Growth status of schoolchildren in a rural Zapotec community in the Valley of Oaxaca, Mexico, in 1968 and 1978

Stature, weight, arm circumference, triceps skinfold and estimated mid-arm muscle circumference were compared in schoolchildren, 6 to 14 years of age, in 1968 and 1978. The children were resident in a rural Zapotec-speaking community in the Valley of Oaxaca in southern Mexico. There were no differences in stature, weight and arm circumference over the ten-year period. Triceps skinfold and estimated mid-arm muscle circumference showed small, significant changes. Multiple classification analysis, adjusting for age and sex variation, indicated that schoolchildren in 1978 were slightly heavier and fatter, but also slightly shorter and less muscular than children in 1968. Results of this follow-up survey indicate little improvement in the growth status of rural Zapotec schoolchildren over ten years from 1968 to 1978, and are consistent with adult stature data which show little evidence of secular change over 80 years.

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 year 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 magnitude 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.

Heritability estimates of somatotype components based upon familial data

Somatotype components were obtained in 239 French-Canadian families from Montreal. Endomorphy, mesomorphy and ectomorphy were anthropometrically assessed in the Health and Carter system. All three components were available in 208 pairs of siblings, while only ectomorphy was estimated in 507 parent-child pairs. Sibling correlations reached 0.40 for endomorphy, 0.30 for mesomorphy, and 0.38 for ectomorphy. Partialling out the effects of 7 socioeconomic indicators permitted an estimate of common familial environment upon covariation between relatives. Residual sibling correlations yielded broad heritability estimates (HB) of 0.50 for endomorphy, 0.42 for mesomorphy and 0.54 for ectomorphy. Narrow heritability (HN) for ectomorphy, controlling for familial indicators, was approximately 0.36 including a positive contribution from assortative mating.

Weight at menarche in deaf girls

Weight at menarche of a mixed longitudinal sample of deaf American girls was analysed with regard to its variability and association with their earlier than normal age at menarche. The 'critical weight' hypothesis of Frisch and Revelle (1970, 1971) specifies the attainment of a certain body weight necessary for the onset of menstruation with a concomitant reduction in its variability. The findings herein suggest this hypothesis is not applicable to deaf girls.

Patterns of childhood mortality and growth status in a rural Zapotec community

Infant and childhood mortality (birth to 14 years), and growth status of 143 schoolchildren (5 to 14 years) are considered for a rural, Zapotec-speaking community (population, 1703) in the Valley of Oaxaca, Mexico. Mortality statistics are based on civil records from 1945 to 1970. Growth status is based on weight and height for age, and weight for weight for height. In the Zapotec community, about 59% of all deaths occur in children under 15 years of age; thus, a considerable percentage of individuals die before reaching reproductive age. Children under 5 years of age, however, account for approximately 54% of all deaths, and mortality in children 1 to 4 years of age is especially high (27% of all deaths). The latter figure suggests chronic malnutrition, frequent disease and generally poor circumstances in the community. This suggestion is supported in the heights and weights of schoolchildren, survivors of the rigorous selection processes of the pre-school years. The majority of children are below the 5th centile for stature in well-nourished American children. Weight for height, however, approximates that of the USA reference data.

Skeletal age and submaximal working capacity in boys

Skeletal age (SA) and Vo2 at a heart rate of 130 (Vo130) during work on a bicycle ergometer were measured in 237 boys 8-18 years of age. Analysis indicates that Vo130 is well correlated with SA, but also is equally well correlated with chronological age (CA), height and body weight. Age-specific correlations show that Vo130 is associated with SA from 12 through 16 years of age. Partialing out SA results in a significant decrease in the correlations of either height or weight with Vo130 only in the 12-16 year subgroup. The total common variance explained in Vo130 when regressed over CA, height and weight is affected by the presence of SA only in the 12-16 age subset. In spite of the high degree of multicollinearity among the independent variates, correlation data seem to indicate that SA and Vo130 have a slightly higher degree of relationship circumpuberally, i.e. between 12 and 16 years of age.

Age of menarche in Oaxaca, Mexico, schoolgirls, with comparative data for other areas of Mexico

Status quo menarcheal information was collected for a mixed urban colonia and rural sample of 315 girls in the Valley of Oaxaca, Mexico. Comparative status quo data for girls from four major urban centres in Mexico, and for a rural sample were also analysed. Median age at menarche (estimated by probit analysis) for Oaxaca girls was 14.27 +/- 0.20 years, about 0.5 year later than that for the rural sample from Tampico-Altamira, Tamaulipas (13.79 +/- 0.20 years), and approximately 1.5 years later than that for girls from the four urban centres in Mexico (12.55 +/- 0.10, 12.61 +/- 0.08, 12.75 +/- 0.10, 12.76 +/- 0.07 years). The timing of menarche in Oaxaca girls is similar to that for rural Mayans in Guatemala. Ages at menarche for urban Mexican girls are somewhat lower than those for girls of North-west European ancestry and of North American girls of European ancestry.

Age at menarche in deaf girls

Using the status quo and retrospective methods, age at menarche was estimated for a sample of 212 deaf girls 7 through 20 years of age. Median age at menarche via probit analysis was 11.91 +/- 0.25 years, while the mean based on recalled age in older girls (greater than or equal to 15.5 years) was 12.56 +/- 0.16 years. These two estimates thus differ by approximately 0.6 years. The probit estimate of median age at menarche in deaf girls is similar to mean ages reported for blind girls. However, the retrospective age is later. Thus, the present data are inconclusive as to whether the sensory deprivation imposed by deafness has an accelerating effect on menarche similar to that hypothesized for light deprivation in blind girls.

Submaximal working capacity, heart size and body size in boys 8-18 years

Heart diameters, heart volume (HV), PWC130, VO2 at 130 heart rate, and cardiorespiratory reactions during work at 3 kgm-s-1 were obtained in 237 boys ranging in age from 8--18 years. Results indicate that heart size, PWC130, VO130, and exercise HR, VO2/HR, f and SBP change significantly with age. On the other hand, HV - kg-1 and work VO2, VE and VE/VO2 remain rather stable throughout the growth period. Correlation analysis indicates that about 85% of the observed variation in the size of the heart during growth can be accounted for by the body weight, while about 70% of the variation in light submaximal working capacity (VO130) can be explained by HV alone. Holding age, height and body weight constant by partial correlation procedures yeilds significant relationships between HV and VO130 (r = 0.461), and between HV - kg-1 and VO130 (r = 0.414). Age, height, weight and size of the heart correlated simultaneously against VO130 account for 75% of the variance in the dependent variable. It would seem important to suggest the need for study of the interactions between age, size and maturity, in addition to indicators of size and efficiency of the oxygen delivery system, and indices of muscle oxygen utilization efficiency. Such an approach will permit a more definite partitioning of the variance in submaximal aerobic capicity during growth, and would probably yeild a more conservative estimate of the relationship between the size of the heart and submaximal working capacity during growth.

Stature and age as factors in the growth of second metacarpal cortical bone in moderately malnourished children

The association of stature and age with measures of second metacarpal cortical bone growth is investigated in a sample of 1586 radiographs taken from Guatemalan Ladino children aged 1-7 years in a setting of endemic mild-to-moderate malnutrition. For given stature, chronological age is positively associated with cortical thickness and cortical area and negatively associated with periosteal and medullary diameter. These different partial correlations are seen as evidence of different kinds of growth. Correlations of cortical bone variables with body size within a chronological age are shown to derive from the overall relationship between age, stature, and measures of cortical bone.

Sexual dimorphism in metacarpal dimensions and body size of Mexican school children

The hypothesis that patterns of sexual dimorphism in transverse dimensions of the metacarpal only reflect sex differences in body size was investigated in a sample of 324 Mexican school children 6.00-10.99 years of age. Several patterns of sexual dimorphism in second metacarpal dimensions are seen with regard to stature and weight. Sex differences in medullary diameter and percent cortical area are not related to sexual dimorphism in body size, while sex differences in cortical thickness are related to, but not fully explained by, differences in body size. Dimorphism in metacarpal diaphyseal diameter is related to differences in body size, but, at a constant body size and age, boys still have significantly larger diaphyseal diameters than girls. Finally, sexual dimorphism in cortical area is closely associated with sex differences in body size.

Sexual dimorphism in bone growth as a function of body size in moderately malnourished Guatemalan preschool age children

The sexual dimorphism in second metacarpal bone growth was investigated in 710 malnourished Guatemalan children one to seven years old to determine if the sex differences seen are only the result of differences in stature and weight. The study sample was mixed-longitudinal and consisted of 1,586 annual examinations. Boys have greater mean stature, weight, periosteal diameter, medullary diameter and cortical area than girls the same age, while girls have greater age specific mean cortical thickness and percent cortical area than boys. When the effects of stature, weight and age are removed boys still have significantly larger periosteal and medullary diameters and less cortical thickness and percent cortical area than girls. These differences between boys and girls therefore cannot be explained by sex differences in body size. However, no sex differences in cortical area remain after accounting for differences in stature, weight and age.

Differential contribution of stature phenotypes to assortative mating in parents of Philadelphia black and white school children

Assortative mating for stature, weight, and the ponderal and Quetelet's indices is considered in a large sample of Philadelphia Blacks and Whites. The husband-wife correlation for stature is positive and significant in Whites (r = 0.34, d.f. = 382), but negligible in Blacks (r = 0.06, d.f. = 420). Correlations for weight and the body indices are positive and significant in both samples, those for body indices showing some dependency on the husband-wife correlations for stature and weight. When couples are grouped into statural mating combinations on the basis of short (S), medium (M) and tall (T), White spouses' statures show an approximately linear relationship to one another. The distribution of Black spouses' statures, however, is not completely independent, even though the husband-wife correlation is close to zero. There are elements of both positive and negative assortative mating among Blacks, resulting in an excess of certain mating types over that expected on the basis of chance. These mating types are usually those in which the husband is shorter than the wife, except at the heterogenous extremes of the bivariate array.

Androgyny of physique in female track and field athletes

Androgyny scores (3 x biacromial breadth - bicristal breadth) were calculated for 66 female track and field five event categories and 76 female non-athletes. Runners (distance and sprinters) did not differ significantly from the non-athletes in androgyny. However, jumpers, discus/javelin throwers, and shotputters were significantly more androgynous in physique. Androgyny scores for participants in jumping and throwing events overlapped considerably those for college-age males.

Skeletal maturity of the hand and wrist in Oaxaca school children

Skeletal maturity of the hand and wrist (Tanner-Whitehouse II system) was assessed in a sample of 394 school children 5 to 18 years of age, in the city of Oaxaca, Mexico. The socio-economic background of the sample was relatively poor and the group appeared to have a poor nutritional history (via height and weight measurements). At most ages, the mean skeletal ages of Oaxaca school children are below the British means, and about 60 per cent of the children have skeletal ages below their chronological ages.

Relationships between skeletal maturity and submaximal working capacity in boys 8 to 18 years

Skeletal age (SA) height, weight, PWC130, Vo2 at 130 heart rate (Vo130) and cardiorespiratory adaptation to work at 3 kgm-sec-1 were measured in 237 boys ranging in age from 8 to 18 years. Correlations for the total population for the variables of the study are generally higher with SA than with chronological age (CA), although there is no significant difference between the two sets of correlations. Analysis of linear trend indicate that significant nonlinear components are more frequent in the relationships between the variables and SA than with CA.Multiple regression analyses for each variate as dependent variable indicate that height and body weight generally contribute more to the explained variance, while SA is the next best predictor. CA is the least significant of the four independent variables. The total variance explained between any of the submaximal working capacity related measures acting as dependent variable and CA, height and weight is not significantly affected by the presence or absence of SA. The present study thus indicates that SA is not a significant factor in explaining submaximal working capacity, beyond CA, height and weight, when considered over the 8 to 18 year age span. However, when considering shorter age spans, or when considering the adolescent period (12-16 years), SA correlates better with PWC130 (.320 less than r less than .675) and with Vo130 (.299 less than r less than .772).

Head and chest circumferences in rural Guatemalan Ladino children, birth to seven years of age

Growth patterns in head and chest circumferences are reported for a mixed-longitudinal sample of rural Guatemalan Ladino children from birth to 7 years of age. The sample is representative of a population with suboptimal nutrition. Both circumferences show similar rapid growth from birth through 9 months, after which chest circumference continues to increase more rapidly, while head circumference increases at a slower rate. Chest circumference provides nutritional information apparently not contained in length and weight. Compared to a sample of well-nourished children from Denver, the head circumferences of Guatemalan children are consistently smaller. Differences are relatively small at birth, are well established by 6 months, and become progressively greater through 24 months. After 2 years the mean smaller head circumference of the Guatemalan children also reflects stunted growth during the first 2 years of life. Similarly, among 5-year-old Guatemalan children of similar stature, head circumference at 5 years of age indicates which of these children were more stunted in stature at 2 years of age.

Length and weight in rural Guatemalan Ladino children: birth to seven years of age

The present study reports 5,029 length and weight measurements as well as percentile distributions for a mixed longitudinal series of 1,119 rural Guatemalan Ladino children. The study sample, birth through seven years, is representative of children in clinically good health, but of suboptimal nutrition. Boys are longer and heavier than girls over the age range. Guatemalan children of both sexes are smaller than American white children from Denver. Differences are least at birth, and increase through two years of age. Between two and five years, differences between the rural Guatemalan Ladino and Denver samples are rather stable, but then increase through seven years. Despite these differences there is a linear weight for length relationship which is the same across all preschool ages, both sexes, and for both the Guatemalan and Denver populations. This implies that age, sex, ethnic differences between the two groups compared, and mild-to-moderate protein-calorie malnutrition do not affect the relationship between weight and length in preschool children.

Nutritional status and the timing of deciduous tooth eruption

The number of deciduous teeth in a sample of rural Ladino Guatemalan children was counted every 3 months through 24 months of age, and at 6-month intervals from 24 to 36 months. Nutritional status at birth, whether expressed as full-term birth weight or as maternal caloric supplementation during pregnancy, influences the timing of deciduous tooth eruption. Furthermore, the timing of deciduous tooth eruption seems more closely associated with postnatal weight than with birth weight. Although indices of nutritional deficiencies are associated with retarded tooth eruption, the use of mean number of deciduous teeth erupted as an estimate of mean chronological age in populations living under conditions of mild-to-moderate malnutrition is relatively accurate because errors of age estimation based on mean values for the present sample only vary between 1 and 2 months.