Search PubMed⌕ Search

Biomedical subjects

W H Mueller

Publications and source records attributed to W H Mueller.

At least 73 records · Page 4Linked to original sources
PubMed1977

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.

Adult↗
PubMed1977

Genetic and environmental determinants of growth of school-aged children in a rural Colombian population.

Parent-offspring correlations and heritabilities of body measurements from midparent-offspring regressions are presented for school-aged children from the village of Tenza, Colombia (N = 403 families). Parent-child correlations and midparent regressions in this subsistence farming sample, are similar in magnitude to those for well nourished, urban industrial samples, suggesting that the environmental component of variability in body size is the same regardless of the environment. Tenza children are significantly shorter and lighter than upper class Bogota children, and Tenza parents have mean heights and weights similar to those of other lower class Colombian samples. Thus, chronic undernutrition has affected the growth of parents and continues to affect the growth of the present generation. Although it has been hypothesized that heritability of growth might be reduced in samples experiencing malnutrition and its sequelae, such a reduction may only be observable where environment of parents during their development is different from that of their offspring, which is not the case here. The pattern of heritabilities with respect to different body measurements in Tenza, is similar to that seen in well nourished samples, except that measurements of breadth (biacromial, bicristal, bicondylar) have heritabilities similar in magnitude to those of linear measurements (height, sitting-height, subischial length) especially in males; and heritabilities of some measurements related to adiposity are significantly higher in daughters than in sons.

Adult↗
PubMed1977

Sibling correlations in growth and adult morphology in a rural Colombian population.

Correlations for body measurement between members of 207 pairs of school-aged and 116 pairs of adult siblings in a mestizo farming community of the Colombian Andes are comparable to those from previous studies of well nourished urban-industrial samples, both in magnitude and pattern of heritabilities. While the genetic potential in physical growth is impeded by undernutrition and disease in childhood in samples such as the present one, hereditary influences on the variability of growth and adult size appear to be as important in such populations as they are in well nourished ones. School-aged sibs have significantly higher correlations than adult sibs and parent-offspring pairs for some measurements, suggesting environmental contributions in physical resemblance of siblings. Fatfold correlations between adult sisters are persistently higher than those of other sib pairings when socio-economic differences, age, and seasonal variation in nutrition are held constant, implying a greater genetic basis for adipose tissue in females.

Adult↗
PubMed1977

Age-associated statural loss and socioeconomic status.

Association between socioeconomic score (SES) and age-related statural loss were investigated in a cross-sectional sample of 718 adults from rural Colombia. Estimates of statural aging were calculated by estimating the maximum statural attainment of each subject from statural relationships with subischial length. Statural loss was correlated with SES, r=-0.06 (not significant) for men, and r=-0.14 (p less than 0.01) for women. Subjects with a high SES tended to lose stature at a slower rate than those with a low SES. For women, the difference in rates of statural loss between the low SES groups was significant (p less than 0.05).

Adult↗
PubMed1976

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.

Adult↗
PubMedDate not supplied

Blood pressure and sexual maturity in adolescents: the Heartfelt Study.

This study investigates sexual maturity as a predictor of resting blood pressures independent of other known predictors, in 179 boys and 204 girls 11-16 years of age from the Heartfelt Study. The sample included youth of African (n = 140), Mexican (n = 117), and European and "other" (n = 126) backgrounds. Sexual maturity was assessed during clinical examination of three standard indicators for each sex. Systolic and diastolic blood pressures were higher in children of maturity stages IV and V, compared to stages I-III, in each gender/ethnic group (P < 0.01 in almost all groups). Boys and girls advanced in sexual maturity for their age group, had significantly higher systolic blood pressures (but not diastolic) than the less advanced in linear models that included height, body mass index (BMI), ethnicity, and age as co-predictors. Diastolic blood pressures were predicted by height in boys and by age and the BMI in girls. This analysis, using a very conservative approach, suggests that sexual maturity provides important and independent information on systolic blood pressure in adolescents. Further investigation of its role in 24-hr blood pressures and in blood pressures taken during physical and emotional stress, is recommended.

Adolescent↗
PubMedDate not supplied

Anger expression, body fat, and blood pressure in adolescents: Project HeartBeat!

This study explores the potential influence of growth, body/composition, and sexual maturity on the relation of anger expression and blood pressure in adolescents. Baseline data from Project HeartBeat! (82 boys and 85 girls, 14 years of age) examined the ability of anger expression (STAXI scale) to predict blood pressure, after controlling for the effects of ethnicity (African-American/ non-African-American), height, weight, percentage body fat, and sexual maturity. Blood pressures were unrelated to anger expression in models that included the above developmental variables. However, girls scoring high on healthy anger expression ("anger-control") had significantly lower levels of percentage body fat (P = 0.015) independent of the above factors. The literature suggests that body fat or body mass is often, though not unanimously, associated with unhealthy forms of anger expression in adolescents. Research is required into the biological, social, and behavioral origins of the association between body fat and anger expression. Height and sexual maturity, virtually ignored in this literature, should be included in future research.

Adolescent↗
PubMedDate not supplied

Psychometric testing of the adolescent version of the Cook-Medley hostility scale.

Hostility, a phenomenon that has been linked to cardiovascular disease and all-cause mortality, is often measured by the Cook-Medley hostility (Ho) scale. Although there is an adolescent version of the Ho scale, it has had little testing with only Anglo-American samples. This pilot study tested the reliability and validity of the adolescent version of the Ho scale with a multiethnic sample of adolescents. Sixty adolescents participated. Reliability was measured using Chronbach's alpha. The Ho scale was correlated with the Speilberger State-Trait Anger Expression Inventory (1988) scales to determine concurrent validity. A factor analysis assessed construct validity; content validity was assessed by analyzing tape-recorded descriptions of a circumstance that provoked anger, as remembered by each adolescent. Internal consistency reliability was .75. The hostility measure was most highly correlated with anger expression (r = .62, p = .000) and trait anger (r = .50, p = .000). The factor analysis generated three factors (suspicious alienation, cynical aggression and justified mistrust), that accounted for 34.5% of the variance. The content analysis resulted in five anger-provoking themes: aggression, unfulfilled personal expectations, mistrust/lying, criticism of effort, and rejection. The majority of items in the scale (74%) were related to one of the themes.

Adolescent↗
PubMedDate not supplied

Strategies for combining and scaling sexual maturity indicators: the Heartfelt Study.

PRIMARY OBJECTIVE: To identify the best variable or combination of sexual maturity variables to use in investigations of adolescent health, and explore possible re-scaling of five-stage sexual maturity stages into dummy variables' ('advanced'/'delayed'). RESEARCH DESIGN: Cross-sectional. SUBJECTS: Tri-ethnic sample of 384 US adolescents 11-16 years of age (Heartfelt Study). METHODS: Sexual maturity variables are genital. breast and pubic hair stages obtained by clinical examination by nurse practitioners, testes size, menarche and age at menarche. RESULTS: Principal factor analysis of sexual maturity variables, height and age, revealed high commonality among the variables, as no more than a single factor appeared in 27 of 28 factor analyses (by sex and age groups). Genital stage (boys) and breast stage (girls) were most highly related to the first principal factor independent of age and ethnicity. ANOVA of 'key variables' indirectly reflecting endocrine function suggested that some stages could be combined. CONCLUSIONS: A single variable should suffice to describe sexual maturity at the studied ages, or variables could be combined in a (unstandardized) sexual maturity index (SMI): SMI (Girls)=0.998 x BREAST+0.900 x PUBIC HAIR + 1.815 x YEARS SINCE MENARCHE. SMI (Boys)= 1.104 x GENITAL + 1.328 x PUBIC HAIR + 5.997 x TESTES SIZE (mL).

Adolescent↗
PubMedDate not supplied

Utility of different body composition indicators: demographic influences and associations with blood pressures and heart rates in adolescents (Heartfelt Study).

PRIMARY OBJECTIVE: To compare the utility of 10 commonly used body composition indicators (BCIs) in relation to demographic characteristics and cardiovascular risk factors. RESEARCH DESIGN: A cross-sectional, school sample was studied. SUBJECTS: Three hundred and eighty-four Black, White and Hispanic adolescents 11-16 years of age from Houston, Texas, USA (Heartfelt Study) were studied. METHODS: BCIs include impedance and skinfold estimates of fat-free mass (FFM); fat mass (FM) and per cent body fat (PBF); resistance mass index (RMI); body mass index (BMI); and waist and abdomen circumferences. The cardiovascular risk factors (blood pressures/heart rates) are summarized by factor analysis. Sexual maturity was clinically assessed. RESULTS: Two distinct classes of BCIs emerged with respect to demographic influences: (1) RMI, impedance and skinfold estimators, for which sexual dimorphism is evident, and (2) BMI and circumferences, for which it is not. All BCIs were strongly related to general (systolic) blood pressure, but only body fat variables were related to heart rates. Skinfold-derived FM, PBF and mid-body circumferences were the variables most strongly related to cardiovascular risk factors. CONCLUSIONS: RMI, impedance or skinfold estimators are necessary for research requiring an accurate description of body composition changes during adolescence and for assessing the role of lean and fat tissue in disease aetiology. A 2-skinfold method is just as effective as the more complicated impedance. Mid-body circumferences are closely related to blood pressures and heart rates, suggesting their importance as indicators of abdominal fat in adolescents.

Adipose Tissue↗
PubMedDate not supplied

Colour-blindness in Colombia.

The frequency of defective colour vision was studied in two neighbouring villages in the Andes Mountains of Colombia using AO H-R-R Pseudoisochromatic plates. The frequency of the red-green colour-blindness in males is almost the same in both villages (2.36-2.53%), being similar to frequencies reported for other mestizo' populations in Latin America. In one of the communities, families in which colour-blindness occurred were wealthier (P is less than 0.05) than non-colour-blind families, but there were no significant differences by colour vision class in numbers of surviving children nor mother's marriage age. These findings are consistent with the idea that in societies at the agricultural level, colour-blindness is selectively neutral. The association of colour-blindness with higher socio-economic status is expected given the history of European conquest in the New World, and suggests that the major cause of varying rates of the defect in Latin American populations is socio-economic heterogeneity and by inference different degrees of European-Amerindian admixture.

Age Factors↗
PubMedDate not supplied

Genetic and environmental influences on growth of Philadelphia Black and White schoolchildren.

Sibling correlations in body size and composition are considered in 114 pairs of American Black and 101 pairs of White sibs, ranging in age from 6 to 12 years. Correlations were similar in the two races. Sibling resemblance was more or less similar for skeletal measurements (0.35-0.48), limb circumferences (0.41-0.43), and skinfolds (0.31-0.41). Age difference between members of a pair was found to affect the sibling correlations, especially for measurements of low genetic control. This is taken as evidence for environmental contributions to sibling resemblance. Higher sister-sister similarities in fat (as compared to brother-brother) were evident in Blacks (as they were in a rural South American sample) but not in Whites. This pattern could arise from similar sex-role differentiation in these two cultures (Afro and Latin American) or similar expression of sex-limited genes under less favourable environmental conditions.

Age Factors↗
PubMedDate not supplied

Fat patterning in athletes in relation to ethnic origin and sport.

Six skinfold measurements of 92 White, Black and Mexican-American high school varsity female athletes were analysed to identify principal components of fatness and relative fat patterning. As in other athletic and non-athletic samples, two principal components were evident: a first component, accounting for 69% of the variation, was positively related to all skinfold sites, and a second principal component, accounting for 11% of the variation, was correlated positively with extremity sites (particularly lower limb sites) and negatively with trunk sites. The first component (fatness) was significantly related to sport (P less than 0.02) but not ethnicity. The second component (extremity/trunk) was significantly related to ethnicity (P less than 0.01) but not sport. These results, although tentative due to the limited sample size, support our earlier findings on Olympic athletes, i.e., fatness is more influenced by sport and by training than is fat patterning.

Adipose Tissue↗
PubMedDate not supplied

Diabetes alert study: weight history and upper body obesity in diabetic and non-diabetic Mexican American adults.

History of adult weight gain and fat patterning is compared in Mexican American diabetics and age and sex matched non-diabetics. Diabetics differed little from non-diabetics in overall body fatness at the time of the examination. However, history of adult weight gain and current fat patterning were very different. Diabetics were heavier than non-diabetics at age 18. They subsequently gained weight faster and attained a substantially higher weight, at an earlier age, than non-diabetics. Discriminant function analysis was used to test for differences in patterning. Diabetics tend to have more trunk fat, as reflected particularly in the subscapular skinfold, and less lower extremity (leg) fat. Fat patterning in this population does not appear to be influenced by age when weight gain occurred, but is related to diabetic status, especially in women.

Adolescent↗