Showing papers in "American Journal of Human Biology in 2000"

How sexually dimorphic are we? Review and synthesis

Abstract: The belief that Homo sapiens is absolutely dimorphic with the respect to sex chromosome composition, gonadal structure, hormone lev- els, and the structure of the internal genital duct systems and external geni- talia, derives from the platonic ideal that for each sex there is a single, universally correct developmental pathway and outcome. We surveyed the medical literature from 1955 to the present for studies of the frequency of deviation from the ideal male or female. We conclude that this frequency may be as high as 2% of live births. The frequency of individuals receiving "cor- rective" genital surgery, however, probably runs between 1 and 2 per 1,000 live births (0.1-0.2%). Am. J. Hum. Biol. 12:151-166, 2000. © 2000 Wiley-Liss, Inc.

Secular change in craniofacial morphology.

Abstract: Five craniofacial variables (glabella-occipital length, basion-bregma height, maximum cranial breadth, nasion-prosthion height, and bizygomatic breadth) were used to examine secular change in morphology from the mid-19(th) century to the 1970s. The 19(th) century data were obtained from the Terry and Hamann-Todd anatomical collections, and the 20(th) century data were obtained from the forensic anthropology databank. Data were available for Blacks and Whites of both sexes. Secular change was evaluated by regressing cranial variables on year of birth. Two analyses were conducted, one using the original variables and one using size and shape. Size is defined as the geometric mean of the cranial variables, and shape is the ratio of each variable to size. The results show remarkable changes in the size and shape of the cranial vault. Vault height increases in all groups in both absolute and relative terms. The vault also becomes longer and narrower, but these changes are less pronounced. Face changes are less than the vault changes, but to the extent that they occur, the face becomes narrower and higher. Overall cranial vault size has increased, but shape changes are greater than size changes. The magnitude of secular change in vault height exceeds that for long bones over a comparable time period, but follows a similar course, which suggests that vault height and bone length respond to the same forces. Changes in vault dimensions must occur by early childhood because of the early development of the vault. Am. J. Hum. Biol. 12:327-338, 2000. Copyright 2000 Wiley-Liss, Inc.

Effect of a change in selection year on success in male soccer players.

Abstract: Since 1997 and following the guidelines of the International Football Association, the Belgian Soccer Federation has used January 1st as the start of the selection year. Previously, August 1 was the start. This shift prompted an investigation of changes in birth-date distributions throughout youth categories for 1996-1997 compared to the 1997-1998 competitive years. Birth dates were considered for national youth league players, ages 10-12, 12-14, 14-16, and 16-18 years. Kolmogorov Smirnov tests assessed differences between observed and expected birth-date distributions. Regression analyses examined the relationship between month of birth and number of participants both before and after the August to January shift. RESULTS indicated that from 1996 to 1997, youth players born from January to March (the early part of the new selection year) were more likely to be identified as "talented" and to be exposed to higher levels of coaching. In comparison, players born late in the new selection year (August to October) were assessed as "talented" in significantly lower proportions. Specific suggestions are presented to reduce the relative age effect. Am. J. Hum. Biol. 12:729-735, 2000. Copyright 2000 Wiley-Liss, Inc. Language: en

Physical fitness, body fatness and physical activity: the Amsterdam Growth and Health Study.

Abstract: The purpose of this study was to examine sex-specific longitudinal relationships between physical fitness (cardiopulmonary and neuromotor fitness) and body fatness (sum of skinfolds) and to examine the influence of physical activity (weighted activity score) on these relationships. The data were obtained from the Amsterdam Growth and Health Study (AGHS), an observational longitudinal study of 98 females and 83 males, with six repeated measurements over a period from 13 to 27 years of age. The longitudinal relationship between body fatness and physical fitness was analyzed using generalized estimating equations (GEE). For each of the eight fitness items used as outcome variables, standardized regression coefficients were calculated for the relationships with body fatness and for the relationships with physical activity with and without correcting for height and weight. In all analyses, body fatness was inversely related to running speed, standing high jump, leg lift speed, and maximal oxygen uptake. Physical activity was positively related to leg lift speed and maximal oxygen uptake, and only in females to the standing high jump. Thus, body fatness is inversely related to most fitness items, while physical activity is positively related to only several fitness items. Further, body fatness and physical activity are independently related to physical fitness. Am. J. Hum. Biol. 12:593-599, 2000. Copyright 2000 Wiley-Liss, Inc.

Growth and nutritional status of rural South African children 3-10 years old: The Ellisras growth study.

Abstract: This study presents cross-sectional data from an ongoing mixed-longitudinal study of growth of rural children from Ellisras, South Africa. The physical growth and nutritional status of 1,335 children (684 boys, 651 girls), 3-10 years of age, was determined using standard anthropometric techniques. Weight-for-age, height-for-age, and weight-for-height were expressed as Z-scores of the NHANES I and II or NCHS reference sample. A Z-score of less than -2 was used as the cut-off point to determine the prevalence of stunting and wasting. Mean heights increased parallel to the 50(th) centile up to 6 years of age, thereafter both sexes diverged from the NHANES reference by approximately 0.5 cm per year. Mean weights followed a more consistent pattern from 3-7 years for both sexes, which was parallel to just below the 10(th) centile, but diverged between 8 and 10 years of age. Z-scores of weight-for-height in both sexes varied between -1 to -2 throughout the age range and BMI values were lower than the 5(th) centile of NHANES, indicating a significant amount of wasting within the sample. The sample exhibited a high prevalence of stunting, rising from less than 10% at 7 years to more than 30% by 10 years of age. Increments of the mean heights and weights indicate that the effects of stress may be a gradually accumulating process and that the growth increments of these children became increasingly poor in contrast to those of the reference sample. Since stunting in childhood is permanent, it may lead to a loss of physical work capacity in adulthood. Therefore, further investigation of the cause of poor growth among these rural children is imperative. Am. J. Hum. Biol. 12:42-49, 2000. Copyright 2000 Wiley-Liss, Inc.

Culture change and stress in Western Samoan youth: Methodological issues in the cross-cultural study of stress and immune function.

Abstract: This study was designed to pursue three objectives: 1) inves- tigate the impact of culture change on children and adolescents in Western Samoa; 2) introduce a cross-cultural perspective to studies of psychosocial stress and immune function; and 3) evaluate the utility of minimally invasive methods for assessing immune function. Seven hundred sixty individuals between the ages of 4 and 20 years were recruited from three distinct geo- graphic regions within Western Samoa that differ in degree of westerniza- tion. Finger prick samples of whole blood were collected from each individual and analyzed for antibodies against the Epstein-Barr virus (EBV; an indirect marker of cell-mediated immune function) and C-reactive protein (a nonspe- cific marker of current infection). After controlling for age, sex, and current infection, EBV antibody levels were significantly elevated in urban Apia and rural Upolu, indicating lower levels of cell-mediated immune function. The results suggest a higher degree of psychosocial stress in these regions, pos- sibly due to exposure to westernizing influences. Am. J. Hum. Biol. 12:792-

Familial resemblance in fatness and fat distribution.

Abstract: The purpose of the study was to estimate the degree of familial resemblance in anthropometric indicators of fatness and fat distribution. The sample consisted of 327 Caucasian participants from 102 nuclear families. Indicators of fatness included the body mass index (BMI), the sum of six skinfolds (SF6: triceps + biceps + medial calf + subscapular + suprailiac + abdominal), and waist circumference (WAIST), while indicators of fat distribution included WAIST adjusted for BMI (WAIST(ADJ)), the trunk-to-extremity skinfold ratio, adjusted for SF6 (TER(ADJ)), and the first principal component of skinfolds, adjusted for the mean skinfold of the individual (PC1). A general familial correlation model was fit to the data, and a series of nested reduced models were also fit so as to test hypotheses about familial resemblance. The hypothesis of no familial resemblance (all familial correlations are zero) was rejected for all phenotypes, indicating that fatness and fat distribution aggregate within families. For the three indicators of fatness (BMI, SF6, and WAIST), the sibling and parent-offspring correlations were significant. Further, there were no sex or generation differences in the familial correlations. For the three indicators of fat distribution (TER(ADJ), WAIST(ADJ), and PC1), there was no parent-offspring resemblance; sibling resemblance was significant for TER(ADJ) and PC1. Further, spouse resemblance was not significant for WAIST(ADJ), but was for TER(ADJ) and PC1. For both WAIST(ADJ) and PC1 there were significant sex differences in the familial correlations. A combination of models including no sex or generation differences and no spouse resemblance was the most parsimonious model for BMI, SF6, and TER(ADJ). The environmental model (all correlations equal) was the most parsimonious for WAIST, the model of no sibling resemblance was the most parsimonious for WAIST(ADJ), and the model of no spousal resemblance was the most parsimonious for PC1. Estimates of maximal heritability range from 46-60% for fatness and from 29-48% for fat distribution, independent of overall fatness, suggesting that in this sample the heritability of fatness is greater than that for fat distribution. Further, the pattern of correlations, which generally includes no spousal resemblance but significant parent-offspring and sibling correlations, suggests the role of genes in explaining at least part of the heritability. Am. J. Hum. Biol. 12:395-404, 2000. Copyright 2000 Wiley-Liss, Inc.

Daily physical activity and physical fitness from adolescence to adulthood: A longitudinal study.

Abstract: The stability of physical fitness and physical activity in Flemish males from 18 to 40 years of age was investigated. In addition, effects of a consistently low-activity or high-activity level during the same age period on physical fitness were studied. The sample consisted of males who were followed longitudinally from age 13 to age 18 years, and were remeasured at the ages of 30, 35, and 40 years. Complete data about physical fitness and physical activity between 13 and 40 years were available for 130 subjects. Stability was measured using Pearson autocorrelations and simplex models. Multivariate analysis of variance (MANOVA) for repeated measurements was used to look for the effects of activity level on physical fitness. Simplex models showed higher stability coefficients than Pearson correlations, and stability of physical fitness was higher than stability of physical activity. Physical fitness showed the highest stability in flexibility (r = 0.91 between 18 and 30 years, r = 0.96 for both the 30-35 and 35-40 ages intervals), while physical activity showed the highest stability during work (r between 0.70 and 0.98 for the 5-year intervals). Results from MANOVA indicated that for some fitness characteristics the high-active subjects were more fit than their low-active peers. Stability of physical activity was higher than assumed and, therefore, it is a useful and independent indicator for further research. Although possible confounding factors are present (e.g., heredity), a higher level of physical activity during work and leisure time on a regular basis benefits physical fitness considerably. Am. J. Hum. Biol. 12:487-497, 2000. Copyright 2000 Wiley-Liss, Inc.

Assessment of skeletal maturity of the hand-wrist and knee: A comparison among methods.

Abstract: This study evaluated the influence of height growth and nutritional status on skeletal maturation of the knee and hand-wrist. Radiographs of 589 subjects (250 girls and 339 boys) from 2 to 15 years were rated according to Greulich-Pyle, TW-20 bone and TW-RUS, RWT knee, and FELS hand-wrist methods and a method combining FELS and RWT indicators. The subjects were referred to the Genoa University Paediatric Department from 1980 to 1987 for short stature, simple obesity, or acute diseases. Bone age was closer to chronological age using the RWT knee method rather than the hand-wrist methods, while bone age assessed at the hand-wrist was closely related to height and BMI. When skeletal maturation was delayed, Greulich-Pyle, TW-20-bone, TW-RUS, and FELS bone ages tended to be lower than RWT knee estimates. Conversely, if maturation was advanced the hand-wrist estimates tended to be higher than RWT knee bone ages. The combined estimates are close to FELS bone age values. These findings show true intraindividual variability of skeletal maturity at the hand-wrist and knee. A certain "laziness" in knee maturation seems to be confirmed. Am. J. Hum. Biol. 12:610-615, 2000. Copyright 2000 Wiley-Liss, Inc.

Changes in menarcheal age in girls exposed to war conditions.

Abstract: The purpose of this study was to assess changes in mean menarcheal age of girls in the city of Sibenik in the period from mid-1980s to the mid-1990s. Sibenik is a Dalmatian town which was exposed to hard war conditions in 1991-1995. Menarcheal status of Sibenik girls was surveyed three times, in 1981, 1985, and 1996, and included 720, 1,207, and 1,680 girls, respectively, ages 9.5-16.5 years. Mean menarcheal age was estimated by the status quo method and application of probit analysis. Results show a slight decrease in menarcheal age from 1981 to 1985 (from 12.97 +/- 0.06 years to 12.87 +/- 0.05), and then a significant increase from 12.87 +/- 0.05 years in 1985 to 13.13 +/- 0.10 years in 1996. The increase in mean menarcheal age occurred in all socioeconomic groups based on parental occupation and number of siblings. In the group of girls whose homes were damaged during war, menarche occurred at an average of 13.53 +/- 0.14 years, while those who lost a family member experienced menarche at an older mean age, 13.76 +/- 0.27 years. However, when the girls who experienced personal tragedies were excluded the onset of menarche was still later than in girls surveyed in the earlier periods. The results suggest that the general reversal in the secular trend of menarcheal age in Sibenik girls can be attributed to persistent psychological pressures and uncertainties associated with conditions of war. Am. J. Hum. Biol. 12:503-508, 2000. Copyright 2000 Wiley-Liss, Inc.

Secular changes in relative leg length in post-war Japan.

Abstract: Longitudinal secular changes of height and estimated leg length (ELL) or subischial leg length of Japanese boys and girls were investigated using data published in "The Statistical Report of the School Health Survey" of the Ministry of Education, Science, Sports and Culture, Japan. A significant trend towards greater relative leg length (long-leggedness) among Japanese children and youth has occurred during the period of about four decades covered by this study. After showing a strikingly consistent trend at all age levels between 6 and 17 years and a dramatic trend during the birth-year age period 1943-1963, the relative growth in leg length has been rapidly slowing or has stopped in both sexes. The relative growth of ELL seemed to be fixed after 11 years in boys and 9 years in girls. Maximum increment ages (MIA), both in height and ELL, were used as estimates of the timing of maximum growth during the adolescent spurt. Regression analysis was used to demonstrate the overall trend patterns of MIA in height and ELL. After removing autocorrelation effects, MIA for height is accelerated by 0.03 year in both sexes, while the MIA in ELL is accelerated by 0.03 year in boys and 0.01 year in girls. Thus, MIA in ELL in girls is occurring earlier but to a smaller extent than in boys. The average maturity difference between boys and girls is 2.07 years in height, but 2.83 years in lower extremity length. Am. J. Hum. Biol. 12:405-416, 2000. Copyright 2000 Wiley-Liss, Inc.

Measurement of subcutaneous adipose tissue topography (SAT-Top) by means of a new optical device, LIPOMETER, and the evaluation of standard factor coefficients in healthy subjects.

Abstract: The quantification of obesity in respect to subcutaneous adipose tissue and fat distribution is a matter of interest. We recently reported on a new optical device, LIPOMETER, and its ability to measure the thickness of subcutaneous adipose tissue and its advantages compared with other methods. To describe the subcutaneous adipose tissue distribution of the human body in a precise, reproducible, and comparable manner, 15 well-defined body sites distributed from neck to calf on the right body side were used. This set of sites defines subcutaneous adipose tissue topography (SAT-Top). To visualize SAT-Top for subjects or groups, special SAT-Top plots were used. Subcutaneous adipose tissue distribution can be recognized easily with these techniques. SAT-Top of 590 healthy men and women was measured. Factor analysis was used to extract the essential information from these 590*15 intercorrelated single measurements and to provide standard factor coefficients for later applications. As an example of how to use the results of factor analysis, the strong SAT-Top deviation of women with clinically proven type-2 diabetes mellitus (NIDDM) from healthy controls is described. Am. J. Hum. Biol. 12:231-239, 2000. Copyright 2000 Wiley-Liss, Inc.

Surname frequency and the isonymy structure of Venezuela.

Abstract: Isonymy in Venezuela was studied analyzing the surnames of 3.9 million adults 40 years and older, selected from the register of electors updated in 1991. The electors were not differentiated by sex and represented all 22 states of Venezuela and its Federal District. The states of Nueva Esparta, an island, and Merida, in the Venezuelan Andes, have the highest coefficients of microdifferentiation (RST) and of inbreeding due to random isonymy. The states of Miranda, Aragua, Carabobo, and the Federal District, which includes the capital, Caracas, or are very close to it, had the lowest RST values. The weighted averages of Fisher's α, a measure of surname abundance, varied by state from 43 in Nueva Esparta to 226 in Miranda, with a value of 210 for the entire country, much smaller than those observed in Switzerland, Germany, or Italy (2,396, 2,855, and 5,855, respectively). The fact that 32% of the total Venezuelan sample has only 40 surnames easily accounts for this small α. The correlation between the Euclidean distance and the log of geographic distance between the capital cities of states in km is high and significant (r = 0.78). The dendrogram built with the Euclidean distance matrix indicates the presence of three main clusters. One is formed by 10 states located in the western-central part of the country. The states of Zulia and Falcon join this cluster at a distance of 0.54 Euclidean units. A second cluster is formed by Barinas and the three Andean states. After combining these two, a third cluster joins them, formed by six Eastern states. Finally, the state of Amazonas enters the dendrogram at a distance of 0.66 units. Am. J. Hum. Biol. 12:352–362, 2000. © 2000 Wiley-Liss, Inc.

Maternal height, pregnancy weight gain, and birthweight

Abstract: The Institute of Medicine recommends that short women gain less weight during pregnancy than taller women in order to reduce the risk of high birthweight, which can lead to feto-pelvic disproportion. This recommendation, however, is based on clinical judgment rather than on epidemiologic evidence, as few studies have examined the relationships between maternal height, pregnancy weight gain, and infant birthweight. Our objective was to determine whether maternal height is an independent risk factor for infant birthweight and to assess whether maternal height modifies the effect of pregnancy weight gain on infant birthweight. We examined the relationship between maternal height and infant birthweight in a multi-ethnic cohort of 8,870 women with uncomplicated pregnancies who delivered singleton infants at the University of California, San Francisco, 1980-1990. Using multiple linear regression, we modeled the contribution of height and weight gain to birthweight in four different ethnic groups. Increasing maternal height was significantly and positively associated with infant birthweight in White, Black, and Asian women, but not Hispanic women. The relationship between pregnancy weight gain and infant birthweight was not modified by maternal height. Am. J. Hum. Biol. 12:682-687, 2000. Copyright 2000 Wiley-Liss, Inc.

Influence of dietary quality on the growth of highland and coastal Ecuadorian children.

Abstract: This study examines variation in dietary patterns and its influence on physical growth among children under 60 months of age from rural households of highland and coastal Ecuador Differences in subsistence ecology between the regions appear to influence infant and early childhood feeding patterns Coastal children are weaned significantly earlier than their highland counterparts (median +/- SE = 159 +/- 17 vs 247 +/- 34 months) and have a weaning/supplemental diet that contains significantly more animal foods In both regions, growth retardation is most severe among infants (<12 months), with growth rates being poorer in the highlands than on the coast Linear growth rates among coastal infants are positively correlated with intakes of animal energy and animal protein, whereas among highland children energy intake from supplemental/weaning foods is negatively correlated with linear growth These divergent patterns appear to be a consequence of the differences in nutrient density of the weaning/supplemental diets Among the coastal infants, higher quality, nutrient dense foods augment breast milk and contribute to better growth rates In contrast, among the highland infants the more filling, less nutrient dense foods appear to be replacing breast milk, and thus compromising growth status In the older cohorts (ie, "weaning age" children: 120-359 months, and completely weaned children: 360-599 months), linear growth rates stabilize with little evidence of "catch up" growth in either region Improved weight gain, however, is seen among the highland children, and is correlated with the nutritional intake (ie, energy, total protein, and animal protein) from weaning foods Overall, marked growth stunting is seen in both regions, but is more pronounced in the highland children These high levels of stunting are largely established in the first 12 months of life Greater growth retardation among the highland children appears to reflect the influence of hypoxia as well as the lower nutrient density of weaning foods in that region Am J Hum Biol 12:825-837, 2000 Copyright 2000 Wiley-Liss Inc

Mitochondrial control-region sequence variation in the Corsican population, France.

Abstract: The mtDNA sequence variation of the hypervariable segment I of the control region was studied in 47 unrelated individuals of Corsican origin from Corte (Corsica, France). Thirty-one different sequences were identified by 40 variable sites, of which five involve transversions. The nucleotide diversity among the sequences was estimated as 1.03%. The pairwise difference agreed with the model proposed by Rogers and Harpending ([1992] Mol Biol Evol 9:552–569) and appeared bell-shaped, with only one peak at 3.71, indicating the occurrence of a single episode of demographic expansion roughly 14,443 to 41,584 years ago. From our results it seems that the ancestral Corsican population expanded more recently than all other studied European populations. Compared to other populations by genetic distances and a neighbor-joining tree, Corsicans appear most closely linked to the Basques and Sardinians than to other populations. Although the results substantiate an east-to-west migration, some problems are evident: 1) the estimates of demographic expansion are not in agreement with paleontological data; 2) the expansion occurred later than the expansion of the Sardinian population; and 3) the genetic affinity between Corsicans, Basques, and Sardinians. Answers will need to come from archaeological, paleontological, genetic, geological, and climatological observations. Finally, the study of mtDNA confirms what had already been shown with classic genetic markers. Am. J. Hum. Biol. 12:339–351, 2000. © 2000 Wiley-Liss, Inc.

Estimating percentage total body fat and determining subcutaneous adipose tissue distribution with a new noninvasive optical device LIPOMETER

Abstract: A newly developed optical device was applied to measure the subcutaneous adipose tissue (SAT) thickness of 20 healthy women and 18 healthy men at specified body sites. These measurements were used to derive equations to estimate percentage total body fat (TBF%). Total body electrical conductivity (TOBEC) was employed as a reference method; caliper techniques and measurements of absorbances of infrared light in fat versus lean tissue were also compared. The LIPOMETER results show good agreement with TOBEC data (r = 0.96). The technique allows the precise determination of the distribution of SAT thickness at specified body sites. The method also permits the construction of profiles of SAT thicknesses, e.g., the profiles are significantly different between women and men. Based on the normal profiles of healthy subjects, patients with proven type-2 diabetes mellitus were also evaluated. The patients showed significantly different profiles. By linear discriminant analysis, classification functions were extracted with good predictive accuracy classification of subjects according to the presence or absence of type-2 diabetes mellitus. The data suggest that measurement of SAT thickness might aid in the diagnosis and/or classification of metabolic disorders. Am. J. Hum. Biol. 12:221-230, 2000. Copyright 2000 Wiley-Liss, Inc.

Seasonal ecology and nutritional status of women and children in a Tanzanian pastoral community.

Abstract: Anthropometric dimensions for 180 women and 347 individual children (0-18 years) from a seminomadic population of Datoga pastoralists living in the Eyasi and Yaeda basins of northern Tanzania are used to assess the nutritional status of the population and the magnitude and prevalence of changes between late wet season and late dry season sampling periods (1989-1991). Results reveal high prevalence of undernutrition among both women and children. Almost one-half of all women were chronically energy deficient (BMI < 18.5) and were estimated to have very low fat stores. Moderate seasonal decreases in fat stores were observed in longitudinal, and also inferred in cross-sectional, samples of the women. The decreases were more marked among lactating individuals. Almost one-half of all children showed evidence of growth retardation due to undernutrition. There was some limited evidence of decreased adiposity among children in the dry period relative to the wet period. Although drier ecological conditions are associated with decreased fat stores among both women and children, the change is of small magnitude. Am. J. Hum. Biol. 12:758-781, 2000. Copyright 2000 Wiley-Liss, Inc.

Statistical effects of varying sample sizes on the precision of percentile estimates.

Abstract: The present study evaluates the precision of outlying percentile estimates, with age- and sex-associated variations and facilitates decisions needed to revise the current NCHS 1977 Growth Charts with regard to 1) the inclusion of 3(rd) and 97(th) percentiles and 2) the selection of survey data for the construction of the revised growth charts. Simulation was performed to obtain data with distribution characteristics similar to those of The Third National Health and Nutritional Examination Survey (NHANES III) (1988-1991) data. NHANES III consists of a two-phase, 6-year, complex stratified multistage probability cluster, cross-sectional survey conducted from 1988 through 1994 to represent the US noninstitutionalized population. Phase I of the survey consisted of 679 boys and 622 girls in age groups 3, 8, 13, and 18 years. Weight and stature, the body mass index (BMI) (weight/stature(2); kg/m(2)) was calculated. The results show that 1) the precision of the percentile estimates is greater for stature than for weight and BMI, 2) percentiles during the pubertal period are less precise than those during the prepubertal and postpubertal periods for weight and BMI but there is little difference for stature, and 3) percentile estimates are more precise for girls than boys for weight and BMI, but not for stature. The present findings suggest that pooling of NHANES III and earlier National Center for Health Statistics (NCHS) survey data is necessary to achieve reasonable precision for the 3(rd) and 97(th) percentile estimates. Am. J. Hum. Biol. 12:64-74, 2000. Copyright 2000 Wiley-Liss, Inc.

Association of dominant somatotype of men with body structure, function during exercise, and nutritional assessment.

Abstract: This study examined the hypothesis that somatotype determines body structure, functional responses at peak exercise, and nutritional status of 63 men ages 18-40 years who lived under controlled conditions. Data were grouped by dominant somatotype to emphasize differences in body types. Dominant ectomorphs (n = 19) had less (P < 0.05) body weight, fat weight, and percent body fat than endomorphs (n = 14) and mesomorphs (n = 30). Fat-free weight (FFW), total body potassium (TBK), and body cell mass (BCM), normalized for stature, were lower (P < 0.05) in the ectomorphs than in the endomorphs and mesomorphs. Comparisons between measured and predicted FFW and TBK showed that only the ectomorphs had less (P < 0.05) FFW and TBK than expected. Although all groups had the same peak power output, the ectomorphs had different functional responses during peak exercise. Ectomorphs had the greatest respiratory exchange ratio (P < 0.05), ventilatory equivalent for oxygen, and end-exercise plasma lactate concentrations (P < 0.05), and lowest peak oxygen uptake (L/min; P < 0.05). Nutrient intakes and blood biochemical markers of nutritional status were within the range of normal values in all groups. Correlations between measures of body structure, function, and nutritional status and dominant somatotype components were calculated after controlling for the effects of the other two somatotype components. Partial correlations were variable, with significant correlations ranging from -0.30 to 0.87. These data indicate that ectomorphs, as compared to endomorphs and mesomorphs, have deficits in FFW and BCM which are associated with differences in functional capacity. Am. J. Hum. Biol. 12:167-180, 2000. Published 2000 Wiley-Liss, Inc.

Basal metabolic adaptation of the Evenki reindeer herders of Central Siberia

Abstract: Previous research has suggested that basal metabolic rates (BMRs of indigenous circumpolar populations are elevated, perhaps as an adaptation to chronic, severe cold stress. This study examines variation in BMR among indigenous (Evenki) and nonindigenous (Russian immigrant) populations living in Central Siberia to determine: 1) whether the Evenki show evidence of increased metabolic rates, and 2) whether the metabolic responses of the Evenki are different from those of the recent Russian migrants ("controls"). BMRs were measured among 58 Evenki (19 men, 39 women) and 24 Russian (8 men, 16 women) adults (18-56 years of age) from three Siberian villages. Measured BMRs were compared to those predicted based on body weight and body SA (Consolazio et al., 1963; Schofield, 1985a,b). BMRs per unit weight and FFM were similar in Evenki and Russian men, whereas Evenki women had higher BMRs than their Russian peers. Relative to the Schofield (body weight) norms, Evenki men and women and Russian men all showed modest elevations in BMR, whereas Russian women had lower than expected BMRs. Compared to the Consolazio (surface area) estimates, both Evenki men and women showed significant elevations in BMR. Russian men also showed higher than expected BMRs, while those of Russian women were slightly below predicted levels. Age-related declines in BMR were evident among the women of both ethnic groups, but not among the men. Additionally, residence location was an important predictor of metabolic variation in the Evenki, with those of the more traditional village showing greater elevations in BMR. These results suggest that the Evenki display elevated metabolic needs, and this long-term adaptation reflects the interaction of genetics and level of acculturation. Am. J. Hum. Biol. 12:75-87, 2000. Copyright 2000 Wiley-Liss, Inc.

Anthropometric changes in urban Sardinian children 7 to 10 years between 1975-1976 and 1996.

Abstract: This study is a comparison of several anthropometric variables in school children of the same age (7-10 years) and sex measured in two primary schools in Cagliari (Sardinia, Italy) at an interval of 20 years (1996 vs. 1975-1976). For both males and females of each age-class, there are significant differences in the following dimensions: weight, stature, estimated lower limb length, biacromial breadth, xiphoid chest circumference, xiphoid chest depth, and bicristal breadth, and also in relative sitting height, cephalic index, and facial index. The means of the relative sitting height, cephalic, and facial indexes are higher in the children measured in 1975-1976 than in those measured in 1996. There are no significant differences in sitting height and arm length. In addition, the estimated BMIs of the 1975-1976 sample are, on average, lower than those of the 1996 sample. The results suggest that urban Sardinian children sampled in 1996 are generally taller, heavier, and larger and have a longer head and wider face than their peers of 20 years earlier. The increase in stature is due more to an increase in lower limb length than in sitting height. Am J. Hum. Biol. 12:782-791, 2000. Copyright 2000 Wiley-Liss, Inc.

The brush inquiry: An opportunity to investigate health outcomes in a well-characterized cohort.

Abstract: The Brush Inquiry was conducted in Cleveland, Ohio, from 1926-1942 to longitudinally document the growth and development of healthy children and adults. The Brush population was a heterogenous group with a broad representation of racial and socioeconomic groups. Data collection included radiographs of several parts of the body; motor, mental, and psychological tests; health, nutrition, and prenatal history; body measurements and family history. The early results of the inquiry were used to establish standards for normal childhood growth and development. Today, many of these subjects (88%) are in the age range of 60-80, facilitating the continuity of the inquiry to study early indicators for later health outcomes. This article reviews the origins of the inquiry, characteristics of the population, and the prospects for future research using this cohort. Am. J. Hum. Biol. 12:1-9, 2000. Copyright 2000 Wiley-Liss, Inc.

Empirical validation of an instrument to measure habitual physical activity in youth from Maputo, Mozambique.

Abstract: To develop a questionnaire to assess habitual physical activity in Mozambican children and youth, a study with school youth of Maputo was done. The study included the assessment of usual activities, development of the questionnaire, and testing its validity and reliability. The questionnaire was initially based on anecdotal observations of the usual activities of this population, then a sample of 20 children was observed during 24 h and interviewed the day before with a model that asked the subjects about the time spent in each activity. Fifteen days later the same students were interviewed with the questionnaire in order to test its validity. After another 15 days, the reliability of the questionnaire was tested. To score the questionnaire, estimation of metabolic equivalents (METS) of the socioculturally specific activities was done. This was based on published tables and heart rate monitoring of the children performing the activities listed on the questionnaire. Intraclass correlations between time observed and time reported ranged form 0.06-0.80, demonstrating limited capacity of the children to report time. However, percentage of agreement between the observations and the questionnaire concerning activity levels was 83%. It was concluded that the questionnaire may be a useful instrument for assessing the patterns of physical activity of African youth and for classifying groups according to levels of activity. However, it has limited utility for estimating energy expenditure. Am. J. Hum. Biol. 12:437-446, 2000. Copyright 2000 Wiley-Liss, Inc.

Change in food availability during pregnancy: Is it related to adult sudden death from cerebro- and cardiovascular disease in offspring?

Abstract: Maternal access to food during pregnancy affects birth weight and other characteristics of offspring. It has been suggested that fluctuations in food availability during infancy, ranging from plentiful to starvation, may influence cerebro-cardiovascular risk factors for the offspring during adult life. This study was designed to test the correlation between food availability changes during life before birth and adult sudden death from disease. This was a follow-up study of ancient cohorts in the parish of Skelleftea, Sweden, comprising 7,572 individuals born between 1805 and 1849 and still alive at age 40. Food availability variations in the parish during their prenatal life were ascertained from historical sources, the main outcome measures being overall mortality and mortality from sudden death in the age range 40-70 years. The risk of sudden death was almost doubled for those whose mothers were struck by a poor harvest during the early stages of pregnancy, but who experienced a good harvest toward the end. Yet almost the same over-risk was evident for the converse case: plentiful food supply in early pregnancy followed by a poor harvest toward the end. A stable maternal access to food during pregnancy is important for the offspring's risk of sudden death from cerebro- and cardiovascular disease as an adult. Am. J. Hum. Biol. 12:447-453, 2000. Copyright 2000 Wiley-Liss, Inc.