Age-specific variation in the secular trend for stature: A comparison of samples from industrialized and nonindustrialized regions

Age-specific secular trend patterns for children in industrialized world regions have a regular pattern, beginning low at age 6 and increasing to a maximum at age 10 to 14, then declining. While magnitude differs, the patterns are ordinarily parallel, especially in the female samples. However, age-specific secular trend values for children from developing regions, or from areas of industrialized countries not benefitting substantially from development, are irregular in pattern and magnitude. Consequently, it is difficult to predict age at maximal secular change. We suggest that fluctuating environmental circumstances in these developing countries influence growth and, hence, the pattern of secular trend. As more stable environmental conditions relating to growth are present in the industrialized countries, this leads to more stable patterns of growth and age-specific patterns of secular change.     

Old Jokes and New Multiculturalisms: Continuity and Change in Vernacular Discourse on the Yucatec Maya Language

ABSTRACT  Much recent literature on indigenous identity politics in Latin America has emphasized the emergence of new discourses on ethnic citizenship. However, the ways in which state-sponsored efforts to validate and revitalize the Yucatec Maya language become relevant to rural Yucatecans reflect far more continuity with older local narratives about the relationship between language use and modernity. Situating contemporary engagements with multicultural language policies within a broader history of locally meaningful language practices complicates the general model of indigenous language communities that has informed many recent studies of Latin American identity politics and reframes scholarly debates that have emphasized contrasts between emergent forms of essentialism or purism and more-traditional means of identity formation. This, in turn, suggests new routes through which multicultural and multilingual policies can be conceptualized for heterogeneous communities of indigenous language speakers.     

Age and secular factors in the stature of adult Zapotec males

Age and secular factors in adult stature were investigated in a sample of 111 Zapotec-speaking males from Oaxaca, Mexico. Comparisons with earlier studies showed no clear evidence of a secular trend. The increase in stature due to age and secular factors was approximately 0.07 cm per year (significant, p < 0.05). When stature was adjusted for the estimated age effects, the estimated secular increase was 0.03 cm per year (not significant). By this analysis a secular trend in adult stature of the magnitude noted for industrialized countries apparently does not occur in developing areas.     

Secular trend in the stature and weight of Mexican-American children in Texas between 1930 and 1970

Statures and weights for four samples of Mexican-American children in Texas, measured in 1929–1931 and 1968–1972, were evaluated for evidence of a secular trend. The age range was 6 to 18 years, with more complete data from 8 through 15 years. There is no secular increase in the statures and weights of 6 year old children, a small increase in 8 years old children, and a larger secular increase at 10, 12, 14, and 15 years of age. From about 9 or 10 years of age on, the more recent Mexican-American children tend to have greater weights for their heights. The magnitudé of the secular change per decade, however, is considerably smaller than rates for US black, white, European, and Japanese children. The estimated rates of secular change in stature for Mexican-American children approximate about one-fourth to one-half of the generalized rates for European and North American children offered by Meredith ('76) and Tanner ('77). Reasons for a limited secular trend in Texas Mexican-American children are probably bound to the matrix of lower socioeconomic circumstances, poorer health conditions, and marginal nutritional status.     

Lack of secular change in male adult stature in rural Mali (West Africa)

A study has been carried out on a sample of 2,158 male subjects between 20 and 50 years old representative of the rural Malian population (West Africa), and the results are compared with historic data obtained since 1885. This comparison suggests that there has been no modification in stature during this century. The analysis of each ethnic group does not show any disparity. Our results are in agreement with the theory that certain factors lead to the secular increase of stature in developed countries. These etiologic factors are not found in our West African population.     

The effects of aging and secular trend on adult stature in rural western Ireland

Cross-sectional data, consisting of anthropometric measurements for 347 adult males and 261 adult females in western Ireland measured during the 1930s, were used to determine the effects of aging and secular change upon stature. Estimates of statural loss due to aging were obtained using partial regression of stature on age while controlling for subischial length, and regression of the difference between observed stature and maximum predicted stature on age. Males show the effects of aging to a greater extent than do females. After correction for the effects of aging, the adjusted values of stature were regressed on age to estimate secular trend of stature. For males, there is a general increase of stature with time, excepting those born around 1878, while females generally show random variation with time. Both male and female adjusted stature decrease sharply around 1878, for which alternative historical explanations are proposed, relating to differential migration and survival.     

Secular trend in body size among college athletes.

Height and weight were compared across five birth decades (1850-1899) among 1,121 Harvard athletes who were lettermen in various sports. There were considerable differences in the magnitude of the secular trend among the sport categories (crew, baseball, football, track, ice hockey, and two or more sports). Comparing the 1890-1899 and 1860-1869 birth-cohort samples, football lettermen were 2.6 inches (6.6 cm) taller (p less than 0.001) and 20 pounds (9.1 kg) heavier (p less than 0.001). Crew lettermen were 2.6 inches taller (p less than 0.001) and 8.5 pounds (3.9 kg) heavier (p less than 0.05). For lettermen in other sports, changes in mean height and weight were smaller in magnitude. Differential selection for body size may explain the differences in the magnitude of the secular trend when analyzed by specific sport.     

The intensification of traditional agriculture among Yucatec Maya Farmers: Facing up to the dilemma of livelihood sustainability

This article discusses the change among Yucatec Maya farmers from traditional shifting milpa agriculture to intensive horticultural production for the Mexican market. The process of agricultural intensification among this group of peasant farmers has involved movement toward an increasingly sedentary form of production which has heightened reliance on the use of chemicals with negative consequences for the environment. The research, which focuses on the pressure on producers to abandon more sustainable forms of cultural controls against crop loss in favor of modern chemical controls, raises the issue of the transferability of sustainable traditional technology to small commercial farmers in the tropics. More specifically, the article draws attention to the sometimes overlooked issue of economic, as well as environmental, sustainability in discussions on agricultural development and resource management.Parts of this article were presented at the 89th Annual Meeting of the American Anthropological Association in New Orleans in November 1990, as well as at a conference in Mérida in Yucatan entitled La modernización de la milpa en Yucatán: utopía o realidad in May 1991.     

Differences in nutritional status between rural and urban Yucatec Maya children: The importance of early life conditions

Early-life conditions shape childhood growth and are affected by urbanization and the nutritional transition. To investigate how early-life conditions (across the “first” and “second” 1000 days) are associated with rural and urban children's nutritional status, we analyzed anthropometric data from Maya children in Yucatan, Mexico. We collected weight, height and triceps skinfold measures, then computed body mass and fat mass indices (BMI/FMI), in a cross-sectional sample of 6-year-olds (urban n = 72, rural n = 66). Demographic, socioeconomic and early-life variables (birthweight/mode, rural/urban residence, household crowding) were collected by maternal interview. We statistically analyzed rural-urban differences in demographic, socioeconomic, early-life, and anthropometric variables, then created linear mixed models to evaluate associations between early-life variables and child anthropometric outcomes. Two-way interactions were tested between early-life variables and child sex, and between early-life variables and rural-urban residence. Results showed that rural children were shorter-statured, with lower overweight/obesity and cesarean delivery rates, compared to urban children. Household crowding was a negative predictor of anthropometric outcomes; the strongest effect was in boys and in urban children. Birthweight positively predicted anthropometric outcomes, especially weight/BMI. Birth mode was positively (not statistically) associated with any anthropometric outcome. Cesarean delivery was more common in boys than in girls, and predicted increased height in urban boys. In conclusion, urbanization and household crowding were the most powerful predictors of Maya 6-year-old anthropometry. The negative effects of crowding may disproportionately affect Maya boys versus girls and urban versus rural children. Early-life conditions shape Maya children's nutritional status both in the “first” and “second” 1000 days.     

38年来济南、青岛儿童少年生长的长期变化

本文分析了济南、青岛1962—2000年7—18岁儿童少年生长发育的长期变化趋势。38年间,济南市7—18岁男女生身高平均增长15 48cm(男)、12 09cm(女),体重平均增长15 76kg(男)、10 01kg(女),胸围平均增长7 88cm(男)、4 10cm(女);青岛市7—18岁男女生身高平均增长17 12cm(男)、13 19cm(女),体重平均增长16 98kg(男)、10 46kg(女),胸围平均增长6 72cm(男)、3 05cm(女)。青岛市男女生身高的增长幅度显著大于济南。     

Adult stature and age at menarche in Zapotec-speaking communities in the Valley of Oaxaca,Mexico, in a secular perspective

Adult stature and the age at menarche among individuals from Zapotec-speaking communities in the Valley of Oaxaca in southern Mexico are considered in a secular perspective. Four sets of observations are utilized: (1) adult stature in males and females from five rural communities; (2) age at menarche in adult women and school girls from a single rural community; (3) earlier studies of adult stature in the Valley of Oaxaca; and (4) estimated stature from long bones excavated in various archaeological sites in the Valley of Oaxaca. There were no significant differences among the five communities for stature; hence, the data were pooled for analysis and comparison. Results of linear regression of stature and stature adjusted for the estimated effects of aging after 30 years of age on year of birth indicate negligible secular changes in either sex. Comparisons with statures from earlier surveys, the earliest dates to 1899, also indicate negligible changes. When adult women are grouped according to age, there are no differences in mean ages at menarche between the older and younger women. Mean age at menarche for the total adult sample is 14.53 ± 0.08 years, which compares favorably with the probit estimate for school girls, 14.70 ± 0.32 years. These results thus suggest virtually no secular change in adult size and maturity of the Zapotec-speaking population in the Valley of Oaxaca over the past 80 years. Differences in stature between contemporary populations and estimated statures from long bones from several archaeological sites in Oaxaca are small, and thus suggests little secular change over the past one to two–thousand years.     

Aging and secular change in adult stature in rural Colombia

Age-associated changes in adult stature of a cross-sectional sample of 634 adults from rural Colombia were estimated by multiple regression of stature and age controlling for subischial length, and from equations predicting maximum attained stature from subischial length. From these analyses the estimated rate of loss in stature due to aging per se for men was 0.12 cm/yr, while for women it was 0.03 cm/yr. When corrected for aging, several secular trends in adult stature were evident, although none were statistically significant.     

Secular trend and age distribution of cribra orbitalia in Japanese

Cribra orbitalia is currently regarded as an indicator of environmental conditions. The prevalence and severity of this lesion in Japanese populations from prehistoric Jomon to modern times were recorded and discussed. Since the lesion was low in both frequency and grade in the late and final Jomon people from Chiba Prefecture, they presumably lived in relatively favorable environmental conditions. The increased prevalence of the lesion in the medieval Muromachi citizens of Kamakura may be attributed to the poor hygiene and social conditions. The high prevalence and marked severity of the lesion in the citizens of Edo (the old name of Tokyo) in the 17th century suggested that they lived under extremely unfavorable situations of nutrition, sanitation and medical care. Cribra orbitalia was most prevalent in adolescence (81.3%) among the Edo citizens. The incidence of the most severe type of lesion rose gradually during childhood, reached a peak in adolescence, and then gradually decreased with age. These findings would reflect intense marrow hyperplasia in the orbital roof associated with both iron deficiency anemia of long standing during the immature period and increased iron requirement in adolescence. The results obtained support the hypothesis that iron deficiency anemia is the primary factor in the etiology of cribra orbitalia. It was concluded that the incidence and severity of cribra orbitalia due to various anemic reactions reflected the dietary, hygienic, social and environmental circumstances of the populations investigated.     

Pubertal origin of the larger sex dimorphism for adult stature of a Chilean population

Students aged 6 to 20 years attending the public schools in the Northern Area of Santiago, Chile, were examined to search for the developmental origin of the large sex dimorphism in adult stature found in this population. Stature, biacromial diameter, and signs of sexual maturation were studied and comparisons were made with European samples. All of the variables showed that Chilean females reach puberty earlier than, and cease growth before Europeans, while males mature at the same pace as Europeans. It is concluded that the large sex dimorphism in adult stature found in this sample is mainly due to this earlier cessation of growth in Chilean females.     

Secular change in growth of native children and adolescents at high altitude Huancayo,Peru (3,280 meters)

Stature and weight of native children, adolescents, and adults at Huancayo, Peru (3,280 meters), were measured in 1977, 1978, and 1982 and compared with mean statures and weights reported in previous studies. The data indicate that in Huancayo there has been a secular increment in child stature, sitting height, and weight from 1937 to 1978–1982. The observed changes in stature are related to a proportionally greater increment in leg length relative to trunk length. It is concluded that the observed secular increase in body size reflects changes in the standard of living and a greater influx of nonnative populations, which are usually characterized by greater stature than natives.     

Skeletal stature compared to archival stature in mid-eighteenth century American: Ft. William Henry

Fourteen soldiers buried at Ft. William Henry, New York, between 1755 and 1757 are compared for stature to a sample of 2,232 New York Provincial soldiers measured anthropometrically in 1760. The William Henry stature mean of 177.3 cm is significantly higher than that of the Provincials (169.7 cm), and their variation of stature is significantly lower-suggesting that the cemetery population was a select group. A historical explanation is offered for this unexpected finding.     

Sensitivity analysis for trend tests: application to the risk of radiation exposure

Trend tests are used to assess the relationship between multiple level treatment X and binary response R. In observational studies, however, there may be a confounder U that is associated with treatment X and causally related to response R. When the data for the confounder U are not observed, an approach for assessing the sensitivity of test results to U is provided. Its use is illustrated by examining data from a study of mutation rate after the Chernobyl accident.