Weight estimation among multi-racial/ethnic infants and children aged 0-5·9 years in the USA: simple tools for a critical measure.

OBJECTIVE: In resource-constrained facilities or during resuscitation, immediate paediatric weight estimation remains a fundamental challenge. We aimed to develop and validate weight estimation models based on ulna length and forearm width and circumference measured by simple and portable tools; and to compare them against previous methods (advanced paediatric life support (APLS), Theron and Traub-Johnson formulas). DESIGN: Cross-sectional analysis of anthropometric measurements. Four ulna- and forearm-based weight estimation models were developed in the training set (n 1016). Assessment of bias, precision and accuracy was examined in the validation set (n 457). SETTING: National Children's Study-Formative Research in Anthropometry (2011-2012). SUBJECTS: Multi-racial/ethnic infants and children aged <6 years (n 1473). RESULTS: Developed Models 1-4 had high predictive precision (R 2=0·91-0·97). Mean percentage errors between predicted and measured weight were significantly smaller across the developed models (0·1-0·7 %) v. the APLS, Theron and Traub-Johnson formulas (-1·7, 9·2 and -4·9 %, respectively). Root-mean-squared percentage error was overall smaller among Models 1-4 v. the three existing methods (range=7·5-8·7 v. 9·8-13·3 %). Further, Models 1-4 were within 10 and 20 % of actual weight in 72-87 and 95-99 % of the weight estimations, respectively, which outperformed any of the three existing methods. CONCLUSIONS: Ulna length, forearm width and forearm circumference by simple and portable tools could serve as valid and reliable surrogate measures of weight among infants and children aged <6 years with improved precision over the existing age- or length-based methods. Further validation of these models in physically impaired or non-ambulatory children is warranted.

The relation of peripubertal and pubertal growth to final adult height in children with classic congenital adrenal hyperplasia.

OBJECTIVES: To determine the relationships between peripubertal and pubertal timing and growth, along with glucocorticoid exposure, to the reduced final adult height seen in patients with congenital adrenal hyperplasia (CAH). STUDY DESIGN: Chart review of 104 children with classic CAH (41 males: 28 salt-wasting, 13 simple-virilizing; 63 females: 38 salt-wasting, 25 simple-virilizing) were selected from a cohort from 3 medical institutions in Minnesota. Triple logistic modeling of longitudinal data was performed to determine patterns of peripubertal and pubertal growth. RESULTS: Hydrocortisone dose was similar between subtypes and during all growth periods. Simple-virilizing boys (P < .01) and girls (P < .01) were diagnosed later than their salt-wasting counterparts. Height at take-off SDS was reduced for patients with salt-wasting (boys: P < .01; girls: P < .01), and bone age at take-off SDS was more advanced for patients with simple-virilizing (boys: P < .01; girls: P = .05). Bone age at pubertal onset SDS was advanced for all patients, but more so for boys and girls with simple-virilizing. Although all patients had reduced final adult height SDS, this was more pronounced in patients with salt-wasting. CONCLUSION: Reduced final adult height SDS in patients with salt-wasting vs simple-virilizing may be attributable in part to a later age of diagnosis and resultant less prolonged exposure to hydrocortisone. This finding suggests that duration of hydrocortisone treatment in the peripubertal period, independent of the hydrocortisone dose, may affect final adult height in patients with CAH.

Predictors of developmental status in young children living in institutional care in Kazakhstan.

The main objective of this study was to assess the developmental status of children living in the severely adverse environment of institutional care and the examination of risk factors with regard to developmental status, including degree of stunting and emotional-behavioral and anemia status. The Bayley Scales of Infant Development were used to assess development status in 103 children aged 14.9 months (SD = 6.8) in six Kazakh institutions. The Behavioral Rating Scales were used to assess emotional-behavioral regulation. Physical growth measures were converted to z scores using World Health Organization growth charts. Venous blood was collected for assessment of anemia. Our findings indicated that young children in institutions were developmentally compromised, with duration of institutional care correlated with the severity of delay. Negative predictors of developmental status included: Poor emotional-behavioral regulation, degree of stunting and age at assessment. A particularly large percentage of children were found to be anemic. Additionally, low birth weight was found to be a significant negative predictor of development. Our findings indicate that institutional care has a detrimental impact on the development and emotional regulation of young children. Time in institutional care is a negative predictor for cognitive status for children placed at birth. Moreover stunting was found to be a useful indicator of the degree of impact of early adversity on cognitive development. Particular attention is needed for special-needs children such as those with low birth weight, since their development was found to be more sensitive to early adversity than that of normal birth weight children.

Impact of hydrocortisone on adult height in congenital adrenal hyperplasia-the Minnesota cohort.

OBJECTIVE: To estimate the impact of the average daily dose of hydrocortisone (HC) on the amount of growth attained in children with congenital adrenal hyperplasia (CAH). The effect of glucocorticoid therapy on adult height (AH) in children with CAH has yet to be elucidated. STUDY DESIGN: Triple-logistic models estimating components of growth and maturation were fitted to longitudinal records of 104 patients with classic CAH from 3 pediatric medical centers in Minnesota between 1955 and 2012. A total of 3664 clinical encounters were examined. Random-effects longitudinal models with time-related covariates were used to estimate the effect of HC therapy on linear growth. RESULTS: The predicted AH z-score (-0.7) was similar between the sexes and among CAH subtypes. The mean growth period HC dose was 18.9 ± 5.6 mg/m(2)/day. In the final regression model, HC dose was negatively associated with predicted AH, with each mg/m(2)/day increase in average growth period HC dose predicting a 0.37-cm decrease in AH (P < .004). CONCLUSION: This study has quantified the fractional reduction in predicted final AH with an incremental increase in HC dose. These findings have important clinical implications in the decision making balance between HC replacement dose and adrenal androgen suppression in children with CAH.

Arm span and ulnar length are reliable and accurate estimates of recumbent length and height in a multiethnic population of infants and children under 6 years of age.

Surrogate measures are needed when recumbent length or height is unobtainable or unreliable. Arm span has been used as a surrogate but is not feasible in children with shoulder or arm contractures. Ulnar length is not usually impaired by joint deformities, yet its utility as a surrogate has not been adequately studied. In this cross-sectional study, we aimed to examine the accuracy and reliability of ulnar length measured by different tools as a surrogate measure of recumbent length and height. Anthropometrics [recumbent length, height, arm span, and ulnar length by caliper (ULC), ruler (ULR), and grid (ULG)] were measured in 1479 healthy infants and children aged <6 y across 8 study centers in the United States. Multivariate mixed-effects linear regression models for recumbent length and height were developed by using ulnar length and arm span as surrogate measures. The agreement between the measured length or height and the predicted values by ULC, ULR, ULG, and arm span were examined by Bland-Altman plots. All 3 measures of ulnar length and arm span were highly correlated with length and height. The degree of precision of prediction equations for length by ULC, ULR, and ULG (R(2) = 0.95, 0.95, and 0.92, respectively) was comparable with that by arm span (R(2) = 0.97) using age, sex, and ethnicity as covariates; however, height prediction by ULC (R(2) = 0.87), ULR (R(2) = 0.85), and ULG (R(2) = 0.88) was less comparable with arm span (R(2) = 0.94). Our study demonstrates that arm span and ULC, ULR, or ULG can serve as accurate and reliable surrogate measures of recumbent length and height in healthy children; however, ULC, ULR, and ULG tend to slightly overestimate length and height in young infants and children. Further testing of ulnar length as a surrogate is warranted in physically impaired or nonambulatory children.

Age at hormonal onset of puberty based on luteinizing hormone, inhibin B, and body composition in preadolescent U.S. girls.

BACKGROUND: Hormonal indicators could be useful for detecting early pubertal onset, but there is little research on how they are related to puberty in U.S. girls. We determined median age at hormonal onset of puberty based on luteinizing hormone (LH) and inhibin B (InB) and explored the extent to which body composition moderates this timing process. METHODS: We analyzed anthropometric and hormone data of 698 US peri-pubertal girls ages 6-11.99 y who had participated in the Third National Health and Nutrition Examination Survey (NHANES III), 1988-1994. RESULTS: Median age of hormonal onset of puberty was 10.43 y by LH and 10.08 y by InB cut-offs (1.04 mIU/ml for LH and 17.89 pg/ml for InB). Postnatal weight gain modulated onset, making it earlier by 10-11 mo among the highest (greater than +1 SD) relative to normal weight gainers. Onset occurred first in non-Hispanic black (NHB) girls, 10.08 y (95% confidence interval (CI): 10.07-10.09), followed by Mexican-American (MXAM) at 10.64 y (95% CI: 10.63-10.65), and at 10.66 y (95% CI: 10.66-10.67) for non-Hispanic white (NHW) girls using LH. With InB, onset occurred first in MXAM girls at 9.9 y, and at 10.3 y and 10.4 y for their NHB and NHW peers, respectively. CONCLUSION: Preadolescent weight gain lowers the age at hormonal onset as defined by LH concentrations. Preventing obesity in childhood may also avert the earlier initiation of the maturation process even at the hormonal level.

Retarded tempo of physiological development in childhood delays the onset of the metabolic syndrome in adulthood.

Using serial data from the Fels Longitudinal Study, we investigated the effects of early and late attainment of the peak height velocity (PHV) in childhood on the timing of the appearance of the metabolic syndrome later in life. We aimed to show if early attainment of PHV engenders greater risks for chronic diseases in boys than in girls. Therefore, we defined those boys and girls in sex-specific quartiles of the study population that were slowest to attain PHV as having a slow tempo of development, and those in the growth that most rapidly attained PHV as having a rapid tempo of development. Boys who experienced an early onset of PHV tended to have a higher risk for the metabolic syndrome, dyslipidemia and impaired fasting glucose than those who had late onset of PHV. Girls who had an early onset of PHV tended to develop more abdominal obesity than females who had a late onset of PHV.

Growth, nutritional, and developmental status of young children living in orphanages in Kazakhstan.

This article describes the nutritional and developmental status of young children living in Baby Houses (orphanages for children ages 0-3 years) in Kazakhstan. In 2009/2010, 308 children under age 3 years living in 10 Baby Houses were measured for height/length and weight. The Bayley Scales of Infant Development (N. Bayley, 2006) were used to assess mental and motor development. Blood was collected on a subsample to assess key nutritional factors. The World Health Organization growth charts were used to calculate Z-scores. Cut points for wasting (moderate to severe low weight for length/height growth), underweight (low weight for age), stunting (low length/height for age), development, and biomarkers used established guidelines. Most (n = 286) children had complete data on z-scores. Of these, 22.1% were experiencing wasting, 31.5% were underweight, and 36.7% had stunting. The nutritional status of the children, based on blood biomarkers, revealed that 37.1% of the children were anemic, 21.4% had low albumin, 38.1% had low vitamin D, 5.5% were iodine-deficient, and 2% had low serum zinc. One half had mild to significant mental and motor delays. Children living at these Baby Houses in Kazakhstan have substantial nutritional deficits and developmental delays. Focused attention is needed to provide a nutritionally enhanced diet and improved developmental opportunities to improve the long-term outcomes for these children.

Associations of home food availability, dietary intake, screen time and physical activity with BMI in young American-Indian children.

OBJECTIVE: To evaluate associations between home environmental factors and BMI of young American-Indian children. DESIGN: Cross-sectional and prospective study. SETTING: School-based obesity prevention trial (Bright Start) on a Northern Plains Indian reservation in South Dakota. Mixed model multivariable analysis was used to examine associations between child BMI categories (normal, overweight and obese) and home food availability, children's dietary intake and physical activity. Analyses were adjusted for age, gender, socio-economic status, parent BMI and school; prospective analyses also adjusted for study condition and baseline predictor and outcome variables. SUBJECTS: Kindergarten children (n = 424, 51 % male; mean age = 5.8 years, 30 % overweight/obese) and parents/caregivers (89 % female; 86 % overweight/obese) had their height and weight measured and parents/caregivers completed surveys on home environmental factors (baseline and 2 years later). RESULTS: Higher fast-food intake and parent-perceived barriers to physical activity were marginally associated with higher probabilities of a child being overweight and obese. Vegetable availability was marginally associated with lower probabilities of being overweight and obese. The associations between home environmental factors and child weight status at follow-up were not significant. CONCLUSIONS: Findings indicate that selected aspects of the home environment are associated with weight status of American-Indian children. Obesity interventions with this population should consider helping parents to engage and model healthful behaviours and to increase availability of healthful foods at home.

Food responsiveness, parental food control and anthropometric outcomes among young American Indian children: cross-sectional and prospective findings.

OBJECTIVE: Assess cross-sectional and prospective associations between food responsiveness and parental food control and anthropometric outcomes among American Indian children. DESIGN: Parents/caregivers completed psychosocial surveys and trained staff measured children's anthropometry at baseline (kindergarten) and at follow-up (1st grade) as part of a school-based obesity prevention trial (Bright Start). SETTING: On/near the Pine Ridge Indian reservation. PARTICIPANTS: 422 child (51% female, mean age=5.8 years, 30% overweight/obese) and parent/caregiver (89% mothers) dyads. MAIN OUTCOME MEASURES: Two independent variables (child's Food Responsiveness and Parental Control scales) and six child anthropometric dependent variables (overweight status, body mass index z-score, % body fat, waist circumference, triceps skinfold, subscapular skinfold). Linear regression analyses, stratified by sex and adjusted for age and treatment condition. RESULTS: Baseline Food Responsiveness scale scores were positively associated with all six baseline anthropometric outcomes among boys (P's all <.01), but not girls. Parental Control scale scores were not significantly associated with outcomes and no prospective associations were statistically significant. CONCLUSIONS: Responsiveness to food may be associated with excess adiposity in young American Indian boys, however, the effects are not detectable over time. Obesity prevention programs for American Indian children may benefit by addressing eating without hunger among boys.

Height, adiposity and body fat distribution and breast density in young women.

INTRODUCTION: Breast density is one of the strongest risk factors for breast cancer, but determinants of breast density in young women remain largely unknown. METHODS: Associations of height, adiposity and body fat distribution with percentage dense breast volume (%DBV) and absolute dense breast volume (ADBV) were evaluated in a cross-sectional study of 174 healthy women, 25 to 29 years old. Adiposity and body fat distribution were measured by anthropometry and dual-energy X-ray absorptiometry (DXA), while %DBV and ADBV were measured by magnetic resonance imaging. Associations were evaluated using linear mixed-effects models. All tests of statistical significance are two-sided. RESULTS: Height was significantly positively associated with %DBV but not ADBV; for each standard deviation (SD) increase in height, %DBV increased by 18.7% in adjusted models. In contrast, all measures of adiposity and body fat distribution were significantly inversely associated with %DBV; a SD increase in body mass index (BMI), percentage fat mass, waist circumference and the android:gynoid fat mass ratio (A:G ratio) was each associated significantly with a 44.4 to 47.0% decrease in %DBV after adjustment for childhood BMI and other covariates. Although associations were weaker than for %DBV, all measures of adiposity and body fat distribution also were significantly inversely associated with ADBV before adjustment for childhood BMI. After adjustment for childhood BMI, however, only the DXA measures of percentage fat mass and A:G ratio remained significant; a SD increase in each was associated with a 13.8 to 19.6% decrease in ADBV. In mutually adjusted analysis, the percentage fat mass and the A:G ratio remained significantly inversely associated with %DBV, but only the A:G ratio was significantly associated with ADBV; a SD increase in the A:G ratio was associated with an 18.5% decrease in ADBV. CONCLUSION: Total adiposity and body fat distribution are independently inversely associated with %DBV, whereas in mutually adjusted analysis only body fat distribution (A:G ratio) remained significantly inversely associated with ADBV in young women. Research is needed to identify biological mechanisms underlying these associations.

Inhibin B and luteinizing hormone levels in girls aged 6-11 years from NHANES III, 1988-1994.

OBJECTIVE: To evaluate inhibin B and luteinizing hormone (LH) levels in a large, representative cross-sectional sample of US girls and characterize the relationships of these laboratory values with age, clinical signs of puberty and other correlates. DESIGN: Cross-sectional analysis of LH and inhibin B in banked serum from 720 girls aged 6-11 years who participated in the Third National Health and Nutrition Examination Survey (NHANES III). MEASUREMENTS: Levels of inhibin B and LH, race, ethnicity and anthropometric measurements were compared for all girls. Visual assessment of pubertal stage was performed on girls aged 8 years and older. A two-part model was used to establish normative data and Tobit regression models were used to evaluate associations with participant characteristics. Receiver operating characteristic (ROC) analysis was performed to identify optimum cut points predictive of puberty onset. RESULTS: Mean hormone levels progressively increased with age. LH levels progressively increased with pubertal stage. Inhibin B levels increased gradually from breast stage I to II, then more sharply to peak at stage III, followed by a plateau at stages IV and V. ROC curves indicated that both hormones were consistent with pubertal onset as indicated by breast stage II. CONCLUSIONS: This study characterizes inhibin B and LH values in a large, representative cross-sectional sample of US girls. Inhibin B can be a useful tool in combination with other clinical and biochemical parameters to evaluate gonadal function as a reflection of pubertal progression in girls.

High food insecurity and its correlates among families living on a rural American Indian Reservation.

OBJECTIVES: We sought to better understand the prevalence and consequences of food insecurity among American Indian families with young children. METHODS: Parents or caregivers of kindergarten-age children enrolled in the Bright Start study (dyad n=432) living on the Pine Ridge Reservation in South Dakota completed a questionnaire on their child's dietary intake, the home food environment, and food security. We assessed food security with a standard 6-item scale and examined associations of food insecurity with family sociodemographic characteristics, parents' and children's weight, children's dietary patterns, and the home food environment. RESULTS: Almost 40% of families reported experiencing food insecurity. Children from food-insecure households were more likely to eat some less healthful types of foods, including items purchased at convenience stores (P= .002), and food-insecure parents reported experiencing many barriers to accessing healthful food. Food security status was not associated with differences in home food availability or children's or parents' weight status. CONCLUSIONS: Food insecurity is prevalent among families living on the Pine Ridge Reservation. Increasing reservation access to food that is high quality, reasonably priced, and healthful should be a public health goal.

Lower acetylcholinesterase activity among children living with flower plantation workers.

BACKGROUND: Children of workers exposed to pesticides are at risk of secondary pesticide exposure. We evaluated the potential for lower acetylcholinesterase activity in children cohabiting with fresh-cut flower plantation workers, which would be expected from organophosphate and carbamate insecticide exposure. Parental home surveys were performed and acetylcholinesterase activity was measured in 277 children aged 4-9 years in the Secondary Exposure to Pesticides among Infants, Children and Adolescents (ESPINA) study. Participants lived in a rural county in Ecuador with substantial flower plantation activity. RESULTS: Mean acetylcholinesterase activity was 3.14 U/ml, standard deviation (SD) of 0.49. It was lower by 0.09 U/ml (95% confidence interval (CI) -0.19, -0.001) in children of flower workers (57% of participants) than non-flower workers' children, after adjustment for gender, age, height-for-age, hemoglobin concentration, income, pesticide use within household lot, pesticide use by contiguous neighbors, examination date and residence distance to nearest flower plantation. Using a 4 level polychotomous acetylcholinesterase activity dependent variable, flower worker cohabitation (vs. not) had odds ratio 3.39 (95% CI 1.19, 9.64) for being <15th percentile compared to the highest tertile. Children cohabitating for ≥5 years (vs. never) had OR of 4.11 (95% CI: 1.17, 14.38) of AChE activity within <15th percentile compared to the highest tertile. CONCLUSIONS: Cohabitation with a flower worker was related to lower acetylcholinesterase activity in children. This supports the hypothesis that the amount of take-home pesticides from flower workers suffices to decrease acetylcholinesterase activity, with lower activity associated with longer exposure.

Is skinfold thickness as good as DXA when measuring adiposity contributions to insulin resistance in adolescents?

OBJECTIVE: We compared adiposity from triceps and subscapular skinfold thickness (SF) with total body fat from dual energy X-ray absorptiometry (DXA) in their associations with HOMA insulin resistance for a large sample of US adolescents. METHODS: We analyzed cross-sectional data from 1496 adolescents, ages 12.0-17.99 year examined as part of the US national health and nutrition examination survey (NHANES) cycles 2001-04. Data collected included skinfold thicknesses, DXA-based total body fat (DXF), serum insulin and fasting glucose for homeostasis model assessment of insulin resistance (HOMA-IR). Regression models adjusting for complex survey design effects and correspondence analyses were used to study associations with HOMA-IR and concordance between the two measures of adiposity. RESULTS: SF and DXA models had identical precisions for estimating continuous HOMA-IR, based on bootstrap estimations. For boys, RMSEs = 0.53 (95% CI: 0.49-0.58) and 0.53 (95% CI: 0.48-0.57) for SF and DXA models respectively; and for girls RMSEs were SF = 0.45 (95% CI: 0.41-0.48) and DXA = 0.46 (95% CI: 0.42-0.48). Both adiposity models identified high proportions of the same individuals (positive percent agreement: 80-81%) with exact agreements exceeding 92% for identifying adolescents at elevated risk of IR in both sexes. CONCLUSIONS: Triceps and subscapular skinfold thicknesses estimate HOMA-IR and identify those at highest risk for insulin resistance as well as total body fat from DXA. Skinfold thickness provides an inexpensive and widely applicable measure of fatness that is appropriate for studies of insulin resistance and perhaps other metabolic variables in adolescents.

Determinants of high weight gain and high BMI status in the first three months in urban Chinese infants.

OBJECTIVES: Investigate the potential factors associated with high weight gain and high BMI status in the first three months of life. METHODS: Totally, 930 healthy neonates (489 boys and 441 girls) were involved in this community-based, prospective study in China. Data on body weight and length were collected at birth, and the 1st and 3rd months. A self-administered questionnaire was used to collect data regarding social demography, gestational status, delivery, and the feeding patterns of children. RESULTS: Prevalences of high BMI status (BMI = 85th p, re WHO BMI standards) increased over time in both sexes, reaching 24.5% and 12.0% for boys and girls, respectively. General linear mixed models indicate high BMI status at 3 months is significantly and inversely associated with breastfeeding, as a proportion of feeding occasions [OR 0.74 (95%CI: 0.56-0.98)] and positively with lower birth weight [OR 2.07 (95%CI: 1.23-3.49)]. High weight gain (=85th p, re WHO velocity standards) in the first 3 months is also significantly associated with breastfeeding [OR 0.76 (95%CI: 0.59-0.96)] and sex, with boys at a higher risk than girls [OR 1.44 (95%CI: 1.07-1.97)]. Living in an extended family is associated with both high weight gain and high BMI status, but with marginal statistical significance. CONCLUSION: Analyses indicate an increasing trend of high BMI status in early infancy. Breastfeeding provides a protective effect for both high weight gain and high BMI status. The results concerning birth weight suggests a target for intervention.

American Indian parents' assessment of and concern about their kindergarten child's weight status, South Dakota, 2005-2006.

INTRODUCTION: Obesity is highly prevalent among American Indians, and effective prevention efforts require caregiver involvement. We examined American Indian (AI) parents' assessment of and level of concern about their kindergarten child's weight status. METHODS: We collected baseline data (fall of 2005 and fall of 2006) on children and their parents or caregivers for a school-based obesity prevention trial (Bright Start) on an AI reservation in South Dakota. The current study uses 413 parent-child pairs. Age- and sex-adjusted body mass index percentiles were categorized as very underweight (<5th percentile), slightly underweight (5th to <15th percentile), normal weight (15th to <85th percentile), overweight (85th to <95th percentile), and obese (≥ 95th percentile). Parents or caregivers reported their assessment of and concerns about their child's weight status as well as sociodemographic characteristics. We used mixed-model multivariable analysis to examine associations between sociodemographic characteristics and the probability of parents underclassifying or overclassifying their child's weight status; analyses were adjusted for school as a random effect. RESULTS: Children were evenly divided by sex and had a mean age of 5.8 years. Twenty-nine percent of children and 86% of parents were overweight or obese. Approximately 33% (n = 138) of parents underclassified and 7% (n = 29) of parents overclassified their child's weight status. Higher parental weight status and higher concern about their child's weight status increased the probability of underclassification (P for trend = .02 for both). CONCLUSION: In this sample of at-risk children, one-third of parents underclassified their child's weight status. Childhood obesity prevention programs need to increase awareness and recognition of childhood obesity and address parental weight issues.

Growing into obesity: patterns of height growth in those who become normal weight, overweight, or obese as young adults.

OBJECTIVES: To study whether patterns of height growth differ by adult obesity status, and determine the contribution of subcutaneous fatness as an explanatory variable for any differences. STUDY DESIGN: A multicenter, prospective longitudinal cohort assessed in 3rd grade (8.8 years), 5th grade (11.1 years), 8th grade (14.1 years), and 12th grade (18.3 years). Exposures were young adult obesity status classified by CDC adult BMI categories at 12th grade. Skinfolds were measured in third, fifth, and eighth grades. Outcome was mean height (cm) at the four measurements using repeated-measures ANCOVA for young adult obesity status, and height increments between grades by adult obesity status in sequential models including initial height and, secondarily, initial skinfolds. RESULTS: Adjusted for age, and race/ethnicity, young adult obesity status explained a small, but statistically significant amount of height growth among both females and males within each of the three intervals. Compared with normal weight young adults, overweight or obese young adults stood taller in childhood, but had relatively less growth in height throughout the teenage years. There was no association between adult height and weight status. Skinfolds explained only a small amount of the height patterns in the three weight groups. CONCLUSION: Childhood and adolescent height growth patterns differ between those who become young adults who are normal weight and those who become overweight or obese. Since differences in fatness explain only a small amount of these height growth patterns, research is needed to identify other determinants.

The co-occurrence of obesity, elevated blood pressure, and acanthosis nigricans among American Indian school children: identifying individual heritage and environment-level correlates.

OBJECTIVE: To estimate the prevalence and explore the social and cultural etiologic roots of weight status, blood pressure, and acanthosis nigricans among American Indian children on a reservation in South Dakota. METHODS: This observational study was conducted in 26 schools from 1998 to 2002 and included 5,422 observations representing 3,841 children, ages 3 to 19. Trained staff measured height, weight, blood pressure, and assessed the presence of acanthosis nigricans (AN). Percent Indian heritage (PIH) was abstracted from tribal records. Sociodemographic environment (SDE) was calculated using the 2000 Census at the city/town level. Descriptive analyses were conducted using one measurement time point, including tests for trend and co-occurrence of risk factors using the [kappa] statistic. Hierarchical, multivariate logistic regression estimated associations with overweight/obesity status, accounting for multiple measures on individuals and SDE. RESULTS: The overall prevalence of overweight/obesity was 46%, of hypertension 9%, and of AN 14%. The co-occurrence of risk factors was moderate to high. PIH and AN were positively associated in unadjusted analysis. Controlling for sex, age, and SDE, higher PIH was a significant correlate of overweight/obesity, although when hypertension (OR = 5.92, CI = 3.27-10.72), prehypertension (OR = 3.80, CI = 1.99-7.26), and AN (OR = 16.20, CI = 8.08-32.48) were included in the model PIH was no longer significant. SDE was not significantly associated with overweight/obesity. CONCLUSION: PIH appeared to be an important correlate of overweight and obesity, except when adjusted for the co-occurrence of high blood pressure and AN. Overall, the prevalence and co-occurrence of various risk factors in this population was high. Obesity prevention initiatives targeting families and communities are needed, as well as access to screening and treatment services.

Summer effects on body mass index (BMI) gain and growth patterns of American Indian children from kindergarten to first grade: a prospective study.

BACKGROUND: Overweight and obesity are highly prevalent among American Indian children, especially those living on reservations. There is little scientific evidence about the effects of summer vacation on obesity development in children. The purpose of this study was to investigate the effects of summer vacation between kindergarten and first grade on growth in height, weight, and body mass index (BMI) for a sample of American Indian children. METHODS: Children had their height and weight measured in four rounds of data collection (yielded three intervals: kindergarten, summer vacation, and first grade) as part of a school-based obesity prevention trial (Bright Start) in a Northern Plains Indian Reservation. Demographic variables were collected at baseline from parent surveys. Growth velocities (Z-score units/year) for BMI, weight, and height were estimated and compared for each interval using generalized linear mixed models. RESULTS: The children were taller and heavier than median of same age counterparts. Height Z-scores were positively associated with increasing weight status category. The mean weight velocity during summer was significantly less than during the school year. More rapid growth velocity in height during summer than during school year was observed. Obese children gained less adjusted-BMI in the first grade after gaining more than their counterparts during the previous two intervals. No statistically significant interval effects were found for height and BMI velocities. CONCLUSIONS: There was no indication of a significant summer effect on children's BMI. Rather than seasonal or school-related patterns, the predominant pattern indicated by weight-Z and BMI-Z velocities might be related to age or maturation. TRIAL REGISTRATION: Bright Start: Obesity Prevention in American Indian Children Clinical Trial Govt ID# NCT00123032.