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Biomedical subjects

W C Chumlea

Publications and source records attributed to W C Chumlea.

At least 73 records · Page 4Linked to original sources
PubMed1992

Fat distribution and blood lipids in a sample of healthy elderly people.

The cross-sectional sample consisted of data for 41 white men and 63 white women, 67-92 years of age who were healthy volunteer participants in the Aging Process Study at the University of New Mexico School of Medicine in Albuquerque, New Mexico. The variables consisted of anthropometric measures of body fatness, blood lipids and blood pressures. Correlations were computed between principal component scores, ratios of body circumferences, W/S2, blood lipid values and blood pressures for each sex. In the men, the significant correlations were of the abdomen/hip and abdomen/thigh ratios with W/S2, and the principal component scores with HDL cholesterol, triglyceride and systolic blood pressure. In the women, the abdomen/hip ratio had a low negative correlation with HDL cholesterol but a low positive correlation with triglyceride levels. The principal component scores also had low correlations with blood pressure and triglycerides. Multiple regressions were used to determine further associations between risk factors and fat distribution indices. In the men, the relationships of age and levels of body fatness with HDL cholesterol were much stronger and more complex than those with triglyceride or systolic blood pressure. In the women, only HDL cholesterol and triglyceride were associated with abdomen/hip ratio after removing the effects of overall fatness. The present findings indicate that a large abdominal circumference, implying a correspondingly large internal adipose tissue deposit, produces negative health alterations in blood lipid levels in this sample of elderly individuals. In younger adults, these changes are considered to increase the risk for cardiovascular disease.

Adipose Tissue↗
PubMed1991

Reference data on gains in weight and length during the first two years of life.

Serial data from studies of infants at the University of Iowa and from the Fels Longitudinal Study were used to develop sex-specific percentiles for increments in weight and recumbent length for selected intervals during the first 24 months of life. Weight increments are presented for 1-month intervals from birth to 6 months, 2-month intervals from birth to 12 months, and 3-month intervals from birth to 24 months. Length increments are presented for 2-month intervals from birth to 6 months, and for 3-month intervals from birth to 24 months of age. Weights and lengths at the target ages were obtained for the Iowa data by simple interpolation, and for the Fels data by fitting families of three-parameter mathematical functions to the serial data from ages 1 to 24 months. The tabular presentations are based on the Iowa data from birth to 3 months of age, on the combined Iowa and Fels data from 3 to 6 months of age, and on the Fels data from 6 to 24 months of age. We believe that these reference data will be useful in screening for deviations from normal growth and may aid in early detection of failure to thrive or excessive weight gain during early life.

Age Factors↗
PubMed1991

Patterns of change in weight/stature2 from 2 to 18 years: findings from long-term serial data for children in the Fels longitudinal growth study.

Serial weight/stature2 (W/S2) data recorded semi-annually from 2 to 18 years in the Fels longitudinal study were analyzed to establish an approach for the investigation of long-term serial changes in body fatness during childhood and adolescence in individuals. To describe patterns of change in body fatness during childhood and adolescence, a family of mathematical models was fitted to individual serial W/S2 data recorded from 250 boys and 246 girls. The selected models fitted the W/S2 data well as judged by the root mean square errors. Based on the fitted models, variables representing patterns of change in an individual were derived. These included estimated value of W/S2 at 2 years of age (W/S(2)2yr), minimum value of W/S2 (W/S2min), age at minimum value of W/S2 (Amin), maximum velocity of W/S (Vmax), age at maximum velocity of W/S2 (AVmax), maximum value of W/S2 (W/S2max), and age at maximum value of W/S2 (Amax). There were highly significant correlations between observed W/S2 at 18 years and all the derived variables except AVmax indicating, for example, that in both sexes about 25 percent of the variation in W/S2 at 18 years could be explained by when Amin occurs or by the value of W/S2min. The negative correlations (r = -0.5) between Amin and W/S2 at 18 years suggested that the earlier children reach their nadir in W/S2, the earlier they began to increase in adiposity and the fatter they were at 18 years. Likewise, the positive correlations (r approximately 0.3 and 0.5, respectively) between the W/S(2)2yr or W/S2min and W/S2 at 18 years indicated that increased childhood adiposity may lead to increased adult adiposity.

Adipose Tissue↗
PubMed1990

Bioelectric impedance methods for the estimation of body composition.

The present use of bioelectric impedance is based upon the greater electrolyte content and conductivity of fat-free mass (FFM). The limitation of the whole body impedance approach may be the use of S2/R as an index of the conductive volume of the body. The use of body lengths that closely resemble the actual length of the conductor rather than stature can improve predictions of FFM. Theoretically, the specific resistivity approach to bioelectric impedance also provides a means of circumventing this problem. Another alternative is the estimation of whole body composition or the composition of body segments from measurements of the lengths and resistances of the segments and the use of the phase angle of the whole body and or body segments. Possible alternative methods for the use of bioelectric impedance would be the measurement of the composition of body segments, the determination of specific resistivities so that estimates of FFM can be calculated without the need for regression equations and the determination of the use of different current frequencies in measuring body composition with bioelectric impedance.

Body Composition↗
PubMed1989

Estimation of body composition from bioelectric impedance of body segments.

The hypothesis that body composition can be estimated accurately from measurements of the length and resistance of the body segments was tested. Weight; stature; whole-body resistance; and the resistances, lengths, and circumferences of the leg, trunk, and arm were measured for 135 white men and women aged 18-58 y. Fat-free mass (FFM) and percent body fat (%BF) were obtained from densitometry. The resistance of the whole body was determined almost entirely by the resistances of the arm and the leg. The accuracy of the prediction of FFM from arm length2/arm resistance and of %BF from weight x arm resistance/arm length2 was only marginally less than that obtained by using whole-body measurements. Thus, measurements of the resistance and length of the arm can be used in place of the whole-body methods for estimating body composition from bioelectric impedance.

Adipose Tissue↗
PubMed1989

Status of anthropometry and body composition data in elderly subjects.

Understanding the normal changes in the body and its composition with increasing old age and their health implications are important to the health care and nutritional support of elderly subjects. Distribution statistics for selected body measurements of persons aged 65-80 y are available from the national health surveys. Recumbent anthropometric techniques and B-mode ultrasound may be applicable to measuring those greater than 80 y who have difficulty standing or are chair- or bedfast. The problems of estimating body composition in elderly subjects could be improved by using a four-compartment model. Noninvasive methods, such as anthropometry and bioelectric impedance, could be used to predict body composition in elderly subjects if appropriate equations were available and validated against direct methods. The most pressing need is for the development of suitable reference data for anthropometry and body composition in large representative samples of black, white, Hispanic and Oriental elderly persons in the US.

Aged↗
PubMed1989

Associations between plasma lipoprotein cholesterols, adiposity and adipose tissue distribution during adolescence.

Associations between changes with age in 'fat pattern' and lipoprotein cholesterols during adolescence were analyzed using serial data for 214 boys and girls between 11 and 18 years of age who were participants in the Fels Longitudinal Study. The logarithms of the ratios of the subscapular to lateral calf and the subscapular to triceps skinfold thicknesses increased with age in each sex, but the increases were greater in the boys. Plasma levels of HDL cholesterol decreased with age in the boys, but not in the girls. Within annual age-groups, neither plasma LDL cholesterol nor HDL cholesterol were correlated with percent body fat or either of the 'fat pattern' indices in each sex. In 51 children with serial data 5 years apart, changes with age in HDL cholesterol had significant negative correlations with changes in the 'fat pattern' indices that were independent of changes in percent body fat in the boys, but not in the girls. In the girls, changes in the indices were due to greater increases in the thickness of the subscapular skinfold than in the triceps and lateral calf skinfolds as percent body fat increased and were not associated with changes in levels of plasma lipoproteins. In the boys, changes in the 'fat pattern' indices were due to decreases in the thicknesses of the lateral calf and triceps skinfolds and increases in thickness of the subscapular skinfold as percent body fat decreased. These results suggest that a redistribution of adipose tissue occurs during adolescence in boys and is associated with decreases in HDL cholesterol.

Adipose Tissue↗
PubMed1988

Bioelectric impedance phase angle and body composition.

The use of bioelectric impedance phase angle for predicting body composition was determined in 53 males and 69 females 9-62 y of age. The phase angle describes the amount of reactance (Xc) in a conductor relative to the amount of resistance (R). Bioelectric resistance (R) and reactance (Xc) were determined for the whole body and separately for arm, leg, and trunk. Weight, stature, and skinfold thicknesses were measured. Body composition was determined from densitometry. Phase angles for the trunk (phi t), leg (phi 1), and whole body (phi w) had significant (p less than 0.05) negative correlations with percent body fat (%BF) in each sex, and positive correlations with fat-free mass (FFM) in males. In multiple regression analyses, phi t was associated significantly with %BF after controlling for age, mean skinfold thickness, and weight/stature2 in each sex. Bioelectric phase angle for the trunk may be useful for predicting %BF in clinical and survey research.

Adipose Tissue↗
PubMed1988

Specific resistivity used to estimate fat-free mass from segmental body measures of bioelectric impedance.

This report provides estimates of specific resistivity for a sample of 123 children and adults aged 9-62 y. The mean muscle-specific resistivities for the upper and lower extremities (arm and leg) and trunk of these participants were used to compute estimates of fat-free mass (FFM) from the sum of the corrected total muscle conductive volumes of the arms, legs, and trunk. Mean values for predictions of FFM from S2/Z or from the product of total muscle conductive volume and the density of FFM were not significantly different from means of FFM estimated from body density by underwater weighing. This analysis demonstrates that an estimate of FFM can be obtained by summing the conductive muscle volumes of each body segment derived from the corresponding segment lengths squared, measures of bioelectric impedance, and mean muscle-specific resistivities. These mean estimates of FFM are not as accurate as mean predictions of FFM from S2/Z in regression equations.

Adipose Tissue↗
PubMed1988

Prediction of body weight for the nonambulatory elderly from anthropometry.

Body weight is one of the most important measurements in assessing nutritional status. Weight is also an important variable in equations that are needed to predict caloric expenditure and in indexes of body composition. Equations to predict the body weight of nonambulatory elderly persons with known errors should make use of body measurements that are indexes of the actual constituents of body composition and that can be collected regardless of an elderly person's level of mobility. The study samples consisted of a validation sample of 228 ambulatory white elderly persons, a cross-validation sample, and a clinical-validation sample of nonambulatory white elderly persons. Equations to predict body weight in the validation sample were derived from recumbent measures of arm and calf circumferences, triceps and subscapular skinfolds, and knee height. The accuracy, sensitivity, and validity of the equations were independently tested in the cross-validation sample; mean signed differences in actual and predicted weight ranged from 0.1 to 1.8 kg. In the clinical-validation sample, the mean differences were larger. Prediction equations are presented using two, three, and four body measurements to allow the selection of an equation based upon those measurements that are possible to collect from a nonambulatory person on an individual basis.

Aged↗
PubMed1987

Fatness and fat patterns: associations with plasma lipids and blood pressures in adults, 18 to 57 years of age.

As a part of the Fels Body Composition Study (an extension of the Fels Longitudinal Study in Yellow Springs, Ohio), the hypothesis was examined that a centripetal fat pattern, characterized by a greater proportion of trunkal than extremity adiposity, was associated independent of age and per cent body fat with levels of plasma lipids and lipoprotein cholesterols and blood pressures. A cross-sectional sample of 303 white men and women, 18 to 57 years of age, measured between September 1976 and August 1979, was selected without regard to diagnosis of hypertension, hyperlipidemia, or obesity. The degree of centripetal adipose tissue distribution was indexed by the logarithm of the ratio of the subscapular to lateral calf skinfold thicknesses. Per cent body fat was estimated by densitometry. In multiple regression equations controlling for age, age2, and per cent body fat, centripetal fat pattern had a small but significant positive association with systolic blood pressure in men (R2 = 0.02, p less than 0.05). In women, centripetal fat pattern had small but significant positive associations with plasma triglycerides (R2 = 0.05, p less than 0.005), and a significant negative association with plasma high density lipoprotein cholesterol (R2 = 0.08, p less than 0.0005) after effects due to age, age2, and per cent body fat had been removed. Centripetal fat patterns appear to be associated with an "atherogenic" lipid profile in women, but the association in men is confounded with effects due to age and total body adiposity.

Adipose Tissue↗