Secular changes are different in distinct subgroups of the growing population

The change of living conditions in East Germany after the German reunification in 1990 led to intensive secular changes in growth and development. Anthropometric data of height, weight, BMI and thickness of the subcutaneous fat layer are compared from two cross-sectional samples of German children and adolescents aged 6 to 18 years. The first sample was measured around 1989 and the second 10 years later around 1999. Both samples contain children and adolescents from the urban as well as from the rural population. The secular changes reported here are based on the comparison of medians of height, weight, BMI and subcutaneous fat layer thickness calculated for yearly age categories. Subsequently, medians of the 10% border categories are compared. These border categories contain the 10% smallest, lightest, slimmest or leanest subjects and the 10% tallest, heaviest, most corpulent or most obese subjects respectively of a yearly age category. The young generation shifted between 1989 and 1999 to a taller stature in the small as well as in the tall category. The secular pattern of measurements, which mark corpulence, is sex-specific and differs from that of length measurements. In general the light or lean subjects changed only little, however, there are clear age- and sex-specific changes in the upper border categories. Weight and BMI increased markedly in the upper border categories in young preadolescent children, but did not change much in adolescent boys of these category aged 15 and 16 and decreased in adolescent girls. Also the subcutaneous fat layer increased in the upper border category in preadolescent children, but decreased in adolescent boys and girls.     

Secular change in growth of native children and adolescents at high altitude Huancayo,Peru (3,280 meters)

Stature and weight of native children, adolescents, and adults at Huancayo, Peru (3,280 meters), were measured in 1977, 1978, and 1982 and compared with mean statures and weights reported in previous studies. The data indicate that in Huancayo there has been a secular increment in child stature, sitting height, and weight from 1937 to 1978–1982. The observed changes in stature are related to a proportionally greater increment in leg length relative to trunk length. It is concluded that the observed secular increase in body size reflects changes in the standard of living and a greater influx of nonnative populations, which are usually characterized by greater stature than natives.     

山东省儿童青少年生长发育20年变化趋势

为了解近20年来山东省儿童青少年生长发育的变化趋势, 本文利用山东省1985年、1995年和2005年学生体质调研资料, 分析了7—18岁儿童青少年生长的长期变化。20年间, 7—18岁身高平均增长6.27cm(城男)、5.02cm(城女)、7.62cm(乡男)、5.69cm(乡女); 体重平均增长9.97kg(城男)、6.02kg(城女)、7.96kg(乡男)、4.87kg(乡女)。BMI明显增长, 7—18岁平均增长2.57kg/m2(城男)、1.46kg/m2(城女)、1.71kg/m2(乡男)、0.93kg/m2(乡女)。发育水平上的城乡差别依然存在, 但身高的城乡差别逐步缩小, 体重的城乡差别明显扩大。下肢长指数(身高—坐高)的增长幅度大于坐高的增长幅度。总之,1985—2005年的20年间,山东省7—18岁儿童青少年在身高、体重、BMI和身材比例等方面都发生了较大变化。     

Can secular trends in child growth be estimated from a single cross sectional survey?

OBJECTIVE--To formulate and evaluate a new method to measure secular trends in child growth based on the cross sectional collection of heights of children and young adults. DESIGN--Trends in child growth obtained from comparison of two national surveys made with an interval of 15 years were compared with estimates obtained from comparison of height deficits of children and young adults in the more recent survey. SETTING--Brazil. SUBJECTS--Random sample of children (6 and 7 years old) and young adults (21 and 22 years old) living in Brazil in 1974 and 1989 (a total of 23,271 subjects in 1974 and 5479 in 1989). MAIN OUTCOME MEASURES--Increments in average heights of 6 and 7 year old children in a 15 year period. RESULTS--Mean height of 6 year old children increased 4.0 cm (boys) and 3.3 cm (girls) from 1974 to 1989. Similar results were obtained by subtracting, in the 1989 survey, mean height deficits found at ages 21 and 6 (3.8 cm for males and 3.5 cm for females). Positive changes in the mean height of 7 year old children could also be predicted by subtracting, in the 1989 survey, height deficits found at ages 7 and 22. CONCLUSIONS--Findings of this study support the hypothesis that secular trends in child growth can be estimated by comparing height deficits observed in children and young adults.     

Growth reference centiles and secular changes in Turkish children and adolescents

The purpose of the study is to develop current reference growth centiles for Turkish children and adolescents. A cross-sectional growth survey was conducted on 1.427 (709 boys and 718 girls) healthy schoolchildren aged 6-17 years in Ankara, the capital city of Turkey. As an indicator of socio-economic status, the occupation of the parents was recorded. Growth references of height, weight, body mass index (BMI), sitting height, iliospinal height, relative iliospinal height and relative sitting height were constructed by the LMS method. Sex differences, association of parental occupation with height and BMI standard deviation scores were assessed by analyses of variance. Results showed significant sexual dimorphism for height, weight, sitting height and iliospinal height (p<0.001). Significant effect of socio-economic background was found on height and BMI. The prevalence of overweight and obesity was found using the International Obesity Task Force (IOTF) reference criteria 22.4% and 5.6% in boys and 21.2% and 3% in girls. Present results demonstrated an increment during the last three decades in height, leg length and weight curves which is more prominent in boys, but not in the sitting height. This positive secular change appears to be a logical outcome of the gradual changes in nutrition, health care and education, and environmental and economic conditions.     

Secular changes in height, body weight, body mass index and pubertal development in male children and adolescents in Krakow, Poland

This study examined the secular changes in height, body weight, body mass index and pubertal development in male children and adolescents in Krakow (Poland) over the past 80 years, with an emphasis on the last decade (2000-2010). The survey of the population of Krakow is a continuation of observations conducted in that area for many years. The analysis aims to determine whether in the last decade Krakow still witnessed the secular trend, and what form the trend took. The body height and weight, and body mass index (BMI), of 1862 boys aged 3.5-18.5 years were analysed, against the background of a survey series from the years 1938 (N = 1801), 1971 (N = 2045), 1983 (N = 3124) and 2000 (N = 2328). The mean body height, in almost all age categories, was greater than in the past; however the final height over the last decade remained the same. The mean values of body weight and BMI increased, especially in the last decade. Also, an acceleration of puberty in boys was observed. The last 10 years saw an over 3-month decrease in the age of initial appearance of pubic hair in boys. In conclusion, the last decade saw cessation of the growing taller trend: maximum body height stabilized at approximately 179 cm, but weight and BMI increased. Also, a distinct acceleration of puberty was noticed. Lack of height increase, at the same time as weight gain and puberty acceleration, indicate a progressing developmental disharmony.     

达斡尔族中小学生体质发育现状及20多年来的变化

本文报道了6~18岁1993名达斡尔族学生8项体质指标(身高、坐高、体重、肩宽、骨盆宽、胸围、腰围和臀围)的测量结果,并计算了10项体质指数。结果发现,达斡尔族在我国属体质发育较高的民族,并表现为一定的城乡差异;20多年来达斡尔族学生身高、体重、胸围全面增长,男女生身高最大增长年龄均提前约1岁左右,男生高年龄组身高和身体充实度增幅较大,但女生变化不大且肩宽和骨盆宽呈下降趋势。提示达斡尔族青少年体质发育表现为以生长突增提前为主的生长长期趋势,但女生高年龄组身高增长不明显、身体充实度有待提高,应采取营养和锻炼等措施促进其生长发育水平全面提高。     

Impact of war on growth patterns in school children in Croatia

The objective of this paper is to present the growth patterns of school children in Osijek--the city which was exposed to severe attacks during the aggression on Croatia. The mean height and weight of Osijek schoolchildren aged 7 to 18 and the menarcheal age in girls in academic year 1995/96 were compared to the analogous data collected in 1980/81. The secular changes in height were heterogeneous. In older age groups from 12 in girls and 13 in boys, the mean height in 1995/96 increased markedly, whereas from 9 to 11 or 12, changes were undulating. In the youngest groups--at the age of 7 in both genders, and at 8 in boys, negative changes were observed. Markedly smaller height in this cohort was still pronounced in 1999/2000 when these children reached the age of 11. However, one year later (2000/01), at the age of 12, boys and girls caught up with their peers in the previous generations. These children during the war were approximately at the age of 2.5 to 4, a period when growth patterns are highly sensitive to adverse environmental influences. It might be possible that the emotional stress caused by a change of environment and separation from home, contributed to the deceleration of growth rate, i.e. the smaller height in a large part of childhood.     

Long-term changes in body weight, BMI, and adiposity rebound among children and adolescents in the Czech republic

The Czech Republic has undergone rapid political, social, and economic transformation since the late 1980s. While obesity rates among children and adolescents in the Czech Republic have been previously relatively low, this has changed in recent years. Across the past 50 years, body weight, body mass index (BMI)-for-age, and adiposity rebound (AR) (the time when a child reaches the lowest BMI before their BMI gradually begins to increase until adulthood) occurs earlier. The most dramatic changes have been observed among school-aged children, where BMI values have increased at the 50th, 90th, and 97th percentiles. In contrast, adolescent girls appear to be thinner than in the past. The analyses of weight-for-height percentiles indicated that the 50th percentile of the body weight among boys and girls remained similar in nearly all age categories across the past 50 years. Although the growth pattern of children at the 50th percentile has not changed, the 10th and 90th percentiles have expanded. Our findings suggest that the secular trend of increased height, accelerated growth, and earlier maturation is responsible for Czech children experiencing adiposity rebound at earlier ages compared to the past.     

Secular trends in anthropometrical measurements observed in three to 11-year-old French children between 1953 and 2005

This study covers a fifty-year period between 1953 and 2005 and looks at secular trends in stature, weight and sitting height sizes among French boys and girls between the ages of 3 and 11. A special modelling in function to the age and variable for each child was established so that a comparison could be made in the kinetic growth patterns over these same two periods. Statistical analysis shows a significant increase in growth, of 0.8cm per decade in stature, characterised by a certain increase in the lower limbs and the weight (0.8kg per decade) together with a proportional increase on the body mass index. Positive secular trends of this anthropometric nature are generally thanks to improved eating and sanitary habits and this study enables us to build and elaborate new standards in growth patterns essential for monitoring auxological development in 3 to 11-year-old children in the years 2000 and onwards.     

青藏高原与安第斯高原地区儿童青少年的身高、体重和胸围的对比

通过青藏高原和安第斯山高原地区儿童青少年身高、体重和胸围的比对,探讨高原地区儿童青少年生长发育的规律和特点,找出儿童青少年生长发育的高原地区差异,进一步改善高原地区居民的健康状态,促进儿童青少年生长发育,为高原医学和高原人类学的发展提供理论基础。本文以青藏高原和安第斯山高原地区儿童青少年为研究对象。选择在西藏出生长大、经体检证明身体健康6-21岁藏族男女(父母3代藏族)共2813例有效样本(男,1417例;女,1396例),在知情同意情况下直接测量了身高、体重和胸围。印度、秘鲁、玻利维亚、智利等国家和地区儿童青少年生长发育资料从文献中获取。去除不完整的无法比较及年代过于久远的材料,排除小样本及数据不全和不符合要求的样本,严格控制质量。所有测量数据输入SPSS13.0统计软件包。对数据进行描述性统计分析、独立样本t检验、方差分析等统计学处理。结果显示:1)青藏高原儿童青少年男女身高高于安第斯山男女。2)青藏高原儿童青少年的体重与安第斯山儿童青少年相近。3)青藏高原儿童青少年的胸围明显小于安第斯山儿童青少年。高原地区与非高原地区儿童青少年生长发育相比有相似性又有特殊性(如发育水平低,胸径较大,生长发育指标普遍低于WHO(2007)和本国国内水平)。西藏藏族儿童青少年比安第斯山的发育好,两者具有不同的体质特征,这可能与生态环境、高原缺氧、遗传因素和社会经济文化等多种因素有关。     

Two centuries of growth among Czech children and youth

The trend of increasing height can be interpreted as a reflection of the unfolding progress of civilization. Height changes among children and adolescents are good markers of this trend. We analyze the secular trend in the heights of children and adolescents in the Czech Republic on the basis of data from anthropological surveys. The earliest height data pertain to Czech youths who attended the Military Schools in Austria in 1800-1809. Data also exist for 1895 and continue in 1951 and at 10-year intervals thereafter. Growth curves were obtained for separate age groups by fitting mean values via third-order polynomial smoothing splines. Between 1951 and 2001, the mean heights of boys and girls aged 2.5 years increased by 2.7 and 3 cm, respectively. Since 1895, the mean height of 13-year-old boys has increased by 19.4 cm, and the mean height of girls has increased by 18.3 cm.     

Secular trend in body height and weight of Australian children and adolescents

Secular changes in growth and maturation have been well documented in various world populations, with secular increase especially noticeable in the developed countries. To assess the trend in both adult size and tempo of growth we compared the data on stature and body weight obtained in 1992-1993 from 1,804 Melbourne school students aged 5 to 17 with historical data collected from white Australians during the last 100 years. We illustrate the age-dependent trend in stature and body weight by means of regression surfaces. These were constructed by fitting local regression models to historical data and by simple plots showing the overall, and per decade, secular increase in both these measures at peripubertal and adult ages. Because of limited information on sample sizes and variability provided by the historical data, statistical comparisons have been performed only between the present 1992-1993 survey and two earlier independent surveys conducted in 1985 and 1970. The results have shown secular increase in adult stature over the last century, with the rate of increase varying between 0.4 and 2.1 cm/decade in males and 0.01 and 1.6 cm/decade in females. While secular increase in stature has significantly slowed down during the last two decades, the increase in body weight is still continuing at a high rate, and this increase is more pronounced in females. The period of strong secular increase, especially in the tempo of growth, coincided both with the shift toward earlier menarche and the improvement of socioeconomic conditions of the Australian population. The need for further studies to identify factors determining the continuing increase in body weight is emphasized, and caution in using the existing national growth standards for stature and weight is recommended.     

Childhood malnutrition and growth in a rural area of Western Kenya

An anthropometric survey was carried out on 1,383 school students aged 5-17 years in Suba district (a rural area of western Kenya). Body size and proportion were computed from height, weight, sitting height, arm circumference, and skinfolds. The aim of the study was to evaluate patterns of growth and nutritional status of the Luo population by assessment of the prevalence and trends of malnutrition among children and adolescents. Very few age-groups show significant sex differences for height, body weight, and arm muscle area. However, there are several differences in skinfold thicknesses and arm circumference, always with higher mean values in girls. Analysis of the nutritional status (weight-for-age, height-for-age, and BMI-for-age) shows significant differences among the age-groups in both sexes. Boys present lower Z-scores than girls and there are higher percentages of malnourished subjects (stunted and underweight) among the males. The Luo data were compared with those of other African populations. Their body dimensions, nutritional status, and growth are similar to those of the other sub-Saharan samples. In conclusion, the Luo children are generally undernourished at the older ages: adolescents (11-16 years of age) show the most severe undernutrition and the highest percentages of undernourished subjects. In addition to the higher risk of undernutrition in teenagers, an emerging problem of over-nutrition is evident among the younger age-groups, with a higher prevalence in females. These findings are discussed in light of sexual dimorphism in sensitivity to adverse environmental conditions.     

Reference values for height, weight and body mass index of German born Turkish children

Turkish children and adolescents born in Northern Europe grow different from native Northern European children, but reference values for height, weight and BMI for these children do not exist. With this study, we intend to provide growth standards for German born Turkish children. Data were obtained from 797 Turkish children and adolescents born in Germany age 0-25.8 years (males), respectively 0-18.3 years (females). We generated synthetic reference values for height, weight, and BMI. The results show that Turkish children and adolescents are heavier after the age of 6 years, and that they remain short after puberty. Eighteen year old Turkish men, and 15-year-old Turkish women are shorter (males 175.2 cm vs. 180.4 cm, p < 0.05; females 159.3 cm vs. 165.0 cm, p < 0.05), and heavier than Germans. Six out of 53 young Turkish men and 9 out of 100 young Turkish women were obese. Twelve out of 53 young Turkish men (23%) and 18 out of 100 young Turkish women (18%) have fallen below the 3rd centile for height. It can be concluded that growth of Turkish children and adolescents born in Germany significantly differs from native children. Reference LMS values for body height, weight and BMI of German born Turkish boys and girls are presented.     

Opportunity for natural selection and gene flow in an isolated Zapotec-speaking community in southern Mexico in the throes of a secular increase in size

Our object in this paper is to analyze the opportunity for natural selection and gene flow in an isolated Zapotec-speaking community in the valley of Oaxaca, southern Mexico, that is undergoing a secular increase in body size. Surveys were conducted in the community in 1968, 1978, and 2000, including anthropometric and census data. No secular change was found in the growth status of schoolchildren and adult height between 1968 and 1978; subsequently, major secular gains in height occurred among children and adolescents between 1978 and 2000. The 1978 household data were used to compute gene flow (3.3%) and opportunity for selection intensity (I = 1.312). Migration and other demographic information was obtained from household census data for 1978 and 2000, and mortality information was extracted from community records and archives. These data were used to compute gene flow and opportunity for natural selection. Gene flow increased from 3.3% to 4.7% and intensity of natural selection decreased from 1.312 to 0.272 from 1978 to 2000. Variance in fertility increased slightly over time (12.25 to 13.69). Opportunity for selection was dominant during the prereproductive period in 1978, but approached 0 for the mortality component in 2000, resulting in a marked decrease in the mortality component (Im) of selection (0.626 and 0.019, respectively) and total opportunity for selection (I = 1.312 and 0.272, respectively). Secular increase in height and markedly decreased opportunity for natural selection (1) were associated with better health and nutritional conditions. Genotype-environment interaction and environmental influences are apparently the predominant causes of the secular trend. If natural selection plays a role in causing the secular trend, it is a small one.     

Results of the study of selected head measurements of Jena children]

Secular changes of head measurements (frontal breadth, bizygomatic breadth, bigonial breadth, auricular height, morphological facial height, lower face height) are analysed. The data are based on the Jena anthropological investigations of school children from 1975 and 1985. The inclusion of the data of the Jena longitudinal study carried out since 1985 allows an analysis of the further secular trend. Noticeable changes are proved in most of the analysed traits (frontal breadth, bigonial breadth, auricular height, morphological facial height, lower face height) between 1975 and 1985. The vertical measurements show greater percentage differences than the horizontal measurements, which, among other things, results in a relative narrowing of the face. In some head measurements (frontal breadth, bigonial breadth, auricular height) the trends continue after 1985. The secular trends show no obvious connection with the temporal acceleration of the dentition in the probands of the longitudinal study. However, a connection seems to be possible between the accelerated puberal growth spurt of the body height and the puberal growth spurt in some head dimensions.     

Growth and secular trend in school-children from Cento, Ferrara, Italy

Growth parameters were surveyed in a sample of 296 Italian children, 6-9 years old, from Cento (Ferrara, Emilia-Romagna). The comparison with children from the same town measured in 1974-75 show changes in some parameters, suggesting an ongoing secular trend. To better understand the observed weight increase and the sex difference, we also evaluated body composition and motricity. The analysis of the present sample is a preliminary part of a longitudinal study dealing with modifications of body composition and motor capacity induced by growth. In our sample the children are growing according to the Italian reference standard. The females present weight, height and Body Mass Index (BMI) values comparable to the 50th centile, while the males present higher values of weight, skinfold thicknesses and BMI. Sex differences in the motor performance were noted. A methodological comparison of obesity assessments based on BMI and percentage of body fat (%F) shows similar conclusions but somewhat different results.     

Estimation of secular trends in adult height, and childhood socioeconomic circumstances in three Eastern European populations

The objective of these analyses was to estimate the strength and direction of secular trends in adult height and childhood socioeconomic circumstances in eight towns in three Eastern European countries in the mid-20th century, and to assess the extent to which childhood conditions might explain the height differences. We used cross-sectional data from the baseline survey of the Health, Alcohol and Psychosocial factors in Eastern Europe (HAPIEE) study, conducted in 2002-2005. The study examined 24,012 men and women born between 1933 and 1957, randomly selected from the general populations of Novosibirsk (Russia), Krakow (Poland) and six towns of the Czech Republic. To allow for age-related height loss we estimated maximum attained height. Parental education and household item ownership at age 10 were used as markers of childhood socioeconomic conditions. In all 5-year birth cohorts, Novosibirsk men and women were shortest. There were positive and statistically significant secular trends in childhood conditions and in maximum adult height. Adjustment for childhood conditions explained about one third of the trend in height. There appeared to be a small reduction in height of persons born during the Second World War which was, however, only significant in Novosibirsk. These results suggest that secular trends in height mirror, but are not wholly explained by, trends in socioeconomic circumstances in early life.