Secular trends in height and weight for healthy Han children aged 0-7 years in China, 1975-2005

Comparative analysis of the growth and development differences of children and adolescents between developed and undeveloped urban and rural areas in China

OBJECTIVES

Our study use the height and weight data of Chinese students aged 7-18 years from 1985 to 2014 to investigate the inequality and changing trend of height and weight of children and adolescents in different regions.

METHODS

Our study extracted data from the 1985, 2000, and 2014 Chinese National Survey on Students' Constitution and Health (CNSSCH) for a comparative analysis of the height and weight of children and adolescents aged 7-18 years in a developed city (Shanghai) and an underdeveloped province (Guizhou). The coefficients of variation (CVs) of height and weight between urban and rural boys and girls were also calculated.

RESULTS

Since 1985, the height difference between urban and rural areas has decreased from 4.24 to 2.41 cm for boys and 3.72 to 1.99 cm for girls. The weight difference for boys and girls increased from 1.83 to 3.10 kg and from 0.97 to 1.80 kg, respectively. However, from 1985 to 2014, the height and weight differences between Shanghai and Guizhou increased. In addition, from 1985 to 2014, the coefficient of height variation was greater for rural students than urban students while the coefficient of weight variation was greater for urban students than rural students.

CONCLUSIONS

Although the difference between urban and rural areas has recently decreased, the difference between developed area (Shanghai) and underdeveloped area (Guizhou) has increased. In particular, the difference in height and weight between children in developed areas (Shanghai) and non-developed areas (Guizhou) has become larger since 1985-2014, rather than gradually decreasing over time.

Association of perinatal factors with suspected developmental delay in urban children aged 1-36 months - a large-scale cross-sectional study in China

BACKGROUND

Studies on perinatal risk factors and the developmental delay of children have been inconclusive and few studies have assessed the association between infants and toddlers' body mass index (BMI) and developmental outcomes.

METHODS

We conducted a cross-sectional study of children aged 1-36 months who had a routine physical examination in the child health departments of hospitals from March 2018 to November 2021 in 16 provinces, 4 autonomous regions and 2 municipalities directly under the central government by using the Infant Toddler Growth Development Screening Test (ITGDST). Normal children were defined as those with scores ≥ mean - 2 standard deviations (SD), while children with developmental delay were those with scores < mean-2SD in terms of overall development, gross motor, fine motor and language development. Binary logistic regression was used to analyze the risk factors of gross motor, fine motor, language and overall neurodevelopment.

RESULTS

After removing some provinces with a small sample size and children with incomplete data, 178,235 children with 12 complete variables were included in the final analysis. The rate of overall developmental delay was 4.5%, while 12.5% of children had at least one developmental delay aspect. Boys, parity, advanced maternal age, multiple birth, cesarean section, neonatal injury, family heredity history, microcephaly, abnormal BMI at birth and at physical examination after controlling the confounding of other factors had a significant effect on development delay (overall neurodevelopment, gross motor, fine motor or language development). Per capita gross domestic product was a protective factor for the children's neuropsychological development.

CONCLUSIONS

This study reveals significant associations of perinatal factors and BMI with developmental delay in the Chinese children aged 1-36 months, which may be crucial for early intervention.

Associations of sleep problems with asthma and allergic rhinitis among Chinese preschoolers

The aim of this study was to examine the associations of sleep problems with asthma and allergic rhinitis among Chinese preschoolers. This cross-sectional survey was conducted in Guangzhou, China. Children aged 3–6 years were recruited from 32 kindergartens in 7 administrative districts. Asthma, allergic rhinitis and sleep problems were evaluated using a valid questionnaire. Binary logistic regression models were employed to estimate the odds ratios (OR) and 95% confidence intervals (CI) for the associations of asthma and allergic rhinitis with short sleep duration, late bedtime and frequent nocturnal awakening. We included 4876 preschool children in the current analysis. Of these, 182 (3.7%) diagnosed as asthma, and 511 (10.5%) diagnosed as allergic rhinitis. Frequent nocturnal awakening was associated with asthma and allergic rhinitis, with adjusted OR were 1.49 (95% CI 1.05–2.13) and 1.59 (95% CI 1.27–1.99), respectively. Subgroup analysis showed the OR for frequent nocturnal awakening with asthma was higher in girls (1.68; 95% CI 1.02–2.78) than in boys (1.35; 95% CI 0.81–2.24), but the OR for frequent nocturnal awakening with allergic rhinitis were similar in girls (1.73; 95% CI 1.15–2.30) and boys (1.57; 95% CI 1.17–2.12). No significant associations of short sleep duration and late bedtime with asthma or allergic rhinitis were identified. Our data suggested that frequent nocturnal awakening was associated with asthma and allergic rhinitis among preschoolers, and the association of frequent nocturnal awakening with asthma differed by gender. Further studies are warranted to address the causal relationship between nocturnal awakening and asthma and allergic rhinitis.

Trends in urban/rural inequalities in physical growth among Chinese children over three decades of urbanization in Guangzhou: 1985-2015

BACKGROUND

Great growth inequalities between urban and rural areas have been reported in China over the past years. By examining urban/rural inequalities in physical growth among children < 7 years old over the past three decades from 1985 to 2015 in Guangzhou, we analyzed altering trends of anthropometric data in children and their association with economic development during the period of rapid urbanization in Guangzhou.

METHODS

The height, body weight and nutrition status of children under 7 years old were obtained from two successive cross-sectional surveys and one health surveillance system. Student's t-test, Spearman's rank-order correlation and polynomial regression were used to assess the difference in physical growth between children in urban and rural areas and the association between socioeconomic index and secular growth changes.

RESULTS

A height and weight difference was found between urban and rural children aged 0-6 years during the first two decades of our research (1985-2005), which gradually narrowed in both sex groups over time. By the end of 2015, elder boys (age group ≥5 year) and girls (age group ≥4 year) in rural areas were taller than their counterparts in urban areas (p < 0.05).The same trend could be witnessed in the weight of children aged 6 years, with a - 1.30 kg difference (P = 0.03) for boys, and a - 0.05 difference (P = 0.82) for girls. When GDP increased, the gap in boys' weight-for-age z-score (WAZ from 0.25 to 0.01) and height-for-age z-score (HAZ from 0.55 to 0.03) between urban and rural areas diminished, and disappeared when the GDP per capita (USD) approached 25,000. In either urban or rural areas, the urbanization rate and GDP were positively associated with the prevalence of obesity (all R > 0.90 with P < 0.05) and negatively correlated with the prevalence of stunted growth (all R < -0.87 with P < 0.05).

CONCLUSION

Growth inequalities gradually decreased with economic development and urbanization, while new challenges such as obesity emerged. To eliminate health problems due to catch-up growth among rural children, comprehensive intervention programs for early child growth should be promoted in rural areas.

Differences between WHO Growth Standards and China Growth Standards in Assessing the Nutritional Status of Children Aged 0-36 Months Old

Background: At present, whether to use the World Health Organization’s (WHO) growth standards or native growth standards to assess the nutritional status in a given population is unclear. This study aimed to compare the differences between the WHO’s growth standards and China’s growth standards in assessing the nutritional status of children aged 0~36 months. Methods: We used z-scores to evaluate the nutritional status of children. The weight-for-age z-scores (WAZs), length/height-for-age z-scores (LAZ/HAZs), and weight-for-length/height z-scores (WLZ/WHZs) were calculated using the WHO’s growth standards and China’s growth standards. MeNemar’s test was used to compare the nutritional status of children. Results: The results in this study showed that there were differences between the WHO’s standards and China’s standards in assessing children’s nutritional status except for stunting and obesity. The prevalence of underweight assessed using China’s standards was higher than when using the WHO’s standards (except when 3 and 36 months old). The prevalence of wasting was significantly higher when assessed using China’s standards than when using the WHO’s standards from 12 to 36 months. The prevalence of overweight was higher when assessed using the WHO’s standards from 3 to 8 months. Conclusions: Both the WHO’s and China’s growth standards are useful measures in assessing children’s nutritional status but with key significant differences. Therefore, caution should be taken in selecting appropriate measures in a given population.

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

OBJECTIVE

To analyse the secular trends in mean value and distribution of weight, height and weight for height in children under 7 years in developed regions in China.

DESIGN

Five repeated cross-sectional surveys were conducted using the same methods at the same sites during 1975-2015.

SETTING

Nine cities in northern, central and southern regions of China.

POPULATION

Healthy children under 7 years; the sample sizes were 94 496 in 1975, 79 177 in 1985, 79 152 in 1995, 69 760 in 2005 and 83 583 in 2015.

MAIN OUTCOME MEASURES

Weight and height were measured by the same methods in the five surveys.

RESULTS

The increasing trends in the mean value of weight, height and weight for height were observed and their distribution was found to have shifted upwards. There were unbalanced increments in various centiles and the relative increments in the 3rd centile of height for children under 7 years were larger than those in the 50th and 97th centiles. Although the relative increments in the 3rd centile of weight for children under 2 years were larger than those in the 50th and 97th centiles, the increments in the 97th centile for children older than 2 years became the largest compared with other centiles. The changes in each centile of weight for height were similar with those of weight. The annual increments of height and weight increased over time and were more significant between birth and 2 years of age for height and between ages 4 years and 6 years for weight. The per-decade increments in 1975-1985, 1985-1995 and 1995-2005 became larger, while those in 2005-2015 slowed down.

CONCLUSIONS

The rapid increasing trends of weight, height and weight for height had slowed down since 2005 in developed regions of China. The relative increments in the low centile of height were more significant, while the high centile of weight and weight for height increased more significantly in older children.

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

Background

Both child under- and over-nutrition are major global public health challenges. We aimed to examine thirty-year trends in physical growth, under- and over-nutrition in Chinese urban and suburban children between 1985 and 2015, and discuss implications for child health programmes.

Methods

A total of 610,785 urban and suburban children from birth to 7 years of age were collected from a series of large-scale national surveys in China. Height, weight and body mass index (BMI) Z-scores and prevalence of stunting, underweight, wasted and possible risk of overweight, overweight and obesity were calculated according to the World Health Organization (WHO) 2006 growth standards. The trends in the prevalence were tested across different survey years by Cochran-Armitage trend test.

Results

Rapid secular growth trend was observed in China over the past 30 years, but the trend showed a slowing sign in urban children in recent 10 years. The growth level of Chinese urban and suburban children surpassed the WHO 2006 growth standards in 2015. Between 1985 and 2015 the stunting, underweight and wasted prevalence decreased from 12.21, 4.44, 1.68 to 0.97%, 0.59, 0.87% for children under 5 years and from 12.69, 10.02, 3.41 to 0.42%, 0.67, 2.17% for children aged 5- < 7 respectively; the possible risk of overweight prevalence increased from 6.51 to 12.57%, overweight from 0.70 to 3.48% and obesity from 0.17 to 0.86% for children aged 2- < 7 and the increasing rates of overweight and obesity prevalence in suburban children first outnumbered urban children in recent 10 years. The overweight prevalence overtook the wasted or underweight in children aged 2- < 7 in 2005 and onward.

Conclusion

Slowing secular height trend and overweight prevalence overtaking the wasted or underweight suggested child nutrition and health strategies should adjust swiftly and deliberately from primarily reducing under-nutrition prevalence to controlling rapid weight gain and promoting integrated early development.

Body weight and BMI percentiles for children in the South-East Asian Nutrition Surveys (SEANUTS)

OBJECTIVE

The present study aimed to (i) calculate body-weight- and BMI-for-age percentile values for children aged 0·5-12 years participating in the South-East Asian Nutrition Survey (SEANUTS); (ii) investigate whether the pooled (i.e. including all countries) SEANUTS weight- and BMI-for-age percentile values can be used for all SEANUTS countries instead of country-specific ones; and (iii) examine whether the pooled SEANUTS percentile values differ from the WHO growth references.

DESIGN

Body weight and length/height were measured. The LMS method was used for calculating smoothened body-weight- and BMI-for-age percentile values. The standardized site effect (SSE) values were used for identifying large differences (i.e. $\left| {{\rm SSE}} \right|$ >0·5) between the pooled SEANUTS sample and the remaining pooled SEANUTS samples after excluding one single country each time, as well as with WHO growth references.

SETTING

Malaysia, Thailand, Vietnam and Indonesia.

SUBJECTS

Data from 14 202 eligible children.

RESULTS

The SSE derived from the comparisons of the percentile values between the pooled and the remaining pooled SEANUTS samples were indicative of small/acceptable (i.e. $\left| {{\rm SSE}} \right|$ ≤0·5) differences. In contrast, the comparisons of the pooled SEANUTS sample with WHO revealed large differences in certain percentiles.

CONCLUSIONS

The findings of the present study support the use of percentile values derived from the pooled SEANUTS sample for evaluating the weight status of children in each SEANUTS country. Nevertheless, large differences were observed in certain percentiles values when SEANUTS and WHO reference values were compared.

Physical growth and diets of school children: Trends from 2001 to 2015 in rural West Java, Indonesia

OBJECTIVES

This study aimed to assess changes in physical growth and diets of school children in rural West Java, Indonesia, between 2001 and 2015, a period of rapid socioeconomic change.

METHODS

In 2001 and 2015, anthropometric measurements (height, weight, mid-upper arm circumference, skin-fold thickness), food consumption surveys, and questionnaires on socioeconomic status were completed by fourth-grade school children in a rural village in West Java.

RESULTS

Height increments of 5.9 cm for boys and 4.7 cm for girls during this 14-year period were calculated as 4.21 cm per decade for boys and 3.36 cm per decade for girls, which is equivalent to height increments observed during rapid economic development periods in other countries. Weights also increased by 3.8 kg for boys and 2.0 kg for girls during this period. Variations in weight status significantly increased in 2015; while 98% of the children were within the 'normal' range in 2001, the prevalence of overweight increased from 2.4% in 2001 to 13.7% in 2015 and that of thinness was 4.3% in 2015. Energy, protein, and fat intakes significantly increased in 2015. In 2015, a significant correlation between nutritional intake and weight status was observed, especially among boys.

CONCLUSIONS

Socioeconomic changes between 2001 and 2015 caused increased heights and weights and greater variation in weight status, especially among boys.

Secular trends in height, weight and body mass index of primary school children in Turkey between 1993 and 2016

BACKGROUND

The aim of the study was to analyze the secular trends in height, weight and body mass index (BMI) of children in a Turkish primary school in a 23-year time interval.

METHODS

The height, weight and BMI of 1099 children between 7 and 15 years old were measured. Data were compared to those of children of the same ages from previous measurements carried out in 1993 (867 children) and in 2003 (1214 children) in the same school. The changes in weight, height and BMI were determined and analyzed statistically.

RESULTS

Weight increments between 7.7 and 16.2 kg/23 years and height increments between 1.1 and 8.3 cm/23 years were observed in boys. For girls, weight increments between 6.5 and 13.4 kg/23 years and height increments between 1.3 and 7.2 cm/23 years were indicated. Usually, there were significant height increments between 1993 and 2016 in both genders. However, there were no significant differences in height between 2003 and 2016 for all age groups. Furthermore, there were significant differences in BMI measurements in all age and gender groups between 1993 and 2016.

CONCLUSIONS

The secular ascending trend in height seems to stop between 2003 and 2016; however, increments in weight and mean BMI tend to continue in Turkish primary school children and adolescents.

Narrowing urban-suburban rural disparities in physical growth among children in China: findings from the 5th national survey in 2015

BACKGROUND

Previous studies have reported a narrowing tendency in urban-suburban rural differences for height, but almost no tendency of narrowing for weight in Chinese children between 1975-2005.

AIM

To examine urban-suburban rural disparities for both height and weight in a recent 10-year period.

SUBJECTS AND METHODS

A representative sample of 161,643 children under 7 years old was obtained from the 5th national survey conducted in urban and suburban rural areas of the nine cities in China in 2015. Trends in urban-suburban rural differences were assessed from 1975-2015.

RESULTS

Generally, urban boys and girls were taller or heavier than their suburban rural counterparts. By 2015, there were almost no obvious differences for urban-suburban rural height differences for children under 3. Urban-suburban rural weight differences narrowed sharply in the 10-year period. There were no obvious differences for urban-suburban rural height differences among the 3rd, 50th and 97th percentiles; however, the weight differences at the 97th percentile were larger than at the 50th percentile for children over 3.

CONCLUSION

The narrowing urban-suburban rural disparities in China suggest the physical growth inequality may be eliminated, along with the sustained improvement of socioeconomic status and the acceleration of urbanisation process in suburban rural areas.

Height inequalities and their change trends in China during 1985-2010: results from 6 cross-sectional surveys on children and adolescents aged 7-18 years

Background

Great health inequalities have been reported in China over the past few years. Height has been used as an important parameter of health and it may also be distributed unequally in different regions. By studying height data of Chinese children and adolescents aged 7 to 18 years, we analyze height inequalities and their change trends during 1985–2010.

Methods

On the base of data from 6 successive cross-sectional surveys of the Chinese National Survey on Student’s Constitution and Health(CNSSCH) conducted in 1985,1991,1995,2000,2005 and 2010, we calculated difference of height for children and adolescents aged 7–18 years in different regions. Coefficients of Variation (CVs) of height were computed in urban and rural areas during 1985–2010.

Results

Great height difference existed between urban and rural, eastern and western, Shanghai and Guizhou children and adolescents aged 7–18 years. The urban-rural difference averagely decreased from 4.24 cm to 2.85 cm for boys and 3.72 cm to 1.31 cm for girls since 1985. Urban-rural difference tend to be more obvious in the poorer provinces, which has short mean statures. From 1985 to 2010, height difference became larger in eastern-western and Shanghai-Guizhou which represented the comparison between the richest and poorest regions. We also found there was a larger height inequality in rural areas compared with that in urban areas, and difference in rural subjects increased greater than their urban peers in eastern-western and Shanghai-Guizhou.

Conclusions

There were obvious height inequalities in China and the urban-rural difference narrowed, while increasing differences happened between regions with different socioeconomic levels especially in their rural residents. More attention should be paid to these differences and policies and strategies should be developed to reduce inequalities in height.

Electronic supplementary material

The online version of this article (doi:10.1186/s12889-017-4402-9) contains supplementary material, which is available to authorized users.

The 5th national survey on the physical growth and development of children in the nine cities of China: Anthropometric measurements of Chinese children under 7 years in 2015

OBJECTIVES

To describe the physical growth of healthy children under 7 years in China based on the latest national survey and provide more data for revising growth reference and monitoring the impact of social development on children's health and growth.

METHODS

In the cross-sectional survey, 161,774 healthy children under 7 years were selected by multistage stratified cluster sampling method in nine cities of China. According to the geographical location, the nine cities were divided into northern, central and southern regions, and each city included urban and suburban areas. Anthropometric measurements were obtained on the spots and other related information was collected with questionnaires.

RESULTS

There were slight urban-suburban difference and obvious regional difference in anthropometric measurements in China. Comparison with the 4th NSPGDC in 2005, measurements increased 0.1-1.1 kg in weight, 0.5-1.8 cm in height in urban areas (except children under 3 years) and 0.1-2.5 kg in weight, 0.2-3.8 cm in height in suburban areas. The urban-suburban difference of those measurements became smaller than 10 years ago, but their regional difference persistently exist. Chinese children were 0.36 SD in weight, 0.43 SD in height in urban areas and 0.30 SD in weight, 0.30 SD in height in suburban areas higher than WHO standards.

CONCLUSIONS

Physical growth of children under 7 years old was undergoing a slowly positive secular trend during the latest decade in more economically developed regions of China. Urban-suburban difference of those measurements became smaller, while their regional difference persistently exist. Chinese healthy children under 7 years in nine cities was taller and heavier than WHO standards.

SECULAR CHANGES IN BIRTH WEIGHTS AND WOMEN’S BODY SIZE IN KRAKÓW AND POZNAŃ (POLAND) DURING THE LAST CENTURY

Changing socioeconomic conditions over the last century have left their mark on neonatal size and final body size of individuals born in those days. The main aim of this study was to investigate how the historical, political and economic changes occurring from the late 19th century to the 2000s have affected the birth weight of newborns. Additionally, changes in weight and body height in the case of young women (potential mothers) were analysed. Data were from two cities in Poland (Kraków and Poznań) covering 15,884 newborns and 3612 women aged 18 years, derived from 1900 to 2010. Despite short-term fluctuations, the results showed significant increasing trends in all studied features. Changes in birth weight were similar in both cities: in Kraków it increased by 184 g (males) and 206 g (females), and in Poznań by 216 g (males) and 120 g (females). Changes in women’s body size were also significant, but the level was different depending on place of residence. In the last century, women’s body height increased by 8.2 cm in Kraków and by 10.2 cm in Poznań, and their body weight increased by 1 kg and 5 kg respectively. The considered period covered the years of socioeconomic change that occurred as a result of the political system transformation. Crises, periods of prosperity and other factors that determine standard of living and health care have influenced the development of the Polish population’s physical features.

Changes in weight, length, head circumference, and ponderal index at birth of healthy term newborns in nine cities in China during the period of rapid social development 1985-2005

The changes in the anthropometric parameters at birth of healthy singleton term newborns in nine cities in China were analyzed by means of the data collected in three large-scale cross-sectional physical growth surveys in 1985, 1995, and 2005 (n=6660, 7109 and 6144). Between 1985 and 2005, average increases in body weight (BW), body length (BL), ponderal index (PI), and head circumference (HC) of newborns were statistically significant: 107g, 0.2cm, 0.6kg/m(3) and 0.4cm, respectively. The relative increase in BW was more than that in BL (3.4% vs 0.4%) in the last two decades, leading to an increase in PI. The distribution of birth size shifted slightly to the right, and the proportion of macrosomia increased from 3.2% in 1985 to 3.4% in 1995 and to 4.3% in 2005. The increases in BW and PI and the increase in rate of macrosomia are concerns from public health perspectives.

Socioeconomic development and secular trend in height in China

The objective of this study was to examine the effect of socioeconomic development on secular trend in height among children and adolescents in China. Body height and spermarcheal/menarcheal ages were obtained from two periodic large-scale national representative surveys in China between 1975 and 2010. Chinese socioeconomic development indicators were obtained from the United Nations world population prospects. The effects of plausible determinants were assessed by partial least-squares regression. The average height of children and adolescents improved in tandem with socioeconomic development, without any tendency to plateau. The increment of height trend presented larger around puberty than earlier or later ages. The partial least-squares regressions with gross national income, life expectancy and spermarcheal/menarcheal age accounted for increment of height trend from 88.3% to 98.3% for males and from 82.9% to 97.3% for females in adolescence. Further, through the analysis of the variable importance for projection, the contributions of gross national income and life expectancy on height increment were confirmed to be significant in childhood and adolescence, and the contribution of spermarcheal/menarcheal age was superior to both of them in adolescence. We concluded that positive secular trend in height in China was significantly associated with socioeconomic status (GNI as indicator) and medical and health conditions (life expectancy as indicator). Earlier onset of spermarche and menarche proved to be an important role in larger increment of the trend over time of height at puberty for a population.

Length and height percentiles for children in the South-East Asian Nutrition Surveys (SEANUTS)

OBJECTIVE

Health and nutritional information for many countries in the South-East Asian region is either lacking or no longer up to date. The present study aimed to calculate length/height percentile values for the South-East Asian Nutrition Survey (SEANUTS) populations aged 0·5-12 years, examine the appropriateness of pooling SEANUTS data for calculating common length/height percentile values for all SEANUTS countries and whether these values differ from the WHO growth references.

DESIGN

Data on length/height-for-age percentile values were collected. The LMS method was used for calculating smoothened percentile values. Standardized site effects (SSE) were used for identifying large or unacceptable differences (i.e. $\mid\! \rm SSE \!\mid$ >0·5) between the pooled SEANUTS sample (including all countries) and the remaining pooled SEANUTS samples (including three countries) after weighting sample sizes and excluding one single country each time, as well as with WHO growth references.

SETTING

Malaysia, Thailand, Vietnam and Indonesia.

SUBJECTS

Data from 14202 eligible children were used.

RESULTS

From pair-wise comparisons of percentile values between the pooled SEANUTS sample and the remaining pooled SEANUTS samples, the vast majority of differences were acceptable (i.e. $\mid\! \rm SSE \!\mid$ ≤0·5). In contrast, pair-wise comparisons of percentile values between the pooled SEANUTS sample and WHO revealed large differences.

CONCLUSIONS

The current study calculated length/height percentile values for South East Asian children aged 0·5-12 years and supported the appropriateness of using pooled SEANUTS length/height percentile values for assessing children's growth instead of country-specific ones. Pooled SEANUTS percentile values were found to differ from the WHO growth references and therefore this should be kept in mind when using WHO growth curves to assess length/height in these populations.

Physical growth of children and adolescents in China over the past 35 years

OBJECTIVE

To examine if economic development in China correlates with physical growth among Chinese children and adolescents.

METHODS

The height, body weight and physical activity level of children and adolescents aged 18 years and under, as well as dietary data, were obtained from seven large surveys conducted in China between 1975 and 2010. Chinese economic development indicators were obtained from the World Bank. Trends in body weight, height, economic data and diet were examined. Tests were conducted to check for correlations between height at 17 years of age and three indicators of economic development: gross domestic product, urbanization and infant mortality rate. Regional differences in physical growth were assessed.

FINDINGS

Between 1975 and 2010, the growth of children and adolescents improved in tandem with economic development. The largest increment in height was observed during the period of puberty. Regional inequalities in nutritional status were correlated with disparities in economic development among regions. Over the past two decades, undernutrition declined among children less than 5 years of age, but in 2010 underweight and stunting were still common in poor rural areas. A large increase in obesity was observed in both urban and rural areas, but especially in large cities and, more recently, in small and medium-sized cities and affluent rural areas.

CONCLUSION

The average weight of children and adolescents has been increasing progressively since the 1970s. Current strategies to combat both child undernutrition and obesity need to be improved, especially in poor rural areas.

Construction of a new growth references for China based on urban Chinese children: comparison with the WHO growth standards

Introduction

Growth references for Chinese children should be updated due to the positive secular growth trends and the progress of the smoothing techniques. Human growth differs among the various ethnic groups, so comparison of the China references with the WHO standards helps to understand such differences.

Methods

The China references, including weight, length/height, head circumference, weight-for-length/height and body mass index (BMI) aged 0–18 years, were constructed based on 69,760 urban infants and preschool children under 7 years and 24,542 urban school children aged 6–20 years derived from two cross-sectional national surveys. The Cole’s LMS method is employed for smoothing the growth curves.

Results

The merged data sets resulted in a smooth transition at age 6–7 years and continuity of curves from 0 to 18 years. Varying differences were found on the empirical standard deviation (SD) curves in each indicator at nearly all ages between China and WHO. The most noticeable differences occurred in genders, final height and boundary centiles curves. Chinese boys’ weight is strikingly heavier than that of the WHO at age 6–10 years. The height is taller than that of the WHO for boys below 15 years and for girls below 13, but is significantly lower when boys over 15 years and girls over 13. BMI is generally higher than that of the WHO for boys at age 6–16 years but appreciably lower for girls at 3–18 years.

Conclusions

The differences between China and WHO are mainly caused by the reference populations of different ethnic backgrounds. For practitioners, the choices of the standards/references depend on the population to be assessed and the purpose of the study. The new China references could be applied to facilitate the standardization assessment of growth and nutrition for Chinese children and adolescents in clinical pediatric and public health.

Eighty-year trends in infant weight and length growth: the Fels Longitudinal Study

OBJECTIVES

To investigate secular trends in weight and length growth from birth to 3 years of age in infants born from 1930 to 2008, and to assess whether these trends were associated with concurrent trends in pace of infant skeletal maturation and maternal body mass index.

STUDY DESIGN

Longitudinal weight and length data from 620 infants (302 girls) were analyzed with mixed effects modeling to produce growth curves and predicted anthropometry for infants born from 1930 to 1949, 1950 to 1969, 1970 to 1989, and 1990 to 2008.

RESULTS

The most pronounced differences in growth occurred in the first year of life. Infants born after 1970 were approximately 450 g heavier and 1.4 cm longer at birth, but demonstrated slower growth to 1 year of age than infants born before 1970. Growth trajectories converged after 1 year of age. There was no evidence that relative skeletal age, maternal body mass index, or maternal age together mediated associations between cohort and growth.

CONCLUSIONS

Recent birth cohorts may be characterized not only by greater birth size, but also by subsequent catch-down growth. Trends over time in human growth do not increase monotonically, and growth velocity in the first year may have declined compared with preceding generations.