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Biomedical subjects

A F Roche

Publications and source records attributed to A F Roche.

At least 19 recordsLinked to original sources
PubMed1992

Serial changes in blood pressure from adolescence into adulthood.

High blood pressure is an established risk factor for cardiovascular disease outcomes in adulthood. Furthermore, numerous longitudinal studies of blood pressure in childhood with length of follow-up from 1 to 17 years indicate that blood pressure levels track over the short term. This study addresses the question of the predictive value of childhood blood pressure readings for adult levels, using repeated blood pressure determinations from a sample of 501 participants in the Fels Longitudinal Study, an ongoing cohort study in southwestern Ohio that began in 1929. A damped autoregressive model indicated tracking correlations from 0.39 (4-year intervals) to 0.24 (20 years) for systolic pressure and 0.37 (4 years) to 0.20 (20 years) for diastolic pressure. These results indicate that tracking of blood pressure persists from age 13 years to age 40 years, which translates into moderate levels of relative risk for adult hypertension (diastolic pressure above 90 mmHg) for adolescents with high normal blood pressure. The estimated relative risks of hypertension at age 35 for white 15-year-olds with a true mean diastolic pressure of 80 mmHg were 1.9 for males and 2.6 for females, relative to 15-year-olds with a true diastolic pressure of 60 mmHg.

Adolescent↗
PubMed1992

Bioelectrical impedance estimation of fat-free body mass in children and youth: a cross-validation study.

The purposes of this study were to develop and cross-validate the "best" prediction equations for estimating fat-free body mass (FFB) from bioelectrical impedance in children and youth. Predictor variables included height2/resistance (RI) and RI with anthropometric data. FFB was determined from body density (underwater weighing) and body water (deuterium dilution) (FFB-DW) and from age-corrected density equations, which account for variations in FFB water and bone content. Prediction equations were developed using multiple regression analyses in the validation sample (n = 94) and cross-validated in three other samples (n = 131). R2 and standard error of the estimate (SEE) values ranged from 0.80 to 0.95 and 1.3 to 3.7 kg, respectively. The four samples were then combined to develop a recommended equation for estimating FFB from three regression models. R2 and SEE values and coefficients of variation from these regression equations ranged from 0.91 to 0.95, 2.1 to 2.9 kg, and 5.1 to 7.0%, respectively. As a result of all cross-validation analyses, we recommend the equation FFB-DW = 0.61 RI + 0.25 body weight + 1.31, with a SEE of 2.1 kg and adjusted R2 of 0.95. This study demonstrated that RI with body weight can predict FFB with good accuracy in Whites 10-19 yr old.

Adipose Tissue↗
PubMed1991

Measures of body composition. Their relationship to blood pressure and use in epidemiologic research.

The association between "overweight" and increased risk of high blood pressure has long been recognized. The quantification of overweight into various aspects of body composition and the relationships of these aspects to blood pressure remain important areas of current research. The manner in which adipose tissue is distributed over the body is proving to be another important risk factor. Methodologies for assessing body composition include a variety of approaches commonly used in epidemiologic studies, ranging from simple indices (e.g., body mass index) to estimation of total body fat mass from equations based on skinfolds and other anthropometry, to newer approaches incorporating bioelectric impedance. Refined laboratory methods for assessing body composition are important in the study of small groups and in the development of predictive equations. These refined methods include the traditional approaches of hydrostatic weighing and K40 determinations, as well as newer improvements on these techniques incorporating estimates of bone mineral content and total body water. Other new sophisticated methodologies include dual-energy x-ray absorptiometry and nuclear magnetic resonance imaging. The approach to assessing body composition may vary among age groups; methodologies applicable to children may not work for the elderly.

Blood Pressure↗
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

Differences between the hand-wrist and the knee in assigned skeletal ages.

Skeletal ages were assessed for 4,902 pairs of hand-wrist and knee radiographs of children aged 2-17 years. The FELS method was used to assess the hand-wrist, and the RWT method was used to assess the knee. These methods have the same conceptual and statistical basis. The mean absolute differences, within age- and sex-specific groups, ranged from 0.34 to 0.87 years. The SD of the differences ranged from 0.31 to 0.68 years and, like the means, tended to increase with age until about 8-11 years. The means and SD were generally larger for the boys than for the girls, except after 14 years. Within age- and sex-specific groups, the maximum absolute differences were from 1.45 to 2.99 years. These maximum differences changed irregularly with age but tended to increase until 11 years in the boys and 9 years in the girls. These large absolute differences between the skeletal ages of the hand-wrist and the knee cannot be explained completely by the effects of observer errors. The means of the relative (signed) differences between the skeletal ages of the hand-wrist and the knee were all close to zero, but there was a wide range within age- and sex-specific groups. These skeletal ages of the hand-wrist and the knee are not interchangeable. The 95th percentiles of the absolute differences show that, in at least 5% of children, the choice of the area for skeletal age assessment will markedly influence the evaluation of individuals. They also demonstrate that descriptions of populations based on distributions of skeletal ages from one part of the skeleton may be misleading.

Adolescent↗
PubMed1979

Absence of triradius d in a three-generation pedigree and other variations of main-line D.

An example is reported of a rare dermatoglyphic variant (absence of triradius d) in a woman of mixed European and Cherokee American Indian ancestry. This variant was not present in her parents, her five siblings, four nephews or one niece. Attention is drawn to the continuum from an absent triradius d to a triradius with an abbreviated main-line associated with either an open field in interdigital area IV, or a loop in interdigital area IV or a tented arch at d. This same continuum occurs at c. The absent triradius at d is extremely rare and the tented arch at d is very rare.

Dermatoglyphics↗
PubMed1979

Physical growth: National Center for Health Statistics percentiles.

Anthropometry is an effective and frequently performed child health and nutrition screening procedure. The value of physical growth data depends on their accuracy and reliability, how they are recorded and interpreted, and what follow-up efforts are made after identification of growth abnormality. The new National Center for Health Statistics percentiles can be used to improve identification of potential health and nutritional problems and to facilitate the epidemological comparison of one group of children with others.

Adolescent↗
PubMed1979

Compressibility of skinfolds and the measurement of subcutaneous fatness.

Compressibility of subcutaneous fat thickness when measured with skinfold calipers was investigated in 65 white American youths. Compression of skinfolds was determined relative to measurements of subcutaneous fat thickness from radiographs at each of seven sites. There is statistically significant heterogeneity among sites in skinfold compression, with skinfolds on the medial and lateral calf being the least compressible of those measured. There is little statistically significant sex difference in skinfold compression in the present sample and, within the range concerned, there were no significant correlations between skinfold compressibility and age. When compressibilities of the seven skinfolds were intercorrelated within individuals, statistically significant average correlations were obtained, indicating that individuals tend toward similar degrees of skinfold compressibility among sites. This communality of skinfold compression within individuals is such that, at least in male youth, there are significant differences among individuals in the average compressibility of the seven skinfolds.

Adipose Tissue↗
PubMed1979

Physical growth in phenylketonuria: II. Growth of treated children in the PKU collaborative study from birth to 4 years of age.

Height, weight, and head circumference data up to age 4 years are reported for 124 children with phenylketonuria (PKU) who had been started on diet management before 4 months (121 days) of age and who were participating in the Collaborative Study of Children Treated for Phenylketonuria. Growth measurements of both the children and their parents corresponded with national and international standards. The growth of children with PKU was compared also with that of a group of normal children in the United States in whom corresponding longitudinal growth data had been obtained at the Fels Research Institute (FRI). Statistically significant differences betweeen the groups were not noted at any age. However, when these groups were compared on coefficients using curve fitting, a trend toward a greater increase in weight as they became older, noted in both sexes in the PKU study group, was significantly higher (P less than .005) in the PKU study girls compared with the FRI sample. Height growth was identical in both groups, and comparison with family data showed that the children with PKU grew as expected for their genetic endowment.

Body Height↗
PubMed1979

The effects of stimulant medication on the growth of hyperkinetic children.

This article reviews the literature on possible growth-suppressing effects of stimulant medications in the long-term treatment of children with the hyperkinetic behavior syndrome. The evidence clearly indicates a temporary retardation in the rate of growth in weight and suggests a temporary slowing of growth in stature, but no effect on adult stature or weight. This temporary effect on growth is present during the first few years of treatment and seems related to drug dosage and to the presence or absence of drug holidays. These conclusions related specifically to treatment during the prepubertal period; little is known of the growth-related effects of treatment extending through pubescence.

Adolescent↗
PubMed1979

Secular trends in human growth, maturation, and development.

Rates of growth during childhood have increased considerably during the past 50-100 years. Because they are associated with increased rates of maturation, these size increases are maximal at ages when recently measured groups are pubescent but those measured in the past had not reached pubescence. Large secular increases in rates of growth and maturation have occurred in all developed countries but not in many other countries. There have been secular increases in recumbent length at birth in Italy and France but little change in the United States. The secular increase in childhood stature is much more obvious, being about 1.5 cm/decade for 12-year-old children, although for young adults the secular increase in stature has been about 0.4 cm/decade in most developed countries. In the United States these trends have been similar for blacks and whites during childhood but greater for black men than white men. Similarly, secular trends in birth weights have been small, but there have been large trends for children (about 1.5 kg/decade for 12-year-olds). These secular changes in size have been associated with an acceleration of maturation that is most evident in the 0.3 years/decade advancement in age at menarche. This advancement has now ceased in Norway and England. The changes in body proportions during recent decades are less marked than those in body size. Leg length, particularly the length of the thigh, seems to have increased more than stature in men but not women; chest circumference has increased more rapidly than stature in each sex. The relationships between stature and weight have changed in different ways in various national groups. Similarly, the relative changes in head length and head breadth vary with the groups studied. Few sets of data allow conclusions about possible secular trends in body composition, but subcutaneous fat thicknesses have increased, especially at the upper percentiles. Also strength, which reflects muscle mass, has increased absolutely, although it has decreased relative to stature. Undoubtedly the secular trend is due to various factors; the identification of causes is necessarily speculative. Changes in nutrition alone could not account for the trends which exceed the original socioeconomic differentials. In the United States, there have been per capita increases in the intake of protein and fat from animal sources, decreases in carbohydrates and fat from vegetable sources, and little change in caloric intake. It is not clear that these changes constitute better nutrition. The secular trends could reflect environmental improvements, specifically changes in health practices and living conditions leading to improvements in mortality rates and life expectancy. These factors are interrelated with those concerning family size. Also genetic factors, especially heterosis, may have played a small role in causing the secular trends...

Body Composition↗