Adolescent growth: genes, hormones and the peer group. Proceedings of the 20th Aschauer Soiree, held at Glücksburg castle, Germany, 15th to 17th November 2013.

The association between poverty, malnutrition, illness and poor socioeconomic conditions on the one side, and poor growth and short adult stature on the other side, is well recognized. Yet, the simple assumption by implication that poor growth and short stature result from poor living conditions, should be questioned. Recent evidence on the impact of the social network on adolescent growth and adult height further challenges the traditional concept of growth being a mirror of health. Twenty-nine scientists met at Glücksburg castle, Northern Germany, November 15th - 17th 2013, to discuss genetic, endocrine, mathematical and psychological aspects and related issues, of child and adolescent growth and final height.

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.

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.

Growth of the Czech child population 0-18 years compared to the World Health Organization growth reference.

Nationwide anthropological surveys of 0-18-year-old children were carried out in the Czech Republic (former Czech regions of Czechoslovakia) five times during the last 40 years, at 10-year intervals. The measurements provide reference data for the growth of the Czech child population and at the same time ample material for comparison with other populations. A comparison of the results of such nationwide anthropometric surveys with the World Health Organization (WHO) growth reference implies that the growth trend of Czech children is comparable with the WHO reference. The greatest similarity in the shape of the WHO height curves and the results obtained in Czechoslovakia was in 1971. The results obtained in the nationwide surveys also imply that the secular trend still exerts its effect. In the case of height, this finding is consistent during the whole period of 40 years. Concerning weight in higher age categories, especially in girls, the trend slowed down or stopped. Furthermore, there is no problem of malnutrition in the Czech child population. Similarly, as in any other developed nations, the prevalence of overweight and obesity is the problem that merits attention. Am. J. Hum. Biol. 9:459-468, 1997. © 1997 Wiley-Liss, Inc.

Social inequality and obesity in Czech school children.

This study uses logistic regressions to consider the effect of social factors, physical activity, meal frequency and BMI of parents on children's body mass index (BMI) values. Three thousand three hundred and sixty-two children aged 7-11 years were examined in 38 schools in the Czech Republic. Six anthropometric characteristics were assessed in 1999-2000. Most important factors influencing children's BMI values were: obesity of both or at least one of the parents, being an only child, residence in small communities, and irregular breakfasts.

Proposed standard definition for child overweight and obesity.

The prevalence of obesity in child population is becoming a serious problem in all advanced countries. Therefore many authors try to find a definition according to which it would be possible to assess overweight and obesity in examined subjects in a simple manner. The simplest way is to plot the subject's data in a percentile zone of reference data according to his BMI value. The problem is dealt with e.g. by Cole et al. (1) who defined internationally acceptable standards of BMI for children and adolescents from 0-18 years. These standards are, however, based only on six national studies and on the assumption that in the population of 18-year-olds there are 10% subjects with BMI values above 25 and 3% subjects with values above 30. The suggested standards thus raise the level of the 90th and 97th percentile, as compared with BMI reference data of 1991 which are used in the Czech Republic. Therefore the ratio of obese children in the Czech Republic and in many other countries would be very small. Internationally acceptable standards should be therefore based on a broader discussion of the professional public.

Bodily characteristics and lifestyle of Czech children aged 7.00 to 10.99 years, incidence of childhood obesity.

In 1991-2000 in the Czech Republic a survey of the prevalence of obesity was made. The assessment was made by the transversal method in elementary schools in all regions of the Czech Republic. Children aged 7.00 to 10.99 years were investigated. The survey comprised a total of 3362 children (1668 girls and 1694 boys). A total of 12 anthropometric dimensions were recorded and questionnaires addressed to the children and parents were analyzed. From the results ensued that the ratio of obese children of both sexes in the CR (i.e. children with BMI values about the 97th percentile of the reference population) increased. This zone comprised 6.0% boys and 5.6% girls of the investigated group. An important finding was also the increase of mean values of the abdominal circumference of the children in all age groups in both sexes. The ratio of obese children in different communities is related unequivocally to the size of the community., In smaller communities there are more obese children (according to our data 6.9%) and in large towns the ratio of obese children is 2.3%. In large towns there is also a greater proportion of thin children - 12.1%, in small communities 8.6%. It was found that there is a higher percentage of obese children in families where the mother has elementary education as compared with children of mothers with secondary and university education. Mothers with elementary education have 9.6% obese children while university educated mothers have only 3.6% obese children. Analysis of the dietary questionnaires revealed that only 62.9% children in large towns eat breakfast, the position in villages is similar - 63.9%. In the group of children with excessive body weight fewer children have breakfast (only 54.1%), in the group of children with a low body weigh the majority eat breakfast (75.3%). The majority of children have a mid-morning snack at school which they bring from home. As regards school lunch the majority of children from large towns replied that they have lunch at school. the number of rural children who had school lunch was smaller. An afternoon snack is taken by less than half the children in different groups.

Influence of positioning of infants on long-term changes of cephalic dimensions.

The submitted investigation describes long-term changes of 3 main cephalic dimensions (head circumference, maximal length and maximal width of the head) and analyses the possible influence of positioning of infants after birth (prone, supine and side sleeping position) on these changes. Information about children aged 6 months to 3.99 years, where the need of up-to-date data is greatest, were collected as part of an extensive anthropological survey implemented in 1995 to 1997 in the entire Czech Republic. The authors confirmed the trend of debrachycephalization, which is manifested by a statistically significant increase of the maximal length of the head and a statistically significant decrease of the maximal width of the head, as compared with children examined in the anthropological survey in 1956 to 1962 (1). These changes were established in the group of boys (200 boys) as well as in the group of girls (167 girls). The differences of the magnitude of long-term changes between boys and girls were not significant. Evaluation of the long-term changes of the head circumference in the entire group of 366 children aged 0.5-3.99 years (the head circumference of one girl was not measured) revealed a statistically significant increase of this dimension. During the period from 1956/62 till 1996, the influence of positioning on the magnitude of long-term changes of head circumference was not proved. We can say the same about the maximal length of the head of boys and girls and about the maximal width of the head of girls. Only between three differently positioned groups of boys (prone, side, supine) statistically significant differences in the magnitude of long-term changes of the maximal width of the head were found (p < 0.05). Highly significant changes of the maximum width and maximum length of the head occurred as compared with a reference group in all three groups of positioning of infants and in both sexes. The trend of debrachycephalization seems to be thus a more potent factor, which affects long-term changes in the shape of the head, then the predominating sleeping position during the first months after birth. This conclusion is supported by the persisting trend of debrachycephalization, although the supine position is now preferred.

Vth nation-wide anthropological survey 1991 in the Czech Republic comparison with 1981 data.

The objective of the survey was to assess whether a secular trend still affected growth of the Czech child population and, if necessary, to update national growth standards. The study was designed in such a manner so that trends in child growth, obtained from comparisons of body height, body weight and head circumference from the two successive nation-wide representative surveys (1981, 1991) of the Czech child population, could be followed. Representative random samples of the Czech child population from 0 to 18 years of age were studied with the following number of examined subjects: 86,846 in 1991 and 117,643 in 1981. Nation-wide standards and growth charts for assessment of growth and development of both individuals and specific groups present main outcome of the survey. Statistically significant differences were found in body height (both sexes) and weight (more in boys). No highly significant differences were registered in head circumference. Based on newly assembled data growth charts for assessment of body height, proportionality and head circumference were designed. The findings of this study did not support the hypothesis that the secular trend in Czech child population has already ceased.

The 6th nationwide anthropological survey of children and adolescents in the Czech Republic in 2001.

The 6th nationwide anthropological survey (NAS) of children and adolescents was carried out in the Czech Republic in 2001 to continue the series of surveys repeated at 10-year intervals since 1951 (with the participation of the Slovak Republic up to 1991). The major objective was to find out the following body measurements of children and adolescents: body height and weight, and head, arm, waist and hip circumferences. Questionnaires were used to find out the body measurements of parents (body height and weight) and some socio-economic characteristics of the child's family (number of siblings, education of parents, breast feeding duration, birth weight and length, child's physical activities, TV watching time, computer gaming time, etc.). A school children questionnaire focused on eating habits was also part of the survey in 2001. A total of 59,000 children aged 0.00 to 18.99 years, i.e. about 3% of the population of the same age range, were enrolled in the survey in 2001. The results obtained presented in diagrammatic and tabular forms are reference standards for monitoring growth of the Czech children and adolescents from birth to the age of 19 years. The survey revealed a substantial slowdown in the long-term trend in body height increase for both boys and girls. The most marked increase in the mean body height is currently recorded in boys at the prepubescent age while the pubescent girls show a practically zero increase for this parameter. A more marked increase in body height at the adult age is not expected any more, but the increase in body height and weight at the prepubescent age is likely to continue for some time. The 6th NAS showed a marked slow down to a stop in the trend in the mean body weight increase. No increase in the mean body weight has been recorded in pubescent girls since the 1970's and in pubescent and postpubescent boys since 1991. Nevertheless, the younger age groups, namely those of preschool and primary school children, continue to show increase in the mean body weight. The secular trend in body weight has been less pronounced compared to that in body height. The rates of overweight and obese children (as assessed by body mass index, BMI) have risen in most age groups of school children compared to those reported in 1991. In contrast, a slight decrease in the rate of overweight children can be seen in boys starting from the age of 16 years and in girls starting from the age of 13 years. The obesity prevalence rate is significantly higher in boys than girls. Statistical analysis confirmed a correlation between the BMI values in children and education of parents (the higher the education, the lower the rate of overweight children) and between the BMI values and the population size of the community where the child lives (the higher the population, the lower the prevalence rates of overweight and obesity). Single children suffer more frequently from overweight and obesity than those with siblings.

Growth and development of school children.

With the support of the Internal Grant Agency of the Ministry of Health of the Czech Republic in 1997-1999 work proceeded on the grant "Semi-longitudinal study of the somatic growth of school children in the Czech Republic". The objective of this project is to assess the growth rate of the basic bodily characteristics in children and youth aged 6 to 14 years, to confirm the positive secular trend in height and body weight or its slowing or stagnation, and also to evaluate the growth and development of children under the new socio-economic conditions. In addition to thirty somatic characteristics which are assessed repeatedly every six months, in 1,925 children some supplementary data were obtained from parents. From hitherto assembled data ensues that there was no significant change of the mean length at birth nor of the birth weight as compared with 1989. The increase in height up to adolescence continues, in the higher age groups probably stagnation occurs. Despite a slight increase of mean body weight values since 1981, a gradual decline of the BMI values was observed. In boys this tendency is less marked than in girls, in particular in the oldest age groups. This trend was confirmed also by the results of the present investigation. As compared with the results of the 5th Nationwide Anthropological Survey in 1991 the group of overweight children, i.e. those above the 90th percentile of BMI comprises 6.9% boys and 8.9% girls from a total of almost 2,000 children, as compared with the expected 10%.

Indicators of risk of ischaemic heart disease in patients with acute myocardial infarction under 65 years and their relatives.

The incidence of risk factors for atherosclerosis was investigated in a group of 846 patients under 65 years of age, hospitalized with acute myocardial infarction (AIM) in coronary hospital units in 21 districts of the Czech Republic in 1996. The group of patients comprises 649 men and 197 women. The incidence of risk factors in patients was compared with the incidence of risk factors in the population of the Czech Republic: the mean values of the investigated indicators are in patients with AIM higher in both sexes (total serum cholesterol, triacylglycerols, BMI, WHR). As to anamnestic data, in the majority low or irregular physical activity predominates, a high percentage of patients reported that they "do not restrict" or "rather do not restrict" their total food intake nor the intake of animal fats. Among the patients 52.6% males and 42.1% females were smokers. The results indicate that patients with AIM have a higher incidence of risk factors for atherosclerosis, a higher percentage of patients have cumulated risks and a higher percentage of patients has a higher risk score than the general population. The incidence of AIM is markedly higher in subjects with lower education.

"Healthy Dubec" -design of a joint Czech-American community project for the reduction of cardiovascular and cerebrovascular disease (adapted from American experience).

The project is a combination of individual and community-based intervention which adapted and modified methods and techniques originally used in The Three-City Community Study and The Stanford Five-City Project in a small community outside Prague. The goal is to reduce cardiovascular and cerebrovascular risk factors by primary and secondary prevention, using a community-based approach. 61.5% of examined population with the low risk score during the baseline survey was exposed to intervention by community-based methods. 38.5% of adult population was included in intervention activities within the framework of secondary prevention in high risk groups. There are described: the method of community oriented intervention and the intervention oriented on high risk groups - nutrition intervention, quit smoking activities, stress control, physical activity promotion.

[The 5th nation-wide anthropological study of children and adolescents held in 1991 (Czech Republic)--selected anthropometric characteristics]. / V. celostátní antropologický výzkum detí a mládeze v roce 1991 (Ceské zeme)--vybrané antropometrické charakteristiky.

The Vth nation-wide survey of children and adolescents which was conducted in autumn 1991 under new conditions comprised again, similarly as the four previous ones, a representative sample selected by random sampling. As compared with the 1981 survey, the anthropometric parameters were extended by the circumference of the relaxed left arm and the hip circumference. A questionnaire for parents was elaborated where by a quite new approach was used. The still positive action of the secular trend of increasing height was confirmed. The action of the trend shifts to younger age groups, as compared with former surveys. The present survey confirmed also a tendency towards slimness in both sexes, however, in particular in girls a shift of this tendency to younger age groups was apparent. It will be certainly necessary to evaluate in future whether this trend reflects also a more favourable ratio of body composition. With regard to these changes the authors submit new percentile charts for evaluation of height, proportionality, and for children under three years, also head circumference.

[The effect of heredity and environment on growth, body weight and physical proportions in children and adolescents]. / Ovlivnení rustu, hmotnosti a telesné proporcionality detí a mládeze dedicností a zivotním prostredím.

Thirty-seven characteristics of children examined during the IVth nation-wide anthropological survey in 1981 were evaluated in relation to variables to body weight, height and Rohrer's index. For processing consecutive regression analysis was used which makes it possible to list individual factors (independent variables) according to their ability to explain the variability of dependent variables. The most important signs explaining the variability of all three dependent variables assessed by this method were signs described as genetic (height and body weight of parents) and maturity, birth length and weight which can be conceived in the wider sense of the word also as genetic characteristics which can be influenced by the environment.

Defining overweight and obesity in pre-school children: IOTF reference or WHO standard?

Two international datasets are used to define overweight and obesity in pre-school children: the International Obesity Task Force (IOTF) reference and the WHO standard. This study compares the performance of the two datasets in defining overweight and obesity in 24-60 months old children. This was done by plotting the IOTF cut-offs against WHO curves and by comparing the prevalence of overweight and obesity, as defined by the IOTF reference and by the WHO standard, using 2001 data from the Czech Republic. The IOTF cut-off for overweight in 24-60 months old children goes from 1.7 to 1.1 z-scores on the WHO chart, and for obesity it shifts with age from 2.7 to 2.2 z-scores. As a consequence, at 5 years of age the prevalence of overweight in Czech girls is 3.4% using the WHO and 15.3% using the IOTF definition. These discrepancies are due to the choice of cut-offs and to the different criteria used to select the sample for the IOTF reference and the WHO standard. Research is urgently needed to identify, for the WHO standard, BMI cut-offs associated with an increased risk of overweight and obesity, and associated health outcomes later in life.

Long-term changes in prevalence of overweight and obesity in Czech 7-year-old children: evaluation of different cut-off criteria of childhood obesity.

The objective of this paper was an evaluation of change in prevalence of overweight and obesity in Czech children, and a comparison of cut-off points for body mass index references from the Czech Republic (CzR), International Obesity Task Force and WHO. The authors conducted a survey in 7-year-old children, and compared data from 1951, 1981, 1991, 2001 and 2008 (WHO cut-offs). 2008 data were evaluated according to different cut-offs. Results showed that since 1951 in boys, overweight prevalence increased from 13.0% in 1951 to 26.8% in 2001, in girls from 10.9% to 22.9%. Obesity increased in boys from 1.7% to 8.3%, in girls from 1.7% to 6.9%. From 2001 to 2008 obesity in boys increased; obesity in girls and overweight in both genders decreased. In 2008 cohort the following values were found: overweight and obesity: CzR criteria, percentage was lowest (14.8% boys and 11.1% girls); WHO criteria, highest prevalence (23.5% boys and 19.5% girls); obesity: lowest ratio International Obesity Task Force criteria (4.4% boys, 3.3% girls), highest ratio boys WHO criteria (10.0%), girls CzR criteria (5.0%). Overweight and obesity prevalence increased in 7-year-old Czech children since 1951; since 2001 prevalence is plateauing with exception of boys. Using different body mass index references resulted in marked differences in overweight and obesity prevalence.

Monitoring the growth dynamics of somatic traits based on a semi-longitudinal study.

Possibilities of conducting longitudinal human growth studies are very limited, since it is necessary to monitor the probands for a long time. Another problem can be a loss of data currency, and the small size of the final sample. The solution can be a follow-up semi-longitudinal observation. This research is drawn up as a short longitudinal monitoring of 1925 children (990 boys, 935 girls), aged 6-15 years, at 20 elementary schools in four regions of the Czech Republic, which has been conducted at the same time. Data of repeatedly examined probands of a wide age range were acquired in a short time period. With the help of a linear regression model with mixed effect, the growth velocity curves of 12 somatic traits have been obtained. The timing, intensity and duration of separate growth spurts have been observed, as well as the mutual location of both points of growth velocity, local maxima and minima, and points of the maximal acceleration and deceleration. The results demonstrate that the velocity of characters with variable growth dynamics (skin-fold thicknesses, circumferences of limbs) - contrary to characters with regular growth velocity - have a higher number of partial growth spurts and an opposite course. In the period of separate growth velocity, peaks of somatic characters with regular growth dynamics reach points of partial local minima. In comparison to previous longitudinal studies of body height growth dynamics, the shift of both the beginning and the peak of boys' and girls' pubertal spurt, to a lower age can be found.

Overweight and obesity in infants and pre-school children in the European Union: a review of existing data.

The objective of this study was to synthesize available information on prevalence and time trends of overweight and obesity in pre-school children in the European Union. Retrieval and analysis or re-analysis of existing data were carried out. Data sources include WHO databases, Medline and Google, contact with authors of published and unpublished documents. Data were analysed using the International Obesity Task Force reference and cut-offs, and the WHO standard. Data were available from 18/27 countries. Comparisons were problematic because of different definitions and methods of data collection and analysis. The reported prevalence of overweight plus obesity at 4 years ranges from 11.8% in Romania (2004) to 32.3% in Spain (1998-2000). Countries in the Mediterranean region and the British islands report higher rates than those in middle, northern and eastern Europe. Rates are generally higher in girls than in boys. With the possible exception of England, there was no obvious trend towards increasing prevalence in the past 20-30 years in the five countries with data. The use of the WHO standard with cut-offs at 1, 2 and 3 standard deviations yields lower rates and removes gender differences. Data on overweight and obesity in pre-school children are scarce; their interpretation is difficult. Standard methods of surveillance, and research and policies on prevention and treatment, are urgently needed.