National trends in stunting, thinness and overweight among Chinese school-aged children, 1985–2014

A national survey of iodine nutrition in children aged 3-6 years in China and its relationship with children's physical growth

Iodine, an essential trace element for the human body, plays a pivotal role in sustaining health. Malnutrition has emerged as a pressing public health concern, posing a significant threat to human well-being. Iodine deficiency poses a substantial threat to the development of children, potentially leading to neurological developmental disorders and mental retardation. Conversely, excessive iodine intake can result in structural and functional abnormalities in the thyroid gland. In this study, we selected children aged 3-6 years through a stratified cluster sampling approach in six regions across China to explore the correlation between iodine nutrition and their physical growth. A total of 5920 preschool children participated in this study, with a median urinary iodine concentration (UIC) of 177.33 [107.06, 269.92] μg/L. Among these children, 250 (4.2%) exhibited stunting, 180 (3.0%) were underweight, 198 (3.3%) experienced wasting, 787 (3.3%) were overweight and 414 (7.0%) were classified as obese. The multivariate linear regression revealed that UIC exhibited a positive correlation with body mass index z-Score (BMIZ) in overweight children (β = 0.038; 95% CI: 0.001, 0.075). In normally growing children, the associations between UIC and height-for-age z-score, weight-for-age z-score and BMIZ displayed nonlinear patterns. Our findings suggest that iodine nutrition is adequate for Chinese children aged 3-6 years. Furthermore, iodine nutrition is intricately linked to the growth and development of these children. Consequently, it is imperative to implement decisive measures to prevent both iodine deficiency and excess.

Secular trends and urban-rural disparities in height of Chinese adolescents aged 18 years from 1985 to 2019

OBJECTIVES

To examine the secular trends and urban-rural disparities in height of Chinese adolescents aged 18 years from 1985 to 2019.

METHODS

Data were extracted from the Chinese National Surveys on Students' Constitution and Health from 1985 to 2019, and the heights of a total of 76 554 boys and 75 908 girls aged 18 years were measured. The Mann-Kendall trend test was used to analyze the secular trends in height. Changes in different periods and urban-rural disparities were tested by z-tests and calculating the ratios of the coefficient of variation (CV) of height.

RESULTS

The height of Chinese boys and girls aged 18 years increased from 168.21 and 157.10 cm in 1985 to 172.15 cm and 160.11 cm in 2019, respectively, with a larger increase in rural areas. The secular trends in height were the largest for boys from 1995 to 2005 and for girls from 2014 to 2019, and the same results were observed in urban and rural areas. The urban-rural disparities for boys and girls decreased by 1.79 and 0.91 cm, respectively, with significant decreases for boys in all regions and for girls in the eastern region. The overall CVs of height increased by 0.13% and 0.25% for boys and girls, respectively, with the largest increase among rural girls.

CONCLUSIONS

The height of Chinese adolescents aged 18 years continued to increase between 1985 and 2019. The urban-rural disparities narrowed, and inequalities within rural areas for girls increased.

A statistical study of postmortem heart weight in Chinese adults

INTRODUCTION

Objective assessment of cardiac hypertrophy in forensic pathology practice is of great significance for forensic pathologists, for whom reference values for normal heart weights are needed. Developed regions such as Europe, the United States, and Japan recalculate the weight of human organs at regular intervals, but in China, there has been no systematic calculation of the weights of human organs since 2006.

AIMS

To statistically analyse the heart weight of Chinese adults postmortem and obtain a reference range.

MATERIALS AND METHODS

4170 adult autopsy reports were collected from 12 forensic departments in 10 provinces in China. The causes of death were classified by sex, and heart weight and the heart weight/body height ratio reference values were further calculated according to different body mass index and body heights. Finally, the cutoff value of cardiac hypertrophy in Chinese adults was calculated.

RESULTS

In the group of non-cardiovascular disease causes of death, the cardiac weight of the electric death group was higher, while the heart weight of the prolonged bed-rest group was significantly reduced. After the electric death and prolonged bed-rest groups were excluded, heart weight, the heart weight/body height ratio, and cutoff values for cardiac hypertrophy were further classified and analysed according to body mass index. The mean reference values for heart weight in men and women with normal weight status were 325.82 ± 41.60 g and 286.39 ± 44.84 g, and the heart weight/body height ratios were 1.95 ± 0.23 in men and 1.82 ± 0.27, respectively. The cutoff values for cardiac hypertrophy were 387.35 g for men and 346.80 g for women.

CONCLUSION

The heart weight reference values of both sexes in this study were significantly higher than those in 2006, which is considered related to the development of China's economy and the improvement of people's living standards. This study also suggests the need for a new round of statistical surveys and updated data on the weight of other organs.

Secular trends and urban-rural disparities in the median age at menarche among Chinese han girls from 1985 to 2019

BACKGROUND

Menarche is a substantial milestone of female puberty. Timing of age at menarche is considered the key to understanding the potential linkages with women's health outcomes later in life. This study aimed to explore the secular trends and urban‒rural disparities in the median age at menarche among Chinese Han girls from 1985 to 2019.

METHODS

Data were extracted from the 1985, 1995, 2005, 2014, and 2019 Chinese National Surveys on Students' Constitution and Health, which were nationally representative cross-sectional studies, and a total of 173,535 Han girls aged 9-18 years were examined. Girls were asked whether menarche had occurred. The median age at menarche was estimated by probit analysis. Z tests were used to compare the differences between survey years and between urban and rural areas.

RESULTS

The median age at menarche among Chinese Han girls decreased from 13.37 years in 1985 to 12.00 years in 2019, and the overall decrease was more significant in rural areas (1.77 years) than in urban areas (0.99 years). The average five-year change in the decrease in the median age at menarche showed an accelerating and then slowing pace; and it was observed similarly in both urban and rural areas. The urban‒rural disparities shrank from 0.64 years in 1985 to 0.44 years in 1995, then to 0.27 years in 2005, 0.24 years in 2014, and finally to - 0.14 years in 2019.

CONCLUSIONS

The median age at menarche among Chinese Han girls continued to decline from 1985 to 2019 but at a slowing pace in the last five years. Urban‒rural disparities gradually narrowed. Sexual and reproductive health education and interventions to prevent the decline in the age of menarche are needed, especially in rural areas.

Trends of obesity and overweight among children and adolescents in China

BACKGROUND

Recent decades have shown a rapid increase in the prevalence of overweight and obesity among Chinese children based on several national surveys. Restrictions due to the coronavirus disease 2019 outbreak have worsened its epidemiology. This review updates the trends in the prevalence of overweight and obesity among Chinese children and adolescents and analyzes the underlying reasons to provide evidence for better policy making.

METHODS

Studies published in English and Chinese were retrieved from PubMed, Google Scholar, China National Knowledge Infrastructure and Wanfang.

RESULTS

The prevalence of overweight and obesity has been increasing for decades and varies with age, sex and geography but is more pronounced in primary school students. The increase in obesity in boys appeared to be slower, whereas that in girls showed a declining trend. The northern areas of China have persistently maintained the highest levels of obesity with a stable trend in recent years. Meanwhile, the prevalence in eastern regions has dramatically increased. Notably, the overall prevalence of obesity in children has shown a stabilizing trend in recent years. However, the occurrence of obesity-related metabolic diseases increased. The effect of migrants floating into east-coast cities should not be neglected.

CONCLUSIONS

The high prevalence of overweight and obesity among Chinese children and adolescents persists but with varying patterns. Obesity-related metabolic diseases occur more frequently despite a stable trend of obesity. Multiple factors are responsible for the changing prevalence. Thus, comprehensive and flexible policies are needed to effectively manage and prevent the burden of obesity and its related complications.

Prevalence and Associated Factors of Premenstrual Syndrome in Chinese Adolescent Girls

Epidemiological data on premenstrual syndrome (PMS) in Chinese adolescents are limited. This study reported the prevalence and associated factors of PMS in a large sample of Chinese adolescents. A total of 5099 adolescent girls who had menarche participated in the baseline survey of Shandong Adolescent Behavior and Health Cohort study in Shandong, China. A self-administered questionnaire was used to ask about PMS, age at menarche, menstrual cycle interval, menstrual flow length, menstrual regularity, period pain, body weight and height, trait anger, stressful life events, and demographics. The mean age of the sample was 15.19 years (SD = 1.32). The overall prevalence of PMS was 24.6%. The prevalence rates of PMS-anxiety, PMS-water retention, PMS-craving, and PMS-depression were 18.9%, 4.0%, 7.9%, and 11.5%, respectively. The most common symptoms were premenstrual irritability (54%) and fatigue (52.5%). Stepwise logistic regression showed that high levels of life stress (OR 2.26), high levels of trait anger (OR 4.65), alcohol consumption (OR 1.28), menstrual cycle interval ≤ 24 days (OR 1.45), and mild (OR 1.50), moderate (OR 2.57) or severe period pain (OR 4.84) were all significantly associated with increased likelihood of PMS. In conclusion, approximately 1 in 4 Chinese adolescent girls suffered from PMS. Multiple psychosocial and menstrual factors were associated with PMS. Further research is needed to understand developmental changes of PMS and its long-term impacts on psychosocial wellbeing in Chinese adolescent girls.

Long-term trends and urban-rural disparities in the physical growth of children and adolescents in China: an analysis of five national school surveys over three decades

BACKGROUND

China's rapid economic growth has brought opportunities for improved health and growth of children and adolescents. We sought to explore the long-term trends and urban-rural inequalities in physical growth (specifically height and BMI) among school-aged children and adolescents in China to identify policy priorities for a healthier generation.

METHODS

We used the 1985, 1995, 2005, 2014, and 2019 cycles of the Chinese National Survey on Students' Constitution and Health from primary and secondary schools in 30 mainland provinces, autonomous regions, and municipalities. We analysed height and BMI data for 7, 12, and 18 year old children and adolescents of Han ethnicity. Children and adolescents who had complete data on age, sex, location, weight, and height were included. All surveys used a multi-stage stratified random cluster sampling method and were nationally representative. A univariate kernel density estimation was used to plot the distribution of height and BMI. Quantile regression was used to examine associations between urban and rural locations and the primary outcomes of height and BMI at specific quantiles of distribution (5th, 25th, 50th, 75th, and 95th).

FINDINGS

Across the five surveys (in 1985, 1995, 2005, 2014, and 2019), 313 973 children and adolescents were included. From 1985 to 2019, the height and BMI distribution curves shifted to the right for each age group and sex, with the BMI curve becoming more dispersed. Median height in adolescents aged 18 years increased by 3·8 cm (95% CI 3·4-4·1) in boys in urban areas and 5·7 cm (5·3-6·1) in boys in rural areas, and 2·7 cm (2·4-3·0) in girls in urban areas and 3·7 cm (3·4-4·0) in girls in rural areas. Children in urban areas were taller than those in rural areas at every quantile, but the magnitude of this disparity narrowed by 2019. In 2019, the median height of boys in urban areas were 1·4 cm (1·0-1·8) greater in those aged 7 years, 2·5 cm (1·9-3·1) greater in those aged 12 years, and 1·1 cm (0·6-1·5) greater in those aged 18 years than their rural counterparts, whereas the median height of girls in urban areas were 1·1 cm (0·7-1·4) greater in those aged 7 years, 1·6 cm (1·1-2·1) greater in those aged 12 years, and 1·1 cm (0·7-1·5) greater in those aged 18 years than rural girls. Over this period, urban-rural differences in BMI disappeared at the lowest quantile, but persisted at higher quantiles. In 2019, the urban-rural differences in BMI for boys aged 12 years were 0·6 kg/m2 (95% CI 0·3-0·8) at the median, 1·0 kg/m2 (0·6-1·4) at the 75th quantile, and 0·7 kg/m2 (0·1-1·3) at the 95th quantile; for girls aged 12 years, 0·3 kg/m2 (0·1-0·5) at the median, 0·5 kg/m2 (0·2-0·8) at the 75th quantile, and 0·9 kg/m2 (0·3-1·5) at the 95th quantile; for boys aged 18 years, 0·6 kg/m2 (0·4-0·8) at the median, 0·8 kg/m2 (0·5-1·2) at the 75th quantile, and 0.7 kg/m2 (0·0-1·5) at the 95th quantile; and for girls aged 18 years, 0·2 kg/m2 (0·1-0·4) at the median, 0·5 kg/m2 (0·3-0·8) at the 75th quantile, and 1·0 kg/m2 (0·5-1·5) at the 95th quantile.

INTERPRETATION

Across three decades, school-aged children and adolescents in China have increased in height and BMI, with less disparity between urban and rural locations. Investments are needed to improve the affordability of healthy foods to help children and adolescents in rural areas reach their potential maximum height. Meanwhile, these changes in BMI necessitate tailored strategies according to urban-rural settings to contain the increase in overweight and obesity and promote optimal growth for children and adolescents.

FUNDING

Capital's Funds for Health Improvement and Research, and National Natural Science Foundation of China.

Exploring the impact of water, sanitation and hygiene (WASH), early adequate feeding and access to health care on urban-rural disparities of child malnutrition in China

To explore the effects of UNICEF-suggested modifiable factors, that is, water, sanitation and hygiene (WASH), early adequate feeding and health care on child malnutrition, and to examine the extent to which each factor contributes to urban-rural disparities of child malnutrition in China. Pooling two waves of regionally representative survey data from Jilin, China, in 2013 and 2018, we report on urban-rural relative risks (RRs) in the prevalence of child stunting, wasting and overweight. We employ Poisson regression to examine the effects of urban-rural setting and the three modifiable factors on the prevalence of each malnutrition outcome, that is, stunting, wasting and overweight. We perform mediation analyses to estimate the extent to which each modifiable factor could explain the urban-rural disparities in each malnutrition outcome. The prevalence of stunting, wasting and overweight were 10.9%, 6.3% and 24.7% in urban, and 27.9%, 8.2% and 35.9% in rural Jilin, respectively. The rural to urban crude RR was 2.55 (95% confidence interval [CI]: 1.92-3.39) for stunting, while the corresponding RRs for wasting and overweight were 1.31 (95% CI: 0.84-2.03) and 1.45 (95% CI: 1.20-1.76), respectively. The rural to urban RR for stunting reduced to 2.01 (95% CI: 1.44-2.79) after adjusting for WASH. The mediation analyses show that WASH could mediate 23.96% (95% CI: 4.34-43.58%) of the urban-rural disparities for stunting, while early adequate feeding and health care had no effects. To close the persistent urban-rural gap in child malnutrition, the specific context of rural China suggests that a multi-sectoral approach is warranted that focuses on the sanitation environment and other wider social determinants of health.

Children who appeared or remained overweight or obese predict a higher follow-up blood pressure and higher risk of hypertension: a 6-year longitudinal study in Yantai, China

Few longitudinal studies have examined the effect of weight status change on blood pressure change over time and incidence of hypertension among Chinese children. The longitudinal study enrolled 17,702 Chinese children aged 7 years in Yantai in 2014 as baseline, with a continuous 5 years of follow-up to 2019. Generalized estimating equation model was fitted to examine the main and interaction effects of weight status change and time with blood pressure and the incidence of hypertension. Compared with the participants who remained normal weight, the participants who remained overweight or obese had higher systolic blood pressure (SBP) (β = 2.89, p < 0.001) and diastolic blood pressure (DBP) (β = 1.79, p < 0.001). Significant interactions were identified between weight status change and time with SBP (χ2interaction = 697.77, p < 0.001) and DBP (χ2interaction = 270.49, p < 0.001). The odds ratio (OR) and 95% confidence interval (CI) of hypertension were 1.70 (1.59-1.82) for participants who appeared overweight or obese, 2.26 (2.14-2.40) for participants who remained overweight or obese, compared with the participants who remained normal weight. Those who switched from overweight or obesity to normal weight had almost the same risk of developing hypertension (OR = 1.13, 95% CI: 1.02 to 1.26) as children who remained normal weight. Children who appeared or remained overweight or obese predict a higher follow-up blood pressure and higher risk of hypertension, whereas losing weight could reduce blood pressure and the risk of hypertension. Children who appeared or remained overweight or obese predict a higher follow-up blood pressure and higher risk of hypertension, whereas losing weight could reduce blood pressure and the risk of hypertension.

Bisphenol A substitutes and childhood obesity at 7 years: a cross-sectional study in Shandong, China

Bisphenol A (BPA) substitutes, such as bisphenol S (BPS) and bisphenol AF (BPAF), are increasingly used due to restrictions on BPA usage, a known endocrine disrupting chemical and putative obesogen. However, little is known about the obesogenic effects of exposure to BPA substitutes in children. A total of 426 children aged 7 years old originally recruited from Laizhou Wan Birth Cohort in Shandong, China, during 2010-2013 participated in the 2019-2020 survey. Urinary BPA and its substitutes including BPS, BPAF, bisphenol B (BPB), bisphenol AP (BPAP), bisphenol Z (BPZ), and bisphenol P (BPP) were determined. Anthropometric measures including height, weight, waist circumference, and body fat percentage were assessed, and overweight/obesity was defined as BMI z-score ≥ 85th percentile. Linear and logistic regressions were used on continuous and binary obesity measures, respectively, and weighted quantile sum (WQS) regression was further used to estimate the mixture effects of exposure to diverse bisphenols, and sex-stratified analysis was performed. BPA substitutes were widely detected (> 75%) in children's urine samples. A positive association with obesity measures was consistently observed for urinary BPS and BPAF, i.e., BMI z-score, waist circumference, and overweight/obesity. Further analysis from the WQS regression model demonstrated a positive association between bisphenol mixtures and all measures of obesity, with BPAF contributing the greatest weighing to the observed associations. Sex difference might exist as the positive associations were only significant in boys. No significant association was found between obesity and BPA or other BPA substitutes. Our study adds to mounting evidence that BPA substitutes BPS and BPAF are linked to obesity in children, especially in boys. Further longitudinal studies with larger sample size with continued biomonitoring these chemicals and their obesogenic effects are necessary.

Secular trends in physical fitness of rural Chinese children and adolescents aged 7-18 years from 1985 to 2019

The main purpose of the study was to evaluate the secular trends in physical fitness of Chinese rural children and adolescents aged 7-18 from 1985 to 2019. The speed, muscular strength, explosive power fitness, cardiorespiratory fitness, and flexibility were investigated by National Survey on Students' Constitution and Health in 1985, 2000, 2010 and 2019. During the period 1985-2000, the physical fitness of Chinese rural children and adolescents improved except for flexibility, and almost all of them reached the maximum increase rate. During the period 2000-2010, in addition to the improvement of flexibility, other fitness showed downward trends, and the decline ranges were large. During the period 2010-2019, the speed of boys rebounded, flexibility, explosive power and muscular strength continued to decrease. Meanwhile, speed, flexibility and muscular strength in girls rebounded, and the explosive power continued to decline. From 2000 to 2019, the body mass index increase accelerated. This study shows that some components of physical fitness of Chinese rural children and adolescents have shown positive trends in recent years, especially for girls and adolescents aged 13-15 years. However, it may also imply inequality between sexes and ages, which provides a reference for the focus of the country's physical fitness and health monitoring and intervention measures.

Proportion of Chinese Children and Adolescents Meeting 24-Hour Movement Guidelines and Associations with Overweight and Obesity

Background: Since there is little knowledge about the 24-hour movement behaviors of Chinese children and adolescents, the purposes of this study were to investigate the proportion of Chinese children and adolescents meeting the 24-Hour Movement Guidelines and to further evaluate its relationship with overweight and obesity. Methods: A total of 440 children and adolescents aged 7−18 years from 7 cities in China were selected to measure physical activity using accelerometers, and sleep (SLP) and screen time (ST) using questionnaires. The data were analyzed with the independent T-test, Mann−Whitney U test, Cox−Stuart test, chi-square test, and logistic regression. Results: The proportion of Chinese children and adolescents meeting the overall 24-Hour Movement Guidelines was 7.3%. Boys (11.8%) were higher than girls (3.4%) (p < 0.001) and showed a downward trend with age (Ptrend = 0.03). The rates of overweight and obesity among children and adolescents who met the ST, MVPA + ST, ST + SLP, and MVPA + SLP + ST guidelines were 39%, 15%, and 36%, and 25% did not meet any guidelines. The rates of overweight and obesity among those who met 1, 2, and 3 guidelines were lower than the rate among those who did not meet any guidelines (odds ratio (OR) = 0.51, 95% confidence interval (CI): 0.22−1.17; OR = 0.32, 95% CI: 0.13−0.77; OR = 0.23, 95% CI: 0.07−0.81) and showed a decreasing trend (Ptrend = 0.006). Conclusions: The proportion of Chinese children and adolescents meeting the overall 24-Hour Movement Guidelines was low. The rate of overweight and obesity among children and adolescents who met the overall 24-Hour Movement Guidelines was the lowest compared with the rates among those who met any one or two. There was a dose−response relationship between the number of guidelines met and the overweight and obesity rate.

Secular trends and sociodemographic determinants of thinness, overweight and obesity among Chinese children and adolescents aged 7-18 years from 2010 to 2018

Background

Most studies have focused on overweight/obesity and its secular trend, with insufficient studies on the factors influencing thinness and trends recently. To examine the trends of prevalence and sociodemographic determinants of thinness, overweight, and obesity among Chinese children and adolescents aged 7 to 18 years from 2010 to 2018.

Methods

This study was based on cross-sectional data of 11,234 children and adolescents aged 7 to 18 years from the Chinese Family Panel Studies (CFPS) in 2010, 2014, and 2018, including anthropometric and sociodemographic characteristics variables. The nutritional status of each individual was determined according to China and WHO criteria. The demographic characteristics of different subgroups were tested by chi-square, and log-binomial regression was used to analyze the trend of prevalence and the relationship between sociodemographic characteristics and different nutritional statuses.

Results

After adjusting for age, from 2010 to 2018, the overall prevalence of thinness decreased, and the prevalence of overweight increased in Chinese children and adolescents. The overall prevalence of obesity declined in boys and increased in girls, but in adolescents aged 16-18 years, it increased significantly. Log-binomial regression analysis showed that among all subjects, time (years), 16-18 years were negatively associated with thinness, while 13-15 years, walking to school, large family size, and paternal age at childbirth older than 30 years old were positively associated with thinness; 10-12/13-15/16-18 years, boarding at school, medium and large family sizes, and mother's education at junior middle school/junior high school and above were negatively associated with overweight/obesity, while time (years), boys were positively associated with overweight/obesity in the multivariate model by adjusting for the statistically significant factors (all p < 0.05).

Conclusion

Chinese children and adolescents are facing a double burden of malnutrition. Future public health policies and interventions should prioritize high-risk groups specifically young age groups, boys, larger family sizes and so on.

Trends of overweight and obesity prevalence in school-aged children among Henan Province from 2000 to 2019

Objectives

Overweight and obesity are harmful to human health. However, the latest trends of Chinese childhood overweight and obesity prevalence are not available. The aim of this study was to examine the trends from 2000 to 2019 among students in China.

Methods

We analyzed data of 66,072 students in the Chinese National Survey on Students' Constitution and Health from 2000 to 2019. Overweight and obesity were defined based on the standard formulated by the International Obesity Task Force (IOTF standard), the World Health Organization (WHO standard), and the Working Group on Obesity in China (WGOC standard), respectively. The χ²-test was used to test the trends of overweight and obesity prevalence and logistic regression was conducted to evaluate the prevalence odds ratios of boys vs. girls and urban vs. rural areas.

Results

The prevalence of obesity/overweight and obesity combined was 6.03/23.58% (IOTF standard), 10.56/25.88% (WGOC standard) and 10.75/29.69% (WHO standard) in 2019. From 2000 to 2019, according to the WGOC standard, the prevalence increased from 2.51 to 10.56% for obesity and increased from 9.81 to 25.88% for overweight and obesity combined (P for trend < 0.001). Obesity/overweight and obesity were greater problems in boys than girls and urban than rural areas, but urban-rural differences decreased over time.

Conclusion

Overweight and obesity prevalence increased significantly in children and adolescents in China from 2000 to 2019. The prevalence of overweight and obesity in rural areas may contribute to a large percentage of children with overweight and obesity.

Association between short-term exposure to ambient PM1 and PM2.5 and forced vital capacity in Chinese children and adolescents

This study aims to examine the association between short-term exposure to ambient PM₁, PM_1-2.5, and PM_2.5 and forced vital capacity (FVC). Population data were obtained from a school-based cross-sectional survey in Shandong in 2014. Distributed lag non-linear models were used to examine the association between exposure to PM₁, PM_1-2.5, and PM_2.5 and FVC at the day of FVC measurement and the previous 6 days (lag 0 to 6 days). A total of 35,334 students aged 9 to 18 years were included in the study, and the mean exposure concentrations of ambient PM₁, PM_1-2.5, and PM_2.5 for them were 47.4 (standard deviation [SD] = 21.3) μg/m³, 32.8 (SD = 32.2) μg/m³, and 80.1 (SD = 47.7) μg/m³, respectively. An inter-quartile range (IQR, 24 μg/m³) increment in exposure to PM₁ was significantly associated with a lower FVC at lag 0 and lag 1 day (β =  - 80 mL, 95% CI =  - 119, - 42, and β =  - 37 mL, 95% CI =  - 59, - 16, respectively), and an IQR (54 μg/m³) increment in exposure to PM_2.5 was significantly associated with a lower FVC at lag 0 and lag 1 day (β =  - 57 mL, 95% CI =  - 89, - 18, and β =  - 34 mL, 95% CI =  - 56, - 12, respectively) after adjustment for gender, age, body mass index category, residence, month of the survey, intake of eggs, intake of milk, physical activity, and screen time. No significant associations were observed for PM_1-2.5. The inverse associations of PM₁ and PM_2.5 with FVC were larger in males, younger children, those overweight or obese, and those with insufficient physical activity levels. Short-term exposure to ambient PM₁ and PM_2.5 was associated with decreased FVC, and PM₁ may be the primary fraction of PM_2.5 causing the adverse pulmonary effects. Our findings emphasize the need to address ambient PM, especially PM₁, pollution for affecting pulmonary health in children and adolescents.

Trends in growth and nutritional status of high school graduates in Hangzhou, China, 2011-2020

Background

During past decades, there was a positive trend in growth and nutrition status of adolescents in China, but there was significant regional disparity. The purpose of this study is to investigate the trends in growth and nutritional status of high school graduates in Hangzhou between 2011 and 2020.

Methods

High school graduates (Grade 12) who finished the physical examination of the national college entrance examination between 2011 and 2020 (n=481,353)were included in this study. Data were obtained from the database of physical examination of the national college entrance exam. Height and weight were measured; body mass index (BMI) was calculated from height and weight. Thinness, overweight and obesity were defined according to the International Obesity Task Force criteria. For the vast majority of the high school graduates were 18 years old or nearly 18 years old, the cutoffs of 18 years were adopted. Those are 18.5, 25 and 30 kg/m², for thinness, overweight and obesity respectively.

Results

There was a significant growth trend in height, weight and BMI in both sexes (P < 0.001). Height increased by 1.80 cm in boys and 1.45 cm in girls. Weight increased by 4.62 kg in boys and 2.51 kg in girls. BMI increased by 1.09 kg/m² in boys and 0.60 kg/m² in girls. An increase trend was found in the prevalence of overweight and obesity in both sexes (P < 0.001). Overweight increased by 7.43% (from 9.05 to 16.48%) among boys and 4.05% (from 4.57 to 8.62%) among girls. Obesity increased by 3.85% (from 2.29 to 6.14%) among boys and 1.76% (from 0.64 to 2.40%) among girls. The prevalence of thinness fluctuated in both boys and girls, 12.42–15.59% among boys and 18.97–23.68% among girls. Boys had higher odds of overweight and obesity and lower odds of thinness than girls (P < 0.001).

Conclusions

There is a positive trend in growth and nutritional status of high school graduates in Hangzhou. However, there is still a considerable prevalence of thinness, it indicates a double burden of undernutrition and overnutrition.

Screen time and health issues in Chinese school-aged children and adolescents: a systematic review and meta-analysis

Backgrounds

Many literature reviews summarized relationships between screen time and child health, but they only included a few studies conducted in Chinese children and adolescents. The potential influence of screen time may vary by social context. The current systematic review and meta-analysis aimed to evaluate relationships between screen time and health issues among Chinese school-aged children and adolescents.

Methods

Peer-reviewed articles written in Chinese and English were retrieved from CNKI, Wanfang, PubMed, Embase, and Web of Science from inception to June 2020. The Downs & Black checklist was applied to assess study quality. Meta analyses used random effect models and mixed effects model to calculate pooled adjusted odds ratios and 95% confidence intervals. Heterogeneity, sensitivity, and publication bias were assessed using Q and I² statistics, “one-study removed” analysis, the funnel plot, trim and fill analysis, and classical fail-safe N, respectively.

Results

In total, we identified 252 articles reporting 268 studies with unique samples. These studies investigated relationships between screen time and health issues of adiposity, myopia, psycho-behavioral problems, poor academic performance, cardiometabolic disease risks, sleep disorder, poor physical fitness, musculoskeletal injury, sub-health, and miscellaneous issues of height and pubertal growth, injury, sick leave, and respiratory symptoms. Proportions of studies reporting positive relationships with screen time were lowest in adiposity (50.6%) and higher in myopia (59.2%) and psycho-behavioral problems (81.8%). Other health issues were examined in 10 or less studies, all of which had more than half showing positive relationships. The pooled odds ratio from 19 studies comparing health risks with the screen time cutoff of 2 hours per day was 1.40 (95% CI: 1.31 to 1.50, I² = 85.9%). The pooled effect size was 1.29 (95% CI: 1.20 to 1.39) after trimming 7 studies for publication bias adjustments.

Conclusions

Findings exclusively generated from Chinese school-aged children and adolescents resonate those mainly from western countries. Evidence suggests that higher levels of screen time are related with greater risks of various health issues, although the relationships appear to be weak and intertwined with other confounding factors. Future studies need to investigate health-specific dose effects and mechanisms of screen time.

Supplementary information

The online version contains supplementary material available at 10.1186/s12889-022-13155-3.

Interventions for health-related physical fitness and overweight and obesity in children with intellectual disability: Systematic review and meta-analysis

BACKGROUND

Poor health-related physical fitness (HRPF) and overweight and obesity are common health problems for children with intellectual disability. This study aimed to review existing lifestyle intervention studies, and identify effective strategies for this population.

METHODS

A systematic search was undertaken in three databases. The random-effects model was used to pool the weighted results by inverse variance methods, and the I² statistic was applied to assess heterogeneity among the included studies.

RESULTS

Most of the identified interventions (27/29) adopted physical activity (PA). For obesity-related outcomes, the results showed no significant effect of PA studies on reducing obesity. For HRPF outcomes, significant effects were found on 6-min walk distance (51.86 m, 95% CI [16.49, 87.22], p < .05).

CONCLUSIONS

PA is the predominant intervention component adopted and may contribute to improving cardiopulmonary fitness; but the lack of research limits our ability to draw any confirmed conclusion on obesity-related outcomes and other HRPF outcomes.

Patterns and Determinants of the Double Burden of Malnutrition Among Adolescents: A 14-Year Follow-Up of a Birth Cohort in Rural China

OBJECTIVE

To examine the prevalence of the double burden of malnutrition and its associated factors among adolescents in rural China.

STUDY DESIGN

A birth cohort of adolescents born to women in northwestern China who participated in a double-blind, randomized, controlled trial of micronutrient supplementation during pregnancy from August 2002 to January 2006 was enrolled. Follow-up was conducted from June to December 2016.

RESULTS

A total of 2115 participants were analyzed (median age 12 years; IQR ± 1), the majority of whom were male (59.7%). The nutritional status distribution was 17.72% underweight, 8.62% overweight, 0.96% obese, and 2.58% stunted. Girls were less likely to be overweight/obese (relative risk ratio [RRR] 0.67, 95% CI 0.48-0.92) but more likely to be underweight (RRR 1.65, 95% CI 1.25-2.17) or stunted (RRR 2.26, 95% CI 1.21-4.22). Children of underweight mothers (RRR 1.63, 95% CI 1.19-2.25) with a history of small for gestational age (RRR 1.64, 95% CI 1.14-2.36) or described as being a "picky eater" (RRR 1.53, 95% CI 1.18-1.99) had a greater risk of being underweight. Children whose fathers' education was primary or below (RRR 2.25, 95% CI 1.11-4.59), with maternal height <150.1 cm (RRR 2.46, 95% CI 1.12-5.39), or who had mothers with underweight (RRR 2.80, 95% CI 1.37-5.72) had a greater likelihood of stunting. Overweight/obesity was associated with high and middle household wealth (RRR 1.62, 95% CI 1.14-2.32), mothers with overweight (RRR 1.86, 95% CI 1.25-2.78), and picky eating (RRR 0.62, 95% CI 0.46-0.84).

CONCLUSIONS

Malnutrition (undernutrition and overweight/obesity) is common in rural Chinese adolescents and is associated with perinatal, genetic, and economic conditions.

Socio-economic disparities in child-to-adolescent growth trajectories in China: Findings from the China Health and Nutrition Survey 1991–2015

Backgrounds

Socio-economic disparities in growth trajectories of children from low-/middle-income countries are poorly understood, especially those experiencing rapid economic growth. We investigated socio-economic disparities in child growth in recent decades in China.

Methods

Using longitudinal data on 5095 children/adolescents (7–18 years) from the China Health and Nutrition Survey (1991–2015), we estimated mean height and BMI trajectories by socio-economic position (SEP) and sex for cohorts born in 1981–85, 1986–90, 1991–95, 1996–2000, using random-effects models. We estimated differences between high (urbanization index ≥median, household income per capita ≥median, parental education ≥high school, or occupational classes I–IV) and low SEP groups.

Findings

Mean height and BMI trajectories have shifted upwards across cohorts. In all cohorts, growth trajectories for high SEP groups were above those for low SEP groups across SEP indicators. For height, socio-economic differences persisted across cohorts (e.g. 3.8cm and 2.9cm in earliest and latest cohorts by urbanization index for boys at 10 year, and 3.6cm and 3.1cm respectively by household income). For BMI, trends were greater in high than low SEP groups, thus socio-economic differences increased across cohorts (e.g. 0.5 to 0.8kg/m² by urbanization index, 0.4 to 1.1kg/m² by household income for boys at 10 year). Similar trends were found for stunting and overweight/obesity by SEP. There was no association between SEP indicators and thinness.

Interpretation

Socio-economic disparities in physical growth persist among Chinese youth. Short stature was associated with lower SEP, but high BMI with higher SEP. Public health interventions should be tailored by SEP, in order to improve children's growth while reducing overweight/obesity.

Funding

MG is supported by UCL Overseas Research Scholarship and China Scholarship Council for her PhD study. WJ is supported by a UK Medical Research Council (MRC) New Investigator Research Grant (MR/P023347/1) and acknowledges support from the National Institute for Health Research (NIHR) Leicester Biomedical Research Centre, which is a partnership between University Hospitals of Leicester NHS Trust, Loughborough University, and the University of Leicester.

Double burden of malnutrition in ethnic minority school-aged children living in mountainous areas of Vietnam and its association with nutritional behavior

BACKGROUND/OBJECTIVES

Although children of ethnic minority groups are experiencing a transition from a predominance of undernutrition to overnutrition, there is little evidence of a dual-malnutrition burden. Therefore, this study examined the double burden of malnutrition among school-aged ethnic minority children living in mountainous areas and its association with their diets.

SUBJECTS/METHODS

A cross-sectional study was conducted from September 2019 to March 2020 in 3 mountainous areas of Northern Vietnam among 1,556 ethnic minority school-aged children. The prevalence of under-nutrition (stunting and thinness) and over-nutrition (overweight and obesity) were measured using the WHO 2006 child growth standards (height-for-age and BMI-for-age Z-score). Nutritional practices were evaluated by the frequency of food consumption based on a 4-level scale.

RESULTS

The percentage of children with stunting and thinness were 14.0% and 5.4%, respectively, while the figure for overweight/obesity was 9.4%. The factors positively associated with stunting were living in a family with more than 2 children or being Muong/other ethnicities compared to the Tay ethnicity. Children who consumed fish/shrimps/crabs or milk weekly/daily were less likely to be undernourished compared to those who never consumed these foods. By contrast, children who never consumed foods rich in vitamin A precursors and vitamin A and fruit or consumed daily snacks/junk food were more likely to be overweight/obese.

CONCLUSIONS

Undernutrition remains a common issue among school-aged children and adolescents of ethnic minority groups, while over-nutrition exists simultaneously. Public health nutrition programs promoting adequate diets and positive lifestyle changes related to nutrition are essential to tackle the double burden of malnutrition among ethnic minority children.

Thinness, overweight and obesity among 6- to 17-year-old Malaysians: secular trends and sociodemographic determinants from 2006 to 2015

OBJECTIVE

To examine secular trends and sociodemographic determinants of thinness, overweight and obesity among Malaysian children and adolescents from 2006 to 2015.

DESIGN

We used cross-sectional data from the National Health and Morbidity Surveys 2006, 2011 and 2015. Individuals were classified into pre- (6-9 years), early (10-13 years) and mid- (14-17 years) adolescence. BMI status was determined according to the International Obesity Task Force (IOTF) and WHO criteria, using measured height and weight. We analysed trends using log-binomial regression, by sex-age groups, stratified by sociodemographic factors (ethnicity, residential area, household size and household income), and accounting for the complex survey design. Associations between sociodemographic factors and prevalence of thinness and overweight (obesity included) in 2015 were assessed using log-Poisson regression.

SETTING

Nationwide population-based surveys, Malaysia.

PARTICIPANTS

Eligible 6-17-year-olds from urban and rural residential areas (n 28 094).

RESULTS

The prevalence of thinness decreased from 2006 to 2015 (IOTF: boys from 22 % to 18 %, girls from 23 % to 19 %; WHO: boys from 9 % to 7 %, girls from 8 % to 6 %), while the prevalence of overweight increased (IOTF: boys from 20 % to 26 %, girls from 19 % to 24 %; WHO: boys from 25 % to 31 %, girls from 22 % to 27 %). These changes were statistically significant in most sex-age groups. Thinness and overweight co-existed in all sociodemographic subgroups, with variation in the prevalence estimates, but similar secular changes in most subgroups.

CONCLUSIONS

Malaysia is facing a double burden of malnutrition at population level with a secular increase in overweight and obesity and a gradual decrease in thinness among 6-17-year-olds from varying sociodemographic backgrounds.

Infant and preschooler feeding behaviors in Chinese families: A systematic review

A systematic review was conducted on the literature on feeding behaviors in Chinese families of children under 6 years old. Forty relevant publications were identified, of which 33 were published in Chinese, 7 in English. All studies were questionnaire-based and used a cross-sectional research design. Approximately half of the studies reported a score for each feeding practice/style, based on a Likert scale; the other half dichotomized these scores into a percentage of the population that reported frequent use of the behaviors. The most commonly reported feeding style of Chinese caregivers was a locally defined "active response" style that somewhat resembled authoritative parenting. The most commonly reported feeding practices were praise, encouraging trying new foods, encouragement of balanced diet and encouragement of healthy eating. Some behaviors showed a great deal of variance in prevalence between studies, which may be at least partially due to differences in methodology and how behaviors were defined. Some feeding behaviors varied in frequency depending on the child's age, although longitudinal studies are needed to better understand how these evolve over time. Child body composition was also associated with feeding behaviors use, although the direction of the association cannot be determined due to the cross-sectional nature of the research. There is still an important gap in the literature regarding the feeding behaviors of non-maternal caregivers, as grandparents often play an important role in childcare in China.

Identification and Analysis of Stunting Risk Factors in Children under Three Years of Age in the Area of Kampar Watershed

Growth and development that is not optimal is a form of chronic malnutrition, one of which is marked by height for age which is below the standard deviation (<-2 SD) and is called stunting. Stunting has a negative impact on children's motor development, reduces children's performance in school, increases the risk of excess nutrition, infectious diseases, and even death as well as reduces productivity in adulthood. The purpose of this study was to identify risk factors for stunting in people living in the Kampar watershed. This research is a mixed-method with an explanatory sequential design which is a modification of (1–3). The research was carried out on people living in the Kampar river basin. The priority areas for specific stunting reduction interventions in this study are the Work Areas of the Kampar Kiri Hulu II Health Center, the Koto Kampar XIII Health Center, and the Kampar Kiri Health Center. This study found that the dominant factors of the five variables were home sanitation and parenting, as both affected the incidence of stunting. The findings obtained are different from the results of data analysis obtained from interviews, observations, and descriptive statistics. Based on the results of data analysis from interviews, observations, and descriptive statistics, it was found that all variables of the three factors became the main factors that had a close relationship with the incidence of stunting in the community in the Kampar watershed.

Ambient air pollution and obesity in school-aged children and adolescents: A multicenter study in China

BACKGROUND

Environmental factors such as air pollution may contribute to the development of childhood obesity. However, current epidemiological evidence is limited and inconsistent.

OBJECTIVE

We investigated the associations between long-term air pollution exposure and obesity in a large population of Chinese children and adolescents.

METHODS

A total of 44,718 children and adolescents (50.5% boys) aged 7 to 18 years were recruited from seven provinces/municipalities in China. Body mass index (BMI), waist circumference, waist-to-height ratio (WHtR) and the prevalence of general and central obesity were measured. Satellite-based spatial-temporal models were used to estimate ambient concentrations of particulate matter with aerodynamic diameter < 1.0 μm (PM₁), <2.5 μm (PM_2.5), <10.0 μm (PM₁₀) and nitrogen dioxide (NO₂). We used mixed-effects linear and logistic regression models to examine the associations between air pollution exposure and body weight measures.

RESULTS

Exposure to PM₁, PM_2.5, PM₁₀ and NO₂ was associated with increased BMI Z-score, waist circumference and WHtR, and higher prevalence of both general and central obesity. Generally, stronger associations were observed for particles, especially PM₁ and PM_2.5, than for NO₂. Also, the associations of particles were generally more stable in two-pollutant models. Overall, the associations were more pronounced in boys than in girls except for general obesity.

CONCLUSIONS

Long-term exposure to air pollution was associated with increased body weight and higher prevalence of obesity in children and adolescents, suggesting potential obesogenic effects of air pollution.

Epidemiology and determinants of obesity in China

Obesity has become a major public health issue in China. Overweight and obesity have increased rapidly in the past four decades, and the latest national prevalence estimates for 2015-19, based on Chinese criteria, were 6·8% for overweight and 3·6% for obesity in children younger than 6 years, 11·1% for overweight and 7·9% for obesity in children and adolescents aged 6-17 years, and 34·3% for overweight and 16·4% for obesity in adults (≥18 years). Prevalence differed by sex, age group, and geographical location, but was substantial in all subpopulations. Strong evidence from prospective cohort studies has linked overweight and obesity to increased risks of major non-communicable diseases and premature mortality in Chinese populations. The growing burden of overweight and obesity could be driven by economic developments, sociocultural norms, and policies that have shaped individual-level risk factors for obesity through urbanisation, urban planning and built environments, and food systems and environments. Substantial changes in dietary patterns have occurred in China, with increased consumption of animal-source foods, refined grains, and highly processed, high-sugar, and high-fat foods, while physical activity levels in all major domains have decreased with increasing sedentary behaviours. The effects of dietary factors and physical inactivity intersect with other individual-level risk factors such as genetic susceptibility, psychosocial factors, obesogens, and in-utero and early-life exposures. In view of the scarcity of research around the individual and collective roles of these upstream and downstream factors, multidisciplinary and transdisciplinary studies are urgently needed to identify systemic approaches that target both the population-level determinants and individual-level risk factors for obesity in China.

Growth and Weight Status in Chinese Children and Their Association with Family Environments

The growth status and weight status of Chinese children have experienced remarkable changes in the past decades. Using China Health and Nutrition Survey (CHNS) data, this paper examines the secular trends and disparity of the growth status and weight status in Chinese children and further investigates the impact of various family environments on children’s growth from 1991 to 2011. We found an increasing trend in standardized growth indicators (height, weight, and BMI), overweight, and obesity from 1991 to 2011. We also observed an increasing disparity in overweight and obesity over time. Family environments had a significant impact on children’s growth status and weight status. In particular, children that live in families with a small size, higher family income, better sanitary conditions, and with well-educated parents or overweight parents tended to be taller and heavier and have a higher BMI, lower risk of being underweight, and higher risk of exhibiting overweight and obesity. Further decomposition analysis showed that more than 70% of the disparity in standardized height, weight, and overweight and around 50% of the disparity in standardized BMI, underweight, and obesity could be attributed to heterogeneity in family environments. Moreover, the disparity associated with family environments tended to increase over time.

Effects of a School-Based Physical Activity Intervention for Obesity and Health-Related Physical Fitness in Adolescents With Intellectual Disability: Protocol for a Randomized Controlled Trial

BACKGROUND

Childhood obesity accompanied by lower levels of health-related physical fitness (HRPF) is a major threat to public health both internationally and locally. Children with intellectual disability, especially adolescents, have a higher risk of being overweight/obese and having poor HRPF levels. Therefore, more interventions are needed to help this population attain their optimal health levels. However, there has been relatively limited research on this population compared with on their typically developing peers.

OBJECTIVE

The proposed study aims to fill this knowledge gap by developing and examining the success of a physical activity (PA) intervention for the target population.

METHODS

The proposed study will be a 12-week, school-based randomized controlled trial. The participants (N=48) will be recruited from special schools for students with mild intellectual disability and then randomly allocated to either the intervention group (IG) or the wait-list control group (CG). During the intervention period, the participants in the IG will receive a fun game-based moderate-to-vigorous PA (MVPA) training program (2 sessions/week, 60 minutes/session, for a total of 24 sessions). The intensity of the activities will increase in a progressive manner. Participants in the CG will receive no program during the study period, but the same PA program will be provided to them after the completion of the study. To observe and evaluate the sustaining effects of the intervention, follow-up testing will be scheduled for the participants 12 weeks after the intervention concludes. The study outcomes will include primary outcomes (obesity- and fitness-related outcomes) and a secondary outcome (blood pressure). All of the measurements will be taken at 3 time points. After the follow-up tests, the same PA training program will be provided to the participants in the CG.

RESULTS

This study is ongoing. The participants were recruited from October 2020 to November 2020. The total duration of the study is 13 months. Study results are expected at the end of 2021.

CONCLUSIONS

The proposed study is expected to reduce obesity and improve HRPF levels in children with intellectual disability. If proven effective, the intervention will be made accessible to more special schools and mainstream schools with students with intellectual disability. Furthermore, the study can serve as an example for international researchers, policy makers, and members of the public who are seeking to tackle the problem of obesity and poor HRPF among children with intellectual disability.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04554355; https://www.clinicaltrials.gov/ct2/show/NCT04554355.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

PRR1-10.2196/25838.

Changes in the age-specific body mass index distribution among urban children between 2002 and 2018 in Changsha, China

BACKGROUND

It had been reported that the increase in the prevalence of childhood overweight and obesity in several developed countries over the decade was largely a consequence of changes in the upper end of the body mass index (BMI) distribution. We speculated that the change in BMI distribution among Chinese children is different from that in developed countries. Therefore, we investigated the changes in the BMI distribution among urban children in Changsha, China.

METHODS

A secondary data analysis of the 2002 and 2018 Annual Survey on Students' Constitution and Health from Yuhua District, Changsha City, China was performed. The BMI distribution of children aged 6-15 years (n=72,061) was examined by calculating the BMI value at 5th, 50th, 85th, and 95th percentiles. Differences in the BMI value at the 5th, 50th, 85th, and 95th percentiles between 2002 and 2018 according to age and sex were calculated.

RESULTS

From 2002 to 2018, the standardized rate of underweight decreased from 6.9% to 3.4%, whereas that of obesity increased from 6.1% to 13.8%. The BMI of the population increased over the 16-year period. The greatest change between the years was seen in the 85th percentile, and moderate changes were seen in the 5th and 50th BMI percentiles. Also, the greatest changes in the BMI percentiles were evident at age 12-14 years.

CONCLUSIONS

The whole spectrum of BMI distribution among school-aged children shifted over the 16-year study period, although the increases were more marked in the upper than lower percentiles. Health professionals and health policymakers should develop strategies and interventions aimed at preventing adverse health effects caused by this change.

Prevalence of thinness, overweight and obesity among Tibetan adolescents aged 12-17 years

OBJECTIVE

To estimate the prevalence of thinness, overweight and obesity among Tibetan adolescents aged 12-17 years.

DESIGN

Cross-sectional survey.

SETTING

Shigatse City of Tibet municipality, with an average altitude of more than 4000 m.

PARTICIPANTS

Study participants included 2642 adolescents aged 12-17 years selected from six schools using a convenient cluster sampling method.

RESULTS

The prevalence of thinness/overweight/obesity among Tibetan adolescents was 9·4 %/5·4 %/1·4 % (China definition), 14·7 %/4·4 %/0·7 % (International Obesity Task Force (IOTF) definition), and 2·8 %/5·7 %/0·9 % (WHO definition). The prevalence of thinness and overweight was significantly different between both sexes based on each of three BMI classification criteria (P < 0·001). There was no significant difference in the prevalence of obesity between both sexes according to each of three BMI criteria. There was no clear trend in the prevalence of thinness across ages according to the China or IOTF definition (both P > 0·05), whereas an upward trend was observed for thinness in boys according to the IOTF definition (Pfor trend <0·05). In contrast, the prevalence of thinness tended to decrease with increasing age in girls according to the IOTF definition and in total sample according to the WHO definition (Pfor trend <0·05).

CONCLUSIONS

Among Tibetan adolescents, the prevalence of overweight and obesity is relatively low, while the prevalence of thinness is high, especially in boys. These data suggest urgent attention is needed to control adolescent thinness in Tibet.

Association of abdominal obesity and high blood pressure with left ventricular hypertrophy and geometric remodeling in Chinese children

BACKGROUND AND AIMS

Many studies have examined the association between overweight or obesity assessed by body mass index and left ventricular hypertrophy (LVH) in children or adolescents, but only few studies have assessed the relation with abdominal obesity in children. This study aimed to assess the association of abdominal obesity assessed by waist circumference (WC), high blood pressure (BP) and their joint effect on LVH and left ventricular (LV) geometric remodeling in Chinese children.

METHODS AND RESULTS

Data were from a cross-sectional survey of 1319 Chinese children aged 6-11 years who had undergone cardiac ultrasound. Compared with normal WC, the adjusted odds ratios (ORs) for abdominal obesity were 6.78 (95% confidence interval [CI] 3.77-12.16) for LVH, 2.80 (1.55-5.05) for CR, 5.43 (2.84-10.39) for EH, and 20.05 (4.46-90.08) for CH, respectively. Compared with children with both normal WC and normal BP, the adjusted ORs for those with abdominal obesity and normal BP were 6.98 (3.71-13.10) for LVH, 2.87 (1.47-5.60) for CR, 5.52 (2.70-11.26) for EH, and 15.20 (4.51-78.13) for CH. The adjusted ORs for those with abdominal obesity and high BP were 7.12 (3.27-15.50) for LVH, 4.71 (2.04-10.85) for CR, 7.49 (3.23-17.40) for EH, and 8.65 (1.32-56.89) for CH. The ORs for those with high BP and normal WC were not significant for these cardiac outcomes (P > 0.05).

CONCLUSIONS

LVH and LV geometric remodeling were associated more strongly with abdominal obesity than with high BP in Chinese children, stressing the need to prevent childhood abdominal obesity for reducing cardiac risk.

Utility of Three Adiposity Indices for Identifying Left Ventricular Hypertrophy and Geometric Remodeling in Chinese Children

BACKGROUND

Previous studies have shown that waist-to-height ratio (WHtR) performed similarly well when compared to body mass index (BMI) and waist circumference (WC) for identifying cardiovascular risk factors. However, to our knowledge, the performance of these three adiposity indices for identifying left ventricular hypertrophy (LVH) and left ventricular geometric (LVG) remodeling in youth has not been assessed. We aimed to determine the utility of BMI, WC and WHtR for identifying LVH and LVG in Chinese children.

METHODS

This study included 1,492 Chinese children aged 6-11 years. Adiposity indices assessed were BMI, WC and WHtR. LVH and high relative wall thickness (RWT) were defined using sex- and age-specific 90th percentile values of left ventricular mass index and RWT, respectively, based on the current population. LVG remodeling included concentric remodeling (CR), eccentric hypertrophy (EH) and concentric hypertrophy (CH), which was defined based on the combination of LVH and high RWT.

RESULTS

The magnitude of association of central obesity defined by WHtR with LVH [odds ratio (OR) =10.09, 95% confidence interval (CI) =6.66-15.29] was similar with general obesity defined by BMI (OR=10.49, 95% CI=6.97-15.80), and both were higher than central obesity defined by WC (OR=6.87, 95% CI=4.57-10.33). Compared with BMI, WHtR had better or similar predictive utility for identifying LVH, EH, and CH [the area under the curve (AUC): 0.84 vs. 0.79; 0.84 vs. 0.77; 0.87 vs. 0.88, respectively]; WC had worse or similar discriminatory utility with AUCs of 0.73, 0.70, 0.83, respectively.

CONCLUSION

WHtR performed similarly or better than BMI or WC for identifying LVH and LVG remodeling among Chinese children. WHtR provides a simple and convenient measure of central obesity that might improve the discrimination of children with cardiac structural damage.

Relationship Between National Economic Development and Body Mass Index in Chinese Children and Adolescents Aged 5-19 From 1986 to 2019

Obesity represents a major risk factor for population health. No studies have evaluated how economic expansion impacts the prevalence of obesity. The purpose of this study was to assess the relationship between national economic development and body mass index (BMI) in Chinese children and adolescents. Data of mean BMI in children and adolescents aged 5-19 from 1986 to 2019 were extracted from an international database of cardiometabolic risk factors. Chinese economic development was quantified by the gross domestic product (GDP), which was extracted from the International Monetary Fund. The relationships between GDP and BMI were assessed in 1-year age groups for ages 5-19 years. In addition, the linear regression from the main data and estimated GDP growth allowed the projections of mean BMI for each age group between 2020 and 2025. The results suggest there was a linear increase in BMI over years, which means that there has been a steady increase in BMI over the economic expansion. Overall, 97% of the variance (Pearson correlation coefficient) of BMI in boys can be explained by the GDP expansion, and the same pattern (98% of the variance) occurred in girls. Projected mean BMI were provided for constructing future national strategies to prevent overweight and obesity in youth. In conclusion, BMI in children and adolescents aged 5-19 trended upwards between 1986 and 2019. Our analyses for the first time suggest that globalization has a major impact on BMI in China. Economic expansion was highly predictive of BMI increases.

Stunting and Combined Overweight with Stunting among Schoolchildren in Kuwait: Trends over a 13-Year Period

OBJECTIVES

This study aimed to investigate the sex- and age-specific trends of stunting and combined overweight with stunting among schoolchildren over a 13-year period in Kuwait.

SUBJECTS AND METHODS

The Kuwait Nutrition Surveillance System objectively measured the height of 172,573 schoolchildren (5-19 years) over a 13-year period (2007-2019). Data on gender and date of birth were extracted from school records. Stunting was defined as height 2 standard deviations (SD) below the World Health Organization growth reference median. Logistic regression models were used to examine the trends of stunting over the study period while stratifying by gender.

RESULTS

In males, the prevalence of stunting increased from 2.46% in 2007 to 4.18% in 2019 (p for trend <0.001). In females, the prevalence of stunting fluctuated but remained around 3.80% in both 2007 and 2019. The odds of stunting significantly increased in the period 2017-2019 compared to the period 2007-2010 among males, adjusted odds ratio (AOR) 1.04 (95% confidence interval [CI]: 1.14-1.76); p = 0.009, but not females, AOR 0.89 (95% CI: 0.73-1.07); p = 0.176. Although not statistically significant, there was a tendency for the odds of combined overweight with stunting to increase in males, AOR 1.65 (95% CI: 0.90-3.04); p = 0.087, but not females, AOR 1.13 (95% CI: 0.88-1.45); p = 0.248.

CONCLUSION

Although the prevalence of stunting and combined stunting with overweight is low, there is an emerging upward trend in schoolboys that warrants further investigation and monitoring. This highlights the need for gender-specific interventions to reduce nutritional abnormalities in high-income countries in the Middle East countries like Kuwait.

Growing fast food consumption and obesity in Asia: Challenges and implications

It is widely believed that better access to fast food (FF) outlets increases FF consumption and thus the risk of obesity; yet, thus far, there are limited results to support this conclusion in Asian countries. A recent study by Hall and his colleagues (in press) examined the cross-sectional relationship between FF restaurant density and the likelihood of being overweight or obese among 1388 female Filipino migrant workers living in Macao, China. It found that FF restaurant density within a 0.5-mile buffer zone around one's home was significantly associated with a 7% increase (95% CI: 1%-14%) in the odds of being overweight or obese in this population. Based on these findings, the authors suggested improving access to healthy foods as one of the means to fight the obesity epidemic. The current article examines literature 1) on the relationship between obesity, FF consumption, and access to FF outlets; 2) on different measures of access to FF outlets; 3) on potential confounders and effect modifiers such as neighborhood deprivation and transportation; and 4) on challenges and implications for researchers and policymakers. Considering the growing consumption of FF and obesity rates in many countries especially in developing countries, it is important to regulate the FF industry and help consumers improve their related knowledge and behaviors. We also recommend that government policies abate obesogenic environments and thus curb the obesity epidemic in the future.

A 3-year Longitudinal Study of Pocket Money, Eating Behavior, Weight Status: The Childhood Obesity Study in China Mega-Cities

The associations between children’s pocket money and their eating behaviors and weight status have not been examined using longitudinal data in China. Examined child and parental factors associated with children’s pocket money, and longitudinal effects of pocket money on children’s eating behaviors and weight status. Data were collected in 2015, 2016, and 2017 from 3261 school-age children and their parents in mega-cities across China (Beijing, Shanghai, Nanjing, Xi’an, Chengdu). Children’s weight, height, and waist circumference were measured; pocket money and eating behaviors were self-reported. Mixed effect models were used. Older children received more pocket money than younger children (incident rate ratio (IRR) = 1.21, 95% confidence interval (CI): 1.15, 1.26). Fathers gave their children more pocket money than mothers did (IRR = 1.22, 95% CI: 1.16, 1.30). Children with fathers having ≥ college education received more pocket money than the others did (IRR = 1.20, 95% CI: 1.04, 1.40). Some nutrition-related parenting behaviors and attitude were also associated with children’s pocket money. Compared with children receiving no weekly pocket money, those having 1–10 or 10–30 or >30-yuan weekly pocket money were 12.0–136% more likely to consume unhealthy foods and were 66–132% more likely to be overweight or obese. Some child and parental factors were associated with children’s pocket money, which increased risks of having unhealthy eating behaviors and being overweight and obese.

Does Dietary Diversity Reduce the Risk of Obesity? Empirical Evidence from Rural School Children in China

Childhood and adolescence overweight and obesity have implications for both health consequences and economic burden. Although it has been an emerging public health problem for primary school children in rural China and the importance of the diet–health link has been stressed for many years, rigorous analysis of the dietary diversity and obesity among children is rare. To clarify this issue, this study provides a better understanding of the functional linkage between dietary diversity and obesity by analyzing data from nearly 8500 rural primary students (aged from 10 to 13 years old) covering three provinces in China. Our estimation results show that there is a significantly negative correlation between dietary diversity and the probability of being overweight among primary students. In particular, for subgroups with higher dietary diversity, the negative correlation between dietary diversity and the incidence of overweight or obesity is stronger, and the absolute value of the coefficient is greater. The results also suggest that the increase in the consumption frequency of all dietary categories can significantly lead to a lower proportion of overweight. Thus, we conclude that higher dietary diversity can help to lower the risk of overweight and obesity among primary school children, presumably through increasing the daily frequency of food intakes and developing a more diverse dietary pattern.

Ethnicity, socioeconomic status and the nutritional status of Chinese children and adolescents: Findings from three consecutive national surveys between 2005 and 2014

BACKGROUND

Economic development has brought rapid shifts in the food environment of Chinese children and adolescents.

OBJECTIVES

To assess the changes in childhood nutritional status across ethnic groups and economic status from 2005 to 2014.

METHODS

664 094 Chinese Han and 224 151 ethnic minority children and adolescents aged 7 to 18 years were assessed in three national cross-sectional surveys (2005, 2010 and 2014). Gross domestic product (GDP) per capita of each ethnic group was categorized into four strata of socioeconomic status. To assess ethnic disparities at each time point, we used logistic regression to estimate the prevalence odds ratios (OR) for thinness, overweight and obesity in the 24 ethnic minority groups vs Han Chinese.

RESULTS

Children in the two upper economic strata (over about US$4000 GDP per capita) had a high prevalence of overweight and obesity, while those in the two lower economic strata (below US$4000 GDP per capita) had a high prevalence of thinness. From 2005 to 2014, the prevalence of thinness decreased from 18.6% to 13.1% in Han children, and from 20.4% to 17.1% in ethnic minority students. At the same time, the prevalence of overweight and obesity increased from 10.4% to 17.7% in Han children, and from 4.3% to 9.2% in ethnic minority students, respectively.

CONCLUSIONS

A rapid nutritional transition has occurred from 2005 to 2014 with shifts from thinness to overweight and obesity in both Han and ethnic minority children and adolescents, reflecting local GDP per capita.

Comparison of growth and nutritional status of Chinese and Japanese children and adolescents

BACKGROUND

The difference in growth and nutritional status, both important indices of population quality, between Chinese and Japanese children and adolescents is unknown.

AIM

This study aimed to compare growth and nutritional status between Chinese and Japanese children and adolescents.

SUBJECTS AND METHODS

The height-for-age and BMI-for-age distribution of 9,226 children and adolescents aged 7-18 years from China and Japan were described with the Lambda Mu and Sigma method. Wasting, overweight and obesity were evaluated based on BMI-for-age cut-offs of the 2007 WHO Child Growth Reference.

RESULTS

For boys, the overall average height, weight and BMI of Chinese participants were 3.0 cm, 4.8 kg and 1.2 kg/m² greater compared with Japanese participants, respectively; for girls, these were 4.6 cm, 3.9 kg and 0.6 kg/m², respectively. Compared with Japanese children, the 3rd, 50th and 97th percentiles of height-for-age, 1Z-score, and 2Z-score of BMI-for-age of Chinese children were greater, whereas the minus 2Z-scores of Chinese children were less. The prevalence of wasting, overweight and obesity among Chinese participants was greater.

CONCLUSIONS

Compared with Japanese children, Chinese children tended to be taller. The worrying burden of overweight, obesity and wasting was recognised among Chinese children.

Sociodemographic disparity in the nutritional status among children and adolescents in Zhejiang Province

OBJECTIVE

To explore the sociodemographic disparity in the nutritional status including BMI, vitamin D and vitamin A status among children and adolescents in Zhejiang Province.

METHODS

Weight, height serum 25-hydroxyvitamin D, and serum retinol were assessed in 2818 children and adolescents (6-17 years of age), using ten investigation sites in Zhejiang Province including urban and rural areas data from the China National Nutritional Study 2016-2017, which is a nationally representative cross-sectional study, to form provincial representative sample of Zhejiang Province. Sociodemographic disparity was explored.

RESULTS

The prevalence of low weight, eutrophic, overweight and obese were 6.7%, 70.4%, 11.6%, and 11.2%, respectively. Significant difference was observed on BMI between males and females (P < 0.05), and between urban and rural areas (P < 0.05). The prevalence of vitamin D deficiency, inadequacy, normal and appropriate were 1.8%, 34.9%, 46.4% and 16.9%, respectively. Significant difference was observed on the concentration of 25-hydroxyvitamin D (25(OH)D) both between genders and between living areas (P < 0.05). The prevalence of vitamin A deficiency, marginal deficiency and appropriate were 4.5%, 24.7%, and 70.9%, respectively. Significant difference was observed on the concentration of retinol between living area (P < 0.05).

CONCLUSIONS

Overweight and obesity, deficiency and inadequacy of vitamin D, deficiency and marginal deficiency of vitamin A were prevalent among children and adolescents. There were disparities between genders and between living areas on the nutritional status. Regional and sex-specific guidelines and public health policies for children and adolescent nutrition are needed.

Undernutrition is associated with change in severe dental caries

OBJECTIVES

To examine the association of baseline prevalence of thinness or stunting and the incidence of dental caries among preschool children in Liaoning Province, China.

METHODS

Children were recruited from 15 kindergartens in Liaoning Province. A total of 772 children were assessed at baseline and follow-up. The mean age of children at baseline was 50.82 months, and the median follow-up time was 10.12 months. Anthropometric measurement, dental caries, and questionnaire were assessed overtime, whereas only baseline questionnaire was used in the data analysis. z-Score for body mass index (BMI)-for-age, weight-for-age, and height-for-age were calculated using World Health Organisation (WHO) Child Growth Standards. Dental caries was assessed according to the fifth WHO Basic Methods for Oral Health Surveys. The presence of pulpal involvement, ulceration, fistula, and abscess (pufa) were used to indicate severe dental caries in deciduous teeth. A structured questionnaire mainly based on the fifth WHO Oral Health Surveys was used to collect sociodemographic and behavior data. Logistic regression was constructed to assess the association between change in severe dental caries and prevalence of thinness and stunting.

RESULTS

There was a positive association between prevalence of stunting and incidence of severe caries in the fully adjusted model [odds ratios 2.88; 95 percent confidence interval (CI): 1.01, 8.27]. Prevalence of thinness showed insignificant positive association with incidence of severe caries.

CONCLUSIONS

While undernutrition indicated by stunting appeared to be a risk factor for severe dental caries, it could also be a marker for other determinants of progress of dental caries including socioeconomic factors and lack of use of dental services.

Body mass index growth trajectories, early pubertal maturation, and short stature

BACKGROUND

Childhood body mass index (BMI) trajectory classes are rarely linked to early puberty risk, particularly among Chinese children. We estimated early puberty risk across BMI trajectory classes, investigated factors contributing to pubertal development, and examined differences in final adult height between children exhibiting early and nonearly pubertal maturation across the classes.

METHODS

The Taiwan Children Health Study recruited 10-year-old children in 2010 from 14 Taiwanese communities and resurveyed them at age 11, 12, and 18 years. The study comprised 3109 children (50.4% boys) with available data for BMI (age 6-11 years) and pubertal stages (age 11, 12, and 18 years).

RESULTS

Classes 1-4 were persistently healthy weight, rapid BMI growth, chronically overweight/obese, and early transient overweight/obese. Children in class 3 exhibited the highest risk of early pubertal maturation. Puberty genetic score, low sleep quality, and high fat-free mass collectively explained 15% of the variance in Tanner stages among class 3 children. Early pubertal maturation was considered to cause short and tall stature in boys and girls, respectively.

CONCLUSIONS

Modifying sleep quality and fat-free mass may reduce early puberty risk in children with chronic overweight/obesity. Vigorous physical activity may reduce adiposity and increase the final adult height in the children.

Sedentary Behavior Research in the Chinese Population: A Systematic Scoping Review

Background: The negative effects of sedentary behavior (SB) on public health have been extensively documented. A large number of studies have demonstrated that high prevalence of SB is a critical factor of all-cause mortality. Globally, the frequency of SB research has continued to rise, but little is known about SB in the Chinese population. Therefore, this review was conducted to scope the research situation and to fill the gaps related to the effects of SB in the Chinese population. Methods: Using a scoping review based on York methodology, a comprehensive search of published journal articles and grey literature was carried out through 12 databases. The literature research was conducted by two authors in July 2019, and included journal articles that targeted on the Chinese population were published between 1999 and 2019. The two authors screened the records independently and included those research topics related to SB in the Chinese population. Results: The number of included studies increased from 1 to 29 per year during the analyzed period, during which, a remarkable climb happened from 8 in 2013 to 19 in July 2019. Out of the 1303 screened studies, a total of 162 studies (81 English and 81 Chinese journal articles) met the inclusion criteria in this review. Most of the included studies (66.0%) reported the overall estimated prevalence of SB, in which, 43.2% of studies reported the average time of SB, and 40.0% of studies reported the cutoff point of SB. Besides this, 54.9% and 23.5% of studies focused on the outcomes and correlates/determinants of SB, and the proportions of studies based on testing the validation of measurement tools and on interventions were 3.7% and 4.9%, respectively. Nearly all of the reviewed articles used data from cross-sectional studies (75.9%) and longitudinal studies (13.6%), while intervention trials are less developed. The majority of the studies (64.8%) used self-reported surveys, and only 3.7% studies used device-based measurement tools. Furthermore, 35.8% of the included studies were focused on children and adolescents, while only a few studies investigated infants/toddlers and older adults. Both female and male were examined in most studies, and non-clinical populations were investigated in the context of SB in a relatively large number of studies. Conclusions: The number of research articles on SB in the Chinese population published per year has increased year by year, indicating a growing interest in this research area. More studies using population subgroup samples are needed, particularly among infants/toddlers, older adults, and clinical populations. To provide stronger evidence of the determinants and outcomes of SB, longitudinal studies using device-based measures of SB are required.

Secular Trends of the Impact of Overweight and Obesity on Hypertension in Yi People: Yi Migrant Study, 1996-2015

Background

Rising hypertension prevalence, coupled with increasing overweight and obesity rates, has been observed in Yi people. Moreover, the growing blood pressure level among Yi people was mostly attributable to the continuous increase of body mass index (BMI). However, little is known about the trend of association between them.

Methods

Consequently, we investigated the impact of overweight/obesity on hypertension over three periods (1996, 2007-2008, 2015) using data from Yi Migrant Study (n = 8749). The Yi Migrant Study incorporated three successive cross-sectional studies which were implemented by the same team with consistent protocols.

Results

Compared with period 1 (1996), the influence of overweight/obesity on hypertension risk significantly increased in period 2 (2007-2008) and period 3 (2015); relative excess risk due to interaction (RERI) was 1.59 (95% CI: 0.12, 3.05) and 1.41 (95% CI: 0.30, 2.78), respectively. Meanwhile, the overweight/obese population in period 3 did not show hypertension risk higher than that in period 2 (RERI = 0.15; 95% CI: -0.76, 1.07). Additionally, we observed a continuously growing trend of hypertension risk among normal weight Yi people.

Conclusions

During the past two decades, there was a significant increase in the association between overweight/obesity and hypertension in Yi people, whereas the increasing trend has leveled off in more recent years. These findings suggest that overweight/obesity and hypertension are becoming more epidemic comorbidity over time. Interventions to prevent hypertension should focus not only on the overweight/obese population, but also on those with normal weight.

Severe dental caries is associated with incidence of thinness and overweight among preschool Chinese children

Objective: To examine the association of incidence and baseline prevalence of severe dental caries with incidences of thinness and overweight among pre-school Chinese children.Materials and methods: A longitudinal study design was used. A total of 772 children recruited from 15 kindergartens in Liaoning Province who completed baseline and follow-up assessments were included. The age range of children at baseline was 24.6-71.1 months. BMI-for-age z-score was calculated to estimate incidence of thinness and overweight. Severe dental caries was indicated by pulpal involvement, ulceration, fistula or abscess (pufa). Baseline prevalence of severe caries included children with pufa ≥1, incidence included those who changed from pufa = 0 to ≥1 at follow-up. Logistic regression was constructed to assess the association of baseline prevalence and incidence of severe caries with each of incidence thinness and overweight.Results: Children with incidence of severe caries had higher odds for incidence thinness (OR: 4.08; 95% CI: 1.08, 15.41). Baseline prevalence of severe caries was not significantly associated with incidence thinness. Participants with severe caries at baseline had higher odds for incidence overweight (OR: 2.33; 95% CI: 1.17, 4.63). The relationship between incidence of severe caries and incidence overweight was insignificant.Conclusions: The findings suggest a U-shaped relationship between severe dental caries and both ends of anthropometric measures among pre-school Chinese children. The findings highlight the importance of integrating oral and general health promotion policies. Primary health care providers are encouraged to incorporate dental screening, counselling and referral for treatment for severe caries to promote appropriate growth and overall health of children.

Differences in Lifestyle Behaviours of Students between Inner Urban and Peri-urban High Schools: A Cross-Sectional Study in Chongqing, China

Background: Lifestyle behaviours of students from schools in different socioeconomic areas may be different. Few studies have investigated such topics in China. This study aimed to explore the differences in lifestyle behaviours between inner urban high school students (IUHSSs) and peri-urban high school students (PUHSSs). Methods: A cross-sectional survey based on a self-report questionnaire was administered among 1560 high school students (726 from inner urban high schools and 834 from peri-urban high schools) in Chongqing, China. Physical activity, sleep time, screen time and dietary behaviours were assessed according to a series of recommendations of Chinese guidelines. Results: No significant difference was found in meeting the recommendation for daily physical activity between IUHSSs and PUHSSs (7.6% vs. 6.8%, p > 0.05). PUHSSs were more likely to meet the recommendations of weekdays’ sleep time (14.9% vs. 5.4%, p < 0.001), weekdays’ and weekends’ screen time (85.4% vs. 76.7%, p < 0.001; 21.1% vs. 14.3%, p < 0.001), and had higher proportion of high-score group of dietary behaviours (58.6% vs. 36.4%, p < 0.001) than those of IUHSSs. IUHSSs were more likely to meet the recommendation of weekends’ sleep time (75.6% vs. 67.9%, p < 0.001) than that of PUHSSs. Conclusions: A low proportion met the recommendations of physical activity, weekdays’ sleep time and weekends’ screen time among high school students in Chongqing, China. Lifestyle behaviours may differ between inner urban and peri-urban high school students. Additional support or targeted health education should be provided by high schools to improve the lifestyle behaviours of students, especially in inner urban districts.

Associations Between Delivery Mode and Early Childhood Body Mass Index Z-Score Trajectories: A Retrospective Analysis of 2,685 Children From Mothers Aged 18 to 35 Years at Delivery

Objective: To investigate the association between cesarean delivery (CD) and trajectory patterns of age- and sex-specific body mass index (BMI) z-score in early childhood. Methods: A retrospective cohort study was conducted among 2,685 children whose maternal age at the time of birth was between 18 and 35 years, and birth data and anthropometric measurement data during their ages 3-60 months were collected. A group-based trajectory modeling approach was used to identify distinct BMI z-score trajectories, and multinomial logistic regressions were applied to estimate the associations among CD (both elective and non-elective combined), elective and non-selective CD, and BMI z-score trajectory classes. Results: Of the 2,685 participants, 46.5% (N = 1,248) were born by vaginal delivery (VD), 20.7% (N = 556) by elective CD, and 32.8% (N = 881) by non-elective CD. Five BMI z-score trajectory patterns were identified, and they were "increasing from moderate to high" (10.1%, n = 270), "increasing from mild to moderate" (34.2%, n = 919), "increasing from low to high" (10.5%, n = 283), "stable mild" (30.1%, n = 808), and "stable low" (15.1%, n = 405) groups. Compared with children delivered by VD, those who delivered by CD (both elective and non-elective combined), elective CD, and non-elective CD were associated with the "increasing from moderate to high" trajectory [odds ratio (OR) = 1.61, 95% confidence interval (CI): 1.13-2.29; OR = 1.64, 95%CI: 1.06-2.54; and OR = 1.59, 95%CI: 1.05-2.39, respectively] and were also associated with the "increasing from low to high" trajectory (OR = 1.60, 95%CI: 1.17-2.19, OR = 1.75, 95%CI: 1.16-2.63; and OR = 1.53, 95%CI: 1.00-2.34, respectively). Conclusion: Both elective and non-elective CD were associated with the risk of accelerated weight gain in early childhood.

Double Burden of Malnutrition: Examining the Growth Profile and Coexistence of Undernutrition, Overweight, and Obesity among School-Aged Children and Adolescents in Urban and Rural Counties in Henan Province, China

OBJECTIVE

To examine the gender, age, and region of residence in the anthropometric and nutritional profiles of children and adolescents aged 6-18 in Henan Province, China's third most populous province.

DESIGN

This cross-sectional study of the China National Nutrition and Health survey (2010-2013) used a multistage cluster sampling technique. The sample included Chinese schoolchildren and adolescents aged 6 to 18 years (1,660 boys and 1,561 girls). Multiple logistic regression models were used to estimate the associations between sociodemographic correlates and overweight or obesity and stunting. Setting. Nine districts/counties in Henan Province. Participants. 3,221 subjects completed the questionnaire. Sociodemographic information was obtained. Body weight and height were measured.

RESULTS

There were statistically significant regional differences in average height and weight for boys in all age groups. Girls followed the same trends except for height when 15-18 years old. The urban-rural residence differences were found in relation to prevalence of stunting and weight status. Subjects in poor rural areas (15.43%) and ordinary rural areas (15.34%) had higher rates of stunting compared to their urban counterparts. Prevalence of overweight or obesity was highest in big city areas (15.71%) and lowest in ordinary rural areas (6.37%). Being a boy (OR = 1.69, 95% CI = 1.314-2.143), living in a big city (OR = 2.10, 95% CI = 1.431-3.073), or in a small-medium city (OR = 2.28, CI = 1.606-3.247), or being in a younger age group was associated with being overweight or obese. In addition, being a boy, living in a big city, or in a small-medium city, or being younger in age meant they were less likely to be stunted.

CONCLUSIONS

A substantial dual burden of malnutrition among children and adolescents in Henan Province was revealed. The urban-rural differences in nutritional status were found. Stunting was more prevalent in rural areas than in urban. In contrast, while the rising problem of childhood and adolescent obesity still exists in the big city, we also found a great spike in obesity in small-medium cities. Evidence also indicated that boys were more likely to be overweight or obese. Our findings suggest that nutrition education, as well as environmental and policy interventions, is needed to target specific geographic regions.