Rapid infant weight gain and advanced skeletal maturation in childhood.

OBJECTIVE: To test the hypothesis that rapid infant weight gain is associated with advanced skeletal maturity in children from the United States and South Africa. STUDY DESIGN: Longitudinal data from 467 appropriate-for-gestational-age infants in the Fels Longitudinal Growth Study (Dayton, Ohio) and 196 appropriate-for-gestational-age infants in the Birth to Twenty birth cohort study (Johannesburg, South Africa) were used. Multiple linear regression models tested the association between internal SD score change in weight from 0 to 2 years and relative skeletal age at 9 years, adjusting for body mass index, stature, and other covariates. RESULTS: In both studies, faster infant weight gain was associated with more advanced skeletal maturity (approximately 0.2 years or 2.4 months per SD score) at age 9 years (P <.0001-.005), even when adjusting for the positive associations of both birth weight and body mass index at age 9 years. This effect appeared to be accounted for by the greater childhood stature of subjects with more rapid infant weight gain. CONCLUSIONS: Relatively rapid infant weight-gain is associated with advanced skeletal development in late childhood, perhaps via effects on stature.

Visceral adiposity and its anatomical distribution as predictors of the metabolic syndrome and cardiometabolic risk factor levels.

BACKGROUND: Despite the recognition that central obesity plays a critical role in chronic disease, few large-scale imaging studies have documented human variation in abdominal adipose tissue patterning. OBJECTIVE: We aimed to compare the associations between abdominal subcutaneous adipose tissue (ASAT) and visceral abdominal tissue (VAT), which were measured at different locations across the abdomen, and the presence of the metabolic syndrome (MS; National Cholesterol Education Program Adult Treatment Panel III definition) and individual cardiometabolic risk factors. DESIGN: This study included 713 non-Hispanic whites aged 18-86 y, in whom VAT and ASAT were assessed by using multiple-image magnetic resonance imaging. The anatomical position of the magnetic resonance image containing the maximum VAT area for each subject was used as a measure of VAT patterning. Multivariate linear and logistic regression analyses were used to examine the relation of VAT, ASAT, and VAT patterning to cardiometabolic risk. RESULTS: VAT mass was a stronger predictor of the MS than was ASAT mass, but ASAT mass (and other measures of subcutaneous adiposity) had signification interactions with VAT mass, whereby elevated ASAT reduced the probability of MS among men with high VAT (P = 0.0008). There was variation across image locations in the association of VAT area with the MS in men, and magnetic resonance images located 4-8 cm above L4-L5 provided the strongest correlations between VAT area and cardiometabolic risk factors. Subjects whose maximum VAT area was higher in the abdomen had higher LDL-cholesterol concentrations (R(2) = 0.07, P < 0.0001), independent of age and adiposity. CONCLUSION: Further studies are needed to confirm the effects of VAT patterning on cardiometabolic risk.

Anatomical patterning of visceral adipose tissue: race, sex, and age variation.

OBJECTIVE: We tested sex, race, and age differences in the patterning of visceral adipose tissue (VAT) and subcutaneous adipose tissue. RESEARCH METHODS AND PROCEDURES: Contiguous 1-cm-thick magnetic resonance (MR) images of the abdomen were collected from 820 African-American and white adults. Repeated-measures ANOVA was used to examine the effects of image location, sex, race, and age (>or=50 vs. <50 years) on adipose tissue areas. Maximum VAT area was identified for each subject from the raw data. RESULTS: Compared to women, men had greater total VAT volume (p < 0.0001), and their maximum VAT area occurred higher in the abdomen (p < 0.0001). Among white men, maximim VAT area most frequently occurred 5 to 10 cm above L4-L5, whereas in the other groups, maximim VAT area most frequently occurred 1 to 4 cm above L4-L5 (p < 0.0001). African-American men had greater total VAT volume than African-American women (p < 0.01), but this sex difference was only significant using single images cranial to L4-L5 + 2 cm. Age-related increases in VAT tended to be greatest 5 to 10 cm above L4-L5 in men and near L4-L5 in women. DISCUSSION: A single MR image 5 to 10 cm above L4-L5 may allow more accurate conclusions than the L4-L5 image regarding group differences in visceral adiposity.

Growth and health in children with moderate-to-severe cerebral palsy.

BACKGROUND: Children with cerebral palsy frequently grow poorly. The purpose of this study was to describe observed growth patterns and their relationship to health and social participation in a representative sample of children with moderate-severe cerebral palsy. METHODS: In a 6-site, multicentered, region-based cross-sectional study, multiple sources were used to identify children with moderate or severe cerebral palsy. There were 273 children enrolled, 58% male, 71% white, with Gross Motor Function Classification System levels III (22%), IV (25%), or V (53%). Anthropometric measures included: weight, knee height, upper arm length, midupper arm muscle area, triceps skinfold, and subscapular skinfold. Intraobserver and interobserver reliability was established. Health care use (days in bed, days in hospital, and visits to doctor or emergency department) and social participation (days missed of school or of usual activities for child and family) over the preceding 4 weeks were measured by questionnaire. Growth curves were developed and z scores calculated for each of the 6 measures. Cluster analysis methodology was then used to create 3 distinct groups of subjects based on average z scores across the 6 measures chosen to provide an overview of growth. RESULTS: Gender-specific growth curves with 10th, 25th, 50th, 75th, and 90th percentiles for each of the 6 measurements were created. Cluster analyses identified 3 clusters of subjects based on their average z scores for these measures. The subjects with the best growth had fewest days of health care use and fewest days of social participation missed, and the subjects with the worst growth had the most days of health care use and most days of participation missed. CONCLUSIONS: Growth patterns in children with cerebral palsy were associated with their overall health and social participation. The role of these cerebral palsy-specific growth curves in clinical decision-making will require further study.

Do changes in body mass index percentile reflect changes in body composition in children? Data from the Fels Longitudinal Study.

OBJECTIVE: Our aim was to examine the degree to which changes in BMI percentile reflect changes in body fat and lean body mass during childhood and how age and gender affect these relationships. METHODS: This analysis used serial data on 494 white boys and girls who were aged 8 to 18 years and participating in the Fels Longitudinal Study (total 2319 observations). Total body fat (TBF), total body fat-free mass (FFM), and percentage of body fat (%BF) were determined by hydrodensitometry, and then BMI was partitioned into its fat and fat-free components: fat mass index (FMI) and FFM index (FFMI). We calculated predicted changes (Delta) in FMI, FFMI, and %BF for each 10-unit increase in BMI percentile using mixed-effects models. RESULTS: FFMI had a linear relationship with BMI percentile, whereas FMI and %BF tended to increase dramatically only at higher BMI percentiles. Gender and age had significant effects on the relationship between BMI percentile and FFMI, FMI, and %BF. Predicted Delta%BF for boys 13 to 18 years of age was negative, suggesting loss of relative fatness for each 10-unit increase in BMI percentile. CONCLUSIONS: In this longitudinal study of white children, FFMI consistently increased with BMI percentile, whereas FMI and %BF had more complicated relationships with BMI percentile depending on gender, age, and whether BMI percentile was high or low. Our results suggest that BMI percentile changes may not accurately reflect changes in adiposity in children over time, particularly among male adolescents and children of lower BMI.

Radiographic joint space of the knee in healthy young adults.

The primary objective of this study was to characterize normal variation in radiographic joint space of the knee in a large sample of healthy young adults and to identify factors that contribute to this variation. We measured radiographic knee joint space in 279 skeletally mature subjects, age between 16 and 22 years, who participated in the Fels Longitudinal Study. Minimum joint space was measured in the medial and lateral knee compartments. Independent sample t tests and correlation analyses were performed to examine sex differences and associations between joint space, joint size, and body size [weight, stature, body mass index (BMI)]. Results show that young men have thicker articular cartilage than young women in both the medial and lateral compartments of the knee. Significant positive correlations were found between joint space and body size measures in the total sample. When the sexes were considered independently, however, correlations between joint space and body size were significant in men only. Regression analyses of the combined-sex sample identified sex, BMI, and joint width as significant explanatory factors of medial joint space, together accounting for 26% of the observed variance. In contrast, sex was the sole significant explanatory factor of lateral joint space, explaining 19% of the observed variance. Results of this study show that during early adulthood, when articular cartilage is healthy and at its peak thickness, men have thicker knee cartilage than women. At this young age body size accounts for a modest proportion of the variation observed in knee cartilage thickness.

Are nutritional status indicators associated with mortality in the Hemodialysis (HEMO) Study?

BACKGROUND: The purpose of this study was to determine if indicators of nutritional status were associated with subsequent mortality in hemodialysis patients. METHODS: Twelve selected nutrition indicators were measured prior to randomization in the Mortality and Morbidity in Hemodialysis (HEMO) Study. Relative risks (RR) of mortality were assessed at <6 months and >6 months of follow-up using Cox regression after controlling for case mix, comorbidity, and treatment assignment (high vs. standard Kt/V and high vs. low membrane flux). RESULTS: Low values of most nutritional status indicators were associated with increased RR of mortality. RRs were greatest over the short term (<6 months) and diminished with increasing follow-up (>6 months). Increases in body mass index (BMI) at lower levels (e.g., < or =25 kg/m(2)) and increases in serum albumin at any level were associated with reduced short-term RR, even after adjusting for case mix, treatment assignment, and for the joint effects of equilibrated normalized protein catabolic rate, total cholesterol, and serum creatinine. For >6 months' follow-up, increases in values among those with lower levels of BMI and serum albumin (< or =3.635 g/dL) and increases in all serum creatinine levels were associated with lower RR. CONCLUSION: Nutrition indicators are associated with subsequent mortality in a time-dependent manner, with greatest effects at <6 months of follow-up. The RR for these indicators may also vary within different ranges of values.

Fifty-year trends in serial body mass index during adolescence in girls: the Fels Longitudinal Study.

BACKGROUND: A decline in the age at menarche was recently reported for US girls. Although it is possible that this recent drop stems from the concurrent increase in childhood obesity, few longitudinal studies of growth and development have been undertaken to specifically address the temporal relation between growth, adiposity, and the age at menarche. OBJECTIVE: The objective was to simultaneously examine the effects of birth cohort (secular trend) and rate of maturation (age at menarche) on the timing and pattern of increases in body mass index (BMI) during adolescence in girls. DESIGN: We applied mixed-effects polynomial models to serial BMI data, spanning from 6 y before menarche to 6 y after menarche, obtained from 211 girls enrolled in the Fels Longitudinal Study. We examined the effects of birth cohort (defined as girls born 1929-1946, 1947-1964, and 1965-1983) and age at menarche (defined as < or =11.9 y, 12.0-13.1 y, and > or =13.2 y) on the magnitude and velocity of BMI during adolescence. RESULTS: BMI and BMI velocity in girls born after 1965 were significantly greater than those of girls of earlier birth cohorts, despite stability in the mean age at menarche. Although girls with early menarche tended to have significantly higher BMIs than did girls with average or later menarche, these differences did not emerge until after menarche. CONCLUSION: These data suggest that increases in relative weight are a consequence, rather than a determinant, of the age at menarche and that secular changes in BMI and in the mean age at menarche could be independent phenomena.

Family history and risk of hair loss.

INTRODUCTION: The genetic basis of androgenetic alopecia (AGA) is well accepted in the medical community and among the general population. However, rigorous studies investigating the familial basis of AGA are lacking. The purpose of the current study was to explore the relationship between family history and expression of AGA in a sample of men from the general community. METHODS: Hair loss was assessed by an independent observer trained by an expert dermatologist using the Norwood/Hamilton classification scale and a 7-point global description of hair loss. Men were classified into two groups, one as having little or no hair loss and the other having hair loss. The family history of hair loss in parents and grandparents was assessed by subject self-report. RESULTS: Adjusting for age, men whose fathers had hair loss were 2.5 times as likely to have had some level of hair loss compared to men whose fathers had no hair loss (95% CI: 1.3-4.9). Likewise, men whose fathers had hair loss were twice as likely to have hair loss than men whose fathers had no hair loss even after adjusting for age (OR = 2.1, 95% CI: 1.2-3.7 and OR = 2.5, 95% CI: 1.4-4.7 for Norwood/Hamilton and global description of hair loss assessments, respectively). CONCLUSION: Results suggest that the probability of male pattern hair loss is dependent on family history and age. Hair loss in a man's father also appears to play an important role in increasing a man's risk of hair loss, either in conjunction with a history of hair loss in the mother or hair loss in the maternal grandfather.

Recent decline in age at menarche: the Fels Longitudinal Study.

A number of recent reports suggest that the average age at menarche of US girls has declined over the past 20 years. Because the putative declines in the age at menarche are concurrent with increases in childhood body mass index (BMI), it has been suggested that these two trends may be causally linked. We examined differences in mean age of menarche in Fels Longitudinal Study girls who were born in six 10-year birth cohorts (1930s, 1940s, 1950s, 1960s, 1970s, and 1980s) and simultaneous cohort changes in mean BMI measured cross-sectionally at selected ages from 3-35 years (n = 371). Girls born in the 1980s had a mean age at menarche of 12.34 years, which was approximately 3-6 months earlier than that of girls born previously (P < 0.001). While the mean BMI values at ages 25 and 35 generally increased from the 1930s to the 1970s, the mean BMI during childhood and adolescence remained constant across the six birth cohorts. In summary, we found no evidence that the recent decline in the age at menarche in the Fels Longitudinal Study girls was reflected in concurrent increases in BMI at any point in childhood or adolescence. Conversely, girls born in the 1960s and 1970s have subsequently become heavier in young and mid-adulthood than were girls from earlier birth cohorts, without any concurrent change in the mean age at menarche over that time period. These two findings suggest that population-level shifts in BMI and the timing of menarche are largely independent, although sometimes coincident, processes.

The effect of dialysis dose and membrane flux on nutritional parameters in hemodialysis patients: results of the HEMO Study.

BACKGROUND: The effect of standard or high dialysis dose and low or high dialysis flux on nutritional status was ascertained in 1846 maintenance hemodialysis patients enrolled in the HEMO Study. METHODS: Serum albumin levels, equilibrated protein catabolic rate, and postdialysis weight were obtained monthly, while adjusted protein and energy intake, self-reported appetite assessment, upper arm circumference, and calf circumference were obtained yearly. To account for patient attrition due to death or transfer, three statistical models were used to test the effects of the study interventions on longitudinal changes in nutritional parameters. RESULTS: During the first 3 years of follow-up, neither mean serum albumin levels, which declined by 0.21 g/dL, nor mean postdialysis weight, which declined by 2.7 kg, were significantly affected by either study intervention. Mean levels of all anthropometric measures declined during follow-up. For years 1, 2, and 3, the mean +/- SE declines in upper arm and calf circumferences were 0.35 +/- 0.16 cm (P= 0.031) and 0.31 +/- 0.13 (P= 0.015) cm less, respectively, in the high flux compared to the low flux group. Appetite scores and mean equilibrated protein catabolic rate also declined in all randomized groups; however, the average decline in equilibrated protein catabolic rate during years 1, 2, and 3 was 0.019 +/- 0.007 g/kg/day less in the high dose than the standard dose group (P= 0.007). There was no significant change in either mean energy or protein intake from diet records over time, and neither parameter was affected by the study interventions. CONCLUSION: Although the dose and flux interventions may subtly influence certain nutritional parameters, neither intervention prevented deterioration in nutritional status over time.

Development of bioelectrical impedance analysis prediction equations for body composition with the use of a multicomponent model for use in epidemiologic surveys.

BACKGROUND: Previous studies to develop and validate bioelectrical impedance analysis (BIA) equations to predict body composition were limited by small sample sizes, sex specificity, and reliance on reference methods that use a 2-component model. OBJECTIVE: This study was designed to develop sex-specific BIA equations to predict total body water (TBW) and fat-free mass (FFM) with the use of a multicomponent model for children and adults. DESIGN: Data from 5 centers were pooled to create a sample of 1474 whites and 355 blacks aged 12-94 y. TBW was measured by dilution, and FFM was estimated with a multicomponent model based on densitometry, isotope dilution, and dual-energy X-ray absorptiometry. RESULTS: The final race-combined TBW prediction equations included stature(2)/resistance and body weight (R(2) = 0.84 and 0.79 and root mean square errors of 3.8 and 2.6 L for males and females, respectively; CV: 8%) and tended to underpredict TBW in black males (2.0 L) and females (1.4 L) and to overpredict TBW in white males (0.5 L) and females (0.3 L). The race-combined FFM prediction equations contained the same independent variables (R(2) = 0.90 and 0.83 and root mean square errors of 3.9 and 2.9 kg for males and females, respectively; CV: approximately 6%) and tended to underpredict FFM in black males (2.1 kg) and females (1.6 kg) and to overpredict FFM in white males (0.4 kg) and females (0.3 kg). CONCLUSION: These equations have excellent precision and are recommended for use in epidemiologic studies to describe normal levels of body composition.

Secondary sexual characteristics in children with cerebral palsy and moderate to severe motor impairment: a cross-sectional survey.

OBJECTIVES: To compare the development of secondary sexual characteristics in children with cerebral palsy (CP) of moderate to severe motor impairment to children in the general population and to relate their sexual maturation to a measure of their body fat. METHODS: A multicenter, cross-sectional survey of 207 children who were 3 to 18 years of age and had CP of moderate to severe motor impairment (Gross Motor Functional Classification System [GMFCS] levels 3, 4, and 5) was conducted at 6 geographic sites; attempts were made to identify all eligible children through multiple methods and enroll them in the study. Trained research assistants performed anthropometric measurements, including subscapular skinfold thickness, determined GMFCS level, and assessed sexual maturation by Tanner stage. Secondary sexual characteristics were compared with the general population of children using cross-sectional surveys of the American Academy of Pediatrics Pediatric Research in Office Settings network and of the National Center for Health Statistics National Health and Nutrition Examination Survey (NHANES) III. Girls were classified as having begun puberty when they were at Tanner stage 2 or greater for pubic hair and breast development and to have completed puberty when they were at Tanner stage 4 or greater for pubic hair and breast development. Boys were classified as having begun puberty when they were at Tanner stage 2 or greater for pubic hair and genital development and to have completed puberty when they were at Tanner stage 4 or greater for pubic hair and genital development. RESULTS: The mean age (standard deviation) of subjects was 9.6 (4.6) years. Of the 207 subjects, 71% were white, 21% were black, and 8% were of other races; 59% were boys, and 41% were girls. Girls with CP (n = 84) entered puberty earlier than did boys with CP (n = 123). In contrast, girls with CP tended to complete puberty later than did boys with CP. Black boys and girls with CP (n = 43) entered puberty earlier than did white boys and girls with CP (n = 147). No difference between races was found in completion of puberty. Only for white children with CP were there a sufficient number of subjects for comparisons of sexual maturation to race-matched children in the general population, using data from the American Academy of Pediatrics Pediatric Research in Office Settings network and the NHANES III study. White girls with CP initiated pubic hair development (Tanner stage 2 or greater) earlier than in the general population, but the age of onset of breast development was similar to the general population, although the age distribution was different. A greater proportion of white girls with CP had early onset of breast development (Tanner stage 2 or greater), and a greater proportion had delayed onset of breast development than in the general population. White girls with CP completed breast development later than in the general population but not pubic hair development. For white boys ages 8 to 18 years with CP (n = 75), pubic hair and genital development both began earlier than in the general population, but genital development was completed later. The estimated median age of menarche for white girls with CP was 14.0 years, which was 1.3 years later (95% confidence interval: 0.7-2.3) than for the general population (estimated median age: 12.8 years; NHANES III). Relationships between sexual maturation and nutritional state, as assessed by subscapular skinfold thickness z score, were determined separately in white boys and in white girls with CP, between the ages of 8 and 18 years. For white girls with CP, more advanced sexual maturation was associated with more body fat, adjusting for age and GMFCS level (Spearman partial correlation: 0.41). In contrast, for white boys with CP, the opposite relationship pertained: more advanced sexual maturation was associated with less body fat (-0.29). CONCLUSIONS: The pattern of sexual maturation in children with CP of moderate to severe motor impairment differs from that of children in the general population. Puberty begins earlier but ends later in white children with CP, compared with white children in the general population. In addition, menarche occurs later in white girls with CP. More advanced sexual maturation was associated with more body fat in girls but less body fat in boys.

Relationship of nutritional status to health and societal participation in children with cerebral palsy.

OBJECTIVES: To describe nutritional status in a population-based sample of children with moderate or severe cerebral palsy (CP) and to explore the relationships between nutritional status and health and functional outcomes. STUDY DESIGN: A population-based strategy was used to enroll children with CP at 6 geographic sites. Research assistants performed anthropometric assessment, determined severity of motor impairment, and interviewed caregivers with the Child Health Questionnaire and a questionnaire designed specifically for this study. Anthropometric measures were converted to Z scores and the relationship between health and nutritional status was assessed using regression models. RESULTS: Among the 235 participants, indicators of malnutrition were common. Poor nutritional status correlated with increased health care utilization (hospitalizations, doctor visits) and decreased participation in usual activities by the child and parent. CONCLUSIONS: Malnutrition is common in children with moderate or severe CP and associated with poorer health status and limitations in societal participation. Further studies are needed to determine the nature of these associations and how to manage nutrition in children with CP to optimize growth and health outcomes.