1.Current status of pubertal sexual characteristics development of 2 704 girls aged 6-18 years in Tongzhou District of Beijing
Yaqin ZHANG ; Huahong WU ; Wen SHU ; Yang LI ; Chengdong YU ; Tao LI ; Guimin HUANG ; Dongqing HOU ; Fangfang CHEN ; Junting LIU ; Shaoli LI ; Xinnan ZONG
Chinese Journal of Pediatrics 2024;62(5):430-437
Objective:To understand the current status of pubertal sexual characteristics development of girls aged 6-18 years in Tongzhou District of Beijing and to compare the differences in sexual characteristics development among girls characterized as thin, normal, overweight, and obese.Methods:A cross-sectional survey was conducted among 2 844 girls aged 6-18 years in Tongzhou District of Beijing from September 2022 to July 2023. The developmental stages of breast and pubic hair were assessed on site, and menarche status was inquired. Weight and height were measured. The girls were subsequently characterized into thin, normal, overweight and obese groups. Basic information (including family and personal history) was obtained through questionnaires. Probit probability unit regression was applied to calculate the age of each Tanner stage of sexual characteristics development and the age of menarche. The χ 2 test was applied to compare the counting data between two or multiple groups. Results:A total of 2 844 girls were surveyed and 2 704 girls met the inclusion criteria, resulting in a valid response rate of 95.1%. Among these girls, 1 105 (40.9%) were aged 6-9 years, 1 053 (38.9%) were aged 10-13 years, and 546 (20.2%) were aged 14-18 years. The of height-for-age Z-score (HAZ), weight-for-age Z-score (WAZ), and body mass index-for-age Z-score (BAZ) were 0.46(-0.23,1.16), 0.69(-0.16,1.67), and 0.67(-0.27,1.73) respectively. The prevalences of thin, overweight, and obesity were respectively 1.7% (45/2 704), 17.3% (467/2 704), and 19.9% (538/2 704), respectively. There were 45 girls in the thin group, 1 654 girls in the normal weight group, 1 005 girls in the overweight and obesity group. The age of Tanner stage breast 2 (B2), Tanner stage pubic hair 2 (P2), and menarche was 9.0 (95% CI 8.9-9.1), 10.5 (95% CI 10.4-10.6), and 11.4 (95% CI 11.3-1.5) years, respectively. The current status of breast and pubic hair maturity in girls with pubertal development shows that 64.6% (1 211/1 874) of these girls had breast development preceding pubic hair development, 32.4% (607/1 874) had concurrent breast and pubic hair development, and 3.0% (56/1 874) had pubic hairs development preceding breast development. The interval age between B2 and B5 was 4.7 (95% CI 4.6-4.8) years, between P2 and P5 was 4.5 (95% CI 4.4-4.6) years, and between B2 and menarche was 2.4 (95% CI 2.3-2.5) years. The ages of sexual characteristics development in overweight and obese groups were earlier than that in normal and thin groups. The ages of B2 in thin, normal, overweight, and obese groups were 10.0 (95% CI 9.5-10.6), 9.3 (95% CI 9.2-9.4), and 8.6 (95% CI 8.4-8.7) years, respectively. The age of menarche in thin, normal, overweight, and obese groups were 13.1 (95% CI 12.4-13.7), 11.6 (95% CI 11.4-11.7), and 11.1 (95% CI 11.0-11.2) years, respectively. The interval ages between B2 and B5 and between P2 and P5 was 4.5 and 4.1 years, respectively in the overweight and obese groups, and those in normal group and thin group was 4.7 and 4.5 years, 4.6 and 4.7 years, respectively. Conclusions:The ages of sexual characteristics development and menarche tend in Tongzhou District of Beijing to be earlier than that being reported of Beijing's survey 20 years ago. Girls characterized as overweight and obese not only start puberty at an earlier age than girls of normal weight, but also have a shorter developmental process.
2.Reference values and growth curves of weight/length, body mass index, and ponderal index of Chinese newborns of different gestational ages
Xinnan ZONG ; Hui LI ; Yaqin ZHANG ; Huahong WU
Chinese Journal of Pediatrics 2021;59(3):181-188
Objective:To establish the reference values and growth curves of weight/length, body mass index, and ponderal index for Chinese newborns with gestational ages of 24 to 42 weeks, in order to provide a reference for the assessment of body proportionality and nutritional status at birth.Methods:Cross-sectional study design was applied. From June 2015 to November 2018, a total of 24 375 singleton live birth newborns with gestational ages of 24 to 42 weeks from 13 cities including Beijing, Harbin, Xi′an, Shanghai, Nanjing, Wuhan, Guangzhou, Fuzhou, Kunming, Tianjin, Shenyang, Changsha, and Shenzhen were selected, excluding those impacting the establishment of the reference values. The generalized additive model for location, scale, and shape (GAMLSS) was employed to establish percentile (P 3, P 10, P 25, P 50, P 75, P 90, P 97) reference values and growth curves of weight/length, body mass index, and ponderal index for male and female newborns with gestational ages of 24 to 42 weeks. The established growth standards in this study were compared with the standards from the 1988 Chinese data, the INTERGROWTH project, and the USA reference values. Results:A total of 24 375 newborns with 12 264 preterm newborns (7 042 males and 5 222 females) and 12 111 full-term newborns (6 155 males and 5 956 females) were included in this study. The percentile reference values and growth curves of weight/length, body mass index, and ponderal index were obtained for male and female newborns with gestational ages of 24 to 42 weeks. Weight/length of males in all gestational ages at P 10, P 50 and P 90 was 0 to 0.2 kg/m higher than that of females, and body mass index of males in all gestational ages at the P 10, P 50 and P 90 was 0.1 to 0.3 kg/m 2 higher than that of females. The established growth curves of weight/length and body mass index at the upper percentile and ponderal index at both upper and lower percentiles were greatly different from those of the 1988 Chinese data, which, for example, reported the difference ranges at P 90 as -1.09 to 0.40 kg/m for weight/length, -1.19 to 0.92 kg/m 2 for body mass index, and -0.64 to 0.81 kg/m 3 for ponderal index. The established weight/length curves were generally consistent with the reference values from the INTERGROWTH project with a difference of -0.17 to 0.20 kg/m at P 50, while being 0.02 to 0.40 kg/m lower at P 90 and 0.13 to 0.41 kg/m higher at P 10 than that of the INTERGROWTH reference values at gestational ages of ≤32 weeks. The established body mass index curves differed from that of the USA reference values with a difference of -0.47 to 0.17 kg/m 2 at P 50, while being 0.53 to 1.10 kg/m 2 lower at gestational ages of ≥37 weeks but 0.17 to 0.45 kg/m 2 higher at gestational ages of ≤28 weeks than that of the USA reference values at P 90. Conclusion:The establishment of the new standardized growth reference values of weight/length, body mass index, and ponderal index for Chinese newborns by different gestational ages are useful for clinical practice and scientific research.
3.Survey on the influential factors of stunting among children under seven years of age in nine cities of China
Yaqin ZHANG ; Huahong WU ; Xinnan ZONG ; Hui LI
Chinese Journal of Pediatrics 2021;59(9):743-751
Objective:To analyze the influential factors of stunting among children under 7 years of age in nine cities of China in order to provide empirical data for early prevention and intervention for stunting.Methods:The survey was carried out with 1∶1 case-control study design in the communities and kindergartens of nine cities (Beijing, Harbin, Xi′an, Shanghai, Nanjing, Wuhan, Guangzhou, Fuzhou, and Kunming) from June to November in 2016. Children of heights lower than the 3 rd percentile according to the 2009 children′s height standard in China were included as the stunting case group ( n=1 281), and those with normal height matched for geolocation, gender, and age were recruited as the control group ( n=1 281). The height and weight were measured on site, and the information related to family, perinatal status, diet and feeding, lifestyle, and medical history was collected by questionnaire. Continuous variables were compared by paired samples t test and Wilcoxon matched-pair signed ranks test, and proportions were compared by paired Chi square test. Multivariate analysis were carried out using conditional Logistic regression model. Results:Among 1 281 pairs of stunting and control group, there were 677 pairs of boys and 604 pairs of girls, with 238 pairs of children under age 3 years and 1 043 pairs of children aged 3 to 7 years. The Z scores for height and weight of stunting group were lower than that of control group (-2.27 (-2.54, -2.08) vs. -0.59 (-1.04, -0.10), -1.85 (-2.35, -1.38) vs. -0.69 (-1.20, -0.21), Z=30.982, 25.580, both P<0.01). Among family related factors, parental education level, height, weight, and height of grandparents in stunting children were all lower than those in control group (all P<0.05). Among individual related factors, proportion of preterm birth, low birth weight, shorter birth length, mother's pregnancy complications, difficulties adding milk or complementary feeding, poor appetite, slow eating, picky and partial eating, passive eating, more snack intake, shorter sleep duration, difficulty falling asleep, disturbed sleep, and recurrent infectious diseases in infant in stunting children were all higher than those in control group (all P<0.05). Multivariate Logistic regression analysis results illustrate that the lower the parental education level and the parental height, the higher the risk of stunting. For example, the risk of stunting in children whose fathers had short stature was 6.46 times (95% CI: 2.73-15.30) of those children whose fathers′ height were medium and the risk of stunting in children whose mothers were short stature was 10.56 times (95% CI: 4.92-22.69) of those children whose mothers′ height were medium. The risks of stunting increase significantly among preterm children or those with low birth weight ( OR=2.27, 95% CI: 1.33-3.88), birth length<45 cm ( OR=3.56, 95% CI: 1.41-8.98), difficulties adding milk or complementary feeding ( OR=2.04, 95% CI: 1.32-3.15), poor appetite ( OR=3.20, 95% CI: 1.74-5.89), slow eating ( OR=1.85, 95% CI: 1.31-2.63), and food allergy ( OR=1.80, 95% CI: 1.02-3.16). Conclusion:Parental short stature, preterm birth or low birth weight, shorter birth length, feeding difficulty in infant, poor appetite, slow eating, and food allergy are the main risk factors for stunting in infants and children.
4. Survey on the stunting of children under seven years of age in nine cities of China
Yaqin ZHANG ; Hui LI ; Huahong WU ; Xinnan ZONG ; Yichen LI ; Jia LI ; Xiaomei XIANG ; Jing ZHANG ; Meiling TONG ; Zhongqiang CAO ; Suifang LIN ; Wei CHEN ; Ke ZHU
Chinese Journal of Pediatrics 2020;58(3):194-200
Objective:
To survey the children under 7 years of age in nine cities of China for a better understanding of the current situation of childhood stunting.
Methods:
According to a stratified cluster sampling design, a cross-sectional survey on children under 7 years of age was carried out in 9 cities (Beijing, Harbin and Xi′an in northern China; Shanghai, Nanjing and Wuhan in central China; and Guangzhou, Fuzhou and Kunming in southern China) from June to November in 2016. A total of 110 499 children were recruited. Height of children was evaluated using the growth standards for Chinese children (2009 edition) .Children with height less than the 3rd percentile of the growth standards were considered as stunting, and children with height between the 3rd and 10th percentiles of the growth standards were considered as relatively short stature. Chi-square test was used for comparison between data of boys and girls, urban and suburban, as well as among different ages and regions.
Results:
Totally 113 084 children under 7 years of age should be investigated and actually 110 499 children were investigated, with a rate of 97.7%. The prevalence of stunting was 1.9% (2 141/110 499) among all the children. The prevalence of stunting in urban children (1.6%, 904/55 524) was lower than that in suburban children (2.3%, 1 237/54 975, χ2=56.246,
5. Timing of permanent tooth emergence and its association with physical growth among children aged from four to seven years in nine cities of China
Yaqin ZHANG ; Hui LI ; Huahong WU ; Xinnan ZONG
Chinese Journal of Pediatrics 2020;58(3):206-212
Objective:
To investigate the timing of permanent tooth emergence and its association with physical growth among children aged 4-7 years in 9 cities of China, and to analyze the trend of permanent teeth development.
Methods:
According to a stratified cluster sampling design, a cross-sectional survey on the timing of permanent tooth emergence children aged 4-7 years was carried out in 9 cities (Beijing, Harbin and Xi′an in northern China; Shanghai, Nanjing and Wuhan in central China; Guangzhou, Fuzhou and Kunming in southern China) from June to October in 2015. A total of 37 973 children (19 035 boys and 18 938 girls) were recruited and were divided into different age groups (4.0-<4.5, 4.5-5.0, 5.0-5.5 and 6.0-<7.0 years of age). The situation of the exfoliation of primary teeth and the eruption of permanent teeth were investigated. Height and weight were measured using the standardized methods. Z-scores of physical growth indicators were calculated using the growth standards for Chinese children in 2009. Probit regression analysis was used to determine the median and percentile age of transition from deciduous to permanent teeth. Chi-square test was used for comparison of categorical data and
6.Percentile reference value of waist circumference for Chinese children aged 3-7 years
Xinnan ZONG ; Hui LI ; Yaqin ZHANG
Chinese Journal of Epidemiology 2020;41(8):1286-1290
Objective:To study and establish the percentile reference values of waist circumference (WC) for Chinese children aged 3-7 years.Methods:A total of 26 480 children aged 3-7 years were collected as part of the National Survey on Physical Growth and Development of Children in nine cities (Beijing, Harbin, Xi’an, Shanghai, Nanjing, Wuhan, Guangzhou, Fuzhou and Kunming) in China from June to November 2015. Sex- and age-specific smoothed percentile reference values of WC were established using the Lambda Mu Sigma method. The P 75 and P 90 curves of WC for children aged 3-7 years in this study were linked with the published P 75 and P 90 cut-off points for Chinese children and adolescents aged 7-18 years. The P 50 percentile of WC in this study was compared with the corresponding percentiles of several foreign studies. Results:The P 5, P 10, P 15, P 20, P 25, P 50, P 75, P 80, P 85, P 90 and P 95 reference values of WC were obtained for boys and girls aged 3-7 years biannually, at the interval of every six months. Results showed that WC at the P 50 had significantly increased from 47.5 cm at the age of 3 to 54.2 cm at the age of 7 for boys and from 47.0 cm at the age of 3 to 52.2 cm for girls at the age of 7. The corresponding WC percentile values appeared a bit higher in boys than those in girls at the same age, with the differences from 0.4 to 3.6 cm. The differences between measured and fitted WC at each empirical percentile ranged from -0.3 to 0.5 cm for both boys and girls aged 3-7 years. The P 75 and P 90 values of WC for boys and girls aged 3-7 years in this study presented a consistent, continuous tendency on age with the published WC cut-off points ( P 75 and P 90) for Chinese children and adolescent aged 7-18. The increasing trend of WC by age in Chinese children aged 3-7 years was consistent with those of foreign studies, at the middle level for boys and lower middle level for girls. Conclusions:Through this study, we established the WC percentile values for Chinese children aged 3-7 years and achieved the continuity in age with the published WC cut-off points for Chinese children and adolescents aged 7-18. These established WC percentile values can be used as reference for clinical practice, health care and scientific research.
7. Development of primary teeth among infants and toddlers in nine cities of China in 2015
Yaqin ZHANG ; Yang LI ; Hui LI ; Huahong WU ; Xinnan ZONG
Chinese Journal of Pediatrics 2019;57(9):680-685
Objective:
To investigate the status of the development of primary teeth and to identify the development patterns among infants and toddlers in nine cities of China in 2015.
Methods:
Healthy children aged 1-<36 months were investigated by across-sectional survey and retrospective studies, which was carried out in 9 cities (Beijing, Harbin and Xi′an in northern China; Shanghai, Nanjing and Wuhan in central China; and Guangzhou, Fuzhou and Kunming in southern China) from June to October in 2015. Subjects (
8.Breastfeeding rates of children under two years old in nine cities of China from 1985 to 2015:a comparison between urban and suburban areas
Huahong WU ; Yaqin ZHANG ; Xinnan ZONG ; Hui LI
Chinese Journal of Perinatal Medicine 2019;22(7):445-450
Objective To analyze the breastfeeding rate of children under two years of age in nine cities of China in 2015 and variations in breastfeeding patterns from 1985 to 2015. Methods All data were collected from a series of national cross-sectional surveys "National Growth Survey of Children under Seven Years Old in Nine Cities of China" (urban and suburban areas of Beijing, Haerbin, Xi'an, Wuhan, Nanjing, Shanghai, Guangzhou, Fuzhou and Kunming) conducted from each May to October in 1985, 1995, 2005 and 2015. Stratified cluster sampling was used to select healthy children at least 150 in each subpopulation. Feeding patterns within 24 h prior to investigation were analyzed through face-to-face interviews using a self-made questionnaire. The rates of exclusive breastfeeding, mixed feeding and formula feeding were described as composition ratios. The difference between urban and suburban areas was analyzed by Chi-square test and the weaning age was calculated with a Probit model. Results (1) In 2015, the exclusive breastfeeding rate for infants under six months of age was 48.8% (9 143/18 722) in urban areas and 48.4% (8 652/17 878) in suburban areas, and the breastfeeding rates at one and two years old were 36.1% (1 351/3 746) and 5.8% (211/3 668) in urban areas and 29.9% (1 128/3 776) and 4.3% (157/3 683) in suburbs. The differences of breastfeeding patterns in ≥1-<2, ≥2-<3, ≥ 3-<4, ≥ 5-<6, ≥ 10-<12, ≥ 12-<15, ≥ 18-<21 and ≥ 21-<24 months of age were all significantly between suburbs and urban areas (χ2=8.575-36.299, all P<0.01). The age at weaning age was 9.4 months and 9.3 months in urban and suburban areas, respectively. (2) From 1985 to 2005, breastfeeding rates showed a decreasing trend, especially in suburban areas where the exclusive breastfeeding rate for infants under six months of age decreased from 60.2% (8 898/14 780) to 42.5% (6 487/15 261) and the continuous breastfeeding rate decreased from 60.1% (2 164/3 600) to 27.6% (783/2 838) at the age of one and from 8.9% (320/3 600) (in 1995) to 3.0% (85/2 850) in 2015 at the age of two. However, from 2005 to 2015, breastfeeding rates were on the rise, especially in urban areas in which the exclusive breastfeeding rate for infants under six months of age increased from 32.8% (5 176/15 782) to 48.8% (9 143/18 722) and the continuous breastfeeding rates at one and two years old respectively increased from 17.0% (499/2 940) to 36.1% (1 351/3 746) and from 1.2% (34/2 856) to 5.8% (211/3 668). Conclusions There are great changes in breastfeeding patterns for Chinese children in the nine cities from 1985 to 2015. In the first two decades, breastfeeding rates decreased and the duration of breastfeeding was shortened, while the last decade have seen increased breastfeeding rates and longer breastfeeding duration. The exclusive breastfeeding rate for infants under six months of age is similar in urban and suburban areas and both have reached about to 50% in 2015, which indicates fruitful results have achieved through the implementation of infant feeding strategies and related measures in China.
9. The preliminary development of reference values of carotid artery intima-media thickness in children aged 6-11 years
Liu YANG ; Xinnan ZONG ; Qin LIU ; Yaping HOU ; Min ZHAO ; Bo XI
Chinese Journal of Preventive Medicine 2019;53(7):696-700
Objective:
To develop the reference values of carotid intima-media thickness (cIMT) in Chinese children aged 6-11 years.
Methods:
A convenient cluster sampling method was used to conduct a cross-sectional survey from November 2017 to January 2018 in a primary school in Huantai County, Zibo City, Shandong Province. A total of 1 033 children aged 6-11 years (excluding children with obesity or hypertension) were included. Percentile curves for cIMT were drawn using the lambda, mu and sigma (LMS) method.
Results:
This study developed the cIMT reference values (
10. Development and validation of a simplified height-specific blood pressure cutoffs table for screening hypertension in Chinese children and adolescents
Yaping HOU ; Qin LIU ; Liu YANG ; Min ZHAO ; Xinnan ZONG ; Bo XI
Chinese Journal of Preventive Medicine 2019;53(7):701-705
Objective:
To develop and validate a simplified height-specific blood pressure cutoffs table for screening hypertension in Chinese children and adolescents.
Methods:
We developed a simplified height-specific blood pressure cut offs table according to Chinese Blood Pressure Reference for Children and Adolescents aged 7-18 years (WS/T 610-2018) (hereafter referred to as "complex definition"). Populations from Early Warning, Diagnosis and Treatment of Children Cardiovascular Disease Project ("Ji′nan sample") and Shandong Children Cardiovascular Cohort Study Project ("Zibo sample") were used as validation populations for evaluating the screening effect of the simplified table for elevated blood pressure and hypertension in children and adolescents.
Results:
We developed simplified height-specific blood pressure cutoffs table including 7 height groups and 28 cutoffs. Both Ji′nan and Zibo samples were selected by convenient sampling method, and the former included 7 233 participants aged 7 to 17 years, among whom 3 790 (52.4%) were boys. Latter population included 1 277 participants aged 7 to 11 years, among whom 681 (53.3%) were boys. The simplified table performed well for identifying elevated blood pressure in Ji′nan sample, with values of area under the receiver operating curve (AUC) (95

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