Utility of waist-to-height ratio, waist circumference and body mass index in predicting clustered cardiometabolic risk factors and subclinical vascular phenotypes in children and adolescents: A pooled analysis of individual data from 14 countries.

AIMS: The clinical utility of waist-to-height ratio (WHtR) in predicting cardiometabolic risk factors (CMRFs) and subclinical markers of cardiovascular disease remains controversial. We aimed to compare the utility of WHtR with waist circumference (WC) and body mass index (BMI) in identifying children and adolescents (youths) at risk for cardiometabolic outcomes, including clustered CMRFs, high carotid intima-media thickness (cIMT), and arterial stiffness (assessed as high pulse wave velocity, PWV). METHODS: We analyzed data from 34,224 youths (51.0 % boys, aged 6-18 years) with CMRFs, 5004 (49.5 % boys, aged 6-18 years) with cIMT measurement, and 3100 (56.4 % boys, aged 6-17 years) with PWV measurement from 20 pediatric samples across 14 countries. RESULTS: WHtR, WC, and BMI z-scores had similar performance in discriminating youths with ≥3 CMRFs, with the area under the curve (AUC) (95 % confidence interval, CI)) ranging from 0.77 (0.75-0.78) to 0.78 (0.76-0.80) using the modified National Cholesterol Education Program (NCEP) definition, and from 0.77 (0.74-0.79) to 0.77 (0.74-0.80) using the International Diabetes Federation (IDF) definition. Similarly, all three measures showed similar performance in discriminating youths with subclinical vascular outcomes, with AUC (95 % CI) ranging from 0.67 (0.64-0.71) to 0.70 (0.66-0.73) for high cIMT (≥P95 values) and from 0.60 (0.58-0.66) to 0.62 (0.58-0.66) for high PWV (≥P95 values). CONCLUSIONS: Our findings suggest that WHtR, WC, and BMI are equally effective in identifying at-risk youths across diverse pediatric populations worldwide. Given its simplicity and ease of use, WHtR could be a preferable option for quickly screening youths with increased cardiometabolic risk in clinical settings.

A proposed simplified definition of metabolic syndrome in children and adolescents: a global perspective.

Metabolic syndrome (MetS) is becoming prevalent in the pediatric population. The existing pediatric MetS definitions (e.g., the International Diabetes Federation (IDF) definition and the modified National Cholesterol Education Program (NCEP) definition) involve complex cut-offs, precluding fast risk assessment in clinical practice.We proposed a simplified definition for assessing MetS risk in youths aged 6-17 years, and compared its performance with two existing widely used pediatric definitions (the IDF definition, and the NCEP definition) in 10 pediatric populations from 9 countries globally (n = 19,426) using the receiver operating characteristic (ROC) curve analyses. In general, the total MetS prevalence of 6.2% based on the simplified definition was roughly halfway between that of 4.2% and 7.7% estimated from the IDF and NCEP definitions, respectively. The ROC curve analyses showed a good agreement between the simplified definition and two existing definitions: the total area under the curve (95% confidence interval) of the proposed simplified definition for identifying MetS risk achieved 0.91 (0.89-0.92) and 0.79 (0.78-0.81) when using the IDF or NCEP definition as the gold standard, respectively.The proposed simplified definition may be useful for pediatricians to quickly identify MetS risk and cardiometabolic risk factors (CMRFs) clustering in clinical practice, and allow direct comparison of pediatric MetS prevalence across different populations, facilitating consistent pediatric MetS risk monitoring and the development of evidence-based pediatric MetS prevention strategies globally.

Secular changes in eruption of primary teeth in Chinese infants and young children from three national cross-sectional surveys.

The eruption of primary teeth is a basic event during physical development of children, which is affected by heredity and environment. This study aimed to analyze the changes in primary teeth eruption among Chinese children with social development. A total of 249,264 healthy children under 2 years were extracted from the 1995, 2005, and 2015 National Survey on the Physical Growth and Development of Children in Nine Cities of China. Their primary teeth were examined and percentiles of primary teeth eruption age were calculated by probit analysis. The median primary teeth eruption age were 6.8 months, 6.7 months, 6.6 months in 1995, 2005 and 2015. Primary teeth eruption age of boys was 0.2 months, 0.3 months, 0.3 months earlier than that of girls in 1995, 2005 and 2015. Primary teeth eruption age was the earliest in children from northern region and was the latest in children from southern region, and this regional difference did not change over time. These findings suggest that primary teeth eruption age slightly advanced with social development, and their gender difference and regional difference have always existed, which supplied some data for understanding the secular trend of primary teeth development in stomatology, pediatrics, anthropology, and other related fields.

Association of height, foot length, and pubertal development in children aged 3-18: a cross-sectional survey in China.

Objective: This study aimed to analyze the growth patterns of height and foot length (FL) among Chinese children aged 3-18 and examine their associations with puberty development. Methods: A cross-sectional survey was conducted in September 2022 in Beijing. Data were collected through questionnaires and on-site physical examinations. The growth patterns and velocity of height and FL in different age groups were described, and their associations with puberty development were analyzed. Results: From an age perspective, the peak FL growth occurred between 9 and 11 years (boys were 11 years and girls were 9 years), while the peak height growth occurred at 11 ~ 13 years for boys and 9 ~ 11 years for girls. Additionally, boys and girls reached 99.0% of their final FL at the ages of 14 and 13, respectively, while they reached 99.0% of their final height at the ages of 16 and 15, respectively. From the perspective of Tanner stage, the age of peak FL growth in boys coincided with the age of the G2 stage, while in girls it occurred slightly earlier than the mean age of the B2 stage. The peak height growth for both boys and girls occurred between Tanner stages 2 and 3. Conclusion: Boys and girls reach their peak FL growth at 11 and 9 years old, respectively, which were both 2 years earlier than their peak height growth. The peak FL growth occurred around the onset of puberty, while the peak height growth occurred between Tanner stages 2 and 3.

Establishing international optimal cut-offs of waist-to-height ratio for predicting cardiometabolic risk in children and adolescents aged 6-18 years.

BACKGROUND: Waist-to-height ratio (WHtR) has been proposed as a simple and effective screening tool for assessing central obesity and cardiometabolic risk in both adult and pediatric populations. However, evidence suggests that the use of a uniform WHtR cut-off of 0.50 may not be universally optimal for pediatric populations globally. We aimed to determine the optimal cut-offs of WHtR in children and adolescents with increased cardiometabolic risk across different countries worldwide. METHODS: We used ten population-based cross-sectional data on 24,605 children and adolescents aged 6-18 years from Brazil, China, Greece, Iran, Italy, Korea, South Africa, Spain, the UK, and the USA for establishing optimal WHtR cut-offs. We performed an external independent test (9,619 children and adolescents aged 6-18 years who came from other six countries) to validate the optimal WHtR cut-offs based on the predicting performance for at least two or three cardiometabolic risk factors. RESULTS: Based on receiver operator characteristic curve analyses of various WHtR cut-offs to discriminate those with ≥ 2 cardiometabolic risk factors, the relatively optimal percentile cut-offs of WHtR in the normal weight subsample population in each country did not always coincide with a single fixed percentile, but varied from the 75th to 95th percentiles across the ten countries. However, these relatively optimal percentile values tended to cluster irrespective of sex, metabolic syndrome (MetS) criteria used, and WC measurement position. In general, using ≥ 2 cardiometabolic risk factors as the predictive outcome, the relatively optimal WHtR cut-off was around 0.50 in European and the US youths but was lower, around 0.46, in Asian, African, and South American youths. Secondary analyses that directly tested WHtR values ranging from 0.42 to 0.56 at 0.01 increments largely confirmed the results of the main analyses. In addition, the proposed cut-offs of 0.50 and 0.46 for two specific pediatric populations, respectively, showed a good performance in predicting ≥ 2 or ≥ 3 cardiometabolic risk factors in external independent test populations from six countries (Brazil, China, Germany, Italy, Korea, and the USA). CONCLUSIONS: The proposed international WHtR cut-offs are easy and useful to identify central obesity and cardiometabolic risk in children and adolescents globally, thus allowing international comparison across populations.

Height and body mass index trajectories from 1975 to 2015 and prevalence of stunting, underweight and obesity in 2016 among children in Chinese cities: findings from five rounds of a national survey.

BACKGROUND: A more comprehensive assessment of growth and nutrition in children is required in China due to rapid socioeconomic processes. We aimed to investigate height and body mass index (BMI) trajectories from 1975 to 2015 and the prevalence of stunting and obesity in 2016 among children in Chinese cities. METHODS: A total of 904,263 children from birth to 6.9 years were collected from a series of nationally representative surveys in China. Height and BMI trajectories and prevalence of stunting, underweight, overweight and obesity were assessed. RESULTS: The average height level of Chinese urban children under 7 years presented a positive secular trend from 1975 to 2015; however, a slowing tendency occurred in 2005‒2015. An apparent increase was observed at the 5th, 50th and 95th percentiles of BMI in urban children aged 3 years and older, with a more prominent increase at the 95th percentile. The total prevalence of stunting and underweight under 7 years was 1.4% and 2.0%, respectively. The total prevalence of overweight and obesity under 7 years was 12.6% and 4.3%, respectively, with 12.7% and 4.9% for boys, 12.6% and 3.6% for girls, 12.1% and 4.0% in urban areas and 13.1% and 4.5% in suburban rural areas. CONCLUSIONS: The average height level of Chinese urban children has reached World Health Organization child growth standards since 2005 and presented a slowing tendency in secular trend in 2005‒2015. More attention and efforts and public health interventions should be urgently made to combat overweight and obesity among preschool children. Video Abstract.

Comparison of updated birth weight, length and head circumference charts by gestational age in China with the INTERGROWTH-21st NCSS charts: a population-based study.

BACKGROUND: INTERGROWTH-21st Newborn Cross-Sectional Study (NCSS) charts were established and recommended for global application. However, whether one international reference is appropriate for all populations is still unclear. We aim to compare the updated Chinese birth size charts by gestational age with INTERGROWTH-21st NCSS charts. METHODS: A cross-sectional survey was carried out, and the birth weight, length and head circumference of 24,375 infants born after uncomplicated pregnancies at gestational age ranging from 24+0 to 42+6 weeks were measured in 13 cities in China from 2015 to 2018. Growth charts were constructed. The measurements of all these infants were evaluated by the methods of calculating their Z scores using the INTERGROWTH-21st standards. The prevalence of small for gestational age (SGA) and large for gestational age (LGA) based on birth weight was analyzed using Chinese charts and INTERGROWTH-21st charts. RESULTS: The mean Z scores were 0.10 for birth weight, 0.35 for length and - 0.02 for head circumference. Compared to the INTERGROWTH-21st charts, the Chinese birth weight percentile curves were higher except for the 90th percentile at 29-37 weeks gestational age, and the length percentile curves were higher after 33 weeks gestational age, while the 10th percentile of the head circumference was lower and the other percentiles were similar. The prevalence of SGA was 10.1% [95% confidence interval (CI) = 9.7%-10.5%] using the Chinese birth weight chart and 6.5% (95% CI = 6.2%-6.8%) using the INTERGROWTH-21st birth weight chart. The prevalence of LGA was 9.9% (95% CI = 9.5%-10.2%) and 8.2% (95% CI = 7.9%-8.6%) using the Chinese and INTERGROWTH-21st birth weight charts, respectively. CONCLUSIONS: Chinese birth size charts based on infants born after uncomplicated pregnancies were different from the INTERGROWTH-21st charts. Differences in the classification of newborns by the two charts should receive attention, and whether the application of INTERGROWTH-21st in Chinese newborns will lead to misclassification needs to be validated in future clinical practice.

Secular trends in age at pubertal onset assessed by breast development among Chinese girls: A systematic review.

Background: The average age at thelarche has trended downwards worldwide since 1970s; however, the onset age of "precocious puberty", defined as the lower percentiles of thelarche age, has been rarely reported. This systematic review aims to evaluate secular trends in age at thelarche among Chinese girls. Methods: This systematic review on the age at thelarche during puberty among Chinese girls was conducted via systematic search of both Chinese (Chinese National Knowledge Infrastructure, WanFang Database, and the Chinese Scientific Journals Database) and English (PubMed, Cochrane Library, and Embase) databases. Data were analyzed using the GraphPad Prism v9.0. Results: A total of 16 studies involving 177,886 Chinese girls were synthesized. The QualSyst scores of these studies were high at an average of 21.25. The timing of Tanner breast stage 2 (B2) occurred earlier over time at the P3, P10, and median ages. Weighted analyses revealed that the overall onset age of B2 tended to be younger at P3, P10, and P25. The age of B2 varied across regions and areas. For example, P3, P10, and median age of B2 in years were younger in southern regions than that in northern regions of China (P3: 5.94 vs. 7.3; P10: 6.6 vs. 7.9; median age: 8.26 vs. 9.5), and median age of B2 in urban areas (8.26 years) was earlier than that in rural areas (10.29 years). In addition, median age of B2 from 12 single-center studies was earlier than that from 4 multicenter studies (8.26 vs. 9.18 years). Conclusions: The current findings indicated that pubertal breast development age among Chinese girls presented an advanced trend over the past 20 years, which urges the necessity to revisit and redefine "precocious puberty" and provides useful recommendations for clinical practice.

Establishing Postnatal Growth Monitoring Curves of Preterm Infants in China: Allowing for Continuous Use from 24 Weeks of Preterm Birth to 50 Weeks.

BACKGROUND: Early postnatal growth monitoring and nutrition assessment for preterm infants is a public health and clinical concern. We aimed to establish a set of postnatal growth monitoring curves of preterm infants to better help clinicians make in-hospital and post-discharge nutrition plan of these vulnerable infants. METHODS: We collected weight, length and head circumference data from a nationwide survey in China between 2015 and 2018. Polynomial regression and the modified LMS methods were employed to construct the smoothed weight, length and head circumference growth curves. RESULTS: We established the P3, P10, P25, P50, P75, P90, P97 reference curves of weight, length and head circumference that allowed for continuous use from 24 weeks of preterm birth to 50 weeks and developed a set of user-friendly growth monitoring charts. We estimated approximate ranges of weight gain per day and length and head circumference gains per week. CONCLUSIONS: Our established growth monitoring curves, which can be used continuously without correcting gestational age from 24 weeks of preterm birth to 50 weeks, may be useful for assessment of postnatal growth trajectories, definition of intrauterine growth retardation at birth, and classification of early nutrition status for preterm infants.

Maternal Pre-pregnancy Body Mass Index Categories and Infant Birth Outcomes: A Population-Based Study of 9 Million Mother-Infant Pairs.

BACKGROUND AND AIMS: Infant adverse birth outcomes have been suggested to contribute to neonatal morbidity and mortality and may cause long-term health consequences. Although evidence suggests maternal prepregnancy body mass index (BMI) categories associate with some birth outcomes, there is no consensus on these associations. We aimed to examine the associations of maternal prepregnancy BMI categories with a wide range of adverse birth outcomes. METHODS: Data were from a population-based retrospective cohort study of 9,282,486 eligible mother-infant pairs in the U.S. between 2016 and 2018. Maternal prepregnancy BMI was classified as: underweight (<18.5 kg/m2); normal weight (18.5-24.9 kg/m2); overweight (25.0-29.9 kg/m2); obesity grade 1 (30-34.9 kg/m2); obesity grade 2 (35.0-39.9 kg/m2); and obesity grade 3 (≥40 kg/m2). A total of six birth outcomes of the newborn included preterm birth, low birthweight, macrosomia, small for gestational age (SGA), large for gestational age (LGA), and low Apgar score (5-min score <7). RESULTS: Maternal prepregnancy overweight and obesity increased the likelihood of infant preterm birth, with odds ratios (ORs) (95% CIs) of 1.04 (1.04-1.05) for overweight, 1.18 (1.17-1.19) for obesity grade 1, 1.31 (1.29-1.32) for obesity grade 2, and 1.47 (1.45-1.48) for obesity grade 3, and also for prepregnancy underweight (OR = 1.32, 95% CI = 1.30-1.34) after adjusting for all potential covariates. Prepregnancy overweight and obesity were associated with higher odds of macrosomia, with ORs (95% CIs) of 1.53 (1.52-1.54) for overweight, 1.92 (1.90-1.93) for obesity grade 1, 2.33 (2.31-2.35) for obesity grade 2, and 2.87 (2.84-2.90) for obesity grade 3. Prepregnancy overweight and obesity was associated with higher odds of LGA, with ORs (95% CIs) of 1.58 (1.57-1.59) for overweight, 2.05 (2.03-2.06) for obesity grade 1, 2.54 (2.52-2.56) for obesity grade 2, and 3.17 (3.14-3.21) for obesity grade 3. Prepregnancy overweight and obesity were also associated with higher odds of low Apgar score, with ORs (95% CIs) of 1.12 (1.11-1.14) for overweight, 1.21 (1.19-1.23) for obesity grade 1, 1.34 (1.31-1.36) for obesity grade 2, and 1.55 (1.51-1.58) for obesity grade 3. CONCLUSION: Our findings suggest maintaining or obtaining a healthy body weight for prepregnancy women could substantially reduce the likelihood of important infant adverse birth outcomes.

Global prevalence of WHO infant feeding practices in 57 LMICs in 2010-2018 and time trends since 2000 for 44 LMICs.

BACKGROUND: The World Health Assembly set a global target of increasing exclusive breastfeeding for infants under 6 months to at least 50% by year 2025. However, little is known about the current status of breastfeeding practice, as well as the trends in breastfeeding practices during recent years. We examined global prevalence of the World Health Organization (WHO) feeding practices in 57 low- and middle-income countries (LMICs) and time trends since 2000 for 44 selected countries. METHODS: We included 57 eligible LMICs that had completed data on breastfeeding and complementary feeding in 2010-2018 from the Demographic and Health Surveys (DHS) for examining current feeding status. We further selected 44 LMICs that had two standard DHS surveys between 2000 and 2009 and 2010-2018 to examine time trends of feeding status. We calculated global, regional, and national weighted prevalence estimates and 95% confidence intervals (CIs) for five breastfeeding indicators and two complementary feeding indicators. FINDINGS: In 57 LMICs during 2010-2018, global weighted prevalence was 51.9% for early initiation of breastfeeding, 45.7% for exclusive breastfeeding under 6 months, 32.0% for exclusive breastfeeding at 4-5 months, 83.1% for continued breastfeeding at 1 year, 56.2% for continued breastfeeding at 2 years, 14.9% for introduction of solid, semi-solid or soft foods under 6 months, and 63.1% for introduction of solid, semi-solid or soft foods at 6-8 months. Eastern Mediterranean (34.5%) and European regions (43.7%) (vs. South-East Asia/Western Pacific (55.2%)), and upper middle-income countries (38.4%) (vs. lower middle-income countries (47.4%)) had poorer performance of exclusive breastfeeding under 6 months. South-East Asia/Western Pacific regions (51.0%) (vs. other regions (68.3%-84.1%)) and low-income (66.4%) or lower middle-income countries (58.2%) (vs. upper middle-income countries (81.7%)) had lower prevalence of introduction of solid, semi-solid or soft foods at 6-8 months. In 44 selected LMICs from 2000 to 2009 to 2010-2018, total weighted prevalence presented an increase of 10.1% for exclusive breastfeeding under 6 months, but a 1.7% decrease for continued breastfeeding at 1 year. Over this period, the Eastern Mediterranean region had a 5.3% decrease of exclusive breastfeeding under 6 months, and the European region had a 2.0% increase for introduction of solid, semi-solid or soft foods under 6 months. The prevalence of introduction of solid, semi-solid or soft foods at 6-8 months decreased in South-East Asia/Western Pacific region by 15.2%, and in lower middle-income countries by 24.4%. INTERPRETATION: Breastfeeding practices in LMICs have continued to improve in the past decade globally, but practices still lag behind the WHO feeding recommendations. Breastfeeding practices differed greatly across WHO regions, with the Eastern Mediterranean and European regions, and upper middle-income countries facing the greatest challenges in meeting targets. Continued efforts are needed to achieve the 2025 global breastfeeding target.

Construction of China national newborn growth standards based on a large low-risk sample.

Most published newborn growth references are based on conventional monitoring data that usually included both low- and high-risk pregnancies. We sought to develop a set of neonatal growth standards constructed from only a large sample of low-risk pregnancies. A total of 24,375 naturally conceived singleton live births with gestational ages of 24-42 weeks were collected in 69 hospitals in thirteen Chinese cities between 2015 and 2018. Unhealthy infants or those with high-risk mother were excluded. Smoothed percentile curves of six anthropometric indicators were established using the Generalized Additive Model for Location, Scale and Shape. The 3rd, 10th, 25th, 50th, 75th, 90th, and 97th percentile references for birth weight, length, head circumference, weight/length, body mass index, and ponderal index were calculated for neonates with gestational ages of 24-42 weeks. This set of neonatal growth standards with six anthropometric indicators can provide more tools for growth and nutrition assessment and body proportionality in neonatal clinical practice. These standards might also help to show the differences between growth curves based on low-risk and mixed low- and high-risk pregnancies.

Stunting, wasting, overweight and their coexistence among children under 7 years in the context of the social rapidly developing: Findings from a population-based survey in nine cities of China in 2016.

The prevalence of stunting, wasting, overweight and their coexistence are various in different populations and they also have changed with social developing and environmental improving. In this paper, we aimed to analyze the prevalence of stunting, wasting, overweight and their coexistence in some developed regions of China. Data were collected in a population-based cross-sectional survey by a multi-stage cluster sampling method in nine cities located in the northern, central, and southern region of China in 2016. Children under seven years (n = 110,491) were measured. WHO growth standards were used to assess the growth status. Stunting, underweight, wasting, overweight and obesity were considered as the primary forms of malnutrition (includes undernutrition and overnutrition) for infant or young children at population-levels. The prevalence of stunting, underweight, wasting, and overweight or obesity were respectively 0.7%, 0.6%, 1.2%, and 7.6%. Most of these children (95.4%) suffered from one form of malnutrition, and only 0.2% of them concurrently stunted and wasted, 0.4% concurrently stunted and overweight, 1.7% concurrently stunted and underweight, 2.3% concurrently underweight and wasted. Among stunted children, 91.2% were appropriate body proportion, and only 2.3% were wasted, 6.5% were overweight or obesity. Among overweight or obese children, only 0.6% were stunted, whereas, 15.8% were high stature and 83.6% were the appropriate ranges of stature. Sex, age, urban/suburban, and region were associated with these primary forms of malnutrition in the multivariate logistic analysis. In conclusion, we found that the coexistence of stunting and overweight was not common at both population-level and individual-level. The situation for undernutrition had significantly improved, and overweight may be the leading public health issue for children under seven years in the nine cities of China.

Growth performance comparison of exclusively breastfed infants with partially breastfed and formula fed infants.

BACKGROUND: Little consensus exists for growth performance of different feeding patterns in infancy. The objective of this study is to assess the growth performance of exclusively breastfed, partially breastfed and formula fed infants in China. METHODS: Data from a total of 109,052 infants aged 1-<12 months were collected from the 4th and 5th China National Surveys in 2005 and 2015. Feeding patterns were classified into three types for infants under 6 months of age: exclusive breastfeeding, partial breastfeeding and formula feeding. Exclusive breastfeeding refers to feeding exclusively from the mother's own milk (bottle-feeding included). RESULTS: 34.0% and 43.9% of infants were exclusively breastfed and 41.5% and 36.3% were partially breastfed at 4-<6 months in 2005 and 2015 respectively. Exclusively breastfed infants were generally a little heavier than partially breastfed and formula fed infants aged 1-<6 months; however, there was not a significant statistical difference between continued breastfeeding and formula feeding infants aged 6-<12 months. No significant statistical difference for length was observed among the three groups for ages 1-<6 months; however, infants who were continued to be breastfed were a little shorter compared to those who were formula fed (ages 6-<12 months). For infants aged 1-<2 months there was not a substantial difference from the 2006 WHO growth standards; however, for infants aged 2-<12 months the average weight and length of different feeding infants in China were a little heavier and longer than the 2006 WHO growth standards. CONCLUSIONS: Partial breastfed and formula fed infants were a little lighter than exclusively breastfed infants in the first half of the first year. Formula fed infants were a little longer than continued breastfed infants in the second half.

International Waist Circumference Percentile Cutoffs for Central Obesity in Children and Adolescents Aged 6 to 18 Years.

CONTEXT: No universal waist circumference (WC) percentile cutoffs used have been proposed for screening central obesity in children and adolescents. OBJECTIVE: To develop international WC percentile cutoffs for children and adolescents with normal weight based on data from 8 countries in different global regions and to examine the relation with cardiovascular risk. DESIGN AND SETTING: We used pooled data on WC in 113,453 children and adolescents (males 50.2%) aged 4 to 20 years from 8 countries in different regions (Bulgaria, China, Iran, Korea, Malaysia, Poland, Seychelles, and Switzerland). We calculated WC percentile cutoffs in samples including or excluding children with obesity, overweight, or underweight. WC percentiles were generated using the general additive model for location, scale, and shape (GAMLSS). We also estimated the predictive power of the WC 90th percentile cutoffs to predict cardiovascular risk using receiver operator characteristics curve analysis based on data from 3 countries that had available data (China, Iran, and Korea). We also examined which WC percentiles linked with WC cutoffs for central obesity in adults (at age of 18 years). MAIN OUTCOME MEASURE: WC measured based on recommendation by the World Health Organization. RESULTS: We validated the performance of the age- and sex-specific 90th percentile WC cutoffs calculated in children and adolescents (6-18 years of age) with normal weight (excluding youth with obesity, overweight, or underweight) by linking the percentile with cardiovascular risk (area under the curve [AUC]: 0.69 for boys; 0.63 for girls). In addition, WC percentile among normal weight children linked relatively well with established WC cutoffs for central obesity in adults (eg, AUC in US adolescents: 0.71 for boys; 0.68 for girls). CONCLUSION: The international WC cutoffs developed in this study could be useful to screen central obesity in children and adolescents aged 6 to 18 years and allow direct comparison of WC distributions between populations and over time.

Secular trends in weight, height and weight for height among children under 7 years in nine cities of China, 1975-2015: results from five repeated cross-sectional surveys.

OBJECTIVE: To analyse the secular trends in mean value and distribution of weight, height and weight for height in children under 7 years in developed regions in China. DESIGN: Five repeated cross-sectional surveys were conducted using the same methods at the same sites during 1975-2015. SETTING: Nine cities in northern, central and southern regions of China. POPULATION: Healthy children under 7 years; the sample sizes were 94 496 in 1975, 79 177 in 1985, 79 152 in 1995, 69 760 in 2005 and 83 583 in 2015. MAIN OUTCOME MEASURES: Weight and height were measured by the same methods in the five surveys. RESULTS: The increasing trends in the mean value of weight, height and weight for height were observed and their distribution was found to have shifted upwards. There were unbalanced increments in various centiles and the relative increments in the 3rd centile of height for children under 7 years were larger than those in the 50th and 97th centiles. Although the relative increments in the 3rd centile of weight for children under 2 years were larger than those in the 50th and 97th centiles, the increments in the 97th centile for children older than 2 years became the largest compared with other centiles. The changes in each centile of weight for height were similar with those of weight. The annual increments of height and weight increased over time and were more significant between birth and 2 years of age for height and between ages 4 years and 6 years for weight. The per-decade increments in 1975-1985, 1985-1995 and 1995-2005 became larger, while those in 2005-2015 slowed down. CONCLUSIONS: The rapid increasing trends of weight, height and weight for height had slowed down since 2005 in developed regions of China. The relative increments in the low centile of height were more significant, while the high centile of weight and weight for height increased more significantly in older children.

Child nutrition to new stage in China: evidence from a series of national surveys, 1985-2015.

BACKGROUND: Both child under- and over-nutrition are major global public health challenges. We aimed to examine thirty-year trends in physical growth, under- and over-nutrition in Chinese urban and suburban children between 1985 and 2015, and discuss implications for child health programmes. METHODS: A total of 610,785 urban and suburban children from birth to 7 years of age were collected from a series of large-scale national surveys in China. Height, weight and body mass index (BMI) Z-scores and prevalence of stunting, underweight, wasted and possible risk of overweight, overweight and obesity were calculated according to the World Health Organization (WHO) 2006 growth standards. The trends in the prevalence were tested across different survey years by Cochran-Armitage trend test. RESULTS: Rapid secular growth trend was observed in China over the past 30 years, but the trend showed a slowing sign in urban children in recent 10 years. The growth level of Chinese urban and suburban children surpassed the WHO 2006 growth standards in 2015. Between 1985 and 2015 the stunting, underweight and wasted prevalence decreased from 12.21, 4.44, 1.68 to 0.97%, 0.59, 0.87% for children under 5 years and from 12.69, 10.02, 3.41 to 0.42%, 0.67, 2.17% for children aged 5- < 7 respectively; the possible risk of overweight prevalence increased from 6.51 to 12.57%, overweight from 0.70 to 3.48% and obesity from 0.17 to 0.86% for children aged 2- < 7 and the increasing rates of overweight and obesity prevalence in suburban children first outnumbered urban children in recent 10 years. The overweight prevalence overtook the wasted or underweight in children aged 2- < 7 in 2005 and onward. CONCLUSION: Slowing secular height trend and overweight prevalence overtaking the wasted or underweight suggested child nutrition and health strategies should adjust swiftly and deliberately from primarily reducing under-nutrition prevalence to controlling rapid weight gain and promoting integrated early development.

Changes of feeding patterns in Chinese city children under 2 years from 1985 to 2015: results from a series of national cross-sectional surveys.

BACKGROUND: In China, as the social transformation and economic development from 1985 to 2015, children's feeding pattern has undergone some changes. So we aimed to analyze the secular trend on feeding patterns of city children in China. METHODS: All data were from a series of national survey which implemented once every 10 years in China from 1985 to 2015. We use same indexes to evaluate the feeding pattern of children in these four surveys. RESULTS: From 1985 to 2005, the exclusive breastfeeding rates in infants under 6 months of age decreased, especially in suburban areas decreased by 17.7%; the continuous breastfeeding rate of 1-year-old children in suburban area decreased from 60.1 to 27.6%. However, from 2005 to 2015, the exclusive breastfeeding rates under 6 months of age increased by 16.0% in urban areas and 5.9% in suburban areas; the continuous breastfeeding rate of 1-year-old children in urban increased from 17.0 to 36.0%. The overall feeding rate of complementary food in infants under 6 months of age declined from 1985 to 2015; the average age at introduction of all complementary foods was around 6 months of age in 2015. CONCLUSIONS: There is an obvious trend on feeding pattern of Chinese children. From 1985 to 2005, the breastfeeding rate decreased, the duration time of breastfeeding was shortened and the age at introduction of complementary food was advanced. From 2005 to 2015, the breastfeeding rate increased, the duration time of breastfeeding was prolonged, and the age at introduction of complementary food was postponed.