Winner-loser effects improve social network efficiency between competitors with equal resource holding power.

Animal societies are structured of dominance hierarchy (DH). DH can be viewed as networks and analyzed by graph theory. We study the impact of state-dependent feedback (winner-loser effect) on the emergence of local dominance structures after pairwise contests between initially equal-ranking members (equal resource-holding-power, RHP) of small and large social groups. We simulated pairwise agonistic contests between individuals with and without a priori higher RHP by Monte-Carlo-method. Random pairwise contests between equal-ranking competitors result in random dominance structures ('Null variant') that are low in transitive triads and high in pass along triads; whereas state-dependent feedback ('Winner-loser variant') yields centralized 'star' structured DH that evolve from competitors with initially equal RHP and correspond to hierarchies that evolve from keystone individuals. Monte-Carlo simulated DH following state-dependent feedback show motif patterns very similar to those of a variety of natural DH, suggesting that state-dependent feedback plays a pivotal role in robust self-organizing phenomena that transcend the specifics of the individual. Self-organization based on state-dependent feedback leads to social structures that correspond to those resulting from pre-existing keystone individuals. As the efficiency of centralized social networks benefits both, the individual and the group, centralization of social networks appears to be an important evolutionary goal.

Stunting is not a synonym of malnutrition.

BACKGROUND: WHO documents characterize stunting as, "…impaired growth and development that children experience from poor nutrition, repeated infection, and inadequate psychosocial stimulation." The equation of stunting with malnutrition is common. This contrasts with historic and modern observations indicating that growth in height is largely independent of the extent and nature of the diet. SUBJECTS: We measured 1716 Indonesian children, aged 6.0-13.2 years, from urban Kupang/West-Timor and rural Soe/West-Timor, urban Ubud/Bali, and rural Marbau/North Sumatra. We clinically assessed signs of malnutrition and skin infections. RESULTS: There was no relevant correlation between nutritional status (indicated by skinfold thickness) and height SDS (hSDS). In total 53% of boys, and 46% girls in rural Soe were stunted, with no meaningful association between mean of triceps and subscapular skinfolds (x̅SF) and height. Skinfold thickness was close to German values. Shortest and tallest children did not differ relevantly in skinfold thickness. The same applied for the association between hSDS and mid-upper-arm circumference (MUAC) using linear mixed effects models with both fixed and random effects. In total 35.6% boys and 29.2% girls in urban Ubud were overweight; 21.4% boys and 12.4% girls obese, but with mean hSDS = -0.3, still short. Relevant associations between hSDS and x̅SF and MUAC were only found among the overweight urban children confirming that growth is accelerated in overweight and obese children. There were no visible clinical signs of malnutrition or chronic infection in the stunted children. CONCLUSION: The present data seriously question the concept of stunting as prima facie evidence of malnutrition and chronic infection.

Correction: Stunting is not a synonym of malnutrition.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Weight and height growth of malnourished school-age children during re-feeding. Three historic studies published shortly after World War I.

BACKGROUND: In view of the ongoing debate on "chronic malnutrition" and the concept of "stunting" as "a better measure than underweight of the cumulative effects of undernutrition and infection (WHO)", we translate, briefly comment and re-publish three seminal historic papers on catch-up growth following re-feeding after severe food restriction of German children during and after World War I. The observations were published in 1920 and 1922, and appear to be of particular interest to the modern nutritionist. RESULTS: The papers of Abderhalden (1920) and Bloch (1920) describe German children of all social strata who were born shortly before World War I, and raised in apparently "normal" families. After severe long-standing undernutrition, they participated in an international charity program. They experienced exceptional catch-up growth in height of 3-5 cm within 6-8 weeks. Goldstein (1922) observed 512 orphans and children from underprivileged families. Goldstein described very different growth patterns. These children were much shorter (mean height between -2.0 and -2.8 SDS, modern WHO reference). They mostly failed to catch-up in height, but tended to excessively increase in weight particularly during adolescence. CONCLUSION: Whereas Abderhalden and Bloch illustrate rapid height catch-up in children from intact social background, Goldstein's observations in orphans and children from poor social background parallel the growth patterns observed in children of modern middle and low-income countries. The historic observations question the current concept of stunting as prima facie evidence of malnutrition and chronic infection, and support the view that "the child's longitudinal growth is largely independent of the extent and nature of the diet".

Stunting, starvation and refeeding: a review of forgotten 19th and early 20th century literature.

AIM: To scrutinize to what extent modern ideas about nutrition effects on growth are supported by historic observations in European populations. METHOD: We reviewed 19th and early 20th century paediatric journals in the Staatsbibliothek zu Berlin, the third largest European library with an almost complete collection of the German medical literature. During a three-day visit, we inspected 15 bookshelf meters of literature not available in electronic format. RESULTS: Late 19th and early 20th century breastfed European infants and children, independent of social strata, grew far below World Health Organisation (WHO) standards and 15-30% of adequately-fed children would be classified as stunted by the WHO standards. Historic sources indicate that growth in height is largely independent of the extent and nature of the diet. Height catch-up after starvation was greater than catch-up reported in modern nutrition intervention studies, and allowed for unimpaired adult height. CONCLUSION: Historical studies are indispensable to understand why stunting does not equate with undernutrition and why modern diet interventions frequently fail to prevent stunting. Appropriateness and effect size of modern nutrition interventions on growth need revision.

Severe postwar malnutrition did not have a negative impact on the earnings and subsequent pensions of German men born in 1945-1948.

AIM: Poverty has often been associated with malnutrition, stunted growth, impaired cognitive development and poor earnings. We studied whether these associations were found in German men born and raised shortly after World War II during severe and long-standing nationwide malnutrition. METHODS: We analysed German old-age pension payments, as a rough measure of lifetime earnings, in German men born from 1932 to 1960 and compared the at-risk-of-poverty rates of German men born in 1945-1948 versus 1935-1938 and 1955-1958. RESULTS: Substantially fewer women worked during this period and their longer life expectancy makes their pension payments difficult to interpret. We therefore limited our analysis to men. Men born in the 1930s received the highest monthly old-age pensions and these declined slightly in men born from 1945 to 1948, indicating a minute impairment in work-related income in cohorts born shortly after the war. We also found that there was no evidence for increased at-risk-of-poverty rates in men born in 1945-1948 versus those born in 1935-1938 and in 1955-1958. CONCLUSION: Being born and raised following World War II was associated with a minute work and pension impairment that was not visible in the at-risk-of-poverty rates. These findings question statements associating early childhood nutrition and future lifetime earnings.

Monte Carlo simulation of body height in a spatial network.

BACKGROUND/OBJECTIVES: Recent evidence suggests clustering of human body height. We want to assess the consequences of connectedness in a spatial network on height clustering in an artificial society. SUBJECTS/METHODS: We used an agent-based computer modelling technique (Monte Carlo simulation) and compared simulated height in a spatial network with characteristics of the observed geographic height distribution of three historic cohorts of Swiss military conscripts (conscripted in 1884-1891; 1908-1910; and 2004-2009). RESULTS: Conscript height shows several characteristic features: (1) height distributions are overdispersed. (2) Conscripts from districts with direct inter-district road connections tend to be similar in height. (3) Clusters of tall and clusters of short stature districts vary over time. Autocorrelations in height between late 19th and early 21st century districts are low. (4) Mean district height depends on the number of connecting roads and on the number of conscripts per district. Using Monte Carlo simulation, we were able to generate these natural characteristics in an artificial society. Already 5% height information from directly connected districts is sufficient to simulate the characteristics of natural height distribution. Very similar observations in regular rectangular networks indicate that the characteristics of Swiss conscript height distributions do not so much result from the particular Swiss geography but rather appear to be general features of spatial networks. CONCLUSIONS: Spatial connectedness can affect height clustering in an artificial society, similar to that seen in natural cohorts of military conscripts, and strengthen the concept of connectedness being involved in the regulation of human height.

The association of weight, weight variability and socioeconomic situation among children.

BACKGROUND/OBJECTIVES: We studied the association of body weight and weight variability among populations from different geographic, historic and socioeconomic background. SUBJECTS/METHODS: We reanalyzed data from 833 growth studies of 78 different countries from 1920 to 2013. We used data from two age groups-infants (age 2 years) and juvenile (age 7 years)-and divided the studies into two geographic-socioeconomic groups. RESULTS: Multiple regressions showed significant interactions between weight, sex, historic year of study, continent and within-study standard deviation. Multiple regression revealed R(2)=0.256 (P<0.001) at age 2 years and R(2)=0.478 (P<0.001) at age 7 years. Although infants and juveniles in more affluent countries are heavier than children in less affluent countries (P<0.001), the within-study standard deviation of the two geographic-socioeconomic groups differs at age 7 years (P<0.001) but not at age 2 years (P>0.15). CONCLUSIONS: The general impression that prosperous conditions lead to growth improvements in height and weight appears to be true only at a large scale: wealthy countries have tall and heavy children. At small scale, the situation is different. Whereas economic and nutritional improvements can exhibit substantial effects in weight gains, the discrepancy between the within-population variation in height and weight strongly suggests that height gains and weight gains are subject to different regulations.

The association of body height, height variability and inequality.

Body height is associated with environmental conditions. It has been suggested that under poor conditions when inequality within a population increases, also the variability in height tends to increase. We studied the association of body height, within-country variability in height and geographic and historic origin in 767 growth studies carried out in 80 countries, published between 1794 and 2013, with data on N = 78,184 infants age 2 years, and N = 2,130,729 juveniles age 7 years. The studies represent almost the whole spectrum of economic diversity in human societies since the end-18(th) century. 207 studies contained data for both infants and juveniles with 50,819 subjects (age 2), and 123,078 subjects (age 7). Multiple linear regressions showed significant interactions between height, sex, historic year of the study, geographic origin, and within-study standard deviation for height with multiple R-squared = 0.527, p < 0.001, at age 2, and multiple R-squared = 0.436, p < 0.001, at age 7. Yet, the two age groups differed in respect to within-study standard deviation for height. We found a significant association between body height and within-study standard deviation for height only at age 2: tall infant populations are less variable in height (r = -0.27, p < 0.01). There was no such association in children aged 7 years. Tall children from affluent and short children from less affluent countries do not differ in the variability of body height. The data suggest that the 'environmental adversity' hypothesis for variation in growth: small mean values for height go along with large standard deviations for height, does not apply for children at age 7.

DEVELOPMENT OF SYNTHETIC GROWTH CHARTS FOR ROMANIAN POPULATION.

There are no new national growth references for the Romanian population and the current recommendations for short stature evaluation is the use of the Swiss growth charts developed based on a longitudinal study.The aim of the present paper is to present the new synthetic growth references for Romanian children. MATERIAL AND METHODS: We used local Romanian data from 9 studies with information on height and weight obtained between 1999 and 2016. Based on their plausibility and methodology six studies were selected for generating the National Synthetic Growth References for Romanian Children based on the specific methodology described previously. The selected studies included 8407 subjects measured in schools/kindergartens. Age is reported in years covering a range from 3-18 years. Height and weight were measured at a precision of 0.1 cm and 0.1 kg. All children were measured at normal temperature, in light clothes, without footwear. RESULTS: We present the charts and tables with the common centiles for height, weight and body mass index for boys and girls. CONCLUSION: We suggest synthetic growth references based upon recent growth data from 6 different Romanian regions as new National Growth Charts for Romanian children.

Final height, target height and the community.

Height varies with age, and it varies with historic time. Final height is determined by endocrine parameters and genetics, by nutrition and health, by environmental factors, by birth weight, early growth, BMI, and developmental tempo. European populations of the 19th century were short, but their shortness did not result from growth impairment at all ages. In those days, shortness was mainly due to a significantly blunted adolescent growth spurt. New modelling approaches suggest an independent regulation of adolescent growth and final height: the target for growth and final height appears to be set by the community. In order to test this hypothesis, we formed a geographic network of Switzerland consisting of 169 nodes (district capitals) and 335 connecting edges (roads), and investigated military conscript data obtained between 2004 and 2009. Average height of Swiss military conscripts was 178.2 cm (SD 6.5 cm). But conscripts from first order neighbouring districts were more similar in height than expected. Short stature districts have short, tall stature districts have tall neighbours. We found significant height correlations between 1st (r=0.58), 2nd (r=0.64), 3rd (r=0.45) and even 4th order neighbours (r=0.42). It appears that tall stature communities generate tall people, short stature communities generate short people, and migrants orientate towards the new height target of their host population (community effect on growth).

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.

Developing differential height, weight and body mass index references for girls that reflect the impact of the menarche.

AIM: Growth is both a matter of amplitude and tempo. We aimed to develop references for body height, body weight and body mass index (BMI) with respect to tempo of maturity. METHODS: Data obtained from the German KiGGS study (2003-2006) on body height, body weight and presence or absence of the menarche were re-analysed in 3776 girls, aged 10-17 years. We developed smoothed centiles for BMI-, body-height- and body-weight-for-age using the LMS method for premenarcheal and postmenarcheal girls. RESULTS: Body height, body weight and BMI differed significantly between premenarcheal and postmenarcheal girls. On average, postmenarcheal girls aged 11-17 years were 5.3 cm taller and 9.7 kg heavier, and their BMI was 2.9 kg/m² higher than in premenarcheal girls of the same calendar age. CONCLUSION: Adolescent BMI rises with calendar age and biological age. New reference charts for adolescent girls aged 10-18 years were generated to be inserted into the currently used references to avoid misclassifying underweight and overweight pubertal girls.

Diversity in auxology: between theory and practice. Proceedings of the 18th Aschauer Soiree, 13th November 2010.

Auxology has developed from mere describing child and adolescent growth into a vivid and interdisciplinary research area encompassing human biologists, physicians, social scientists, economists and biostatisticians. The meeting illustrated the diversity in auxology, with the various social, medical, biological and biostatistical aspects in studies on child growth and development.

How much chicken is food? Questioning the definition of food by analyzing amino acid composition of modern convenience products.

BACKGROUND: Substantial differences exist between traditionally cooked and chemically designed ready-to-serve products and raise questions about the general principles and requirements of current food law. METHODS: Differences in amino acid patterns were analyzed in four examples of chicken preparations (boiled chicken meat, traditionally prepared broth from whole chicken, and two commercial chicken broths), and four examples of vegetable broth (traditionally prepared, two commercial products one of which was claimed a BIO-product, and the classic German bouillon cube). RESULTS: Chicken meat contained 284 mg of free amino acids in 100 ml of the boiled meat homogenate, with physiological peaks of glutamate (14.5 mg/100 ml), glutamine (8.5 mg/100 ml), anserine (88 mg/100 ml) and carnosine (55 mg/100 ml). The patterns significantly differ in industrially designed chicken soups with elevated peaks of glutamate, and missing anserine or carnosine. Similar results were obtained in vegetable broths. In the classic German bouillon cube, glutamate accounts for 96% of all free amino acids. CONCLUSIONS: The amino acid composition of modern ready-to-serve chicken soups and vegetable broths are far from being similar to any natural composition. We need to question current legal definitions of food, and consider its impact on eating habits, appetite regulation and obesity.

Harmonizing national growth references for multi-centre surveys, drug monitoring and international postmarketing surveillance.

AIM: National European growth references differ. We aimed to convert (harmonize) currently used charts into a single unified interchangeable LMS format for each European nation. METHODS: Nine currently used national European growth references from Belgium (2009), France (1979), Poland (2001), Sweden (2002), Switzerland (1989), the UK (1990), Italy (2006) and Germany (1979 and 1997) were harmonized and compared with the international WHO child growth standards and WHO growth reference data for 5-19 years. RESULTS: European growth charts can be harmonized. The approach appears useful as height, and body mass index (BMI) is inappropriately represented by WHO references. European height references exhibit warping when plotted against the WHO reference. The French appears too short, the other Europeans too tall. Also, the BMI is not appropriately represented by the WHO references. CONCLUSIONS: Harmonizing references is a novel, convenient and cost-effective approach for converting historic and/or incomplete local or national growth reference charts into a unified interchangeable LMS format. Harmonizing facilitates producing growth references 'on demand', for limited regional purposes, for ethnically, socio-economically or politically defined minorities, but also for matching geographically different groups of children and adolescents for international growth and registry studies.