Catch-up growth is a better indicator of undernutrition than thresholds for stunting.

OBJECTIVE: Stunting (height-for-age < -2 sd) is one of the forms of undernutrition and is frequent among children of low- and middle-income countries. But stunting perse is not a synonym of undernutrition. We investigated association between body height and indicators of energetic undernutrition at three critical thresholds for thinness used in public health: (1) BMI SDS < -2; (2) mid-upper arm circumference divided by height (MUAC (mm) × 10/height (cm) < 1·36) and (3) mean skinfold thickness (SF) < 7 mm and to question the reliability of thresholds as indicators of undernutrition. DESIGN: Cross-sectional study; breakpoint analysis. SETTING: Rural and urban regions of Indonesia and Guatemala - different socio-economic status (SES). PARTICIPANTS: 1716 Indonesian children (6·0-13·2 years) and 3838 Guatemalan children (4·0-18·9 years) with up to 50 % stunted children. RESULTS: When separating the regression of BMI, MUAC or SF, on height into distinguishable segments (breakpoint analysis), we failed to detect relevant associations between height, and BMI, MUAC or SF, even in the thinnest and shortest children. For BMI and SF, the breakpoint analysis either failed to reach statistical significance or distinguished at breakpoints above critical thresholds. For MUAC, the breakpoint analysis yielded negative associations between MUAC/h and height in thin individuals. Only in high SES Guatemalan children, SF and height appeared mildly associated with R2 = 0·017. CONCLUSIONS: Currently used lower thresholds of height-for-age (stunting) do not show relevant associations with anthropometric indicators of energetic undernutrition. We recommend using the catch-up growth spurt during early re-feeding instead as immediate and sensitive indicator of past undernourishment. We discuss the primacy of education and social-economic-political-emotional circumstances as responsible factors for stunting.

As tall as my peers - similarity in body height between migrants and hosts.

ABSTRACT: Background: We define migrants as people who move from their place of birth to a new place of residence. Migration usually is directed by "Push-Pull" factors, for example to escape from poor living conditions or to find more prosperous socio-economic conditions. Migrant children tend to assimilate quickly, and soon perceive themselves as peers within their new social networks. Differences exist between growth of first generation and second generation migrants. Methods: We review body heights and height distributions of historic and modern migrant populations to test two hypotheses: 1) that migrant and adopted children coming from lower social status localities to higher status localities adjust their height growth toward the mean of the dominant recipient social network, and 2) social dominant colonial and military migrants display growth that significantly surpasses the median height of both the conquered population and the population of origin. Our analytical framework also considered social networks. Recent publications indicate that spatial connectedness (community effects) and social competitiveness can affect human growth. Results: Migrant children and adolescents of lower social status rapidly adjust in height towards average height of their hosts, but tend to mature earlier, and are prone to overweight. The mean height of colonial/military migrants does surpass that of the conquered and origin population. Conclusion: Observations on human social networks, non-human animal strategic growth adjustments, and competitive growth processes strengthen the concept of social connectedness being involved in the regulation of human migrant growth.

Global effects of income and income inequality on adult height and sexual dimorphism in height.

OBJECTIVES: Average adult height of a population is considered a biomarker of the quality of the health environment and economic conditions. The causal relationships between height and income inequality are not well understood. We analyze data from 169 countries for national average heights of men and women and national-level economic factors to test two hypotheses: (1) income inequality has a greater association with average adult height than does absolute income; and (2) neither income nor income inequality has an effect on sexual dimorphism in height. METHODS: Average height data come from the NCD-RisC health risk factor collaboration. Economic indicators are derived from the World Bank data archive and include gross domestic product (GDP), Gross National Income per capita adjusted for personal purchasing power (GNI_PPP), and income equality assessed by the Gini coefficient calculated by the Wagstaff method. RESULTS: Hypothesis 1 is supported. Greater income equality is most predictive of average height for both sexes. GNI_PPP explains a significant, but smaller, amount of the variation. National GDP has no association with height. Hypothesis 2 is rejected. With greater average adult height there is greater sexual dimorphism. CONCLUSIONS: Findings support a growing literature on the pernicious effects of inequality on growth in height and, by extension, on health. Gradients in height reflect gradients in social disadvantage. Inequality should be considered a pollutant that disempowers people from the resources needed for their own healthy growth and development and for the health and good growth of their children.

Stature signals status: The association of stature, status and perceived dominance - a thought experiment.

SUMMARY: Background: There is a common perception that tall stature results in social dominance. Evidence in meerkats suggests that social dominance itself may be a strong stimulus for growth. Relative size serves as the signal for individuals to induce strategic growth adjustments. Aim: We construct a thought experiment to explore the potential consequences of the question: is stature a social signal also in humans? We hypothesize that (1) upward trends in height in the lower social strata are perceived as social challenges yielding similar though attenuated upward trends in the dominant strata, and that (2) democratization, but also periods of political turmoil that facilitate upward mobility of the lower strata, are accompanied by upward trends in height. Material and methods: We reanalyzed large sets of height data of European conscripts born between 1856-1860 and 1976-1980; and annual data of German military conscripts, born between 1965 and 1985, with information on height and school education. Results: Taller stature is associated with higher socioeconomic status. Historic populations show larger height differences between social strata that tend to diminish in the more recent populations. German height data suggest that both democratization, and periods of political turmoil facilitating upward mobility of the lower social strata are accompanied by a general upward height spiral that captures the whole population. Discussion: We consider stature as a signal. Nutrition, health, general living conditions and care giving are essential prerequisites for growth, yet not to maximize stature, but to allow for its function as a lifelong social signal. Considering stature as a social signal provides an elegant explanation of the rapid height adjustments observed in migrants, of the hitherto unexplained clustering of body height in modern and historic cohorts of military conscripts, and of the parallelism between changes in political conditions, and secular trends in adult human height since the 19th century.

Auxology - an editorial.

Auxology (Greek αυξω - I let grow) is the science of human growth and development. Significant public interest focuses on questions like: how does my child grow? How did our ancestors grow? How do other people around the world grow? Are there advantages to being tall and disadvantages to being short? Am I too fat? And many questions are related to the treatment of growth failure.

Modeling determinants of growth: evidence for a community-based target in height?

BACKGROUND: Human growth is traditionally envisaged as a target-seeking process regulated by genes, nutrition, health, and the state of an individual's social and economic environment; it is believed that under optimal physical conditions, an individual will achieve his or her full genetic potential. METHODS: Using a panel data set on individual height increments, we suggest a statistical modeling approach that characterizes growth as first-order trend stationary and allows for controlling individual growth tempo via observable measures of individual maturity. A Bayesian framework and corresponding Markov-chain Monte Carlo techniques allowing for a conceptually stringent treatment of missing values are adapted for parameter estimation. RESULTS: The model provides evidence for the adjustment of the individual growth rate toward average height of the population. CONCLUSION: The increase in adult body height during the past 150 y has been explained by the steady improvement of living conditions that are now being considered to have reached an optimum in Western societies. The current investigation questions the notion that the traditional concept in the understanding of this target-seeking process is sufficient. We consider an additional regulator that possibly points at community-based target seeking in growth.

The variation in age at menarche: an indicator of historic developmental tempo.

Ample literature describes the history of the association between the advances in the health and wealth of people, and mortality rates, life expectancy and adult height. Twenty-nine German studies with n > 200 subjects published since 1848 on menarcheal age, were reanalyzed, and 101 studies from various other European and non-European countries. On average, mean age at menarche declined since the mid-19th century. Historic urban samples tended to decline earlier than rural groups, upper class women earlier than working class women. In Germany, minimum values for the age at menarche were seen already between the two World Wars (Leipzig 12.6 years in 1934, Halle 13.3 years in 1939). Values for mean age and SD for age at menarche were strongly associated. With improving historic circumstances, the two parameters declined in parallel. The standard deviation for menarcheal age dropped from over 2.5 years in mid-19" century France to little more or even less than 1 year in most modern countries. In the German studies the correlation between menarcheal age and SD was almost complete with r = 0.96 (y = 0.35x - 3.53). Similar associations between mean age at menarche and SD for age were found in other European countries. The obvious and immediate effects of historic events on menarcheal age, and particularly on the age distribution, indicate that menarche is a sensitive indicator of public health and wealth, and may be an appropriate estimator for the socio-economic background of historic populations.

Statistical agreement and cost-benefit: Comparison of methods for constructing growth reference charts.

BACKGROUND: Growth reference charts are important tools for adequate paediatric decisions. AIM: In view of the workload required to construct empirical growth reference charts we debate practicable and less demanding alternatives and took the recent national 2000-2002 Lithuanian growth charts as an example. Two options appeared reasonable: (1) applying international WHO child growth standards and WHO growth reference data for 5-19 years that are recommended for global use; or (2) replacing the costly empirical method of deriving national growth references by more convenient low-cost statistics, e.g. the method of generating synthetic references for the Lithuanian population. METHODS: We analysed the degree of agreement between the 2000-2002 Lithuanian growth charts, and the international WHO child growth standards and WHO growth reference data for 5-19 years and synthetic references for the Lithuanian population using the Bland-Altman method. RESULTS: Synthetically generated references for the Lithuanian population slightly surpassed the national Lithuanian reference for body height (males +0.3 (SD 0.9) cm; females +0.2 (SD 0.6) cm) particularly at young age, which may be regarded clinically irrelevant. WHO international child growth standards and the WHO growth reference data for 5-19 years, however, failed to match the Lithuanian references as they underestimated mean height in boys by -2.8 (SD 1.4) cm and in girls by -2.9 (SD 1.1) cm, with extremely discrepant estimates of more than -6 cm occurring in several adolescent cohorts. CONCLUSIONS: The analysis revitalizes the debate on clinically relevant and at the same time practicable but less demanding alternatives for constructing growth reference charts, and for economic reasons, strongly suggests replacing the traditional empirical methods by synthetic growth references.

Village distance from urban centre as the prime modernization variable in differences in blood pressure and body mass index of adults of the Purari delta of the Gulf Province, Papua New Guinea.

OBJECTIVE: The study examined the extent to which the geographical proximity of villages to an urban centre and other modernization variables are associated with variation in blood pressure and body mass index (BMI) of adults of the Purari delta of the Gulf Province, Papua New Guinea (PNG). METHODS: Mean BMI, systolic blood pressure (SBP) and diastolic blood pressure (DBP) of 292 adults surveyed in 1995-1997 in the Purari delta, PNG, are reported by village of residence, and related to modernization variables, including village of residence, urban life, urban connectedness, economic status and education. RESULTS: Mean BMI, SBP and DBP differ according to village of residence, there being a gradient in mean blood pressure from highest in the village closest to the urban centre, Baimuru, and lowest in the village most distant from it. The gradients in these variables across the three villages are not due to differences in age structures between the villages. Place of residence, which represents the distance from town, has the greatest impact on the BMI of males, while among the females, the number of relatives living in urban centres had a significant effect on BMI. For both males and females, place of residence has the strongest effect on SBP. While for the males, place of residence is the only significant factor associated with SBP, for the females, SBP is also associated with BMI, level of income and to a lesser extent with age. Very similar results were obtained for DBP. CONCLUSIONS: Distance to urban centre appears to have a strong effect, relative to other modernization variables, on BMI and blood pressure, this effect being far stronger for males than for females. In large part, this effect operates by way of differences in number of sources of income as well as number of close relatives of women who are resident in an urban centre. Reasons for the male-female differences observed may include gender differences in degree of mobility, and possibly greater physical sensitivity of males to the environment than females. Traditionally, there have been clear divisions of labour between males and females, the latter spending longer in subsistence activities than the former. It is speculated that males have more free time to travel to town should they wish, while women may travel to town to take produce to market, and be limited by how much time they spend in town when they are there, by the need to return to carry out household and subsistence tasks. It may also be that young adult males are more susceptible to modernization, in that they exhibit a greater degree of non-conformity than young women, and may be more favourably disposed to adopt aspects of western lifestyle.