) in 2011), and the difference showed statistical significance (overweight:χ(2) = 236.123 in 2007 and χ(2) = 292.892 in 2011; obesity:χ(2) = 158.533 in 2007 and χ(2) = 247.794 in 2011. All P values < 0.05). Further analysis found that significant increases occurred in boys aged 16 and 17 years old and in girls aged 12 years old (boy: 16 years old,χ(2) = 6.820, P < 0.05. 17 years old, χ(2) = 4.893, P < 0.05. girl: 12 years old,χ(2) = 5.921, P < 0.05). RESULTS: of Join-point regression showed that for boys less than 10 years old the prevalence increased with age increasing (in 2007, APC = 3.75; in 2011, APC = 1.76), while over 10 years old the prevalence decreased with age increasing (in 2007, 10-18 years old's APC = -18.58; in 2011, 10-18 years old's APC = -15.95). While for girls the prevalence of obesity increased with age increasing between 7-9 years old (APC = 12.16), decreased with age increasing through 9 to 18 years old (APC = -17.23) in 2007. The prevalence decreased with age increasing for girls in 2011 (APC = -4.66). CONCLUSION: The prevalence of obesity is high and still increasing in children and adolescents in Guangzhou, and it is higher in boys than in girls. It is more likely to become obesity at 10 years for boys, and for girls the prevalence decrease with age increasing.

[Correlation of resistance to peer pressure and risky decision-making with adolescent health risk behaviors].

OBJECTIVE: To explore possible interrelationships among resistance to peer pressure, risky decision-making and health risk behaviors among young adolescents. METHODS: Based on the cluster sampling method, the participants who were recruited from 5 junior middle schools in Guangzhou and 3 junior middle schools in Shenyang city on October, 2010, were administered to complete the questionnaire concerned with their experiences with drinking and smoking during the past 30 days preceding the survey, and the hours using computer daily both in weekdays and in weekend. The level of resistance to peer influence and risky decision-making were assessed by Resistance to peer influence scale (RPIS) and Youth decision-making questionnaire (YDMQ). Logistic regression was used to explore possible interrelationships among resistance to peer influence, risky decision-making and health risk behaviors among young adolescents. RESULTS: A total of 1985 questionnaires were valid, including 1001(50.4%) boys and 984 (49.6%) girls. About 27.1% (537/1985) junior middle school students reported having health risk behaviors, boys' (30.7%, 307/1001) was higher than girls' (23.4%, 230/984) with significant gender difference (P < 0.05). The prevalence of smoking, drinking during the past 30 days before the survey and using computer over 3 hours daily in weekdays and in weekend were 5.1% (102/1985), 14.3% (284/1985), 3.5% (70/1985) and 13.7% (272/1985), respectively. The rate of drinking, using computer over 3 hours daily in weekdays and in weekend were higher in males (16.4% (164/1001), 4.5% (45/1001), 16.2% (162/1001)) than those in females (12.2% (120/984), 2.5% (25/984), 11.2% (110/984)) (P < 0.05). The scores of RPIS and YDMQ of the two cities adolescents were 2.82 ± 0.39 and 1.68 ± 0.62. The students reported smoking, drinking during the past 30 days before the survey and using computer over 3 hours daily in weekend gained lower RPIS scores (2.43 ± 0.40, 2.61 ± 0.41, 2.77 ± 0.40) than their counterparts who didn't report these kind of health risk behaviors (2.84 ± 0.38, 2.85 ± 0.38, 2.82 ± 0.39)(P < 0.05). And those reported smoking, drinking during the past 30 days before the survey and using computer over 3 hours daily in weekdays and in weekend gained higher YDMQ scores (2.38 ± 0.66, 2.06 ± 0.66, 1.97 ± 0.72, 1.84 ± 0.64, respectively) than their counterparts who didn't report these kind of health risk behaviors (1.64 ± 0.38, 1.61 ± 0.58, 1.67 ± 0.61, 1.65 ± 0.61, respectively) (P < 0.05). After adjusting gender, area, parental education degree, self-reported family economic condition, multi-variant logistic regression analysis indicated that the low and middle level of resistance to peer influence (low and middle level vs high level, had odds ratios of 2.97 (1.96 - 4.50) and 1.51 (1.05 - 2.16)), and also the middle and high level of risky decision-making (middle and high level vs low level, had odds ratios of 1.62 (1.19 - 2.22) and 3.43 (2.39 - 4.90)) were all the risk factors of adolescent health risk behaviors. CONCLUSION: Adolescents with poor ability of resistance to peer pressure and high risky decision-making were both the risk factors of adolescent health risk behaviors.

Online social networking addiction and depression: The results from a large-scale prospective cohort study in Chinese adolescents.

BACKGROUND AND AIMS: The 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. METHODS: A 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. RESULTS: Adolescents 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). CONCLUSION: The findings indicate a bidirectional association between OSNA and depression, meaning that addictive online social networking use is accompanied by increased level of depressive symptoms.

Secular Trends in Overweight and Obesity among Urban Children in Guangzhou China, 2007-2011.

BACKGROUND: No studies have been reported on children obesity prevalence of Guangzhou, one of the most urbanized areas in China. This study tracks the secular trends of obesity prevalence of children. METHODS: The data were derived from the surveys on students' constitution and health carried out by government. Randomly, 3832 students in 2007, 13141 in 2008, 14052 in 2009, 13750 in 2010, and 15225 in 2011, aged 7-12 years, from urban primary school were examined. Anthropometric parameters were measured in all students. RESULTS: The mean of body mass index increased significantly from 16.6 in 2008 to 16.8 in 2011 in the total group of children, and the total prevalence of overweight and obesity increased from 9.4 and 6.2 to 10.5 and 7.5 from 2007 to 2011, respectively. The minimum value of the mean body mass index and the overweight and obesity prevalence in the total age group all appeared in 2008. The prevalence of overweight and obesity in males was significantly higher than that in females in each year among the 5 years. CONCLUSION: Although the prevalence of children obesity in Guangzhou in 2011 is still lower than the average values of Chinese large coastal cities, a significant increase was found in their prevalence from 2007 to 2011 and the total obesity prevalence of children is even higher than that of adolescent. Furthermore, we found that the minimum value of overweight and obesity prevalence of the total group and almost all gender-specific age groups appeared in 2008.

National estimates of the pubertal milestones among urban and rural Chinese girls.

PURPOSE: To provide clinically meaningful, normative reference data that describe pubertal timing indicators among urban and rural Chinese girls. METHODS: Girls of Chinese Han ethnicity from grade 1 in elementary schools through grade 12 in junior high schools in eight regions participated in China Puberty Research Collaboration from October 2010 to May 2011. At examination, stages of breast and pubic hair development were assessed by trained physicians. Data on menses were collected through questionnaire survey. RESULTS: A total of 15,388 girls aged 6.0-18.9 years participated in this collaboration study. Among them, approximately 53.5% (8,238) came from rural areas. The median ages at stage 2 of breast development of Chinese girls were 9.18 (95% confidence interval: 8.91-9.44) years and at stage 2 for pubic hair growth were 11.65 (95% confidence interval: 11.41-11.90) years. Girls with body mass index ≥85th percentile had earlier age for B2 (Tanner stage 2 for breast development), B3 (Tanner stage 3 for breast development), PH2 (Tanner stage 2 for pubic hair development), PH3 (Tanner stage 3 for pubic hair development), and menarche compared with girls with body mass index < 85th percentile. Urban girls achieved PH2, PH3, and menarche at a much earlier age than rural girls, except for B2 and B3 attainment. Mean menarcheal age is 12.43 years. CONCLUSIONS: This study presented up-to-date data on female pubertal timing in a national sample of Chinese Han ethnicity girls and separately for urban and rural areas.

[A matched case-control study on risk factors related to sports injuries in primary and secondary school students in Guangzhou].

OBJECTIVE: To investigate the risk factors and to provide evidence for prevention and reduction of sports injuries in primary and secondary school students in Guangzhou. METHODS: 1:1 case-control study was conducted on both 349 cases and controls under the same distribution of sex, age and grade. Conditional univariate and multivariate logistic regression were used to explore the relationships between risk factors and injuries. RESULTS: Severe soles wear (OR = 7.20, 95%CI: 2.37 - 21.84), tiredness (OR = 14.34, 95%CI: 2.29 - 89.66) or sickness (OR = 1.96, 95%CI: 1.29 - 3.06) when participating in sports at a high frequency and history of previous injuries (OR = 2.11, 95%CI: 1.41 - 3.96) were risk factors related to sports injury while guidance by teachers and physical education provided by teachers during training (OR = 0.46, 95%CI: 0.26 - 0.79), appropriate protection (OR = 0.36, 95%CI: 0.20 - 0.64) as well as warming-up exercise (OR = 0.31, 95%CI: 0.14 - 0.67) at a high frequency were protective factors for sports injury. CONCLUSION: Prevention and control on sports injury need to improve the awareness on sports safety for students and teachers in order to develop positive behavior on sports safety.

[A matched case-control study on the risk factors of burn injury among primary and secondary school students in Guangzhou].

OBJECTIVE: To investigate the relative factors of burn injury among primary and secondary school students in Guangzhou and to provide scientific evidence for intervention. METHODS: 1:1 case-control study was conducted in 428 cases and 428 controls based on different sex and classes. The relationship between relative factors and burn injury was analyzed by univariate and multivariate conditional logistic regression. RESULTS: Following facts were discovered: burn injury mainly occurred in the upper limbs (57.9%), home was the place that most of burn injury (58.2%) took place, 51.0% of the burn injuries was caused by hot liquid, 43.9% burn injury needed medical treatment and 7.7% burn injury left with sequelae as dysfunction or disability. Data from the multivariate conditional logistic regression showed that boarding students (OR = 2.47), older age of the mothers (OR = 1.03), non-nuclear family (OR = 1.25 - 1.84) were risk factors of burn injury. Being the only child (OR = 0.60), having sufficient time for sleep (OR = 0.84), good performance record (OR = 0.85), higher maternal education background were protective factors on burn injury. CONCLUSION: Among primary and secondary school students in Guangzhou, burn injury mainly occurred in the upper limbs, and home was the place that most of burn injury took place.

Factors associated with Internet addiction among adolescents.

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.

[Study on food preference and dietary behavior to overweight/obesity in school children and adolescents in Guangzhou: a case-control study].

OBJECTIVE: This study assessed the effect of food preference and dietary behaviors on the risk of overweight or obesity in school children and adolescents aged 6 - 19 years. METHODS: All overweight or obese students, with age- and school-matched controls were recruited for this case-control study from 28 elementary and secondary schools in Guangzhou urban districts from October 2006 to April 2007. Weight and height were measured, and body mass index was calculated for the classification of obesity, overweight and underweight. Their food preference and behaviors were assessed using a structured questionnaire completed by their parents. Behavior and food preference were classified into four levels, and the relevant bottom levels were defined as control groups. Logistic regression was used to assess independent determinants of overweight and obesity. RESULTS: Among 7136 participants, 1947 cases and 2136 normal weight controls from 5755 students with valid questionnaire data were included in the study. Results from univariate analysis showed that odds ratios for overweight or obesity were 0.60-0.69 in those with most preference (top group) on vegetables, fruits, candy, evening snacks, 0.50 in the students of less food partiality, 1.84, 1.30 and 1.26 in those of most preference for pork, beef and deep-fried foods, and 5.14 in students with fastest speed during eating, respectively (all P < 0.05). Vegetable intake, evening snacks preference, speed during eating and food partiality remained with significant association with overweight and obesity in multivariate analysis after adjusted for age, sex, family socio-economical status and their parents' body build. The adjusted odds ratios (OR) and 95% confidence intervals (95%CI) of the above items became 0.55 (0.42 - 0.73), 0.48 (0.35 - 0.65), 0.50 (0.39 - 0.65), and 4.32 (3.23 - 5.80) as compared to the relevant lowest categories, respectively. CONCLUSION: Behaviors as eating more vegetables and slow-eating might be protective factors against overweight and obesity in school children.

[Validity and reliability of Pediatric Quality of Life Inventory Version 4.0 Generic Core Scales in Chinese children and adolescents].

OBJECTIVE: To evaluate the reliability and validity of parent proxy-report scales of Pediatric Quality of Life Inventory Version 4.0 (PedsQL 4.0) Generic Core Scales, the Chinese Version. METHODS: 3493 school students aged 6-18 years were recruited using multistage cluster sampling method. Health-related quality of life was assessed using the above-mentioned PedsQL 4.0 scales. The internal consistency was assessed, using Cronbach's a coefficient, while its validity was tested through correlation analysis, t-test and exploratory factor analysis. RESULTS: The internal consistency reliability for Total Scale Score (Cronbach's alpha = 0.90), Physical Health Summary Score (alpha= 0.81), and Psychosocial Health Summary Score (alpha= 0.89) were excellent. Six major factors were extracted by factor analysis which basically matched the designed structure of the original version accounting for nearly 66% of the variance. The total Scale Score significantly decreased by 3.5 to 13.3 (P < 0.05) in children and adolescents who had diseases including cold, skin hypersensitiveness, food allergy, courbature or arthralgia, breathlessness with a frequency of 6 times or more per year or had asthma as compared to those with lower frequency (< or = 5 times/y) of the diseases or without asthma. We found moderate to high correlations between items and the subscales. Correlation coefficients ranged between 0.45 to 0.84 (P < 0.01). CONCLUSION: The reliability and validity of the parent proxy-report scales of PedsQL 4.0 Generic Core Scales of the Chinese Version were as good as the original version. Our findings suggested that the scales could be applied to evaluate the health-related quality of life in childhood children in similar Chinese regions to Guangzhou.