Association of Upper Respiratory Streptococcus pneumoniae Colonization With Severe Acute Respiratory Syndrome Coronavirus 2 Infection Among Adults.

BACKGROUND: Streptococcus pneumoniae interacts with numerous viral respiratory pathogens in the upper airway. It is unclear whether similar interactions occur with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). METHODS: We collected saliva specimens from working-age adults undergoing SARS-CoV-2 molecular testing at outpatient clinics and via mobile community-outreach testing between July and November 2020 in Monterey County, California. After bacterial culture enrichment, we tested for pneumococci by means of quantitative polymerase chain reaction targeting the lytA and piaB genes, and we measured associations with SARS-CoV-2 infection using conditional logistic regression. RESULTS: Analyses included 1278 participants, with 564 enrolled in clinics and 714 enrolled through outreach-based testing. The prevalence of pneumococcal carriage was 9.2% (117 of 1278) among all participants (11.2% [63 of 564] in clinic-based testing and 7.6% [54 of 714] in outreach-based testing). The prevalence of SARS-CoV-2 infection was 27.4% (32 of 117) among pneumococcal carriers and 9.6% (112 of 1161) among noncarriers (adjusted odds ratio [aOR], 2.73 [95% confidence interval (CI): 1.58-4.69). Associations between SARS-CoV-2 infection and pneumococcal carriage were enhanced in the clinic-based sample (aOR, 4.01 [95% CI: 2.08-7.75]) and among symptomatic participants (3.38 [1.35-8.40]), compared with findings within the outreach-based sample and among asymptomatic participants. The adjusted odds of SARS-CoV-2 coinfection increased 1.24-fold (95% CI: 1.00-1.55-fold) for each 1-unit decrease in piaB quantitative polymerase chain reaction cycle threshold value among pneumococcal carriers. Finally, pneumococcal carriage modified the association of SARS-CoV-2 infection with recent exposure to a suspected coronavirus disease 2019 case (aOR, 7.64 [95% CI: 1.91-30.7] and 3.29 [1.94-5.59]) among pneumococcal carriers and noncarriers, respectively). CONCLUSIONS: Associations of pneumococcal carriage detection and density with SARS-CoV-2 suggest a synergistic relationship in the upper airway. Longitudinal studies are needed to determine interaction mechanisms between pneumococci and SARS-CoV-2.

Meta-analysis of epigenome-wide associations between DNA methylation at birth and childhood cognitive skills.

Cognitive skills are a strong predictor of a wide range of later life outcomes. Genetic and epigenetic associations across the genome explain some of the variation in general cognitive abilities in the general population and it is plausible that epigenetic associations might arise from prenatal environmental exposures and/or genetic variation early in life. We investigated the association between cord blood DNA methylation at birth and cognitive skills assessed in children from eight pregnancy cohorts within the Pregnancy And Childhood Epigenetics (PACE) Consortium across overall (total N = 2196), verbal (total N = 2206) and non-verbal cognitive scores (total N = 3300). The associations at single CpG sites were weak for all of the cognitive domains investigated. One region near DUSP22 on chromosome 6 was associated with non-verbal cognition in a model adjusted for maternal IQ. We conclude that there is little evidence to support the idea that variation in cord blood DNA methylation at single CpG sites is associated with cognitive skills and further studies are needed to confirm the association at DUSP22.

Associations between prenatal phthalate exposure and childhood epigenetic age acceleration.

BACKGROUND: Phthalates, a group of pervasive endocrine-disrupting chemicals found in plastics and personal care products, have been associated with a wide range of developmental and health outcomes. However, their impact on biomarkers of aging has not been characterized. We tested associations between prenatal exposure to 11 phthalate metabolites on epigenetic aging in children at birth, 7, 9, and 14 years of age. We hypothesized that prenatal phthalate exposure will be associated with epigenetic age acceleration measures at birth and in early childhood, with patterns dependent on sex and timing of DNAm measurement. METHODS: Among 385 mother-child pairs from the CHAMACOS cohort, we measured DNAm at birth, 7, 9, and 14 years of age, and utilized adjusted linear regression to assess the association between prenatal phthalate exposure and Bohlin's Gestational Age Acceleration (GAA) at birth and Intrinsic Epigenetic Age Acceleration (IEAA) throughout childhood. Additionally, quantile g-computation was utilized to assess the effect of the phthalate mixture on GAA at birth and IEAA throughout childhood. RESULTS: We found a negative association between prenatal di (2-ethylhexyl) phthalate (DEHP) exposure and IEAA among males at age 7 (-0.62 years; 95% CI:-1.06 to -0.18), and a marginal negative association between the whole phthalate mixture and GAA among males at birth (-1.54 days, 95% CI: -2.79 to -0.28), while most other associations were nonsignificant. CONCLUSIONS: Our results suggest that prenatal exposure to certain phthalates is associated with epigenetic aging in children. Additionally, our findings suggest that the influence of prenatal exposures on epigenetic age may only manifest during specific periods of child development, and studies relying on DNAm measurements solely from cord blood or single time points may overlook potential relationships.

Prevalence and Clinical Profile of Severe Acute Respiratory Syndrome Coronavirus 2 Infection among Farmworkers, California, USA, June-November 2020.

During the ongoing coronavirus disease (COVID-19) pandemic, farmworkers in the United States are considered essential personnel and continue in-person work. We conducted prospective surveillance for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and antibody prevalence among farmworkers in Salinas Valley, California, during June 15-November 30, 2020. We observed 22.1% (1,514/6,864) positivity for SARS-CoV-2 infection among farmworkers compared with 17.2% (1,255/7,305) among other adults from the same communities (risk ratio 1.29, 95% CI 1.20-1.37). In a nested study enrolling 1,115 farmworkers, prevalence of current infection was 27.7% among farmworkers reporting >1 COVID-19 symptom and 7.2% among farmworkers without symptoms (adjusted odds ratio 4.16, 95% CI 2.85-6.06). Prevalence of SARS-CoV-2 antibodies increased from 10.5% (95% CI 6.0%-18.4%) during July 16-August 31 to 21.2% (95% CI 16.6%-27.4%) during November 1-30. High SARS-CoV-2 infection prevalence among farmworkers underscores the need for vaccination and other preventive interventions.

Dioxin exposure associated with fecundability and infertility in mothers and daughters of Seveso, Italy.

STUDY QUESTION: Is there an association between 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) exposure and fecundability and infertility among Seveso women and their daughters? SUMMARY ANSWER: TCDD exposure is associated with a decrease in fecundability and increased risk of infertility in women, as well as their daughters. WHAT IS KNOWN ALREADY: In animal studies, maternal exposure to TCDD is associated with decreased fertility in offspring. Effects of TCDD are mediated by activation of the aryl hydrocarbon receptor (AHR) pathway. STUDY DESIGN, SIZE, DURATION: The Seveso Women's Health Study (SWHS) has followed 981 women exposed to TCDD in a 1976 accident since 1996. In 2014, we initiated the Seveso Second Generation Study to follow-up their children. PARTICIPANTS/MATERIALS, SETTING, METHODS: We obtained information on pregnancy history including time of trying to conceive from SWHS women and their daughters who were 18 years or older. We considered TCDD exposure as initial 1976 serum TCDD concentration and estimated TCDD at pregnancy. We examined relationships of TCDD exposure with time to pregnancy (TTP, the monthly probability of conception within the first 12 months of trying) and infertility (≥12 months of trying to conceive). We also assessed contributions of polymorphisms in the AHR pathway via genetic risk score. MAIN RESULTS AND THE ROLE OF CHANCE: Among SWHS women (n = 446), median TTP was 3 months and 18% reported taking ≥12 months to conceive. Initial 1976 TCDD (log10) was associated with longer TTP (adjusted fecundability odds ratio = 0.82; 95% CI 0.68-0.98) and increased risk of infertility (adjusted relative risk = 1.35; 95% CI 1.01-1.79). TCDD at pregnancy yielded similar associations. Among SWHS daughters (n = 66), median TTP was 2 months and 11% reported taking ≥12 months to conceive. Daughters showed similar, but non-significant, associations with maternal TCDD exposure. LIMITATIONS, REASONS FOR CAUTION: A limitation of this study is time to pregnancy was reported retrospectively, although previous studies have found women are able to recall time to conception with a high degree of accuracy many years after the fact. The number of SWHS daughters who had a live birth was small and we were unable to examine fecundability of SWHS sons. WIDER IMPLICATIONS OF THE FINDINGS: Consistent with previous findings in animal studies, our study found that TCDD exposure may be associated with decreased fertility in Seveso mothers and potentially in their daughters exposed in utero. There may be susceptible genetic subgroups. The literature has largely considered the genetics of the AHR pathway in the context of male fertility but not female fertility, despite strong biological plausibility. These findings should be replicated in larger populations and of different ancestry. Future studies in Seveso should examine the sons and the grandchildren of exposed mothers given the animal literature suggesting potential heritable epigenetic effects. STUDY FUNDING/COMPETING INTEREST(S): This study was supported by grant numbers F06 TW02075-01 from the National Institutes of Health, R01 ES07171 and 2P30-ESO01896-17 from the National Institute of Environmental Health Sciences, R82471 from the U.S. Environmental Protection Agency and #2896 from Regione Lombardia and Fondazione Lombardia Ambiente, Milan, Italy. J.A. was supported by F31ES026488 from the National Institutes of Health. The authors declare they have no actual or potential competing financial interests. TRIAL REGISTRATION NUMBER: N/A.

Prenatal exposure to phthalates and maternal metabolic outcomes in a high-risk pregnant Latina population.

BACKGROUND: Phthalates are a group of endocrine disrupting chemicals that are heavily used throughout industry in flexible plastic and personal-care products. As a result, detectable levels of their metabolites are readily found in humans. Some studies have shown associations of phthalates with diabetes, but associations with gestational diabetes mellitus (GDM) are less clear. OBJECTIVE: To investigate the association of 11 prenatal urinary phthalate metabolites and development of GDM, impaired glucose tolerance (IGT), continuous plasma glucose level, and excessive gestational weight gain (GWG) in a population of pregnant Latina women (N = 415) enrolled in the Center for the Health Assessment of Mothers and Children of Salinas (CHAMACOS) cohort study. METHODS: Phthalate metabolite levels were measured via mass spectrometry from two urine samples collected in the end of the first and second trimester. Maternal plasma glucose levels, prior diabetes diagnosis, GDM diagnosis, and weight gain were abstracted from medical records. Multiple regression was used to evaluate the association between the average of the two urinary phthalate metabolites levels and maternal metabolic outcomes. In our sensitivity analysis, phthalate levels were categorized by level (as quartiles of exposure) and by timing of urine sample collection (as taken in first and second half of pregnancy). RESULTS: Consistent with findings from a nationally representative sample, all of the individual phthalate metabolites were detected in majority of mothers. Thirty-one mothers (7.5%) were diagnosed with GDM, 49 mothers (14.7%) displayed IGT, and 223 mothers (55.1%) gained an excessive amount of weight during their pregnancy. MEP concentrations were associated with an increased odds of excessive GWG (OR: 1.1, 95% CI: 1.0 to 1.3). We did not find an association between any phthalate metabolite and any maternal glucose outcome. CONCLUSION: Contrary to previous studies, our findings do not support an association of prenatal phthalate levels and increased odds for hyperglycemia, IGT, or GDM. But, we did find an increased odds of excessive GWG, a well-known risk factor for GDM.

Traffic-related air pollution is associated with glucose dysregulation, blood pressure, and oxidative stress in children.

BACKGROUND: Metabolic syndrome increases the risk of cardiovascular disease in adults. Antecedents likely begin in childhood and whether childhood exposure to air pollution plays a contributory role is not well understood. OBJECTIVES: To assess whether children's exposure to air pollution is associated with markers of risk for metabolic syndrome and oxidative stress, a hypothesized mediator of air pollution-related health effects. METHODS: We studied 299 children (ages 6-8) living in the Fresno, CA area. At a study center visit, questionnaire and biomarker data were collected. Outcomes included hemoglobin A1c (HbA1c), urinary 8-isoprostane, systolic blood pressure (SBP), and BMI. Individual-level exposure estimates for a set of four pollutants that are constituents of traffic-related air pollution (TRAP) - the sum of 4-, 5-, and 6-ring polycyclic aromatic hydrocarbon compounds (PAH456), NO2, elemental carbon, and fine particulate matter (PM2.5) - were modeled at the primary residential location for 1-day lag, and 1-week, 1-month, 3-month, 6-month, and 1-year averages prior to each participant's visit date. Generalized additive models were used to estimate associations between each air pollutant exposure and outcome. RESULTS: The study population was 53% male, 80% Latinx, 11% Black and largely low-income (6% were White and 3% were Asian/Pacific Islander). HbA1c percentage was associated with longer-term increases in TRAP; for example a 4.42 ng/m3 increase in 6-month average PAH456 was associated with a 0.07% increase (95% CI: 0.01, 0.14) and a 3.62 µg/m3 increase in 6-month average PM2.5 was associated with a 0.06% increase (95% CI: 0.01, 0.10). The influence of air pollutants on blood pressure was strongest at 3 months; for example, a 6.2 ppb increase in 3-month average NO2 was associated with a 9.4 mmHg increase in SBP (95% CI: 2.8, 15.9). TRAP concentrations were not significantly associated with anthropometric or adipokine measures. Short-term TRAP exposure averages were significantly associated with creatinine-adjusted urinary 8-isoprostane. DISCUSSION: Our results suggest that both short- and longer-term estimated individual-level outdoor residential exposures to several traffic-related air pollutants, including ambient PAHs, are associated with biomarkers of risk for metabolic syndrome and oxidative stress in children.

Early-Life Home Environment and Obesity in a Mexican American Birth Cohort: The CHAMACOS Study.

OBJECTIVE: Little is known about the impact of the home environment on biomarkers of obesity, such as adipokines, in children. In this study, we examined the relationship of maternal depressive symptoms and potentially protective social factors, including maternal support and the home learning environment, with body mass index and adipokines. METHODS: Data were obtained from 326 Mexican American participants from the Center for the Health Assessment of Mothers and Children of Salinas cohort. Plasma adipokine levels were assessed in 326 children by enzyme-linked immunoassay at birth or ages 5, 9, or 14 years. Maternal depressive symptoms were evaluated using the Center for Epidemiological Studies Depression Scale when children were 1, 3.5, 7, and 9 years old; social support was assessed by the Duke-University of North Carolina Questionnaire at ages 1 and 5 years; and home learning environment by the Home Observation for the Measurement of the Environment (HOME) at ages of 6 months and 1, 2, 3.5, 7, 9, and 10.5 years. RESULTS: Age was significantly associated with adiponectin (B = -5.0, SE = 0.2) and leptin (B = 0.01, SE = 0.003) levels. Individual time point analyses identified significant positive associations of HOME scores in childhood with adiponectin at ages 9 years (HOME score; age 3.5 years: B = 0.9, p = .04) and 14 years (HOME score; age 7 years: B = 0.6, p = .02, age 9 years: B = 0.6, p = .05, age 10.5 years: B = 0.5, p = .04). We observed significant relationships of maternal depressive symptoms at age 9 years with adiponectin and body mass index z-score at age 14 years (B = -0.2, p = .003 and B = 0.02, p = .002, resp.), which were confirmed in longitudinal models. CONCLUSIONS: This study adds new evidence that adverse and protective aspects of the home environment could lead to altered obesity status in children.

5-Hydroxymethylcytosine in cord blood and associations of DNA methylation with sex in newborns.

DNA methylation has been widely studied for associations with exposures and health outcomes. Both 5-methylcytosine (5mC) and 5-hydroxymethylcytosine (5hmC) are epigenetic marks that may function differently to impact gene expression; however, the most commonly used technology to assess methylation for population studies in blood use are the Illumina 450K and EPIC BeadChips, for which the traditional bisulfite conversion does not differentiate 5mC and 5hmC marks. We used a modified protocol originally developed by Stewart et al. to analyse oxidative bisulfite-converted and conventional bisulfite-converted DNA for the same subject in parallel by the EPIC chip, allowing us to isolate the two measures. We measured 5mC and 5hmC in cord blood of 41 newborn participants of the Center for Health Assessment of Mothers and Children of Salinas (CHAMACOS) birth cohort and investigated differential methylation of 5mC + 5hmC, isolated 5mC and isolated 5hmC with sex at birth as an example of a biological variable previously associated with DNA methylation. Results showed low levels of 5hmC throughout the epigenome in the cord blood samples in comparison to 5mC. The concordance of autosomal hits between 5mC + 5hmC and exclusive 5mC analyses were low (25%); however, overlap was larger with increased effect size difference. There were 43 autosomal cytosine nucleotide followed by a guanine nucleotide (CpG) sites where 5hmC was associated with sex, 21 of which were unique to 5hmC after adjustment for cell composition. 5hmC only accounts for a small portion of overall methylation in cord blood; however, it has the potential to impact interpretation of combined 5hmC + 5mC studies in cord blood, especially given that effect sizes of differential methylation analyses are often small. Several significant CpG sites were unique to 5hmC, suggesting some functions distinct from 5mC. More studies of genome-wide 5hmC in children are warranted.

Prenatal high molecular weight phthalates and bisphenol A, and childhood respiratory and allergic outcomes.

BACKGROUND: The prevalence of asthma and allergy is increasing in US children. In utero exposure to chemicals used in personal care products and plastics may contribute to increase in these diseases. METHODS: We quantified urinary concentrations of eight phthalate metabolites and bisphenol A in mothers twice during pregnancy in 1999-2000 in Salinas, California. We assessed probable asthma, aeroallergies, eczema, and spirometry in their children at age 7, and measured T helper 1 and T helper 2 cells in blood at ages 2, 5, and 7 (N = 392). We employed Bayesian model averaging to select confounders from additional biomarkers measured in this population and controlled for them in logistic and linear regressions. RESULTS: Monocarboxyisooctyl phthalate was associated with increased odds for probable asthma (odds ratio: 1.54, 95% CI: 1.12, 2.12), and with lower forced expiratory volume in one second (ß: -0.09 L, 95% CI: -0.15, -0.03) and forced expiratory flow from 25% to 75% of forced vital capacity (ß: -7.06 L/s, 95% CI: -11.04, -2.90). Several other associations were attenuated in final models that controlled for additional biomarkers. CONCLUSION: Monocarboxyisooctyl phthalate was associated with lower respiratory health after controlling for related chemical exposure, which suggests that confounding by multiple chemical exposures should be considered in future research.

Heterogeneity in childhood body mass trajectories in relation to prenatal phthalate exposure.

Phthalates, compounds commonly used in plastics and personal care products, have been associated with childhood obesity in cross-sectional and some longitudinal studies. Using advanced statistical methods, we characterized the heterogeneity in body mass development patterns over childhood (ages 2-14 years) and explored associations with maternal prenatal urinary concentrations of phthalates among 335 children in the Center for the Health Assessment of Mothers and Children of Salinas (CHAMACOS) cohort study. Height and weight were measured every one to two years in this cohort, which had a high prevalence of obesity and overweight. Building upon a previous analysis that showed a positive association between prenatal phthalate exposure and body mass index (BMI) in CHAMACOS children, we used three advanced statistical methods: generalized additive models, growth mixture models, and functional principal component analysis with tree-based methods to identify patterns of childhood BMI development and allow for non-linear relationships with the environmental exposures. Our results highlight the heterogeneity in childhood BMI development patterns and suggest a sex-specific non-linear association between prenatal monoethyl phthalate urinary concentrations and BMI level in children, confirmed across a variety of statistical methods. There is also evidence to suggest positive associations between DEHP metabolites and BMI stabilization during puberty for girls.

Polybrominated Diphenyl Ethers, Polychlorinated Biphenyls, and 2,2-Bis(4-chlorophenyl)-1,1-dichloroethene in 7- and 9-Year-Old Children and Their Mothers in the Center for the Health Assessment of Mothers and Children of Salinas Cohort.

We report longitudinal serum concentrations of select persistent organic pollutants (POPs) in children at ages 7 and 9 years and in their mothers prenatally and again when the children were 9 years old. The participating families were enrolled in the Center for the Health Assessment of Mothers and Children of Salinas (CHAMACOS), a longitudinal birth cohort study of low-income Hispanic families residing in the Salinas Valley, California. We observed decreasing concentrations in the mothers with year of serum collection (2009 vs 2011) for six out of seven polybrominated diphenyl ether (PBDE) congeners and for 2,2',4,4',5-pentachlorobiphenyl (CB-99; p < 0.05). The 9-year-old children had similarly decreasing serum concentrations of all seven PBDE congeners, CB-99, and 2,2',3,4,4',5'- and 2,3,3',4,4',6-hexachlorobiphenyl (CB-138/158) with year of serum collection (2009 vs 2011; p < 0.05). In mixed effect models accounting for weight gain as the children aged from 7 to 9 years, we observed an annual decrease (-8.3% to -13.4%) in tri- to hexaBDE concentrations (p < 0.001), except for 2,2',3,4,4'-tetrabromodiphenyl ether (BDE-85) and 2,2',4,4',5,5'-hexabromodiphenyl ether (BDE-153). The concentrations of these congeners were not associated with time of serum collection and instead showed an -0.9% to -2.6% decrease per kilogram of weight gain during the study period (p < 0.05). In the case of tetra- to heptachlorobiphenyls, we observed -0.5% to -0.7% decrease in serum concentration per kilogram of weight gain (p < 0.05) and -3.0% to -3.7% decrease in serum concentration per year of aging (p < 0.05), except for 2,3',4,4',5-pentachlorobiphenyl (CB-118) and 2,2',4,4',5,5'-hexachlorobiphenyl (CB-153), which were not associated with time of serum draw. 2,2-Bis(4-chlorophenyl)-1,1-dichloroethene (p,p'-DDE) decreased -2.4%/kg of weight gain between the two sampling points (p < 0.001). These findings suggest that as children grow, dilution in a larger body size plays an important role in explaining reductions in body burden in the case of traditional POPs such as PCBs and p,p'-DDE. By contrast, in the case of PBDEs, reductions are likely explained by reduction in exposure, as illustrated by decreased concentrations in more recent years, possibly amplified by presumed shorter biological half-life than other POPs.

Residential proximity to agricultural fumigant use and respiratory health in 7-year old children.

OBJECTIVES: To examine the relationship between residential proximity to agricultural fumigant use and respiratory symptoms and lung function in 7-year old children. METHODS: Participants were 294 children living in the agricultural Salinas Valley, California and enrolled in the Center for the Health Assessment of Mothers and Children Of Salinas (CHAMACOS) study. We obtained information on respiratory symptoms and asthma medication use from maternal questionnaires and children performed spirometry to determine the forced expiratory volume in one second (FEV1), forced vital capacity (FVC), and forced expiratory flow 25-75% (FEF25-75) at 7-years of age. We estimated agricultural fumigant use within 3, 5 and 8 km of residences during pregnancy and from birth to age 7 using California's Pesticide Use Report data. We evaluated the association between prenatal and postnatal residential proximity to agricultural use of methyl bromide, chloropicrin, metam sodium and 1,3-dichloropropene with respiratory symptoms and use of asthma medication with logistic regression models and continuous lung function measurements with linear regression models adjusted for confounders. RESULTS: There were no significant associations between residential proximity to use of fumigants and respiratory symptoms or use of asthma medication. We did not observe any adverse relationships between residential proximity to fumigant use and lung function measurements. Unexpectedly, we observed suggestive evidence of improved FEV1 and FEF25-75 with higher use of methyl bromide and chloropicrin during the prenatal period. For example, for each 10-fold increase in methyl bromide use during the prenatal development period we observed higher FEV1 (ß = 0.06 L/s; 95% CI: 0.00, 0.12) and higher FEF25-75 (ß = 0.15 L/s; 95% CI: 0.03, 0.27). Maternal report of child allergies (runny nose without a cold during the previous year) modified the relationship between FEV1 and prenatal proximity to methyl bromide use (p = .07) and we only observed higher FEV1 among children without allergies (ß = 0.08 L/s; 95% CI: 0.02, 0.14 for a 10-fold increase in methyl bromide use during the prenatal period). CONCLUSIONS: Residential proximity to agricultural fumigant use during pregnancy and childhood did not adversely affect respiratory health in the children through 7 years of age. These findings should be explored in larger studies.

CpG Methylation across the adipogenic PPARγ gene and its relationship with birthweight and child BMI at 9 years.

BACKGROUND: To examine methylation of the peroxisome proliferator-activated receptor γ (PPARγ) gene and its relationship with child weight status, at birth and 9 years. METHODS: We measured PPARγ methylation across 23 CpG sites using the Infinium Illumina 450 k array for children from the Center for the Health Assessment of Mothers and Children of Salinas (CHAMACOS) cohort at birth (N = 373) and 9 years (N = 245). RESULTS: Methylation level correlation patterns across the 23 PPARγ CpG sites were conserved between birth and 9-year ages. We found high inter-CpG correlations between sites 1-3 (methylation block 1) and also between sites 18-23 (methylation block 2) for both time points, although these patterns were less pronounced at 9 years. Additionally, sites 1-3 (north shore) had the highest intra-CpG correlations over time (r = 0.24, 0.42, and 0.3; P = 0.002, P < 0.001, P < 0.001, respectively). PPARγ methylation levels tended to increase with age, and the largest differences were observed for north shore sites (7.4%). Adjusting for sex, both site 1 and site 20 (gene body) methylation at birth was significantly and inversely associated with birth weight (ß = -0.13, P = 0.033; ß = -0.09, P = 0.025, respectively). Similarly, we found that site 1 and site 20 methylation at 9 years was significantly and inversely associated with 9-year BMI z-score (ß = -0.41, P = 0.015; ß = -0.23, P = 0.045, respectively). CONCLUSION: Our results indicate that PPARγ methylation is highly organized and conserved over time, and highlight the potential functional importance of north shore sites, adding to a better understanding of regional human methylome patterns. Overall, our results suggest that PPARγ methylation may be associated with child body size.

Inter-laboratory consistency and variability in the buccal micronucleus cytome assay depends on biomarker scored and laboratory experience: results from the HUMNxl international inter-laboratory scoring exercise.

The buccal micronucleus cytome (BMNcyt) assay in uncultured exfoliated epithelial cells from oral mucosa is widely applied in biomonitoring human exposures to genotoxic agents and is also proposed as a suitable test for prescreening and follow-up of precancerous oral lesions. The main limitation of the assay is the large variability observed in the baseline values of micronuclei (MNi) and other nuclear anomalies mainly related to different scoring criteria. The aim of this international collaborative study, involving laboratories with different level of experience, was to evaluate the inter- and intra-laboratory variations in the BMNcyt parameters, using recently implemented guidelines, in scoring cells from the same pooled samples obtained from healthy subjects (control group) and from cancer patients undergoing radiotherapy (treated group). The results indicate that all laboratories correctly discriminated samples from the two groups by a significant increase of micronucleus (MN) and nuclear bud (NBUD) frequencies and differentiated binucleated (BN) cells, associated with the exposure to ionizing radiation. The experience of the laboratories was shown to play an important role in the identification of the different cell types and nuclear anomalies. MN frequency in differentiated mononucleated (MONO) and BN cells showed the greatest consistency among the laboratories and low variability was also detected in the frequencies of MONO and BN cells. A larger variability was observed in classifying the different cell types, indicating the subjectivity in the interpretation of some of the scoring criteria while reproducibility of the results between scoring sessions was very good. An inter-laboratory calibration exercise is strongly recommended before starting studies with BMNcyt assay involving multiple research centers.

Association of prenatal urinary phthalate metabolite concentrations and childhood BMI and obesity.

BackgroundAlthough experiments in animals suggest that phthalates may have obesogenic effects, studies on prenatal exposure in children show inconsistent results.MethodsWe measured urinary concentrations of 11 phthalate metabolites collected twice during pregnancy from mothers participating in the Center for the Health Assessment of Mothers and Children of Salinas (CHAMACOS) cohort study (N=345). Height, weight, waist circumference, and percent body fat were assessed in their children between 5 and 12 years of age. We used generalized estimating equations to examine associations at each age and tested for interaction by sex.ResultsMetabolites of diethyl phthalate (DEP), di-n-butyl phthalate (DBP), butyl benzyl phthalate, and di(2-ethylhexyl) phthalate (DEHP) were positively associated with BMI z-score, waist circumference z-score, and percent body fat at multiple ages. At age 12, we observed increased odds of being overweight/obese with each doubling of prenatal concentrations of DEP (odds ratio=1.3; 95% confidence intervals: 1.1, 1.4), DBP (1.2; 1.0, 1.4), and DEHP (1.3; 1.0, 1.6) metabolites. Results were similar in boys and girls except for DBP metabolites and the non-specific metabolite mono-(3-carboxypropyl) phthalate, which showed positive associations only in boys.ConclusionIn utero exposure to certain phthalates is associated with increased BMI and risk for overweight/obesity in childhood.

Residential proximity to agricultural fumigant use and IQ, attention and hyperactivity in 7-year old children.

OBJECTIVES: Our objective was to examine the relationship between residential proximity to agricultural fumigant use and neurodevelopment in 7-year old children. METHODS: Participants were living in the agricultural Salinas Valley, California and enrolled in the Center for the Health Assessment of Mothers and Children Of Salinas (CHAMACOS) study. We administered the Wechsler Intelligence Scale for Children (4th Edition) to assess cognition and the Behavioral Assessment System for Children (2nd Edition) to assess behavior. We estimated agricultural fumigant use within 3, 5 and 8km of residences during pregnancy and from birth to age 7 using California's Pesticide Use Report data. We evaluated the association between prenatal (n = 285) and postnatal (n = 255) residential proximity to agricultural use of methyl bromide, chloropicrin, metam sodium and 1,3-dichloropropene with neurodevelopment. RESULTS: We observed decreases of 2.6 points (95% Confidence Interval (CI): -5.2, 0.0) and 2.4 points (95% CI: -4.7, -0.2) in Full-Scale intelligence quotient for each ten-fold increase in methyl bromide and chloropicrin use within 8km of the child's residences from birth to 7-years of age, respectively. There were no associations between residential proximity to use of other fumigants and cognition or proximity to use of any fumigant and hyperactivity or attention problems. These findings should be explored in larger studies.

DNA methylation of LINE-1 and Alu repetitive elements in relation to sex hormones and pubertal timing in Mexican-American children.

BACKGROUND: The molecular mechanisms linking environmental exposures to earlier pubertal development are not well characterized. Epigenetics may play an important role, but data on the relationship between epigenetic marks and puberty, particularly in humans, is limited. METHODS: We used pyrosequencing to measure Alu and long interspersed nucleotide elements (LINE-1) methylation in DNA isolated from whole blood samples collected from newborns and 9-y-old children (n = 266). Tanner staging was completed six times between ages 9 and 12 y to determine pubertal status, and hormone levels were measured in 12-y-old boys. RESULTS: Among girls, we observed a suggestive trend of increased odds of breast and pubic hair development with higher Alu and LINE-1 methylation in 9-y-old blood, respectively. The strongest association identified was an inverse association of LINE-1 methylation in 9-y-old girls with odds of experiencing menarche by age 12 (OR (95% CI): 0.63 (0.46, 0.87); P = 0.005). We observed a consistent inverse relationship for Alu and LINE-1 methylation at 9 y with luteinizing hormone (LH), testosterone and follicle-stimulating hormone levels in boys but it was only significant between LINE-1 and LH. CONCLUSION: DNA methylation of Alu and LINE-1 may be involved in puberty initiation and development. This relationship should be confirmed in future studies.

Bacterial microbiome of breast milk and child saliva from low-income Mexican-American women and children.

BACKGROUND: The childhood salivary microbiome, which plays an important role in healthy development, may be influenced by breast milk consumption. The composition of the milk microbiome and the role it plays in the establishment of the infant microbiome are not well understood. METHODS: Here, we sequenced the bacterial 16S rRNA gene to characterize microbial communities in breast milk and 5-year-old child saliva from 10 low-income, Mexican-American mother-child pairs with a high prevalence of obesity. RESULTS: Members of the genus Streptococcus dominated both milk and salivary microbial communities in most subjects. Staphylococcus was observed predominately in milk samples while Prevotella was more prevalent in child saliva. No statistically significant relationships were observed between maternal and child microbiomes or between child microbiome and BMI. However, prepregnancy BMI was correlated with both lower Streptococcus abundance (r = -0.67) and higher microbial diversity (r = 0.77) in breast milk (P < 0.05 for both). Diversity estimates were notably similar to data from other low-income cohorts or children. CONCLUSION: These findings contribute to the currently limited state of knowledge regarding the breast milk and salivary microbiomes in mother-child pairs and may inform future studies seeking to elucidate the relationship between early-life microbial exposures and pediatric health.

Maternal phthalate exposure during pregnancy is associated with DNA methylation of LINE-1 and Alu repetitive elements in Mexican-American children.

Phthalates are frequently used in personal care products and plasticizers and phthalate exposure is ubiquitous in the US population. Exposure to phthalates during critical periods in utero has been associated with a variety of adverse health outcomes but the biological mechanisms linking these exposures with disease are not well characterized. In this study, we examined the relationship of in utero phthalate exposure with repetitive element DNA methylation, an epigenetic marker of genome instability, in children from the longitudinal birth cohort CHAMACOS. Methylation of Alu and long interspersed nucleotide elements (LINE-1) was determined using pyrosequencing of bisulfite-treated DNA isolated from whole blood samples collected from newborns and 9 year old children (n=355). Concentrations of eleven phthalate metabolites were measured in urine collected from pregnant mothers at 13 and 26 weeks gestation. We found a consistent inverse association between prenatal concentrations of monoethyl phthalate, the most frequently detected urinary metabolite, with cord blood methylation of Alu repeats (ß(95%CI): -0.14 (-0.28,0.00) and -0.16 (-0.31, -0.02)) for early and late pregnancy, respectively, and a similar but weaker association with LINE-1 methylation. Additionally, increases in urinary concentrations of di-(2-ethylhexyl) phthalate metabolites during late pregnancy were associated with lower levels of methylation of Alu repeats in 9 year old blood (significant p-values ranged from 0.003 to 0.03). Our findings suggest that prenatal exposure to some phthalates may influence differences in repetitive element methylation, highlighting epigenetics as a plausible biological mechanism through which phthalates may affect health.