Secular Changes in Childhood, Adolescent and Adult Stature (original) (raw)
Related papers
Rapid change in height and body proportions of Maya American children
American Journal of Human Biology, 2002
Maya families from Guatemala migrated to the United States in record numbers from the late 1970s to the early 1990s. Births to Maya immigrant women have created a sizable number of Maya American children. The height and sitting height of 5 to 12 years children (n = 431) were measured in 1999 and 2000. Leg length was estimated and the sitting height ratio was calculated. These data were compared with a sample of Maya children living in Guatemala measured in 1998 (n = 1,347). Maya American children are currently 11.54 cm taller and 6.83 cm longer-legged, on average, than Maya children living in Guatemala. Consequently, the Maya Americans have a significantly lower average sitting height ratio (i.e., relatively longer legs in proportion to length of the head and trunk) than do the Maya in Guatemala. These results add support to the hypothesis that both the height and body proportions of human populations are sensitive indicators of the quality of the environment for growth. Am. J. Hum. Biol. 14:753–761, 2002. © 2002 Wiley-Liss, Inc.
American Journal of Human Biology
Objectives: Plasticity in the growth of body segments between populations has been researched in relation to migration, temporal change and highaltitude studies. We study the within population variation in body segments, thus controlling for some of the environmental and genetic differences that could be at play in between populations studies. We test a version of the thrifty phenotype hypothesis, where the growth of head-trunk and hand are prioritized due to their functional significance over height and leg growth. Materials and methods: A total of 3913 Guatemalan, rural, semi-urban and urban, Maya and Ladino children 6 to 15 years old were studied. Height, sitting height, leg length, and metacarpal length were studied in relation to three proxies for living conditions: height-and leg length-forage , and maternal education. Estimation statistics and null hypothesis significance testing were used to analyze the data. Results: Metatarsal length and sitting height values were higher than height and leg length respectively. Relative metacarpal length was conserved across height-forage groups. Females were less affected than males for metacarpal length and sitting height, but more affected for leg length. Conclusion: Our results agree with the thrifty phenotype hypothesis, where metacarpal and sitting height growth would be prioritized over height and leg length due to greater functional significance.
Anthropometric Variation and Health: A Biocultural Model of Human Growth
Journal of Children's Health, 2003
This review is a synthesis of the many strands of evidence for a biocultural model of human growth. The model allows use to better understand (??) the causes of variation and plasticity in human growth and development. The model helps us to identify and ameliorate factors that impair health, growth, and development. The biocultural perspective focuses on the recurring interaction between the biology of human development and the sociocultural environment. Not only does the latter influence the former, but human developmental biology modifies social and cultural processes as well. There are two essential messages of this synthesis. First, the biocultural nature of human growth and development is best understood via a life history perspective. The second essential message is that neither biology nor culture has primacy in human development. Rather, both work simultaneously and subtly during all stages of life to produce human phenotypic variability. That variability leads to individual and population differences in susceptibility to environmental disease. To illustrate these points, examples are given of the growth of ethnic Maya children and juveniles living in Guatemala and the United States, and Cape Verde immigrants living in Lisbon, Portugal.
Secular change in height, sitting height and leg length in rural Oaxaca, southern Mexico: 1968–2000
Annals of Human Biology, 2004
Objective: To evaluate secular changes in height, sitting height and estimated leg length between 1968 and 2000 in residents in a rural Zapotec-speaking community in Oaxaca, southern Mexico. Materials and methods: Height and sitting height were measured in school children 6-13 was estimated as height minus sitting height. The sitting height/ height ratio was calculated. Subjects were grouped by sex into four age categories: 6-9, 10-13, 13-17 and 19-29 years for analysis. The Preece-Baines Model I growth curve was fitted to cross-sectional means for 1978 and 2000. Results: There were no differences between children 6-9 and 10-13 years in 1968 and 1978 with the exception of the sitting height ratio in girls 6-9 years. Children of both sexes 6-13 years and adolescent boys 13-17 years were significantly larger in the three dimensions in 2000 compared to 1978; adolescent girls differed only in height and sitting height. Adult males in 2000 were significantly taller with longer legs than those in 1978, but the samples did not differ in sitting height and the ratio. Adult females in 1978 and 2000 did not differ significantly in the three dimensions. Rates of secular change in height and sitting height between 1978 and 2000 were reasonably similar in the three age groups of male children and adolescents, but the rate for estimated leg length was highest in 10-13-year-old boys. Secular gains were smaller in adult males, but were proportionally greater in estimated leg length. Girls 6-9 and 10-13 years experienced greater secular gains in height, sitting height and estimated leg length than adolescent and young adult females, while secular gains and rates decreased from adolescent girls to young adult women. Ages of peak velocity for height, sitting height and estimated leg length declined in boys, while only ages of peak velocity for height and estimated leg length declined in girls. Conclusions: There are major secular increases in height, sitting height and estimated leg length of children and adolescents of both sexes since 1978. Secular gains in height are of similar magnitude in boys and girls 6-13 years, but are greater in adolescent and young adult males than females. The secular increase in height of young adults of both sexes is smaller than that among adolescents. Estimated leg length accounts for about 60% of the secular increase in height in children of both sexes. Estimated leg length and sitting height contribute equally to the secular increase in height in adolescent boys, whereas estimated leg length accounts for about 70% of the secular increase in height in young adult males. Sitting height contributes about two-thirds of the secular increase in height in adolescent and young adult females.
American Journal of Physical Anthropology, 1992
The rate of growth in height and the timing of adolescent growth events are analyzed for two samples of Guatemalan children. One sample includes Mayan school children, 33 boys and 12 girls between the ages of 5.00 to 17.99 years, living under poor conditions for growth and development. The second sample includes ladino children, 78 boys and 85 girls of the same age range, living under favorable conditions for growth. The Preece-Baines model I function is used to estimate mean values for rates and timing of childhood and adolescent growth events for the two groups. Significant statistical contrasts (t-tests) of these means show Mayan boys reach the age of “take-off” (TO; the onset of the adolescent growth spurt) 1.45 years later, achieve peak height velocity (PHV) 1.68 years later, and continue growing for about 2.0 years longer than do the ladino boys. Despite the Mayan boys' increased duration for growth they grow significantly more slowly than the ladinos. Mayan boys are 6.60 cm shorter than ladinos at the age of TO and are estimated to be 7.71 cm shorter than the ladinos at adulthood. Mayan girls reach the age of TO 0.93 years later than do the ladina girls, but the two groups do not differ in the age at PHV or the age at adulthood. The mean height of Mayan girls is significantly less than that of ladinas at the age of TO (6.5 cm), and this difference increases to an estimated 11.14 cm at adulthood. Possible causes of these ethnic and sex-related differences in amounts and rates of growth are discussed in relation to hypotheses about the genetic and environmental determinants of human development. © 1992 Wiley-Liss, Inc.
Longitudinal growth in height, weight, and bone age of Guatemalan Ladino and Indian schoolchildren
American Journal of Human Biology, 1989
Three longitudinal samples of Guatemalan schoolchildren are compared for amounts and rates of growth in height, weight, and bone age. The samples include children of two ethnic backgrounds: Ladinos, Spanish-speaking people of, generally, Western cultural orientation; and Indians, people of Mayan cultural descent. The Indians are of very low socioeconomic status (SES) and attend a public school in a rural village. The Ladinos come from two SES groups living in Guatemala City, one of high SES attending a private school and the other of low SES attending a public school. Graphical and statistical analyses show that for all samples of boys and girls there are generally, significant differences between samples (high SES>low SES>Indian) for amounts of growth in height, weight, and bone age. Boys show significant differences in rates of growth between samples, with the high SES sample growing more rapidly than the two low SES samples. Girls show significant differences in the rate of growth in height, but not in the rate of growth in weight or bone age. For Both boys and girls, rates of growth in height and weight differ more between samples than does rate of Skeltal development. These results demonstrate that (1) SES-related deficits in growth are cumulative during childhood and early adolescence, that (2) rates of growth for boys are, generally, more sensitive to the influence of SES than are the growth rates of girls, and that (3) childhood growth deficits of low SES children of low SES children are likely to carry over into adulthood.
American Journal of Physical Anthropology, 1982
Three groups of children, those of European parentage, those of Guatemalan parentage, and those of mixed European-Guatemalan parentage were measured for height, weight, and skeletal maturity. The children were born between 1945 and 1965, they were all of high socioeconomic status, and they all attended the same private school in Guatemala City. At 7 years, the boys of the European group were significantly taller than boys of the Guatemalan group. European and mixed European-Guatemalan girls were significantly taller than Guatemalan girls. These results are maturity independent. The influence of skeletal age was removed statistically by analysis of covariance. Girls of the mixed group were significantly heavier than girls of European and Guatemalan groups. Mixed group girls also had more significantly advanced skeletal ages than European girls. When the patterns of size and maturity status are analyzed by sex, there is evidence for a relatively greater environmental influence on the boys and a relatively greater genetic influence on the girls. Dividing the data into two birth year cohorts, 1945 to 1955, and 1956 to 1965, does not provide evidence for secular trends in growth or maturation. These results are similar to those from studies in developed nations that report an end to the secular trend for the “well off” population of those countries.
Evolutionary Perspective in Child Growth
Rambam Maimonides Medical Journal, 2011
Hereditary, environmental, and stochastic factors determine a child's growth in his unique environment, but their relative contribution to the phenotypic outcome and the extent of stochastic programming that is required to alter human phenotypes is not known because few data are available. This is an attempt to use evolutionary life-history theory in understanding child growth in a broad evolutionary perspective, using the data and theory of evolutionary predictive adaptive growth-related strategies. Transitions from one life-history phase to the next have inherent adaptive plasticity in their timing. Humans evolved to withstand energy crises by decreasing their body size, and evolutionary short-term adaptations to energy crises utilize a plasticity that modifies the timing of transition from infancy into childhood, culminating in short stature in times of energy crisis. Transition to juvenility is part of a strategy of conversion from a period of total dependence on the family and tribe for provision and security to self-supply, and a degree of adaptive plasticity is provided and determines body composition. Transition to adolescence entails plasticity in adapting to energy resources, other environmental cues, and the social needs of the maturing adolescent to determine lifespan and the period of fecundity and fertility. Fundamental questions are raised by a life-history approach to the unique growth pattern of each child in his given genetic background and current environment.