To provide an updated birth weight-for-gestational age (BW-for-GA) reference in the United States by using the most recent, nationally representative birth data with obstetric estimates of ...gestational age (GA).
We abstracted 3 285 552 singleton births between 22 and 42 weeks' gestation with nonmissing race and/or ethnicity, infant sex, parity, birth weight, and obstetric estimate of GA from the 2017 US natality files. We used 2 techniques (nonlinear, resistant smoothing 4253H and lambda-mu-sigma) to derive smoothed BW-for-GA curves and compared resulting BW-for-GA cut-points at the third, 10th, 90th, and 97th percentiles with US references from 1999 to 2009.
The smoothed BW-for-GA curves from both techniques overlapped considerably with each other, with strong agreements seen between the 2 techniques (>99% agreement; κ-statistic >0.9) for BW-for-GA cut-points at the third, 10th, 90th, and 97th percentiles across all GAs. Cut-points from 2017 using the lambda-mu-sigma method captured 9.8% to 10.2% of births <10th and >90th percentiles and 2.6% to 3.3% of births below the third and above the 97th percentile across all GAs. However, cut-points from US references in 1999 and 2009 (when GA was based on last menstrual period) captured a much larger range of proportions of 2017 births at these thresholds, especially among preterm and postterm GA categories.
We have provided an updated BW-for-GA reference in the United States using the most recent births with obstetric estimates of GA and information to calculate continuous measures of birth size that are sex or parity specific.
IMPORTANCE: Inadequate sleep duration and quality increase the risk of obesity. Sleep timing, while less studied, is important in adolescents because increasing evening preferences (chronotypes), ...early school start times, and irregular sleep schedules may cause circadian misalignment. OBJECTIVE: To investigate associations of chronotype and social jet lag with adiposity and cardiometabolic risk in young adolescents. DESIGN, SETTING, AND PARTICIPANTS: Starting in 1999, Project Viva recruited pregnant women from eastern Massachusetts. Mother-child in-person visits occurred throughout childhood. From January 23, 2012, to October 16, 2016, 804 adolescents aged 12 to 17 years completed 5 days or more of wrist actigraphy, questionnaires, and anthropometric measurements. A cross-sectional analysis using these data was conducted from April 31, 2018, to May 1, 2019. EXPOSURES: Chronotype, measured via a continuous scale with higher scores indicating greater evening preferences, and social jet lag, measured as the continuous difference in actigraphy sleep midpoint in hours from midnight on weekends vs weekdays, with higher values representing more delayed sleep timing on weekends. MAIN OUTCOMES AND MEASURES: Adiposity, measured via anthropometry and dual-energy x-ray absorptiometry. For a subset of 479 adolescents with blood samples, cardiometabolic risk scores were computed as the mean of 5 sex- and cohort-specific z scores for waist circumference, systolic blood pressure, inversely scaled high-density lipoprotein cholesterol, and log-transformed triglycerides and homeostatic model of insulin resistance. RESULTS: Among the 804 adolescents in the study, 418 were girls and 386 were boys, with a mean (SD) age of 13.2 (0.9) years. In multivariable models adjusted for age, puberty, season, and sociodemographics, associations of chronotype and social jet lag with adiposity varied by sex. For girls, greater evening preference was associated with a 0.58-cm (95% CI, 0.12-1.03 cm; P = .04 for interaction) higher waist circumference and 0.16 kg/m2 (95% CI, 0.01-0.31 kg/m2; P = .03 for interaction) higher fat mass index as measured by dual-energy x-ray absorptiometry; each hour of social jet lag was associated with a 1.19-cm (95% CI, 0.04-2.35 cm; P = .21 for interaction) higher waist circumference and 0.45 kg/m2 (95% CI, 0.09-0.82 kg/m2; P = .01 for interaction) higher fat mass index as measured by dual-energy x-ray absorptiometry. Associations of social jet lag and evening chronotypes persisted for many measures of adiposity after adjustment for sleep duration and other lifestyle behaviors. By contrast, no associations were observed in boys. There were no associations with the cardiometabolic risk score for either sex, although statistical power was low for this outcome. CONCLUSIONS AND RELEVANCE: Evening chronotypes and social jet lag were associated with greater adiposity in adolescent girls but not adolescent boys. Interventions aimed at improving sleep schedules may be useful for obesity prevention, especially in girls.
Background: Methylmercury (MeHg) is a known neurotoxicant. Emerging evidence indicates it may have adverse effects on the neurologic and other body systems at common low levels of exposure. Impacts ...of MeHg exposure could vary by individual susceptibility or be confounded by beneficial nutrients in fish containing MeHg. Despite its global relevance, synthesis of the available literature on low-level MeHg exposure has been limited. Objectives: We undertook a synthesis of the current knowledge on the human health effects of low-level MeHg exposure to provide a basis for future research efforts, risk assessment, and exposure remediation policies worldwide. Data sources and extraction: We reviewed the published literature for original human epidemiologic research articles that reported a direct biomarker of mercury exposure. To focus on high-quality studies and those specifically on low mercury exposure, we excluded case series, as well as studies of populations with unusually high fish consumption (e.g., the Seychelles), marine mammal consumption (e.g., the Faroe Islands, circumpolar, and other indigenous populations), or consumption of highly contaminated fish (e.g., gold-mining regions in the Amazon). Data synthesis: Recent evidence raises the possibility of effects of low-level MeHg exposure on fetal growth among susceptible subgroups and on infant growth in the first 2 years of ufe. Low-level effects of MeHg on neurologic outcomes may differ by age, sex, and timing of exposure. No clear pattern has been observed for cardiovascular disease (CVD) risk across populations or for specific CVD end points. For the few studies evaluating immunologie effects associated with MeHg, results have been inconsistent. Conclusions: Studies targeted at identifying potential mechanisms of low-level MeHg effects and characterizing individual susceptibility, sexual dimorphism, and nonlinearity in dose response would help guide future prevention, policy, and regulatory efforts surrounding MeHg exposure.
Studies have found that higher maternal weight entering pregnancy increases risk for obesity and its cardiometabolic complications among offspring. Epidemiologic studies have found that higher ...maternal gestational weight gain is associated with higher weight and consequent risk for obesity, and elevated blood pressure among children. While these associations are partly mediated by shared genes and behaviors, the abundance of human evidence, supported by extensive data from experimental animal studies, suggests that intrauterine exposure to an obese intrauterine environment programs offspring obesity risk by influencing appetite, metabolism, and activity levels. Efforts to interrupt this cycle of obesity are important for public health and economical, as a successful intervention could benefit the child, the mother, her future pregnancies, and subsequent generations.
The Institute of Medicine (IOM) guidelines are the most widely used guidelines on gestational weight gain; however, accumulation of evidence that body composition in Asians differs from other races ...has brought concern regarding whether their direct application is appropriate. We aimed to study to what extent optimal gestational weight gain among women in Japan differs by pre-pregnancy body mass index (BMI) and to compare estimated optimal gestational weight gain to current Japanese and Institute of Medicine (IOM) recommendations.
We retrospectively studied 104,070 singleton pregnancies among nulliparous women in 2005–2011 using the Japanese national perinatal network database. In five pre-pregnancy BMI sub-groups (17.0–18.4, 18.5–19.9, 20–22.9, 23–24.9, and 25–27.4 kg/m2), we estimated the association of the rate of gestational weight gain with pregnancy outcomes (fetal growth, preterm delivery, and delivery complications) using multivariate regression.
Weight gain rate associated with the lowest risk of adverse outcomes decreased with increasing BMI (12.2 kg, 10.9 kg, 9.9 kg, 7.7 kg, and 4.3 kg/40 weeks) for the five BMI categories as described above, respectively. Current Japanese guidelines were lower than optimal gains, with the lowest risk of adverse outcomes for women with BMI below 18.5 kg/m2, and current IOM recommendations were higher than optimal gains for women with BMI over 23 kg/m2.
Optimal weight gain during pregnancy varies largely by pre-pregnancy BMI, and defining those with BMI over 23 kg/m2 as overweight, as proposed by the World Health Organization, may be useful when applying current IOM recommendations to Japanese guidelines.
•We estimated gestational weight gain that optimizes pregnancy outcomes in Japanese.•Optimal gain was 12.2 kg/40 weeks for pre-pregnancy BMI 17.0–18.4 kg/m2.•Optimal gain was 4.3 kg/40 weeks for pre-pregnancy BMI 25.0–27.4 kg/m2.•Current national guidelines are too low for women with pre-pregnancy BMI < 18.5 kg/m2.•BMI > 23 kg/m2 should be defined as overweight if applying IOM recommendations.
Objective The purpose of this study was to examine the associations of gestational weight gain with child adiposity. Study Design Using multivariable regression, we studied associations of total ...gestational weight gain and weight gain according to 1990 Institute of Medicine guidelines with child outcomes among 1044 mother-child pairs in Project Viva. Results Greater weight gain was associated with higher child body mass index z-score (0.13 units per 5 kg 95% CI, 0.08, 0.19), sum of subscapular and triceps skinfold thicknesses (0.26 mm 95% CI, 0.02, 0.51), and systolic blood pressure (0.60 mm Hg 95% CI, 0.06, 1.13). Compared with inadequate weight gain (0.17 units 95% CI, 0.01, 0.33), women with adequate or excessive weight gain had children with higher body mass index z-scores (0.47 95% CI, 0.37, 0.57 and 0.52 95% CI, 0.44, 0.61, respectively) and risk of overweight (odds ratios, 3.77 95% CI: 1.38, 10.27 and 4.35 95% CI: 1.69, 11.24). Conclusion New recommendations for gestational weight gain may be required in this era of epidemic obesity.
Abstract
Associations of prenatal exposure to perfluoroalkyl substances (PFAS), ubiquitous chemicals used in stain- and water-resistant products, with adverse birth outcomes may be confounded by ...pregnancy hemodynamics. We measured plasma concentrations of 4 PFAS in early pregnancy (median length of gestation, 9 weeks) among 1,645 women in Project Viva, a study of a birth cohort recruited during 1999–2002 in eastern Massachusetts. We fitted multivariable models to estimate associations of PFAS with birth weight-for-gestational age z score and length of gestation, adjusting for sociodemographic confounders and 2 hemodynamic markers: 1) plasma albumin concentration, a measure of plasma volume expansion, and 2) plasma creatinine concentration, used to estimate glomerular filtration rate. Perfluorooctane sulfonate (PFOS) and perfluorononanoate (PFNA) were weakly inversely associated with birth weight-for-gestational age z scores (adjusted β = −0.04 (95% confidence interval (CI): −0.08, 0.01) and adjusted β = −0.06 (95% CI: −0.11, −0.01) per interquartile-range increase, respectively). PFOS and PFNA were also associated with higher odds of preterm birth (e.g., for highest PFOS quartile vs. lowest, adjusted odds ratio = 2.4, 95% CI: 1.3, 4.4). Adjusting for markers of pregnancy hemodynamics (glomerular filtration rate and plasma albumin), to the extent that they accurately reflect underlying pregnancy physiology, did not materially affect associations. These results suggest that pregnancy hemodynamics may not confound associations with birth outcomes when PFAS are measured early in pregnancy.
Though disparities in birth weight by race/ethnicity have been extensively reported in the United States, few studies have systematically investigated factors attributing to its variability. For ...10,638,415 singleton infants born during 2009-2012 in the United States, we examined birth weight differences among 14 races and ethnicities (non-Hispanic white, non-Hispanic Black, American Indian, Asian Indian, Chinese, Filipino, Japanese, Korean, Vietnamese, Hawaiian, Guamanian, Mexican, Puerto Rican and Cuban), after sequentially adjusting for maternal, socio-economic and behavioral factors. Average birthweight of non-Hispanic white infants was 3381 g, while for other races/ethnicities birth weight ranged from being 289 g smaller in Japanese to 126 g larger in Samoan infants. Factors explaining differences of more than 50 grams in birth weight compared to white infants were: gestational age for black infants, height and body mass index for all Asian and Samoan mothers, and gestational weight gain for Japanese mothers. Difference in maternal age, parity, socioeconomic and behavioral characteristics did not account for significant portion of birthweight variations for any race. Our findings suggest that differences in maternal anthropometrics, gestational weight gain, and preterm birth rate, but not in maternal age, parity, socioeconomic or behavioral characteristics contribute to racial/ethnic differences in birthweight.
•We examined associations of PFAS mixtures with maternal and neonatal thyroid function.•Results from WQS regression and BKMR analyses were relatively consistent.•The PFAS mixture was inversely ...associated with maternal FT4I and neonatal T4.•PFOA, PFHxS, EtFOSAA, and MeFOSAA primarily contributed to the joint effect on FT4I.•PFHxS and MeFOSAA primarily contributed to the joint effect on neonatal T4 levels.
Maternal and neonatal thyroid function is critical for growth and neurodevelopment. Exposure to individual per- and polyfluoroalkyl substances (PFAS) can alter circulating thyroid hormone levels, but few studies have investigated effects of combined exposure to multiple PFAS.
Estimate associations of exposure to multiple PFAS during early pregnancy with maternal and neonatal thyroid function.
The study population consisted of 726 mothers and 465 neonates from Project Viva, a Boston, Massachusetts area longitudinal pre-birth cohort. We measured six PFAS perfluorooctanoate (PFOA), perfluorooctane sulfonate (PFOS), perfluorononanoate (PFNA), perfluorohexane sulfonate (PFHxS), 2-(N-ethyl-perfluorooctane sulfonamido)acetate (EtFOSAA), and 2-(N-methyl-perfluorooctane sulfonamido)acetate (MeFOSAA) and thyroxine (T4), Free T4 Index (FT4I), and thyroid stimulating hormone (TSH) in maternal plasma samples collected during early pregnancy, and neonatal T4 in postpartum heel sticks. We estimated individual and joint effects of PFAS exposure with thyroid hormone levels using weighted quantile sum (WQS) regression and Bayesian kernel machine regression (BKMR), and evaluated potential non-linearity and interactions among PFAS using BKMR.
Higher concentrations of the PFAS mixture were associated with significantly lower maternal FT4I, with MeFOSAA, EtFOSAA, PFOA, and PFHxS contributing most to the overall mixture effect in BKMR and WQS regression. In infants, higher concentrations of the PFAS mixture were associated with lower T4 levels, primarily in males, with PFHxS and MeFOSAA contributing most in WQS, and PFHxS contributing most in BKMR. The PFAS mixture was not associated with maternal T4 or TSH levels. However, in maternal BKMR analyses, ln-PFOS was positively associated with T4 levels (Δ25th to 75th percentile: 0.21 µg/dL; 95% credible interval: −0.03, 0.47) and ln-PFHxS was associated with a non-linear effect on TSH levels.
These findings support the hypothesis that there may be combined effects of prenatal exposure to multiple PFAS on maternal and neonatal thyroid function, but the direction and magnitude of these effects may vary across individual PFAS.
Few studies have examined whether prenatal exposure to perfluoroalkyl substances (PFASs) is associated with childhood adiposity.
We examined associations of prenatal exposure to PFASs with adiposity ...in early and mid-childhood.
We measured plasma PFAS concentrations in 1,645 pregnant women (median, 9.6 weeks gestation) enrolled in Project Viva, a prospective pre-birth cohort study in Massachusetts (USA), between 1999 and 2002. We assessed overall and central adiposity in 1,006 children in early childhood (median, 3.2 years) and 876 in mid-childhood (median, 7.7 years) using anthropometric and dual X-ray absorptiometry (DXA) measurements. We fitted multivariable linear regression models to estimate exposure-outcome associations and evaluated effect modification by child sex.
Median (25-75th percentiles) prenatal plasma perfluorooctanoate (PFOA), perfluorooctane sulfonate (PFOS), perfluorohexane sulfonate (PFHxS), and perfluorononanoate (PFNA) concentrations in children assessed in early childhood were 5.6 (4.1-7.7), 24.8 (18.4-33.9), 2.4 (1.6-3.8), and 0.6 (0.5-0.9) ng/mL, respectively. Among girls, each interquartile range increment of prenatal PFOA concentrations was associated with 0.21 kg/m
(95% CI: -0.05, 0.48) higher body mass index, 0.76 mm (95% CI: -0.17, 1.70) higher sum of subscapular and triceps skinfold thickness, and 0.17 kg/m
(95% CI: -0.02, 0.36) higher DXA total fat mass index in mid-childhood. Similar associations were observed for PFOS, PFHxS, and PFNA. We observed null associations for boys and early-childhood adiposity measures.
In this cohort, prenatal exposure to PFASs was associated with small increases in adiposity measurements in mid-childhood, but only among girls. Citation: Mora AM, Oken E, Rifas-Shiman SL, Webster TF, Gillman MW, Calafat AM, Ye X, Sagiv SK. 2017. Prenatal exposure to perfluoroalkyl substances and adiposity in early and mid-childhood. Environ Health Perspect 125:467-473; http://dx.doi.org/10.1289/EHP246.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, OILJ, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK, VSZLJ
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