Precision of recumbent crown-heel length when using an infantometer.

Background: Crown-heel length (CHL) measurement is influenced by technique, training, experience and subject cooperation. We investigated whether extending one or both of an infant's legs affects the precision of CHL taken using an infantometer. The influence of staff training and infant cooperation were also examined.

Validation of Maturity Offset in the Fels Longitudinal Study.

Sex-specific equations for predicting maturity offset, time before or after peak height velocity (PHV), were evaluated in 63 girls and 74 boys from the Fels Longitudinal Study. Serially measured heights (0.1 cm), sitting heights (0.

An update of the statistical methods underlying the FELS method of skeletal maturity assessment.

Background: Evaluation of skeletal maturity provides clinicians and researchers a window into the developmental progress of the skeleton. The FELS method for maturity assessment provides a point estimate and standard error based on 98 skeletal indicators.

Aim: This paper outlines the statistical methodology used by the original FELS method and evaluates improvements that address the following: serial correlation in the calibration sample is now considered, a Bayesian estimation method is now employed to improve estimation near ages 0 and 18 years and uncertainty in the calibration due to sampling is now accounted for when computing confidence limits.

Predicting the timing of maturational spurts in skeletal age.

Measures of maturity provide windows into the timing and tempo of childhood growth and maturation. Delayed maturation in a single child, or systemically in a population, can result from either genetic or environmental factors. In terms of the skeleton, delayed maturation may result in short stature or indicate another underlying issue.

Secular trends in the fat and fat-free components of body mass index in children aged 8-18 years born 1958-1995.

Background: It is unknown whether the secular trend in childhood BMI reflects increases in fat-free mass as well as fat mass.

Methods: This study decomposed BMI trends in 488 participants in the Fels Longitudinal Study born between 1958-1995 and aged 8-17.99 years into their fat and fat-free components.

The influence of age at menarche on cross-sectional geometry of bone in young adulthood.

Elucidating the somatic and maturational influences on the biomechanical properties of bone in children is crucial for a proper understanding of bone strength and quality in childhood and later life, and has significant potential for predicting adult fracture and osteoporosis risks. The ability of a long bone to resist bending and torsion is primarily a function of its cross-sectional geometric properties, and is negatively impacted by smaller external bone diameter. In pubescent girls, elevated levels of estrogen impede subperiosteal bone growth and increase endosteal bone deposition, resulting in bones averaging a smaller external and internal diameter relative to boys.

Cortical bone health shows significant linkage to chromosomes 2p, 3p, and 17q in 10-year-old children.

Genes play an important role in lifelong skeletal health. Genes that influence bone building during childhood have the potential to affect bone health not only throughout childhood but also into adulthood. Given that peak bone mass is a significant predictor of adult fracture risk, it is imperative that the genetic underpinnings of the normal pediatric skeleton are uncovered.

Clinical trials on sarcopenia: methodological issues regarding phase 3 trials.

Phase 3 trials estimate the effectiveness of an intervention to prevent, delay the onset of, or treat sarcopenia. Participants should have sarcopenia or present a sarcopenia risk profile. Control group should be characterized by the best standard of clinical care.

A genome-wide linkage scan for quantitative trait loci influencing the craniofacial complex in humans (Homo sapiens sapiens).

The genetic architecture of the craniofacial complex has been the subject of intense scrutiny because of the high frequency of congenital malformations. Numerous animal models have been used to document the early development of the craniofacial complex, but few studies have focused directly on the genetic underpinnings of normal variation in the human craniofacial complex. This study examines 80 quantitative traits derived from lateral cephalographs of 981 participants in the Fels Longitudinal Study, Wright State University, Dayton, Ohio.

Significant associations of age, menopausal status and lifestyle factors with visceral adiposity in African-American and European-American women.

Background: Elevated visceral adiposity is strongly predictive of cardiometabolic disease, but, due to the high cost of biomedical imaging, assessment of factors contributing to normal variation in visceral (VAT) and subcutaneous (SAT) adipose tissue partitioning in large cohorts of healthy individuals are few, particularly in ethnic and racial minority populations.

Objective: To describe age, menopausal status, smoking and physical activity differences in VAT and abdominal subcutaneous adipose tissue (ASAT) mass in African-American (AA) and European-American (EA) women.

Methods: Magnetic resonance imaging measures of VAT and ASAT mass and VAT% (VAT/VAT+ASAT, %) were obtained from a cross-sectional sample of 617 EA and 111 AA non-diabetic women aged 18-80 years.

Validity of adolescent diet recall 48 years later.

Few studies have evaluated the validity of adolescent diet recall after many decades. Between 1943 and 1970, yearly diet records were completed by parents of adolescents participating in an ongoing US study. In 2005-2006, study participants who had been 13-18 years of age when the diet records were collected were asked to complete a food frequency questionnaire regarding their adolescent diet.

Body composition methods: comparisons and interpretation.

The incidence of obesity in the United States and other developed countries is epidemic. Because the prevalence of comorbidities to obesity, such as type 2 diabetes, has also increased, it is clear there is a great need to monitor and treat obesity and its comorbidities. Body composition assessments vary in precision and in the target tissue of interest.

Genetic and environmental influences on infant weight and weight change: the Fels Longitudinal Study.

Despite significant progress in understanding the mechanisms by which the prenatal/maternal environment can alter development and adult health, genetic influences on normal variation in growth are little understood. This work examines genetic and nongenetic contributions to body weight and weight change during infancy and the relationships between weight change and adult body composition. The dataset included 501 white infants in 164 nuclear and extended families in the Fels Longitudinal Study, each with 10 serial measures of weight from birth to age 3 years and 232 with body composition data in mid-adulthood.

Quantitative genetics of cortical bone mass in healthy 10-year-old children from the Fels Longitudinal Study.

The genetic influences on bone mass likely change throughout the life span, but most genetic studies of bone mass regulation have focused on adults. There is, however, a growing awareness of the importance of genes influencing the acquisition of bone mass during childhood on lifelong bone health. The present investigation examines genetic influences on childhood bone mass by estimating the residual heritabilities of different measures of second metacarpal bone mass in a sample of 600 10-year-old participants from 144 families in the Fels Longitudinal Study.

Preschool diet and adult risk of breast cancer.

Events before puberty may affect adult risk of breast cancer. We examined whether diet during preschool age may affect a woman's risk of breast cancer later in life. We conducted a case-control study including 582 women with breast cancer and 1,569 controls free of breast cancer selected from participants in the Nurses' Health Study and the Nurses' Health Study II.

Early menarche and the development of cardiovascular disease risk factors in adolescent girls: the Fels Longitudinal Study.

The purpose of this study was to evaluate the influence of menarcheal age on changes in insulin, glucose, lipids, and blood pressure during adolescence and to assess whether body composition modifies this relationship. We examined 391 girls, a subset of Fels Longitudinal Study female participants (8-21 yr of age). Self-reported menarcheal age was classified based on the National Health and Nutrition Examination Survey III distribution, in which early menarche was at the 25th percentile or less (11.

Heritability of calcaneal quantitative ultrasound measures in healthy adults from the Fels Longitudinal Study.

Quantitative ultrasound (QUS) measurements of bone have been reported to predict osteoporotic fracture risk in postmenopausal women and older men. Although many studies have examined the heritability of bone mineral density (BMD), few studies have estimated the heritability of calcaneal QUS phenotypes. In the present study, we examined the genetic regulation of calcaneal QUS parameters in individuals from nuclear and extended families.

Measurement and standardization protocols for anthropometry used in the construction of a new international growth reference.

Thorough training, continuous standardization, and close monitoring of the adherence to measurement procedures during data collection are essential for minimizing random error and bias in multicenter studies. Rigorous anthropometry and data collection protocols were used in the WHO Multicentre Growth Reference Study to ensure high data quality. After the initial training and standardization, study teams participated in standardization sessions every two months for a continuous assessment of the precision and accuracy of their measurements.

Nutritional status assessed from anthropometric measures in the HEMO study.

Objective: Anthropometric methods are screening techniques for assessing nutritional stores of fat and lean tissues among persons with renal disease. This report presents cross-sectional baseline data on anthropometric indicators of nutritional status from a group of hemodialysis patients in a multicenter clinical trial, the Hemodialysis (HEMO) Study.

Design: The HEMO Study is a prospective, multicenter, randomized, 2 x 2 factorial clinical trial to evaluate the efficacy of the delivered dose of dialysis, defined by Kt/V, and membrane flux in reducing morbidity and mortality in (maintenance) hemodialysis patients.

Nutritional status affects quality of life in Hemodialysis (HEMO) Study patients at baseline.

Objective: To evaluate associations between frequently used indicators for assessing nutritional status and health-related quality of life in hemodialysis patients after controlling for demographics, comorbidity, and dialysis dose.

Design: Survey of 1,387 hemodialysis patients enrolled at baseline in the Hemodialysis (HEMO) Study. Nutritional status indicators included dietary energy intake, equilibrated normalized protein catabolic rate (enPCR), serum creatinine (SCr), serum albumin (SAlb), body mass index (BMI), calf circumference, and appetite.

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

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.

Balance and strength of elderly Chinese men and women.

The purpose of this study was to examine whether there was a difference between Chinese men and women in postural balance, and muscular strength and endurance; and the effect of participation and non-participation in regular exercise by these elderly Chinese adults on postural balance, and muscular strength and endurance. Chinese men (n = 328) and women (n = 210), age 65 to 80 years, were recruited as subjects (n=538). They were grouped by age: 65-69 (G1), 70-74 (G2), and 75-80 (G3) years old, and classified by exercise status as participation (E) and non-participation in regular exercise (NE).

Serial changes in blood pressure from childhood into young adulthood for females in relation to body mass index and maturational age.

This study determines: (1) patterns of change from childhood to young adulthood in body mass index (BMI), systolic blood pressure (SBP), and diastolic blood pressure (DBP), (2) effects of elevated BMI values on changes in blood pressures (BP), (3) extent of tracking for SBP, DBP, and BMI, and (4) prediction of future risk for elevated BP from earlier values. Annual serial BP and BMI data were available for 198 white females, ages 8-22 years, enrolled in the Fels Longitudinal Study. Patterns of change in BMI were described by a random effects model with a time series model for the correlated residuals.

Reliability for multiple frequency bioelectric impedance.

Multifrequency impedance may help to quantify body fluid compartments and levels of hydration among individuals. Most studies of bioelectric impedance use impedance machines operating at a frequency of 50 kHz, and observer error is low. The present study evaluates multifrequency impedance measurements at 15 frequencies from 5 to 1,300 kHz to determine observer reliability in 20 White subjects of each sex, 18-65 years of age.