Growth and development of children in China: achievements,problems and prospects

Xin-Nan Zong ·Hui Li

Growth ref lects the general condition of society,and is a measure of the nutritional and hygienic status of a population [1,2].Nutrition is one of the most important components of children’s well-being [3].The Chinese government attaches great importance to children’s health and development,with a clear statement and consistent practice for“Children are the future and hope of the motherland”.In the past decades,China has made outstanding progress in development goals related to reducing maternal and child mortality [4].In 1975,China launched its f irst national child growth survey,namely,the National Survey on Physical Growth and Development of Children (NSPGDC) [5].Thereafter,every 10 years,China conducts a new round of national surveys in the same survey cities,and f ive rounds of the NSPGDC were conducted between 1975 and 2015.To meet the development needs of different historical periods,some sub-projects were added to the 1985 NSPGDC and subsequent surveys (Fig.1).The NSPGDC series was the f irst large-scale national special survey on children’s growth,development and nutrition,with f ixed survey period (every 10 years),f ixed survey regions (nine cities of China) and f ixed survey method (design and content);and the data of any subsequent survey are comparable to previous survey data,which provides an important reference for developing national health strategies and the primary data for establishing growth standards and growth curves for Chinese children[6,7 ].

Fig.1 Framework of the National Survey on Physical Growth and Development of Children (NSPGDC) in China

Fig.2 Increments in height among children and adolescents between 1975 and 2014/2015.Data were from the NSPGDC and CNSSCH series.NSPGDC National Survey on Physical Growth and Development of Children,CNSSCH Chinese National Survey on Students’Constitution and Health

With the socioeconomic improvement after the introduction of market economic reforms in 1978,the physical growth of Chinese children showed a rapid positive secular trend [8].Continuous monitoring data from the NSPGDC series showed that child nutrition status has entered a new stage in urban areas of China,with a slowing secular height trend and overweight prevalence overtaking wasted or underweight prevalence [9].Overall,undernutrition is no longer the main concern for nutritional status of Chinese urban children.In 2021,China achieved the goal of eradicating absolute poverty,and the living standards in rural areas have greatly improved.The prevalence of undernutrition in rural and undeveloped regions of China is declining.Therefore,nutrition and health strategies for children should shift from a focus on reducing undernutrition prevalence to controlling rapid weight gain and promoting integrated early development.In this paper,we summarized the achievements of the past as well as current problems and challenges in China based on evidence from the NSPGDC series and several other large-sample studies in China over the past decades and shared experiences and lessons to emerging markets and developing countries.

Achievements

Continuous improvement of growth level

Data from the NSPGDC series showed that height and weight of children under 7 years presented a rapid increasing trend in urban and rural areas of China from 1975 to 2005 [10].Data from the Chinese National Survey on Students’ Constitution and Health (CNSSCH) showed a positive secular height trend in children aged 7—18 years in urban and rural areas of China from 1985 to 2010,with an overall average increase rates of 2.4 and 1.7 cm/decade for urban boys and girls and 3.1 and 2.4 cm/decade for rural boys and girls,respectively [11,12].However,data from the 2015 NSPGDC showed a slowing sign in the rapid increasing trend in children’s height under 7 years in Chinese cities between 2005 and 2015 [13].Data from the 2014 CNSSCH showed that the height in adolescents aged 18 years also had a slower increase during 2005-2014 compared with the increments during 1995-2005 [14].Figure 2 shows the average increments of height among children and adolescents between 1975 and 2014/2015,with total increments of 5.8 cm and 4.7 cm at age 3 years,11.5 cm and 11.5 cm at age 11 years and 5.6 cm and 3.6 cm at age 17 years for boys and girls,respectively.The improvement in growth level of children is mainly because the government has highlighted protection and promotion of children’s health as a major strategy and priority task,and is also consistent with the sustainable development of socioeconomic status in China over the past decades.Overall,Chinese children have been approaching their genetic growth potential in developed regions.

Steady decline in urban-rural differences in height

Data from the NSPGDC series showed that the urban-rural differences in height of children under 7 years continued to decrease from 1975 to 2015 [10,15],with differences of 2.9 cm in 1975,2.5 cm in 1985,2.1 cm in 1995,1.7 cm in 2005 and 0.3 cm in 2015 for boys aged 2 years;3.1 cm,2.8 cm,2.2 cm,1.7 cm and 0.2 cm for girls aged 2 years;4.9 cm,4.4 cm,3.6 cm,2.6 cm and 0.6 cm for boys aged 6 years;and 4.9 cm,3.8 cm,3.6 cm,2.4 cm and 0.4 cm for girls aged 6 years (Fig.3).Trend analysis of CNSSCH data showed that the urban-rural inequality in height of children aged 7—18 years narrowed between 1985 and 2014 [16],with differences of 4.1 cm in 1985,3.8 cm in 1995,3.7 cm in 2005 and 2.9 cm in 2014 for boys aged 7—12 years;4.6 cm,3.9 cm,3.3 cm and 2.4 cm for girls aged 7—12 years;5.3 cm,4.5 cm,4.0 cm and 2.5 cm for boys aged 13—15 years;3.3 cm,2.8 cm,2.4 cm and 1.8 cm for girls aged 13—15 years;3.4 cm,2.6 cm,2.2 cm and 1.4 cm for boys aged 16—18 years;and 2.4 cm,1.9 cm,1.8 cm and 1.3 cm for girls aged 16—18 years (Fig.3).Owing to the differences in social-economical levels between urban and rural areas,the growth level of urban children is usually higher than that of rural children [17].In China,the urbanrural gap in living conditions was a serious social problem;however,sub-urban/rural living conditions have greatly improved with the rapid development of the social economy and urbanization in the last two decades,and the growth level and nutritional status of sub-urban/rural children are rapidly catching up to those of urban children.Efforts should be continued to improve the living environment,food supply and healthcare in rural areas,especially in poor rural areas,to further reduce the urban-rural disparity in nutritional status.

Fig.3 Urban-rural differences in height among children and adolescents between 1975 and 2014/2015.Data were from the NSPGDC and CNSSCH series.a Boys;b girls.NSPGDC National Survey on Physical Growth and Development of Children,CNSSCH Chinese National Survey on Students’ Constitution and Health

Outstanding gain in height compared with the rest of the world

Trend analysis from the NSPGDC series showed that the growth level of Chinese urban children under 5 years has undergone a major change from lagging in 1995 and before,being close in 2005 to thereafter surpassing the WHO child growth standards [9,18].A longitudinal study of physical growth conducted in 2007-2008 showed that the growth potential of rural breastfed infants in China reached the WHO child growth standards [19].In 2011,Chinese urban children under 5 years of age were the tallest among 141 low and middle-income countries (LMICs),and Chinese rural children were ranked ninth among 141 LMICs with respect to rural height [17].A pooled analysis of height change in school-aged children and adolescents in 200 countries and territories worldwide showed that the largest gain in height occurred in Chinese population from 1985 to 2019 [20].For example,among emerging economies,the gain in mean height at age 19 years in China was larger than that in India by 3.5 cm for boys and 2.3 cm for girls.

Rapid decline in undernutrition

Data from the China Food and Nutrition Surveillance showed that the prevalence of stunting (Zscore <-2)declined from 33.4% to 10.5% and the prevalence of underweight (Zscore <-2) declined from 19.1% to 6.9% among children under 5 years from 1990 to 2005 [21].Data from the China National Nutrition and Health Survey showed that the prevalence of stunting (Zscore <-2),underweight (Zscore <-2) and wasting (Zscore <-2) in children under 5 years declined from 17.2% to 5.5%,from 8.7% to 3.2% and from 4.4% to 2.3% from 2002 to 2013,respectively [22,23].Sub-national data of China from the 2015 Global Burden of Disease Study illustrated that the disease burden caused by nutritional def iciencies among children under 5 years showed a downward trend from 1990 to 2015 [24].Data from a sub-project of the NSPGDC showed that the prevalence of short stature (<3rd percentile) was 1.9% in children under 7 years in nine cities of China in 2016 [25].A largesample survey in nine provinces of China illustrated that the prevalence of combined stunting and wasting decreased from 9.2% to 6.6% and from 5.5% to 4.2% for boys and girls aged 7—17 years from 2000 to 2018,respectively [26].Data from the 2014 CNSSCH showed that the prevalence of short stature (<3rd percentile) was 3.7% in children and adolescents aged 7—18 years across China in 2014 [27].Data from the 2019 CNSSCH showed that undernutrition in school-age children continued to improve compared with the 2014 CNSSCH [28].Chinese children have shown a shift in anthropometric measures,indicating a transition from undernutrition to over-nutrition over the past decades[29].Active intervention measures should be undertaken to steadily improve undernutrition,and also focus on obesity prevention and control among children and adolescents in China [26].Given the socioeconomic development and policy continuity in China,child undernutrition will remain at a low level for a long time.However,undernutrition remains a major public health problem among children in some vulnerable areas and subgroups [30,31],and sustainable child nutrition measures should be undertaken in rural areas,especially in poor rural areas.

Problems

Widespread epidemic of overweight and obesity

In the 1980s,there was no obesity epidemic in China [32,33].Since 1995,a marked increase in weight disproportionate to the height increase has occurred among Chinese children [33,34].The obesity prevalence in children under 7 years was 0.9% in 1986,which increased over 3.5 times from 1986 to 2016,reaching 4.2% (4.9% for boys and 3.6% for girls,Fig.4) in Chinese cities [35].The obesity prevalence among 7—18-year-old children and adolescents increased steadily during 1985—2014,with the annual increase rate ranging from 0.1% to 0.6%,and reached 8.4%(boys 11.1% and girls 5.8%,Fig.4) in 2014 [36].In recent years,overweight and obesity have presented a more rapid increase in rural areas than in urban areas [36,37] and have spread to small and medium-sized cities and affiuent rural areas [8].Data from the 2017 Physical Activity and Fitness in China exhibited a low prevalence of moderate—vigorous physical activity and a high prevalence of overweight and obesity in children and adolescents [38].Data from the China Health and Nutrition Survey showed that the overweight and obesity prevalence among children and adolescents aged 7—17 years in 16 provinces of China increased between 2000 and 2018 [39].A recent review further revealed that long-standing health problems (e.g.,mortality and malnutrition) have greatly improved in Chinese children,but non-communicable diseases have become epidemic [40].The current upward trend in the prevalence of childhood obesity is expected to continue.

Fig.4 Prevalence of obesity among children and adolescents between 1985/1986 and 2014/2016.Data were from the NSPGDC and CNSSCH series.NSPGDC National Survey on Physical Growth and Development of Children,CNSSCH Chinese National Survey on Students’ Constitution and Health

Regional inequalities in growth and nutritional status of children

China has a vast territory,with unequal social and economic conditions.Data from the NSPGDC and another large-sample survey showed that urban boys and girls were heavier and taller than their sub-urban and rural peers [41].The average height of urban children aged 7—18 years was highest in megacities followed by other large cities,and lower in moderate and small cities [11].The average height of rural children in the eastern China was highest,followed by central China and western China [12].In general,short stature is associated with lower socioeconomic position,and high body mass index (BMI) is associated with higher socioeconomic position [42].As China has been strictly implementing the national policy of eliminating poverty and achieving prosperity for all,the gap in height due to social-economical levels may continue to narrow in the future.However,on the other hand,children are generally taller in the northern areas and shorter in the southern areas,and the growth level in height of children in the coastal areas was generally higher than that in the inland areas [10,43].There was a high prevalence of short stature in rural,underdeveloped areas and in southwestern China [44].Considering the differences in geographical conditions and the fact that diet and living habits are difficult to change,the geographical inequality in height may exist for a long time and eventually stabilize as a relative difference in the future.

Prospects

Integrated obesity prevention and control policies and measures

The global prevalence of obesity in individuals aged 5—19 years increased from 0.9% in 1975 to 7.8% in 2016 in boys and from 0.7% in 1975 to 5.6% in 2016 in girls[45].The epidemic of childhood obesity is a serious global public health problem,and the situation in China is likely to be worse due to its large population [20,46,47].There are numerous studies on obesity prevalence and risk factors providing sufficient evidence.From a macro perspective,the growing burden of obesity is driven by economic developments,sociocultural norms,and policies that have shaped individual-level risk factors for obesity through urbanization,urban planning and built environments and food systems and environments.In terms of personal lifestyles,the incidence of obesity was related to an unhealthy diet (e.g.,excessive intake of animal-source foods,ref ined grains,high-sugar and high-fat foods),decreased physical activity with increased sedentary behaviors,and other individuallevel risk factors (e.g.,genetic susceptibility,obesogens,in-utero and early-life exposures and psychosocial factors)[48].Hence,obesity prevention and control have remained very challenging worldwide over the past decades [46].Currently,the Chinese government follows “Health in All Policies” and has set a goal of highlighting social responsibility for health.Instead of a lack of coordination among different sections,we recommend building high-quality,and population-based integrated childhood obesity prevention and control strategies,such as incorporating obesity prevention and control into all policies,establishing zero-level prevention from early childhood (even during pregnancy),advocating individual and family self-governing healthy weight,integrating family-based and school-based intervention strategies,and using taxes and industry regulations to change eating and drinking behaviors.We hope that future childhood obesity policies will be more efficient,scientif ic and sustainable.

Scientif ic evaluation of children’s growth status

Scientif ic evaluation of growth and health status is a precondition for improved health and functioning,and reduced disability.The following issues should be highlighted.First,the choice of which growth standards or references to use depends on the purpose of research or clinical practice.International growth charts and cutoffs may be used for population-based estimation for international comparisons.Physical growth in children varies across countries or regions.Since national growth charts and cutoffs are constructed from local real-world sample population,they should be f irst used for both population-based estimation and individual clinical use for diagnosis and management.In recent years,China has established its own growth charts and cutoffs,including national newborn growth standards (for 24—42 weeks of gestation) [7,49— 51],postnatal growth monitoring charts (from 24 weeks of preterm birth to 50 weeks) [52],national child growth standards (for 0—18 years) [53— 56],BMI cutoffs for overweight and obesity (for 2—18 years) [56,57] and waist circumference cutoffs for central obesity (for 3—18 years) [58,59].Second,various anthropometric variables maintain a dynamic,balanced development;each measure shows distinct relationships with specif ic aspects,and no single anthropometric measure appears to be sufficient for evaluating children’s growth and development,and related diseases.Researches are lacking on the associations of physical growth with other development and functions,such as psychological behaviors,physical f itness,bone health,bone maturity and puberty development.Extensive correlation researches and comprehensive assessment methods are needed.

Future perspectives

Children in China are experiencing lifestyle changes including rapid nutritional transition and a lack of physical activity,which has led to an alarming increase in overweight and obesity [38,60].According to the latest 2019 CNSSCH,the prevalence of overweight and obesity reached 23.4%,and the prevalence of obesity alone reached 9.6% in 2019.The prevalence of overweight and obesity among rural children and adolescents will exceed that of urban children and adolescents by 2025,and the prevalence of overweight and obesity will increase from 23.4% in 2019 to 32.7% in 2030,and the prevalence of obesity alone will increase from 9.6% to 15.1% [61].China is currently in stage 2 of the obesity transition but may soon enter stage 3,while the obesity prevalence among those with lower socioeconomic status surpassing that among those with higher socioeconomic status[62].The obesity epidemic in China has three features.First,the prevalence of overweight and obesity in Chinese children and adolescents is characterized by substantial geographic disparities and ongoing “urban-rural reversal” and “provincial reversal” trends [61,63].Hence,regional-specific obesity prevention and control strategies should be implemented.Second,the high prevalence of overweight and obesity among Chinese children and adolescents persists and obesity-related metabolic diseases will occur more frequently [64].More attention should be paid to obesity-related complications in children,adolescents and even adults [65].Third,only one in four Chinese children with overweight or obesity were taken for treatment by their parents [66].Parents may underestimate their child’s weight,so pediatricians and public health practitioners should identify those parents and inquire about their lifestyle and dietary habits [67,68].Parents and families need training on knowledge,attitude and practices for preventing and controlling their children’s overweight or obesity.Over the past four decades,the growth potential of Chinese children has been fully realized,and undernutrition is no longer a major health problem for Chinese children.These remarkable achievements are inextricably linked to China’s rapid socioeconomic development and its greatly improved living and health standards.However,China is in the midst of a growing childhood obesity epidemic that requires urgent action.Although risk factors for childhood obesity have not been fully understood and there are some differences in the reported factors across different periods,most of them have been observed and confirmed in numerous studies.Future research on childhood obesity should focus on the development,continuous improvement and implementation of prevention and control strategies.Childhood obesity and related comorbidities have been increasing rapidly,suggesting that in the process of reducing undernutrition,that is,at the early stages of the obesity epidemic,it may be possible to reduce the dramatic increase in obese children and adolescents if effective health education and comprehensive interventions are emphasized and implemented.In addition,growth and development inequalities and dual nutritional burden should be sufficiently addressed.

Author contributionsZXN contributed to conceptualization,methodology,data curation and writing of the original draft.LH contributed to conceptualization,supervision,reviewing and editing.All authors read,reviewed and approved the f inal manuscript as submitted.

FundingNone.

Data availabilityAll data generated or analyzed during this study are included in this published article.

Declarations

Conflict of interestNo f inancial or non-f inancial benef its have been received or will be received from any party related directly or indirectly to the subject of this article.The authors have no conf lict of interest to declare.