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.

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.

Growth variation, final height and secular trend. Proceedings of the 17th Aschauer Soiree, 7th November 2009.

Growth and body height have always been topics interesting to the public. In particular, the stupendous increase of some 15-19cm in final adult height during the last 150 years in most European countries (the "secular trend"), the concomitant changes in body and head proportions, the tendency towards early onset of sexual maturation, the changes in the age when final height is being reached, and the very recent trend in body mass index, have generated much scientific literature. The marked plasticity of growth in height and weight over time causes problems. Child growth references differ between nations, they tend to quickly become out of date, and raise a number of questions regarding fitting methods, effects caused by selective drop-out, etc. New findings contradict common beliefs about the primary importance of nutritional and health related factors for secular changes in growth. There appears to be a broad age span from mid-childhood to early adolescence that is characterised by a peculiar insusceptibility. Environmental factors that are known to influence growth during this age span appear to have only little or no impact on final height. Major re-arrangements in height occur at an age when puberty has almost been completed and final height has almost been reached, implying that factors, which drive the secular trend in height, are limited to early childhood and late adolescence.

Infant carrying: the role of increased locomotory costs in early tool development.

Among the costs of reproduction, carrying one's infant incurs one of the greatest drains on maternal energy, simply because of the added mass alone. Because of the dearth of archaeological evidence, however, how early bipeds dealt with the additional cost of having to carry infants who were less able to support their body weight against gravity is not particularly well understood. This article presents evidence on the caloric drain of carrying an infant in one's arms versus having a tool with which to sling the infant and carry her passively. The burden of carrying an infant in one's arms is on average 16% greater than having a tool to support the baby's mass and seems to have the potential to be a greater energetic burden even than lactation. In addition, carrying a baby in one's arms shortens and quickens the stride. An anthropometric trait that seems to offset some of the increased cost of carrying a baby in the arms is a wider bi-trochanteric width.

[Body height, body mass and head circumference in children from birth to 3 years of age]. / Körperlänge, Körpermasse und Kopfumfang bei Kindern von der Geburt bis zum 3. Lebensjahr.

Starting with a number of 3301 newborns body height, body mass and head circumference amongst other values were measured in a prospective anthropometric study. After 3 years 339 children could be measured again. Average values for the above measures were taken at birth and after 3, 12, 24 and 36 months. In addition to it the respective average speeds of growth were determined. During the first trimenon the children are growing very intensively. Concerning the absolute measures boys are mostly taller than girls. These differences decrease at the end of the third year of life. Girls have a larger speed of growth since the second year of life.

[Development of selected physical measurements with reference to body height (relative measurements) in children from birth to the 3 years of age]. / Entwicklung ausgewählter Körpermasse in Bezug zur Körperhöhe (Relativmasse) bei Kindern von der Geburt bis zum 3. Lebensjahr.

In 1985 a prospective anthropometric study was started in order to assess the development of newborns and infants. At birth 3301 children were measured and after 36 months again 339 children. From the measures taken, relative measures in percentage to body height were calculated. Within the first 36 months of life clear changes in the proportions could be seen. With the exception of the subscapular skinfold thickness the relative measures in boys are larger than in girls. This means that at this age boys are more robust than girls, although boys have less subcutaneous body fat.