Neonatal Antiepileptic Medication Treatment Patterns: A Decade of Change.

OBJECTIVE: This study aims to describe the frequency and characteristics of anticonvulsant medication treatments initiated in the neonatal period. STUDY DESIGN: We analyzed a cohort of neonates with a seizure diagnosis who were discharged from institutions in the Pediatric Health Information System between 2007 and 2016. Adjusted risk ratios and 95% confidence intervals for characteristics associated with neonatal (≤ 28 days postnatal) anticonvulsant initiation were calculated via modified Poisson regression. RESULTS: A total of 6,245 infants from 47 institutions were included. There was a decrease in both phenobarbital initiation within the neonatal period (96.9 to 91.3%, p = 0.015) and continuation at discharge (90.6 to 68.6%, p <0.001). Levetiracetam (7.9 to 39.6%, p < 0.001) initiation within the neonatal period and continuation at discharge (9.4 to 49.8%, p < 0.001) increased. Neonates born at ≥ 37 weeks' gestation and those diagnosed with intraventricular hemorrhage, ischemic/thrombotic stroke, other hemorrhagic stroke, and hypoxic ischemic encephalopathy (HIE) had a higher probability of anticonvulsant administration. The most prevalent diagnosis was HIE (n = 2,223, 44.4%). CONCLUSION: Phenobarbital remains the most widely used neonatal seizure treatment. Levetiracetam is increasingly used as a second line therapy. Increasing levetiracetam use indicates a need for additional study to determine its effectiveness in reducing seizure burden and improving long-term outcomes.

Comparative Effectiveness of Nonsteroidal Anti-inflammatory Drug Treatment vs No Treatment for Patent Ductus Arteriosus in Preterm Infants.

Importance: Patent ductus arteriosus (PDA) is associated with increased mortality and worsened respiratory outcomes, including bronchopulmonary dysplasia (BPD), in preterm infants. Nonsteroidal anti-inflammatory drugs (NSAIDs) are efficacious in closing PDA, but the effectiveness of NSAID-mediated PDA closure in improving mortality and preventing BPD is unclear. Objective: To determine the effectiveness of NSAID treatment for PDA in reducing mortality and moderate/severe BPD at 36 weeks postmenstrual age. Design, Setting, and Participants: This cohort study included 12 018 infants born at 28 gestational weeks or younger discharged between January 2006 and December 2013 from neonatal intensive care units in 25 US children's hospitals included in the Pediatric Health Information System. We performed an instrumental variable analysis that incorporated clinician preference-based, institutional variation in NSAID treatment frequency to determine the effect of NSAID treatment for PDA on mortality and BPD. Exposures: Proportion of NSAID-treated infants born at each infant's institution within ±6 months of that infant's birth. Main Outcomes and Measures: The primary composite outcome was death, moderate, or severe BPD at 36 weeks postmenstrual age. Results: Of the 6370 male and 5648 female infants in this study, 4995 (42%) were white, 3176 (26%) were African American, 1823 (15%) were Hispanic, and 1555 (13%) were other races/ethnicities. The proportion of NSAID-treated infants at each infant's hospital within ±6 months of that infant's birth was associated with NSAID treatment and not associated with gestation, race/ethnicity, or sex. An infant's chances of receiving NSAID treatment increased by 0.84% (95% CI, 0.8-0.9; P < .001) for every 1% increase in the annual NSAID treatment percentage at a given hospital. An instrumental variable analysis demonstrated no association between NSAID treatment and the odds of mortality or BPD (odds ratio, 0.94; 95% CI, 0.70-1.25; P = .69), mortality (odds ratio, 0.73; 95% CI, 0.43-1.13; P = .18), or BPD (odds ratio, 1.01; 95% CI, 0.73-1.45; P = .94) in survivors. Conclusions and Relevance: When we incorporated clinician preference-based practice variation as an instrument to minimize the effect of unmeasured confounding, we detected no changes in the odds of mortality or moderate/severe BPD among similar preterm infants born at 28 weeks or younger following NSAID treatment for PDA initiated 2 to 28 days postnatally. Our findings agree with available randomized clinical trial evidence and support a conservative approach to PDA management.

Patterns of Empiric Antibiotic Administration for Presumed Early-Onset Neonatal Sepsis in Neonatal Intensive Care Units in the United States.

Objective To evaluate current patterns in empiric antibiotic use for early-onset neonatal sepsis (EONS). Study Design Retrospective population-based cohort study of newborns admitted on postnatal day 0 to 1 and discharged from NICUs participating in the Pediatric Health Information System (PHIS 2006-2013). Analyses included frequency of antibiotic initiation within 3 days of birth, duration of first course, and variation among hospitals. Results Of 158,907 newborns, 118,624 (74.7%) received antibiotics on or before postnatal day 3. Within 3 days of treatment, 49.4% (n = 58,610) were discharged home or remained hospitalized without antibiotics. There was marked interhospital variation in the proportion of infants receiving antibiotics (range: 52.3-90.9%, mean 77.9%, SD 11.0%) and in treatment days (range: 3.2-8.6, mean 5.3, SD 1.4). Facilities with higher number of newborns started on antibiotics had longer courses (r = 0.643, p < 0.001). The cost of admissions for infants born at ≥35 weeks started on antibiotics and discharged home after no more than 3 days of antibiotics was $76,692,713. Conclusion Site variation in antibiotic utilization suggests antibiotic overtreatment of infants with culture unconfirmed EONS is common and costly.

Neonatal Histamine-2 Receptor Antagonist and Proton Pump Inhibitor Treatment at United States Children's Hospitals.

OBJECTIVE: To determine treatment frequency and duration of histamine-2 receptor antagonist (H2RA)/proton pump inhibitor (PPI) use among infants hospitalized within US children's hospital neonatal intensive care units and evaluate diagnoses/demographic factors associated with use. STUDY DESIGN: We retrospectively analyzed a cohort of neonatal intensive care unit infants admitted to 43 US children's hospitals within the Pediatric Health Information System database between January 2006 and March 2013 to determine H2RA/PPI treatment frequency, timing/duration of treatment, factors associated with use, percent of infants remaining on treatment at discharge, and interhospital prescribing variation. We used a modified Poisson regression to calculate the adjusted probability of infants ever receiving H2RAs/PPIs in relation to diagnosis, gestation, and sex. RESULTS: Of the 122 002 infants evaluated, 23.8% (n = 28 989) ever received an H2RA or PPI; 19.0% received H2RAs (n = 23 187), and 10.5% (n = 12 823) received PPIs. Extremely preterm infants and term infants were the most likely to receive H2RA and PPI treatment. Infants with gastroesophageal reflux disease (relative risk [RR] = 3.13) and congenital heart disease (RR = 2.41) had the highest H2RA/PPI treatment probabilities followed by those with an ear, nose, and throat diagnosis (RR = 2.34; P < .05). The majority of treated infants remained treated at discharge. CONCLUSIONS: Despite limited evidence and increasing safety concerns, H2RAs/PPIs are frequently prescribed to extremely preterm neonates and those with congenital anomalies and continued through discharge. Our findings support the need for innovative studies to examine the comparative effectiveness and safety of H2RA/PPIs vs no treatment in these high-risk neonatal populations.

Development and Validation of an Algorithm to Determine Spontaneous versus Provider-Initiated Preterm Birth in US Vital Records.

BACKGROUND: Determining whether initiation of preterm birth was spontaneous, or through labour induction or caesarean without labour or membrane rupture is critical in surveillance and aetiological research on preterm birth, although this information is not explicitly included on the US Birth Certificate. Algorithms combining several fields from birth certificates have been developed to infer the initiating event, but none has been validated against manual review of original obstetric records. Our objective was to develop a birth certificate-based algorithm to determine initiation of preterm birth and validate it by manual review of original records. METHODS: We developed an algorithm from the 2003 US Standard Birth Certificate to determine spontaneous vs. indicated preterm birth. The algorithm was first tested on obstetrical records from 80 preterm (<37 weeks) births in Columbus OH (2006-12) abstracted by an obstetrics research nurse and reviewed by an obstetrician-gynecologist. Onset of delivery was spontaneous if the initiating event was premature rupture of membranes (PROM) or contractions, or indicated if the initiating event was induction or caesarean without labour or PROM. The algorithm was validated in an independent sample of 100 preterm births from four hospitals. RESULTS: Codes for tocolysis, fetal intolerance of labour, and anaesthesia during labour did not predict labour and were dropped. The final algorithm correctly classified 73/80 cases, kappa = 0.83. In the validation, 86/100 cases were correctly classified. The kappa statistic was 0.68 (0.52, 0.83); predictive values for spontaneous and indicated onset were 85% (75%, 92%) and 89% (71%, 98%). CONCLUSIONS: The algorithm distinguished spontaneous from indicated preterm birth, using birth certificates, with good accuracy.

Nonsteroidal anti-inflammatory administration and patent ductus arteriosus ligation, a survey of practice preferences at US children's hospitals.

UNLABELLED: We surveyed neonatal leadership at 46 US children's hospitals via web-based survey to identify local preferences and concerns regarding indomethacin prophylaxis, nonsteroidal anti-inflammatory drug (NSAID) treatment, and patent ductus arteriosus (PDA) ligation. We received a 100 % survey response (N = 46). Practice guidelines for prophylactic indomethacin were reported at 28 % of NICUs, for NSAID treatment of PDA at 39 % and for surgical ligation at 27 %. Respondents noted intra-institutional practice variation for indomethacin prophylaxis (33 %), NSAID treatment (70 %), and PDA ligation (73 %). The majority of institutions did not prescribe indomethacin prophylaxis (72 %). For PDA treatment, indomethacin was preferred over ibuprofen (80 %). We validated our survey results via comparison with billing data as documented in the Pediatric Health Information System (PHIS) database, finding that survey responses directly correlated with local billing data (p < 0.0001). At institutions that did not typically administer NSAIDs for PDA closure or surgical PDA ligation, a lack of evidence for their effectiveness in improving long-term outcomes and the risk of treatment-associated adverse effects were the most often cited reasons. CONCLUSION: No consensus exists among providers at US children's hospitals regarding prophylactic indomethacin, NSAID treatment, or PDA ligation. Lack of evidence and safety concerns play a prominent role. WHAT IS KNOWN: • NSAIDs and surgical PDA ligation are efficacious in preventing intraventricular hemorrhage (IVH) and closing PDA in preterm infants, but have not been shown to improve long-term respiratory, neurodevelopmental, or mortality outcomes. What is New: • Practice preferences for indomethacin prophylaxis, NSAID, and surgical PDA treatment vary both among and within institutions. Lack of treatment effectiveness and the risk of adverse effects are major concerns.

Sildenafil Treatment of Infants With Bronchopulmonary Dysplasia-Associated Pulmonary Hypertension.

OBJECTIVE: This study had 2 goals: (1) to identify clinical and demographic characteristics associated with sildenafil exposure for infants with bronchopulmonary dysplasia (BPD)-associated pulmonary hypertension (PH); and (2) to characterize hospital-specific treatment frequency, age at first administration, and length of sildenafil treatment. METHODS: This retrospective cohort study used data from the Pediatric Health Information System to determine variables associated with sildenafil exposure and between-hospital variations in sildenafil utilization patterns. The study included infants with BPD-PH who were discharged between January 1, 2006, and December 31, 2013. RESULTS: Within 36 US pediatric hospitals, 3720 infants were diagnosed with BPD, of whom 598 (16%) also had a diagnosis of PH (BPD-PH). Among infants with BPD-PH, 104 infants (17%) received sildenafil. The odds for sildenafil treatment among infants born between 25 and 26 weeks' gestational age (GA) and <24 weeks' GA, respectively, were 2.26 (95% confidence interval [CI]: 1.20-4.24) and 3.21 (95% CI: 1.66-6.21) times those of infants born at 27 to 28 weeks' GA. Severity of BPD correlated with sildenafil exposure, with adjusted odds ratios (ORs) for moderate BPD (OR: 3.03 [95% CI: 1.03-8.93]) and severe BPD (OR: 7.56 [95% CI: 2.50-22.88]), compared with mild BPD. Greater rates of sildenafil exposure were observed among small for GA neonates (OR: 2.32 [95% CI: 1.21-4.46]). The proportion of infants with BPD-PH exposed to sildenafil varied according to hospital (median: 15%; 25th-75th percentile: 0%-25%), as did the median duration of therapy (52 days; 25th-75th percentile: 28-109 days). CONCLUSIONS: The odds of sildenafil treatment were greatest among the most premature infants with severe forms of BPD. The frequency and duration of sildenafil exposure varied markedly according to institution. Patient-centered trials for infants with BPD-PH are needed to develop evidence-based practices.

Utilization of inhaled corticosteroids for infants with bronchopulmonary dysplasia.

OBJECTIVE: To determine demographic and clinical variables associated with inhaled corticosteroid administration and to evaluate between-hospital variation in inhaled steroid use for infants with bronchopulmonary dysplasia (BPD). DESIGN: Retrospective Cohort Study. SETTING: Neonatal units of 35 US children's hospitals; as recorded in the Pediatric Health Information System (PHIS) database. PATIENTS: 1429 infants with evolving BPD at 28 days who were born at <29 weeks gestation with birth weight <1500 grams, admitted within the first 7 postnatal days, and discharged between January 2007-June 2011. RESULTS: Inhaled steroids were prescribed to 25% (n = 352) of the cohort with use steadily increasing during the first two months of hospitalization. The most frequently prescribed steroid was beclomethasone (n = 194, 14%), followed by budesonide (n = 125, 9%), and then fluticasone (n = 90, 6%). Birth gestation <24 weeks, birth weight 500-999 grams, and prolonged ventilation all increased the adjusted odds of ever receiving inhaled corticosteroids (p<0.05). Wide variations between hospitals in the frequency of infants ever receiving inhaled steroids (range: 0-60%) and the specific drug prescribed were noted. This variation persisted, even after controlling for observed confounders. CONCLUSIONS: Inhaled corticosteroid administration to infants with BPD is common in neonatal units within U.S. Children's hospitals. However, its utilization varies markedly between centers from no treatment at some institutions to the majority of infants with BPD being treated at others. This supports the need for further research to identify the benefits and potential risks of inhaled steroid usage in infants with BPD.

Cross race comparisons between SES health gradients among African-American and white women at mid-life.

This study explored how multiple indicators of socioeconomic status (SES) inform understanding of race differences in the magnitude of health gains associated with higher SES. The study sample, 1268 African-American women and 2066 white women, was drawn from the National Longitudinal Surveys of Youth 1979. The outcome was the Physical Components Summary from the SF-12 assessed at age 40. Ordinary least squares regressions using education, income and net worth fully interacted with race were conducted. Single measure gradients tended to be steeper for whites than African-Americans, partly because "sheepskin" effects of high school and college graduation were higher for whites and low income and low net worth whites had worse health than comparable African-Americans. Conditioning on multiple measures of SES eliminated race disparities in health benefits of education and net worth, but not income. A discussion of current public policies that affect race disparities in levels of education, income and net wealth is provided.

Disparities in women's health across a generation: a mother-daughter comparison.

BACKGROUND: The U.S. Centers for Disease Control and Prevention has set national goals to eliminate health disparities by race, sex, and socioeconomic status. Progress in meeting these goals has been mixed. This paper provides a different view on the evolving health of U.S. women by examining a sample of daughters and their mothers. METHODS: The aim was to determine if the health risk profiles of daughters (born 1975-1992) were different from their mothers (born 1957-1964) measured when both were between the ages of 17 and 24 years. The U.S.-based National Longitudinal Survey of Youth 1979 and associated Children and Young Adult Surveys were used. The sample was 2411 non-Hispanic white and African American girls born to 1701 mothers. Outcomes were height, weight, body mass index (BMI), age of menarche, and self-reported health. RESULTS: In both races, daughters were taller but entered adulthood at greater risk for the development of chronic illness than their mothers. Racial differences were greater in the daughters' generation than in the mothers'. Whites in both generations experienced educational differences in health based upon the mother's educational level, with fewer years of maternal education associated with poorer health. African Americans of both generations experienced differences by maternal education in self-reported health. However, when African American daughters were compared with their mothers, daughters born to college educated women gained more weight and had higher BMI and earlier menarche than did daughters born to high school dropouts. CONCLUSION: Health deterioration across generations in both races suggests that much work is needed to meet Healthy People 2020 goals of health equity.

The effects of state-level scope-of-practice regulations on the number and growth of nurse practitioners.

BACKGROUND: It is widely recognized that there is significant state-level variation in scope-of-practice regulations (SSoPRs) for nurse practitioners (NPs). PURPOSE: This study was designed to examine whether SSoPRs influence labor markets for NPs. METHOD: Cross-sectional analysis examining how SSoPRs influence the number and growth in NPs; data from the Area Resource File and 2008 Pearson report were used. DISCUSSION: Restrictive SSoPRs reduced the number of NPs by about 10 per 100,000 and reduced the growth rate by 25%. No difference was found between states with the most restriction and those with some restrictions. CONCLUSIONS: These results imply that changes to practice regulations should not be incremental but should follow the current practices in the least restrictive states. Results also indicate that other factors (poverty, uninsurance rates, rurality) decreased the number of NPs, suggesting that solving the primary care provider shortage will require multiple strategies.

Variation in the use of diuretic therapy for infants with bronchopulmonary dysplasia.

OBJECTIVES: To determine (1) between-hospital variation in diuretic use for infants with bronchopulmonary dysplasia (BPD), including hospital-specific treatment frequency, treatment duration, and percentage of infants receiving short (≤5 consecutive days) versus longer (>5 days) courses, and to determine (2) demographic and clinical variables associated with diuretic administration. METHODS: A retrospective cohort study was conducted with the use of the Pediatric Health Information System to determine between-hospital variation in diuretic utilization patterns (primary outcome) and variables associated with diuretic use among <29-week-gestation infants with evolving BPD at age 28 days who were discharged between January 2007 and June 2011. RESULTS: During the 54-month study period, 1429 infants within 35 hospitals met the inclusion criteria for BPD at age 28 days, with 1222 (86%) receiving diuretic therapy for a median of 9 days (25th-75th percentile: 2-33 days). Short courses were administered to 1203 (83%) infants, and 570 (40%) infants received treatment for >5 consecutive days. Furosemide was the most widely prescribed diuretic (1218 infants; 85%), although chlorothiazide had the longest median duration of use (21 days; 25th-75th percentile: 8-46 days). The range of infants receiving a diuretic course of >5 days duration varied by hospital from 4% to 86%, with wide between-hospital variation even after adjustment for confounding variables. CONCLUSIONS: The frequency of diuretic administration to infants with BPD at US children's hospitals, as well as the specific diuretic regimen used, varies markedly by institution. Safety and effectiveness research of long-term diuretic therapy for BPD patients is needed to develop evidence-based recommendations.

The impact of prepregnancy obesity on children's cognitive test scores.

To examine the association between maternal prepregnancy obesity and cognitive test scores of children at early primary school age. A descriptive observational design was used. Study subjects consist of 3,412 US children aged 60-83 months from the National Longitudinal Survey of Youth 1979 Mother and Child Survey. Cognitive test scores using the Peabody Individual Achievement Test reading recognition and mathematics tests were used as the outcomes of interest. Association with maternal prepregnancy obesity was examined using the ordinary least square regression controlling for intrauterine, family background, maternal and child factors. Children of obese women had 3 points (0.23 SD units) lower peabody individual achievement test (PIAT) reading recognition score (p = 0.007), and 2 points (0.16 SD units) lower PIAT mathematics scores (p < 0.0001), holding all other factors constant. As expected, cognitive test score was associated with stimulating home environment (reading: ß = 0.15, p < 0.0001, and math: ß = 0.15, p < 0.0001), household income (reading: ß = 0.03, p = 0.02 and math: ß = 0.04, p = 0.004), maternal education (reading: ß = 0.42, p = 0.0005, and math: ß = 0.32, p = 0.008), and maternal cognitive skills (reading: ß = 0.11, p < 0.0001, and math: ß = 0.09, p < 0.0001). There was a significant association between maternal prepregnancy obesity and child cognitive test scores that could not be explained by other intrauterine, family background, maternal, and child factors. Children who live in disadvantaged postnatal environments may be most affected by the effects of maternal prepregnancy obesity. Replications of the current study using different cohorts are warranted to confirm the association between maternal prepregnancy obesity and child cognitive test scores.

African-American/white differences in the age of menarche: accounting for the difference.

Lifetime health disparity between African-American and white females begins with lower birthweight and higher rates of childhood overweight. In adolescence, African-American girls experience earlier menarche. Understanding the origins of these health disparities is a national priority. There is growing literature suggesting that the life course health development model is a useful framework for studying disparities. The purpose of this study was to quantify the influence of explanatory factors from key developmental stages on the age of menarche and to determine how much of the overall race difference in age of menarche they could explain. The factors were maternal age of menarche, birthweight, poverty during early childhood (age 0 through 5 years), and child BMI z-scores at 6 years. The sample, drawn from the US National Longitudinal Surveys of Youth Child-Mother file, consisted of 2337 girls born between 1978 and 1998. Mean age of menarche in months was 144 for African-American girls and 150 for whites. An instrumental variable approach was used to estimate a causal effect of child BMI z-score on age of menarche. The instrumental variables were pre-pregnancy BMI, high gestational weight gain and smoking during pregnancy. We found strong effects of maternal age of menarche, birthweight, and child BMI z-score (-5.23, 95% CI [-7.35,-3.12]) for both African-Americans and whites. Age of menarche declined with increases in exposure to poverty during early childhood for whites. There was no effect of poverty for African-Americans. We used Oaxaca decomposition techniques to determine how much of the overall race difference in age of menarche was attributable to race differences in observable factors and how much was due to race dependent responses. The African-American/white difference in childhood BMI explained about 18% of the overall difference in age of menarche and birthweight differences explained another 11%.

Impact of urinary tract infection on inpatient healthcare for congenital obstructive uropathy.

PURPOSE: Congenital obstructive uropathy (COU) is a leading cause of pediatric chronic kidney disease (CKD). Urinary tract infections (UTIs) pose a risk for ascending infections and CKD in patients with COU. We evaluated the impact of comorbid UTIs on hospital charges and length of stay (LOS) for pediatric COU discharges. MATERIALS AND METHODS: The study sample (n = 2832) was drawn from the 2003 and 2006 US Healthcare Cost and Utilization Project Kids' Inpatient Database. Data were analyzed using logistic and linear regression. RESULTS: Comorbid UTIs complicated 6.7% of COU discharges, and were most common in patients with posterior urethral valves (15.7% of discharges). Comorbid UTIs increased mean charges by $7910 (95% confidence interval (CI) $4770-$11,040; p < 0.001) and prolonged mean LOS by 2.66 days (95% CI 2.03-3.29; p < 0.001) compared to COU discharges without UTI. After controlling for LOS, charges for COU with a secondary diagnosis of UTI were no longer significantly higher. Mean charges in inflation-adjusted dollars increased by $2710, a 15.8% increase unexplained by covariate diagnoses and procedures. CONCLUSIONS: Comorbid UTIs contribute significantly to inpatient charges for COU, by prolonging LOS.

Do declining private insurance coverage rates influence pediatric hospital charging practices?

OBJECTIVE: To analyze trends in primary payer composition for pediatric hospitalizations and insurance coverage rates from 2000 to 2006 and possible effects on hospital charging practices. DESIGN: We documented national trends in hospital charge-to-cost ratios and primary payer mixes for pediatric discharges from 2000 to 2006 using the Healthcare Cost and Utilization Project (HCUP) Kid's Inpatient Database (KID). We then performed regression analyses at the hospital level to analyze associations between pediatric insurance coverage rates and hospital charge-to-cost ratios. RESULTS: We found pediatric inpatient charge-to-cost ratios increased dramatically during study period. Charge-to-cost ratios were higher for hospitals located in states with either higher uninsurance rates or a public-private coverage mix that was skewed towards public coverage. CONCLUSIONS: This study provides evidence of both important changes in pediatric health insurance distribution in the United States and hospital charging practices.

Effects of heritability, shared environment, and nonshared intrauterine conditions on child and adolescent BMI.

Heritability studies of BMI, based upon twin samples, have identified genetic and shared environmental components of BMI, but have been largely silent about the nonshared environmental factors. Intrauterine factors have been identified as having significant long-term effects on BMI and may be a critical source of nonshared environmental influence. Extant studies based on samples of either unrelated individuals or twins cannot separate the effects of genetics, shared environments, and nonshared intrauterine conditions because the one lacks variation in the degree of relatedness and the other has insufficient variation in intrauterine conditions. This study improves upon these prior studies by using a large, sibling-based sample to examine heritability, shared environmental, and nonshared intrauterine influences on BMI during two age periods in childhood (6-8 years; 12-14 years). The primary interest was in determining the effects of the intrauterine environment on BMI as a component of the nonshared environment and in determining whether there were sex-specific differences in heritability and/or in the intrauterine factors. These were estimated using regression-based techniques introduced by DeFries and Fulker. Heritability of BMI was estimated to be 0.20-0.28 at 6-8 years and 0.46-0.61 at 12-14 years. Differences in heritability were found at 12-14 years between same-sex as compared to mixed-sex pairs. The shared environmental effect was significant at 6-8 years but insignificant at 12-14 years. Differences in birth weight were significant in all groups at 6-8 years suggesting long-term effects of the nonshared intrauterine environment; at 12-14 years, birth weight was no longer significant for girls.

Pathways to adolescent overweight: Body mass index and height percentile change in childhood.

OBJECTIVE: To study the magnitude and timing of changes in body mass index (BMI) and height percentiles in four groups of children defined by overweight status in early childhood and adolescence: nonoverweight-nonoverweight (N-N), nonoverweight-overweight (N-O), overweight-nonoverweight (O-N), and overweight-overweight (O-O). The aim was to determine if monitoring percentile changes can provide early warnings about risk for adolescent overweight before a chronic pattern of overweight is established. METHODS: Data on 3 408 children from the US based National Longitudinal Survey of Youth's Child-Mother file were used. Each child was interviewed on average 5.7 times, with a total of 19,470 person/year observations. BMI and height percentiles were estimated as polynomial functions of age in months for each of the four groups using fixed coefficients and random coefficients models. The models were compared using the Aikake information criterion. RESULTS: There was significant transition between initial and final weight states. Children who transitioned to overweight experienced larger increases in BMI percentile points at 2-6 years than at 7-10 years of age. N-O girls, but not boys, had significantly larger increases in height percentile than N-N girls, with the largest increases occurring by age 7. The height percentiles curves for N-O and O-O girls converged by age 8 years. O-N children experienced steeper declines in BMI percentile over longer periods of time than O-O children. CONCLUSIONS: Monitoring changes in BMI and height percentiles can give early warnings about children at risk for adolescent overweight while there is ample time for intervention.

Growth differences by age of menarche in African American and White girls.

BACKGROUND: Because of the rapid increases in childhood obesity coupled with decreases in the median age of menarche, there is interest in how growth (body mass index [BMI] and height) in childhood may be associated with timing of menarche. OBJECTIVES: Two research questions were addressed in this article: (a) Within each race, at what ages were BMI and height differences evident among the early-, the mid-, and the late-onset groups? And (b) within each timing group, at what ages were BMI and height differences evident between White and African American girls? METHODS: The mother/child files of the National Longitudinal Survey of Youth were used for this study. Menarcheal timing groups were identified using the 25th and the 75th percentile of the age distribution for each race. Longitudinal statistical techniques were used to estimate BMI and height as polynomial functions of age and age relative to menarche for African American and White girls. RESULTS: Significant differences in BMI by timing group were found. By 3 years of age, significant differences were found between early- and mid-onset African American girls, by 5 years of age between mid- and late-onset African American girls, and by 6 years of age among the three timing groups of White girls. Significant height differences were evident by 5 years of age when comparing early- to mid-onset and mid- to late-onset girls in both race groups. Comparing across race and within timing group, BMI and height differences were evident. African American girls were more likely than White girls to experience accelerated growth and earlier menarche. DISCUSSION: This is one of the few longitudinal studies of differences in growth by timing of menarche that includes data on girls younger than 5 years with large samples of both African American and White girls. Understanding when differences are first apparent is critical in establishing the critical period for prevention of these high-risk growth patterns.

Comparing the influence of childhood and adult economic status on midlife obesity in Mexican American, white, and African American women.

OBJECTIVE: This research addresses the following 2 questions. What is the effect of childhood and adult economic status on midlife obesity in Mexican American women? How do these economic patterns in Mexican American women compare with patterns seen in White women and in African American women? METHOD: Data were drawn from the U.S. National Longitudinal Survey of Youths 1979-2002 waves. The sample consisted of 422 Mexican Americans, 2,090 Whites, and 1,195 African Americans. The economic indicator used for childhood economic status was parent education; for adult economic status, the participant's own education and adult per capita income were used. Unadjusted and adjusted odds ratios were estimated for the relationship between midlife obesity and economic indicator, stratified by race/ethnic group. RESULTS: There was an increased risk for midlife obesity with disadvantaged economic status measured during childhood and at midlife in Mexican American women. The economic effects on midlife obesity in Mexican American women were similar to those found for White, but not African American women. Few economic influences on obesity at midlife were found for African American women. CONCLUSIONS: Strategies that broadly improve the economic conditions of Mexican American women may be one important way to address the obesity epidemic in this population.