Prenatal Phthalate Exposures and Childhood Fat Mass in a New York City Cohort

Early-life exposures to phenols, parabens and phthalates and fat mass at 3 years of age in the SEPAGES cohort

BACKGROUND

Early-life exposure to short half-life chemicals may influence adiposity growth, a precursor to obesity. Previous studies often relied on limited urine samples that inadequately represent exposure during pregnancy or infancy. Additionally, childhood adiposity is commonly estimated using body mass index, which does not accurately reflect body composition. We aimed to investigate associations between early-life exposures to phenols, parabens, phthalates and fat mass percent at 3 years of age among 341 mother-child couple from the SEPAGES cohort. We further assessed potential effect modification by sex.

METHODS

We measured 8 phenols, 4 parabens, 13 phthalates and 2 non-phthalate plasticizer metabolites from weekly pooled urine sample collected from mothers during pregnancy (three urine samples a day, median 18 and 34 gestational weeks), and from their infant (one urine sample a day, at 2 and 12 months). Clinical examinations at 3 years included standardized skinfold thickness measurements and bioelectrical impedance analysis to calculate fat mass percentage.

RESULTS

Positive associations were identified between prenatal exposures to bisphenol S, mono-benzyl phthalate (MBzP), monoethyl phthalate (MEP), and mono-n-butyl phthalate and fat mass percentage at 3 years, while triclosan showed a negative association. MBzP and MEP showed effect modification by sex, with stronger associations among females. No significant associations were detected for postnatal exposures.

CONCLUSION

This study suggests associations between prenatal exposures to short half-life chemicals and percent fat mass in preschool children. Furthermore, this study is the first investigating the impact of prenatal bisphenol S exposure, highlighting the need for investigation of this overlooked compound.

Short-Half-Life Chemicals: Maternal Exposure and Offspring Health Consequences-The Case of Synthetic Phenols, Parabens, and Phthalates

Phenols, parabens, and phthalates (PPPs) are suspected or known endocrine disruptors. They are used in consumer products that pregnant women and their progeny are exposed to daily through the placenta, which could affect offspring health. This review aims to compile data from cohort studies and in vitro and in vivo models to provide a summary regarding placental transfer, fetoplacental development, and the predisposition to adult diseases resulting from maternal exposure to PPPs during the gestational period. In humans, using the concentration of pollutants in maternal urine, and taking the offspring sex into account, positive or negative associations have been observed concerning placental or newborn weight, children's BMI, blood pressure, gonadal function, or age at puberty. In animal models, without taking sex into account, alterations of placental structure and gene expression linked to hormones or DNA methylation were related to phenol exposure. At the postnatal stage, pollutants affect the bodyweight, the carbohydrate metabolism, the cardiovascular system, gonadal development, the age of puberty, sex/thyroid hormones, and gamete quality, but these effects depend on the age and sex. Future challenges will be to explore the effects of pollutants in mixtures using models and to identify the early signatures of in utero exposure capable of predicting the health trajectory of the offspring.

Prenatal EDC exposure, DNA Methylation, and early childhood growth: A prospective birth cohort study

BACKGROUND

Exposure to endocrine-disrupting chemicals (EDCs) has been found to be associated with growth and developmental abnormalities in children. However, the potential mechanisms by which exposure to EDCs during pregnancy increases the risk of obesity in children remain unclear.

OBJECTIVE

We aimed to explore associations between prenatal EDC exposure and the body mass index (BMI) of children at age two, and to further explore the potential impact of DNA methylation (DNAm).

METHOD

This study included 285 mother-child pairs from a birth cohort conducted in Wuhan, China. The BMI of each child was assessed at around 24 months of age. The concentrations of sixteen EDCs at the 1st, 2nd, and 3rd trimesters were measured using ultra-high performance liquid chromatography coupled to a triple quadrupole mass spectrometer. The research utilized general linear models, weighted quantile sum regression, and Bayesian Kernel Machine Regression to assess the association between prenatal EDC exposure and childhood BMI z-scores (BMIz). Cord blood DNAm was measured using the Human Methylation EPIC BeadChip array. An epigenome-wide DNAm association study related to BMIz was performed using robust linear models. Mediation analysis was then applied to explore potential mediators of DNAm.

RESULTS

Urinary concentrations of seven EDCs were positively associated with BMIz in the 1st trimester, which remained significant in the WQS model. A total of 641 differential DNAm positions were associated with elevated BMIz. Twelve CpG positions (annotated to DUXA, TMEM132C, SEC13, ID4, GRM4, C2CD2, PRAC1&PRAC2, TSPAN6 and DNAH10) mediated the associations between urine BP-3/BPS/MEP/TCS and elevated BMIz (P < 0.05).

CONCLUSION

Our results revealed that prenatal exposure to EDCs was associated with a higher risk of childhood obesity, with specific DNAm acting as a partial mediator.

Associations of parental preconception and maternal pregnancy urinary phthalate biomarker and bisphenol-a concentrations with child eating behaviors

BACKGROUND

Eating behaviors are controlled by the neuroendocrine system. Whether endocrine disrupting chemicals have the potential to affect eating behaviors has not been widely studied in humans. We investigated whether maternal and paternal preconception and maternal pregnancy urinary phthalate biomarker and bisphenol-A (BPA) concentrations were associated with children's eating behaviors.

METHODS

We used data from mother-father-child triads in the Preconception Environmental exposure And Childhood health Effects (PEACE) Study, an ongoing prospective cohort study of children aged 6-13 years whose parent(s) previously enrolled in a fertility clinic-based prospective preconception study. We quantified urinary concentrations of 11 phthalate metabolites and BPA in parents' urine samples collected preconceptionally and during pregnancy. Parents rated children's eating behavior using the Child Eating Behavior Questionnaire (CEBQ). Using multivariable linear regression, accounting for correlation among twins, we estimated covariate-adjusted associations of urinary phthalate biomarkers and BPA concentrations with CEBQ subscale scores.

RESULTS

This analysis included 195 children (30 sets of twins), 160 mothers and 97 fathers; children were predominantly non-Hispanic white (84%) and 53% were male. Paternal and maternal preconception monobenzyl phthalate (MBzP) concentrations and maternal preconception mono-n-butyl phthalate (MnBP) were positively associated with emotional overeating, food responsiveness, and desire to drink scores in children (β's= 0.11 [95% CI: 0.01, 0.20]-0.21 [95% CI: 0.10, 0.31] per loge unit increase in phthalate biomarker concentration). Paternal preconception BPA concentrations were inversely associated with scores on food approaching scales. Maternal pregnancy MnBP, mono-isobutyl phthalate (MiBP) and MBzP concentrations were associated with increased emotional undereating scores. Maternal pregnancy monocarboxy-isononyl phthalate concentrations were related to decreased food avoiding subscale scores.

CONCLUSIONS

In this cohort, higher maternal and paternal preconception urinary concentrations of some phthalate biomarkers were associated with increased food approaching behavior scores and decreased food avoiding behavior scores, which could lead to increased adiposity in children.

The Role of Endocrine Disruptors Bisphenols and Phthalates in Obesity: Current Evidence, Perspectives and Controversies

Excess body weight constitutes one of the major health challenges for societies and healthcare systems worldwide. Besides the type of diet, calorie intake and the lack of physical exercise, recent data have highlighted a possible association between endocrine-disrupting chemicals (EDCs), such as bisphenol A, phthalates and their analogs, and obesity. EDCs represent a heterogeneous group of chemicals that may influence the hormonal regulation of body mass and adipose tissue morphology. Based on the available data from mechanistic, animal and epidemiological studies including meta-analyses, the weight of evidence points towards the contribution of EDCs to the development of obesity, associated disorders and obesity-related adipose tissue dysfunction by (1) impacting adipogenesis; (2) modulating epigenetic pathways during development, enhancing susceptibility to obesity; (3) influencing neuroendocrine signals responsible for appetite and satiety; (4) promoting a proinflammatory milieu in adipose tissue and inducing a state of chronic subclinical inflammation; (5) dysregulating gut microbiome and immune homeostasis; and (6) inducing dysfunction in thermogenic adipose tissue. Critical periods of exposure to obesogenic EDCs are the prenatal, neonatal, pubertal and reproductive periods. Interestingly, EDCs even at low doses may promote epigenetic transgenerational inheritance of adult obesity in subsequent generations. The aim of this review is to summarize the available evidence on the role of obesogenic EDCs, specifically BPA and phthalate plasticizers, in the development of obesity, taking into account in vitro, animal and epidemiologic studies; discuss mechanisms linking EDCs to obesity; analyze the effects of EDCs on obesity in critical chronic periods of exposure; and present interesting perspectives, challenges and preventive measures in this research area.

Phthalate exposure and risk of metabolic syndrome components: A systematic review

Metabolic syndrome is a cluster of conditions that increase the risk of cardiovascular disease, i.e. obesity, insulin resistance, hypertriglyceridemia, low high-density lipoprotein cholesterol (HDL-c) levels and arterial hypertension. Phthalates are environmental chemicals which might influence the risk of the aforementioned disturbances, although the evidence is still controversial. The objective of this work was to synthesize the evidence on the association between human phthalate exposure and metabolic syndrome or any of its components. In this systematic review, the PRISMA guidelines were followed and the literature was search in PubMed, Web of Science and Scopus. Longitudinal and cross-sectional studies were included, the later only if a subclinical marker of disease was evaluated. The methodological quality was assessed with the Newcastle Ottawa Scale and a checklist for Analytical Cross-Sectional Studies developed in the Joanna Briggs Institute. A total of 58 articles were identified that showed high heterogenicity in the specific phthalates assessed, time-window of exposure and duration of follow-up. The quality of the studies was evaluated as high (n = 46, score >7 points) or medium (n = 12, score 4-6). The most frequently studied phthalates were DEHP-MEHP, MBzP and MEP. The evidence revealed a positive association between prenatal (in utero) exposure to most phthalates and markers of obesity in the offspring, but contradictory results when postnatal exposure and obesity were assessed. Moreover, postnatal phthalate exposure showed positive and very consistent associations with markers of diabetes and, to a lesser extent, with triglyceride levels. However, fewer evidence and contradictory results were found for HDL-c levels and markers of hypertension. The suggested mechanisms for these metabolic effects include transcription factor PPAR activation, antagonism of thyroid hormone function, antiandrogenic effects, oxidative stress and inflammation, and epigenetic changes. Nevertheless, as the inconsistency of some results could be related to differences in the study design, future research should aim to standardise the exposure assessment.

Prenatal exposure to phthalates and child growth trajectories in the first 24 months of life

BACKGROUND

Phthalates are a class of environmental chemicals with endocrine-disrupting properties. Prenatal phthalate exposure has been associated with adverse developmental outcomes in childhood. However, data assessing the effects of prenatal phthalate exposure on postnatal infant growth trajectories are sparse.

OBJECTIVES

To evaluate the associations of prenatal phthalate exposure with child growth trajectories from birth to 24 months old.

METHODS

Within a Chinese birth cohort study, 1051 mother-offspring pairs were included. Seven phthalate metabolites were quantified in maternal urine collected between weeks 33 and 39 of gestation. The trajectories for weight-for-age z-score (WAZ), length-for-age z-score (LAZ), weight-for-length z-score (WLZ) and head-circumference-for-age z-score (HCZ) were determined by group-based trajectory modeling (GBTM). Multinomial logistic regression and the weighted quantile sum approach (WQS) were used to investigate the association between individual and phthalate mixture exposure and the growth trajectories of four anthropometric metrics.

RESULTS

Five trajectory groups were identified for each anthropometric measure using GBTM. Higher prenatal exposure to several phthalate metabolites (MEHP, MEHHP, MEOHP, MECCP, summed DEHP metabolites, as well as MBP) was associated with child growth trajectories, especially for WAZ and LAZ in the first 24 months of life. The associations were further confirmed by a mixture analysis of phthalate metabolites and a sex-specific effect was observed in the WAZ and LAZ trajectories.

CONCLUSION

Prenatal phthalate exposure had heterogeneous associations with postnatal growth trajectories. More studies are warranted to confirm and elucidate the meaning of our findings.

Phthalates, physical activity, and diet, which are the most strongly associated with obesity? A case-control study of Chinese children

PURPOSE

Phthalate esters have been a research hotspot recently owing to potential obesogenic activity, but conflicting results have been reported. This case-control study was designed to investigate whether there was an association between phthalate metabolites and childhood obesity in China.

METHODS

A total of 240 pairs of obese/overweight children and age- (±3 months) and gender-matched controls were recruited. Nine phthalate metabolites were analyzed in the first morning urine sample. Physical activity and dietary intake were recorded using validated questionnaires.

RESULTS

In monofactor analysis, the levels of monomethyl phthalate (MMP) and monobutyl phthalate (MnBP) in controls were significantly higher than those of overweight/obese children (p < 0.05). Moderate physical activity (p = 0.004), consumption of vegetables, fruits, and tonic were significantly higher in controls (all p < 0.05), and consumption of fried food, western fast food, carbonated drinks, and juice were higher in cases (all p < 0.05). After adjusting for physical activity and dietary intake, neither MMP [OR = 0.825, (95% CI: 0.559-1.217)] nor MnBP [(OR = 0.808, 95% CI: 0.556-1.176)], were significantly associated with obesity. In all models, moderate physical activity was negatively associated and high glucose high fat dietary patterns were positively associated with the risk of childhood obesity (p < 0.01).

CONCLUSION

Diet and physical activity, but not phthalate metabolites were associated with childhood obesity. Further studies are needed to verify our findings. The trial was registered at clinicaltrials.gov as NCT05622513.

Midpregnancy Phthalate and Phenol Biomarkers in Relation to Infant Body Composition: The Healthy Start Prospective Cohort

BACKGROUND

Gestational phthalate and phenol exposure disrupts adipogenesis, contributing to obesity in mice. Whether gestational phthalate or phenol exposure is associated with infant body composition has not been investigated in humans.

OBJECTIVE

We examined associations between biomarkers of phthalate and phenol exposure in midpregnancy and infant size and body composition at birth and at 5 months of age.

METHODS

Analyses were conducted among 438 infants from the Healthy Start prospective pregnancy cohort. Sixteen phthalate and phenol biomarkers were quantified in spot urine samples collected at 24-28 wk of gestation. Infant outcomes measured at birth and at 5 months of age included size [weight (in grams)] and body composition [fat and lean masses (in grams); percentage fat mass]. Single- (linear) and multipollutant (quantile g-computation) models were used to estimate associations of phthalate and phenol biomarkers with infant outcomes at birth and at 5 months of age. Models were adjusted for sociodemographics, sample collection timing, and lifestyle factors and used to examine for effect modification by infant sex.

RESULTS

In single-pollutant models, mono-benzyl phthalate and di-n -butyl phthalate were inversely associated with percentage fat mass [β : - 0.49 (95% CI: - 0.91 , - 0.08 ) and - 0.51 (95% CI: - 1.02 , 0.01), respectively] in male but not female infants at birth. Similar, but less precise, associations were observed at 5 months of age. In multipollutant models, a 1-quartile increase in the phthalate and phenol biomarker mixture was inversely associated with percentage fat mass at birth [- 1.06 (95% CI: - 2.21 , 0.1)] and at 5 months of age [- 2.14 (95% CI: - 3.88 , - 0.39 )] among males, but associations were null among females [0.48 (95% CI: - 0.78 , 1.75) and - 0.64 (95% CI: - 2.68 , 1.41), respectively]. Similar associations were observed with infant weight.

CONCLUSION

In this U.S.-based prospective cohort, gestational phthalate and phenol biomarkers were inversely associated with infant weight and fat mass, particularly in males. https://doi.org/10.1289/EHP12500.

Occurrence of bisphenol diglycidyl ethers and bisphenol analogs, and their associations with DNA oxidative damage in pregnant women

Bisphenol diglycidyl ethers (BDGEs) and Bisphenol A and its analogs (bisphenols) may have the same exposure routes and coexposure phenomenon in sensitive populations such as pregnant women. Previous biomonitoring studies on BDGEs are limited. Levels of fifteen bisphenols, six BDGEs and the DNA oxidative damage biomarker 8-hydroxy-2-deoxyguanosine (8-OHdG) were measured in the urine of pregnant women recruited in south China (n = 358). We aimed to provide the occurrence of bisphenols and BDGEs in pregnant women, and to investigate the potential relationship between their exposure and oxidative stress. Bisphenol A, bisphenol S, bisphenol F, bisphenol AP and all BDGEs (except for BADGE·2HCl) were frequently detected. The total concentrations of all bisphenols and BDGEs were 0.402-338 and 0.104-32.5 ng/mL, with geometric means of 2.87 and 2.48 ng/mL, respectively. BFDGE was the most abundant chemical of BDGEs, with a median concentration of 0.872 ng/mL, followed by BADGE·H2O·HCl (0.297 ng/mL). Except for pre-pregnancy obesity, maternal age/height, employment, fasting in the morning and parity did not affect the urinary concentrations of BDGEs. Significant and weak correlations were observed between concentrations (unadjusted) of total bisphenols and BDGEs (r = 0.389, p < 0.01), indicating their similar sources and exposure routes. The biomarker 8-OHdG was detected in all samples, with concentrations ranging from 1.98 to 32.6 ng/mL (median: 9.96 ng/mL). Levels of 8-OHdG were positively correlated with urinary several bisphenol concentrations (adjusted β range: 0.037-0.089, p < 0.05) but were not correlated with those of BDGEs. Further studies should focus on whether BDGEs and bisphenols exert combined effects on oxidative stress. Our study provided the first BDGEs exposure data in pregnant women and indicated that BDGEs exposure was highly prevalent in pregnant women as early as 2015 in south China.

Phthalates' exposure leads to an increasing concern on cardiovascular health

Being an essential component in the plastics industry, phthalates are ubiquitous in the environment and in everyday life. They are considered environmental contaminants that have been classified as endocrine-disrupting compounds. Despite di-2-ethylhexyl phthalate (DEHP) being the most common plasticizer and the most studied to date, there are many others that, in addition to being widely used in the plastic, are also applied in the medical and pharmaceutical industries and cosmetics. Due to their wide use, phthalates are easily absorbed by the human body where they can disrupt the endocrine system by binding to molecular targets and interfering with hormonal homeostasis. Thus, phthalates exposure has been implicated in the development of several diseases in different age groups. Collecting information from the most recent available literature, this review aims to relate human phthalates' exposure with the development of cardiovascular diseases throughout all ages. Overall, most of the studies presented demonstrated an association between phthalates and several cardiovascular diseases, either from prenatal or postnatal exposure, affecting foetuses, infants, children, young and older adults. However, the mechanisms underlying these effects remain poorly explored. Thus, considering the cardiovascular diseases incidence worldwide and the constant human exposure to phthalates, this topic should be extensively studied to understand the mechanisms involved.

A study on the association of placental and maternal urinary phthalate metabolites

BACKGROUND

Phthalate exposure in pregnancy is typically estimated using maternal urinary phthalate metabolite levels. Our aim was to evaluate the association of urinary and placental tissue phthalates, and to explore the role of maternal and pregnancy characteristics that may bias estimates.

METHODS

Fifty pregnancies were selected from the CANDLE Study, recruited from 2006 to 2011 in Tennessee. Linear models were used to estimate associations of urinary phthalates (2nd, 3rd trimesters) and placental tissue phthalates (birth). Potential confounders and modifiers were evaluated in categories: temporality (time between urine and placenta sample), fetal sex, demographics, social advantage, reproductive history, medication use, nutrition and adiposity. Molar and quantile normalized phthalates were calculated to facilitate comparison of placental and urinary levels.

RESULTS

Metabolites detectable in >80% of both urine and placental samples were MEP, MnBP, MBzP, MECPP, MEOHP, MEHHP, and MEHP. MEP was most abundant in urine (geometric mean [GM] 7.00 ×102 nmol/l) and in placental tissue (GM 2.56 ×104 nmol/l). MEHP was the least abundant in urine (GM 5.32 ×101 nmol/l) and second most abundant in placental tissue (2.04 ×104 nmol/l). In aggregate, MEHP differed the most between urine and placenta (2.21 log units), and MEHHP differed the least (0.07 log units). MECPP was positively associated between urine and placenta (regression coefficient: 0.31 95% CI 0.09, 0.53). Other urine-placenta metabolite associations were modified by measures of social advantage, reproductive history, medication use, and adiposity.

CONCLUSION

Phthalates were ubiquitous in 50 full-term placental samples, as has already been shown in maternal urine. MEP and MEHP were the most abundant. Measurement and comparison of urinary and placental phthalates can advance knowledge on phthalate toxicity in pregnancy and provide insight into the validity and accuracy of relying on maternal urinary concentrations to estimate placental exposures.

IMPACT STATEMENT

This is the first report of correlations/associations of urinary and placental tissue phthalates in human pregnancy. Epidemiologists have relied exclusively on maternal urinary phthalate metabolite concentrations to assess exposures in pregnant women and risk to their fetuses. Even though it has not yet been confirmed empirically, it is widely assumed that urinary concentrations are strongly and positively correlated with placental and fetal levels. Our data suggest that may not be the case, and these associations may vary by phthalate metabolite and associations may be modified by measures of social advantage, reproductive history, medication use, and adiposity.

Prenatal exposure to mixtures of phthalates and phenols and body mass index and blood pressure in Spanish preadolescents

BACKGROUND

Pregnant women are simultaneously exposed to several non-persistent endocrine-disrupting chemicals, which may influence the risk of childhood obesity and cardiovascular diseases later in life. Previous prospective studies have mostly examined single-chemical effects, with inconsistent findings. We assessed the association between prenatal exposure to phthalates and phenols, individually and as a mixture, and body mass index (BMI) and blood pressure (BP) in preadolescents.

METHODS

We used data from the Spanish INMA birth cohort study (n = 1,015), where the 1st and 3rd- trimester maternal urinary concentrations of eight phthalate metabolites and six phenols were quantified. At 11 years of age, we calculated BMI z-scores and measured systolic and diastolic BP. We estimated individual chemical effects with linear mixed models and joint effects of the chemical mixture with hierarchical Bayesian kernel machine regression (BKMR). Analyses were stratified by sex and by puberty status.

RESULTS

In single-exposure models, benzophenone-3 (BP3) was nonmonotonically associated with higher BMI z-score (e.g. Quartile (Q) 3: β = 0.23 [95% CI = 0.03, 0.44] vs Q1) and higher diastolic BP (Q2: β = 1.27 [0.00, 2.53] mmHg vs Q1). Methyl paraben (MEPA) was associated with lower systolic BP (Q4: β = -1.67 [-3.31, -0.04] mmHg vs Q1). No consistent associations were observed for the other compounds. Results from the BKMR confirmed the single-exposure results and showed similar patterns of associations, with BP3 having the highest importance in the mixture models, especially among preadolescents who reached puberty status. No overall mixture effect was found, except for a tendency of higher BMI z-score and lower systolic BP in girls.

CONCLUSIONS

Prenatal exposure to UV-filter BP3 may be associated with higher BMI and diastolic BP during preadolescence, but there is little evidence for an overall phthalate and phenol mixture effect.

Prenatal single and combined exposure to phthalates associated with girls' BMI trajectory in the first six years

Evidence of the influence of prenatal phthalate exposure on childhood longitudinal obesity markers is limited. Nested on the Ma'anshan birth cohort study, 990 mother-daughter pairs were included. Seven phthalate metabolites were determined in urine collected in each trimester. Each child underwent a physical examination from birth to 6 years of age twelve times. Latent class growth models were used to identify three trajectories of girls' body mass index (BMI). Logistic regression, quantile g-computation and Bayesian kernel machine regression models analyzed the relationships of prenatal exposure to individual and mixed phthalates with girls' body mass index (BMI) trajectory. Compared to the "lowest trajectory" class, prenatal average concentrations of mono(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP, OR_crude = 2.095, 95 % CI = 1.014-4.328) and di(2-ethylhexyl) phthalate (DEHP, OR_crude = 2.336, 95 % CI = 1.022-5.338) during pregnancy were associated with an increased probability of being in the "highest trajectory" class. The average concentration of DEHP (OR_crude = 1.879, 95 % CI = 1.002-3.522) was associated with an increased probability of being in the "moderate trajectory" class. Stratified analyses by trimester of pregnancy mainly showed that third-trimester exposure to monoethyl phthalate (MEP, OR_adjusted = 1.584, 95 % CI = 1.094-2.292), mono(2-ethyl-5-oxohexyl) phthalate (MEOHP, OR_adjusted = 2.885, 95 % CI = 1.367-6.088), MEHHP (OR_adjusted = 2.425, 95 % CI = 1.335-4.407), DEHP (OR_adjusted = 2.632, 95 % CI = 1.334-5.193) and high molecular weight phthalate (OR_adjusted = 2.437, 95 % CI = 1.239-4.792) was associated with an increased probability of being in the "highest trajectory" class. However, the mixture of phthalates was not significantly related to the girl's BMI trajectory. In conclusion, in utero exposure to phthalates, including MEP and DEHP metabolites (MEHHP and MEOHP), was significantly associated with early childhood high BMI trajectories in girls. The third trimester of pregnancy seemed to be the window of vulnerability to phthalate exposure for girls' high BMI trajectory at periods of prenatal development. No evidence supported a significant relationship between combined exposure to phthalate metabolites and girls' high BMI trajectory.

Diethyl phthalate (DEP) perturbs nitrogen metabolism in Saccharomyces cerevisiae

Phthalates are ubiquitously used as plasticizers in various consumer care products. Diethyl phthalate (DEP), one of the main phthalates, elicits developmental and reproductive toxicities but the underlying mechanisms are not fully understood. Chemogenomic profiling of DEP in S. cerevisiae revealed that two transcription factors Stp1 and Dal81 involved in the Ssy1-Ptr5-Ssy5 (SPS) amino acid-sensing pathway provide resistance to DEP. Growth inhibition of yeast cells by DEP was stronger in poor nitrogen medium in comparison to nitrogen-rich medium. Addition of amino acids to nitrogen-poor medium suppressed DEP toxicity. Catabolism of amino acids via the Ehrlich pathway is required for suppressing DEP toxicity. Targeted metabolite analyses showed that DEP treatment alters the amino acid profile of yeast cells. We propose that DEP inhibits the growth of yeast cells by affecting nitrogen metabolism and discuss the implications of our findings on DEP-mediated toxic effects in humans.

Urine Di-(2-ethylhexyl) Phthalate Metabolites Are Independently Related to Body Fluid Status in Adults: Results from a U.S. Nationally Representative Survey

Purpose: Di-(2-ethylhexyl) phthalate (DEHP) has been utilized in many daily products for decades. Previous studies have reported that DEHP exposure could induce renin–angiotensin–aldosterone system activation and increase epithelial sodium channel (ENaC) activity, which contributes to extracellular fluid (ECF) volume expansion. However, there is also no previous study to evaluate the association between DEHP exposure and body fluid status. Methods: We selected 1678 subjects (aged ≥18 years) from a National Health and Nutrition Examination Survey (NHANES) in 2003–2004 to determine the relationship between urine DEHP metabolites and body composition (body measures, bioelectrical impedance analysis (BIA)). Results: After weighing the sampling strategy in multiple linear regression analysis, we report that higher levels of DEHP metabolites are correlated with increases in body measures (body weight, body mass index (BMI), waist circumference), BIA parameters (estimated fat mass, percent body fat, ECF, and ECF/intracellular fluid (ICF) ratio) in multiple linear regression analysis. The relationship between DEHP metabolites and the ECF/ICF ratio was more evident in subjects of younger age (20–39 years old), women, non-Hispanic white ethnicity, and subjects who were not active smokers. Conclusion: In addition to being positively correlated with body measures and body fat, we found that urine DEHP metabolites were positively correlated with ECF and the ECF/ICF ratio in the US general adult population. The finding implies that DEHP exposures might increase ECF volume and the ECF/ICF ratio, which may have adverse health outcomes on the cardiovascular system. Further research is needed to clarify the causal relationship.

Prenatal exposure to phthalate and decreased body mass index of children: a systematic review and meta-analysis

Phthalates are well-known endocrine-disrupting chemicals. Many detrimental health effects of phthalates were investigated, but studies on the association of phthalates with obesity in children showed inconsistent results. Thus, this systematic review and meta-analysis were performed to clarify whether prenatal and postnatal exposures to phthalates are associated with physical growth disturbances in children. We performed the systematic review and meta-analysis following the PRISMA 2020 statement guidelines, and found 39 studies that met our inclusion criteria, including 22 longitudinal and 17 cross-sectional studies. We observed a significant negative association between the prenatal exposure to DEHP and the body mass index (BMI) z-score of the offspring (β = - 0.05; 95% CI: - 0.10, - 0.001) in the meta-analysis, while no significant association between the prenatal exposure to DEHP and the body fat percentage of the offspring was observed (β = 0.01; 95% CI: - 0.41, 0.44). In the systematic review, studies on the association between phthalates exposure in childhood and obesity were inconsistent. Prenatal exposure to phthalates was found to be associated with decreased BMI z-score in children, but not associated with body fat percentage. Our findings suggest that phthalates disturb the normal muscle growth of children, rather than induce obesity, as previous studies have hypothesized.

Obesity II: Establishing causal links between chemical exposures and obesity

Obesity is a multifactorial disease with both genetic and environmental components. The prevailing view is that obesity results from an imbalance between energy intake and expenditure caused by overeating and insufficient exercise. We describe another environmental element that can alter the balance between energy intake and energy expenditure: obesogens. Obesogens are a subset of environmental chemicals that act as endocrine disruptors affecting metabolic endpoints. The obesogen hypothesis posits that exposure to endocrine disruptors and other chemicals can alter the development and function of the adipose tissue, liver, pancreas, gastrointestinal tract, and brain, thus changing the set point for control of metabolism. Obesogens can determine how much food is needed to maintain homeostasis and thereby increase the susceptibility to obesity. The most sensitive time for obesogen action is in utero and early childhood, in part via epigenetic programming that can be transmitted to future generations. This review explores the evidence supporting the obesogen hypothesis and highlights knowledge gaps that have prevented widespread acceptance as a contributor to the obesity pandemic. Critically, the obesogen hypothesis changes the narrative from curing obesity to preventing obesity.

Killing two birds with one stone: Pregnancy is a sensitive window for endocrine effects on both the mother and the fetus

Pregnancy is a complex process requiring tremendous physiological changes in the mother in order to fulfill the needs of the growing fetus, and to give birth, expel the placenta and nurse the newborn. These physiological modifications are accompanied with psychological changes, as well as with variations in habits and behaviors. As a result, this period of life is considered as a sensitive window as impaired functional and physiological changes in the mother can have short- and long-term impacts on her health. In addition, dysregulation of the placenta and of mechanisms governing placentation have been linked to chronic diseases later-on in life for the fetus, in a concept known as the Developmental Origin of Health and Diseases (DOHaD). This concept stipulates that any change in the environment during the pre-conception and perinatal (in utero life and neonatal) period to puberty, can be "imprinted" in the organism, thereby impacting the health and risk of chronic diseases later in life. Pregnancy is a succession of events that is regulated, in large part, by hormones and growth factors. Therefore, small changes in hormonal balance can have important effects on both the mother and the developing fetus. An increasing number of studies demonstrate that exposure to endocrine disrupting compounds (EDCs) affect both the mother and the fetus giving rise to growing concerns surrounding these exposures. This review will give an overview of changes that happen during pregnancy with respect to the mother, the placenta, and the fetus, and of the current literature regarding the effects of EDCs during this specific sensitive window of exposure.

Prenatal Phthalate Exposure and Child Weight and Adiposity from in Utero to 6 Years of Age

BACKGROUND

Prenatal phthalate exposure has been associated with lower birth weight but also higher weight in childhood. Few studies have examined weight or adiposity from birth to childhood and thus cannot assess growth trajectories associated with exposure.

OBJECTIVE

We assessed associations between maternal phthalate exposures in pregnancy and child weight and adiposity measured prenatally through childhood (3-6 years of age).

METHODS

Within The Infant Development and the Environment Study (TIDES), a prospective pregnancy cohort, we analyzed a panel of phthalate metabolites in urine collected at two visits from early and late gestation (N=780). We estimated average phthalate metabolite associations with child weight z-scores from ∼20wk gestation (estimated by ultrasound), birth, and 1, 3, 4, and 6 years of age using linear mixed-effects (LME) models. We also modeled associations with adiposity z-scores from birth (weight for length) and 1, 3, 4, and 6 years of age [body mass index (BMI)] using LME models.

RESULTS

For weight, we observed inverse associations between several phthalate metabolites and birth weight z-scores, but no associations were observed with postnatal weight z-scores in LME models. Regarding adiposity, we observed inverse associations between phthalate metabolites and weight-for-length z-scores at birth, but positive associations were observed with BMI z-scores at 3-4 years of age in LME models. For example, mono-ethyl phthalate was associated with a 0.17-unit decrease in birth weight-for-length z-score [95% confidence interval (CI): -0.29, -0.05] and a 0.18-unit increase in 4-years-of-age BMI z-score (95% CI: 0.04, 0.32).

DISCUSSION

We observed associations between prenatal exposure to phthalates and lower weight at birth but not at childhood follow-up visits. However, for adiposity, we observed an interesting pattern of association with low adiposity at delivery as well as high adiposity at 3-4 years of age. Although it is not clear from our results whether these associations occur within the same children, such a pattern of adiposity in early life has been linked to cardiometabolic disease in adulthood and deserves special attention as an outcome in the study of prenatal exposures in the developmental origins of health and disease. https://doi.org/10.1289/EHP10077.

Maternal exposure to bis(2-ethylhexyl) phthalate during the thyroid hormone-dependent stage induces persistent emotional and cognitive impairment in middle-aged offspring mice

Prenatal DEHP exposure can cause offspring neurodevelopmental toxicity, but the persistent effects of such exposure window are unclear. This study aimed to investigate the lasting neurobehavioral impact of DEHP on offspring following early exposure from GD9.5 (fetal neural tube closure) to GD16.5 (fetal thyroxin, TH, synthesis). Data showed maternal exposure to DEHP during the thyroid hormone-dependent stage induced a range of neurobehavioral phenotypic changes in adult and middle-aged mice, including anxiety, depression and cognitive impairment. Significant reductions in free TH, TH transporters, and TH metabolic enzyme deiodinase II (D2) were observed in the fetal brain, whereas D3 was elevated, indicating that TH signaling disruption was caused by in utero exposure. Gene expression analyses suggested the expression levels of the TH receptors Trα1, Trβ1 and their downstream target, brain-derived neurotrophic factor, were significantly attenuated, which may partially explain the mechanisms of neurodevelopmental impairment. This study provides new evidence of the persistent effects of sex-specific neurodevelopmental impairment due to in utero DEHP exposure, possibly through damage to the fetal brain TH signaling systems that causes lifelong brain damage. These results further suggest a profound neurobehavioral toxicity of DEHP that may be programmed during early developmental stage exposure and manifested later in life.

Developmental Exposure to Endocrine Disrupting Chemicals and Its Impact on Cardio-Metabolic-Renal Health

Developmental origin of health and disease postulates that the footprints of early life exposure are followed as an endowment of risk for adult diseases. Epidemiological and experimental evidence suggest that an adverse fetal environment can affect the health of offspring throughout their lifetime. Exposure to endocrine disrupting chemicals (EDCs) during fetal development can affect the hormone system homeostasis, resulting in a broad spectrum of adverse health outcomes. In the present review, we have described the effect of prenatal EDCs exposure on cardio-metabolic-renal health, using the available epidemiological and experimental evidence. We also discuss the potential mechanisms of their action, which include epigenetic changes, hormonal imprinting, loss of energy homeostasis, and metabolic perturbations. The effect of prenatal EDCs exposure on cardio-metabolic-renal health, which is a complex condition of an altered biological landscape, can be further examined in the case of other environmental stressors with a similar mode of action.

Interactions of agricultural pesticide use near home during pregnancy and adverse childhood experiences on adolescent neurobehavioral development in the CHAMACOS study

BACKGROUND

Studies have documented independent adverse associations between prenatal and early-life exposure to environmental chemicals and social adversity with child neurodevelopment; however, few have considered these exposures jointly. The objective of this analysis is to examine whether associations of pesticide mixtures and adolescent neurobehavioral development are modified by early-life adversity in the Center for the Health Assessment of Mothers and Children of Salinas (CHAMACOS) cohort.

METHODS

We used linear mixed effects Bayesian Hierarchical Models (BHM) to examine the joint effect of applications of 11 agricultural pesticides within 1 km of maternal homes during pregnancy and youth-reported Adverse Childhood Experiences (ACEs) with maternal and youth-reported internalizing behaviors, hyperactivity, and attention problems assessed via the Behavior Assessment for Children (BASC) (mean = 50, standard deviation = 10) at ages 16 and 18 years (n = 458).

RESULTS

The median (25th-75th percentiles) of ACEs was 1 (0-3); 72.3% of participants had low ACEs (0-2 events) and 27.7% had ACEs (3+ events). Overall, there was little evidence of modification of exposure-outcome associations by ACEs. A two-fold increase in malathion use was associated with increased internalizing behaviors among those with high ACEs from both maternal- (β = 1.9; 95% Credible Interval (CrI): 0.2, 3.7 for high ACEs vs. β = -0.1; 95% CrI: 1.2, 0.9 for low ACEs) and youth-report (β = 2.1; 95% CrI: 0.4, 3.8 for high ACEs vs. β = 0.2; 95% CrI: 0.8, 1.2 for low ACEs). Applications of malathion and dimethoate were also associated with higher youth-reported hyperactivity and/or inattention among those with high ACEs.

CONCLUSION

We observed little evidence of effect modification of agricultural pesticide use near the home during pregnancy and adolescent behavioral problems by child ACEs. Future studies should examine critical windows of susceptibility of exposure to chemical and non-chemical stressors and should consider biomarker-based exposure assessment methods.

Prenatal maternal phthalate exposures and trajectories of childhood adiposity from four to twelve years

BACKGROUND/AIM

Adiposity trajectories reflect dynamic process of growth and may predict later life health better than individual measures. Prenatal phthalate exposures may program later childhood adiposity, but findings from studies examining these associations are conflicting. We investigated associations between phthalate biomarker concentrations during pregnancy with child adiposity trajectories.

METHODS

We followed 514 mother-child pairs from the Mexico City PROGRESS cohort from pregnancy through twelve years. We measured concentrations of nine phthalate biomarkers in 2nd and 3rd trimester maternal urine samples to create a pregnancy average using the geometric mean. We measured child BMI z-score, fat mass index (FMI), and waist-to-height ratio (WHtR) at three study visits between four and 12 years of age. We identified adiposity trajectories using multivariate latent class growth modeling, considering BMI z-score, FMI, and WHtR as joint indicators of latent adiposity. We estimated associations of phthalates biomarkers with class membership using multinomial logistic regression. We used quantile g-computation to estimate the potential effect of the total phthalate mixture and assessed effect modification by sex.

RESULTS

We identified three trajectories of child adiposity, a "low-stable", a "low-high", and a "high-high" group. A doubling of the sum of di (2-ethylhexyl) phthalate metabolites (ΣDEHP), was associated with 1.53 (1.08, 2.19) greater odds of being in the "high-high" trajectory in comparison to the "low-stable" group, whereas a doubling in di-isononyl phthalate metabolites (ΣDiNP) was associated with 1.43 (1.02, 2.02) greater odds of being in the "low-high" trajectory and mono (carboxy-isononyl) phthalate (MCNP) was associated with 0.66 (0.45, 97) lower odds of being in the "low-high" trajectory. No sex-specific associations or mixture associations were observed.

CONCLUSIONS

Prenatal concentrations of urinary DEHP metabolites, DiNP metabolites, and MCNP, a di-isodecyl phthalate metabolite, were associated with trajectories of child adiposity. The total phthalate mixture was not associated with early life child adiposity.

Prenatal phthalate exposure associated with age-specific alterations in markers of adiposity in offspring: A systematic review

Childhood obesity and metabolic disorders are of concern and are public health problems globally. Environmental endocrine disruptors, including phthalates, are well known as "obesogens" and "metabolic disruptors". Several studies have investigated the relationships between prenatal phthalate exposure and childhood obesity with inconsistent conclusions. Given the child growth trajectory/pattern as a possible early marker of metabolic disorders, we aimed to assess the effect of prenatal phthalate exposure on offspring growth trajectory. A systematic literature search was conducted using MEDLINE (accessed through PubMed), Web of Science, and CNKI (Chinese National Knowledge Infrastructure) until July 2021. We evaluated the risk of bias for adherence to the prespecified criteria. Fourteen eligible articles were finally included in this systematic review according to the defined PECOS statement. The risk of bias of the included studies was "low" or "probably low", and few were "probably high" and "high". These studies were mostly carried out in the United States (N = 6); others were conducted in China (N = 2), Mexico (N = 2), France (N = 1), Spain (N = 1), Greece (N = 1), and Australia (N = 1) and published from 2015 to 2021. The combined subjects of the 14 studies were 10,396 mother-child pairs. Except for 3 studies not reporting the sex ratio, at least 4001 boys and 3366 girls were included. For the association of prenatal phthalate exposure with an absolute adiposity marker (at a specific visit timepoint), only a few studies were using the same obesity marker as the outcome endpoint and using the same statistical method to explore their associations. However, MEP appeared to be positively associated with several obesity markers, such as the absolute BMI z score, weight-for-age z score, waist circumference, and overweight status. For the association of prenatal phthalate exposure with a repeated measurement of the adiposity marker over the age range, neither associations of adiposity markers with a specific phthalate metabolite nor relationships of a specific adiposity marker with prenatal phthalate exposure were of a consistent result. All four articles reported that phthalate metabolite exposure during pregnancy was associated with children's growth trajectory. Three suggested a sex-specific association between prenatal phthalate exposure and obesity trajectory. In conclusion, the current articles did not show any relationship between prenatal phthalate exposure and children's age-specific outcomes, except for positive associations of prenatal MEP exposure with absolute adiposity markers. However, epidemiological data supported a weak relationship between prenatal phthalate exposure and children's obesity trajectory in a sex-specific manner.

Adipogenic Activity of Chemicals Used in Plastic Consumer Products

Bisphenols and phthalates, chemicals frequently used in plastic products, promote obesity in cell and animal models. However, these well-known metabolism-disrupting chemicals (MDCs) represent only a minute fraction of all compounds found in plastics. To gain a comprehensive understanding of plastics as a source of exposure to MDCs, we characterized the chemicals present in 34 everyday products using nontarget high-resolution mass spectrometry and analyzed their joint adipogenic activities by high-content imaging. We detected 55,300 chemical features and tentatively identified 629 unique compounds, including 11 known MDCs. Importantly, the chemicals extracted from one-third of the products caused murine 3T3-L1 preadipocytes to proliferate, and differentiate into adipocytes, which were larger and contained more triglycerides than those treated with the reference compound rosiglitazone. Because the majority of plastic extracts did not activate the peroxisome proliferator-activated receptor γ and the glucocorticoid receptor, the adipogenic effects are mediated via other mechanisms and, thus, likely to be caused by unknown MDCs. Our study demonstrates that daily-use plastics contain potent mixtures of MDCs and can, therefore, be a relevant yet underestimated environmental factor contributing to obesity.

Adipogenic Activity of Chemicals Used in Plastic Consumer Products

Bisphenols and phthalates, chemicals frequently used in plastic products, promote obesity in cell and animal models. However, these well-known metabolism-disrupting chemicals (MDCs) represent only a minute fraction of all compounds found in plastics. To gain a comprehensive understanding of plastics as a source of exposure to MDCs, we characterized the chemicals present in 34 everyday products using nontarget high-resolution mass spectrometry and analyzed their joint adipogenic activities by high-content imaging. We detected 55,300 chemical features and tentatively identified 629 unique compounds, including 11 known MDCs. Importantly, the chemicals extracted from one-third of the products caused murine 3T3-L1 preadipocytes to proliferate, and differentiate into adipocytes, which were larger and contained more triglycerides than those treated with the reference compound rosiglitazone. Because the majority of plastic extracts did not activate the peroxisome proliferator-activated receptor γ and the glucocorticoid receptor, the adipogenic effects are mediated via other mechanisms and, thus, likely to be caused by unknown MDCs. Our study demonstrates that daily-use plastics contain potent mixtures of MDCs and can, therefore, be a relevant yet underestimated environmental factor contributing to obesity.

Urinary Phthalate Levels in Relation to Obesity among a Sample of Egyptian Children

BACKGROUND: Childhood obesity is considered a risk factor for chronic diseases later in life. Phthalates (phthalate acid esters), predominant constituents of plasticizers, are well-thought-out global environmental contaminants. AIM: This study aims to investigate the relationship between obesity and urinary phthalates in Egyptian children. MATERIALS AND METHODS: This cross-sectional study included 210 children; 71 children were obese. Age ranged between 8.8 and 16 years with a mean of 12.93 ± 1.29 years. Sociodemographic data were collected. Clinical examination included measuring body weight, height, waist and hip circumferences (WC and HC), and calculation of body mass index (BMI). The lipid profile was analyzed. Urine samples were tested for phthalates levels using high-performance liquid chromatography. RESULTS: Urinary phthalates metabolites mono benzyl (MBzP), monobutyl (MBP), monoethyl (MEP), and mono (2ethylhexyl) phthalate (MEHP) were detected in all urinary samples with varying levels. The median concentrations of MBzP, MEHP, MBP, and MEP were 1.4, 54.5, 29.9, and 490 (ng/ml), respectively. In obese children, urinary MBP, MEP, and MEHP demonstrated significantly higher mean levels than in non-obese children. Physical indicators of obesity as body weight, BMI, WC, and HC were significantly positively correlated with urinary levels of MEHP and MEP, while urinary MBzP demonstrated a significant positive association with serum triglycerides levels. CONCLUSION: The present study suggests an association between phthalates exposure and childhood and adolescent adiposity.

Profile of Environmental Chemicals in the Korean Population-Results of the Korean National Environmental Health Survey (KoNEHS) Cycle 3, 2015-2017

The Korean National Environmental Health Survey (KoNEHS) program provides useful information on chemical exposure, serves as the basis for environmental health policies, and suggests appropriate measures to protect public health. Initiated on a three-year cycle in 2009, it reports the concentrations of major environmental chemicals among the representative Korean population. KoNEHS Cycle 3 introduced children and adolescents into the analysis, where the blood and urine samples of 6167 participants were measured for major metals, phthalates, phenolics, and other organic compounds. Lead, mercury, cadmium, metabolites of DEHP and DnBP, and 3-phenoxybenzoic acid levels of the Korean adult population tended to decrease compared to previous survey cycles but remained higher than those observed in the US or Canada. Both bisphenol A (BPA) and trans,trans-muconic acid concentrations have increased over time. Heavy metal concentrations (blood lead, and cadmium) in children and adolescents were approximately half that of adults, while some organic substances (e.g., phthalates and BPA) were high. BPA showed higher levels than in the US or Canada, whereas BPF and BPS showed lower detection rates in this cycle; however, as these are increasingly used as a substitute for BPA, further research is necessary. As environmental chemicals may affect childhood health and development, additional analyses should assess exposure sources and routes through continuous observations.

Effect of childhood phthalates exposure on the risk of overweight and obesity: A nested case-control study in China

BACKGROUND

There was growing interest in endocrine disrupting chemicals that might have effect on the obesity epidemic, but few studies on the association of phthalates (PAEs) with childhood overweight and obesity in China based on longitudinal cohort study were available, which was the purpose of the present study.

METHODS

A nested case-control study was conducted in a prospective cohort of 2298 children aged 7-13 years from October 2017 to October 2020 with five waves visits in Xiamen city, China. A total of 829 children remained in the first wave of follow up with collection of urine for measuring seven PAEs metabolites, including mono-methyl phthalate (MMP), mono-ethyl phthalate (MEP), mono-n-butyl phthalate (MBP), mono-iso-butyl phthalate (MiBP), mono-2-ethylhexyl phthalate (MEHP), mono-2-ethyl-5-oxohexyl phthalate (MEOHP) and mono-2-ethyl-5-hydroxyhexyl phthalate (MEHHP), utilizing ultra high performance liquid chromatography-triple quadrupole mass spectrometry. Overweight and obesity, defined by WHO classifications, were allocated to the cases group, and those of all normal weight and matched cases with normal weight in each wave of follow-up as two control groups. Logistic regression models after adjusting for confounders were utilized to analyze the effect of PAEs on overweight and obesity in children with divided four groups based on the quartile distribution of each and total PAEs concentration.

RESULTS

The detection rates of children for each PAEs metabolite were 99.4% for MMP, 99.4% for MEP, 99.8% for MBP, 54.5% for MEHP, 84.4% for MEOHP, 99.9% for MEHHP, and 97.2% for MiBP. The geometric mean of concentrations of PAEs, MMP, MEP, MBP, MEHP, MEHHP, and MiBP were 310.085, 34.658, 9.127, 166.347, 7.043, 3.400, 18.571, and 24.093 (ng/ml), respectively. The total PAEs and seven metabolites concentrations were positively associated with childhood BMI Z-Scores with statistically significant slope rates and correlation coefficients, and were higher in the cases group than those in two controls groups in each wave of follow-up. The PAEs concentrations in the cases group was 5.90 (95 %CI: 5.79, 6.01) ng/ml in the first wave of survey, which was higher than those normal controls group (5.68 (95 %CI: 5.61, 5.75) ng/ml, P < 0.001) and matched controls group (5.72 (95 %CI: 5.61, 5.84) ng/ml, P = 0.018). The prevalence and ORs of overweight and obesity increased with quartile group of each and total PAEs concentrations accompanying a dose-response relationship. Compared with the quartile1 reference group with lowest total PAEs concentrations, the ORs of overweight and obesity in quartile2, quartile3 and quartile4 group increased gradually and reached at 1.20 (0.74-1.95), 1.49 (0.93-2.38) and 2.22 (1.41-3.48), respectively (P_trend < 0.001). The strength of the associations between PAEs and overweight and obesity was sex-specific in children.

DISCUSSION

Children in China were extensively exposed to PAEs, and the exposure to PAEs during childhood could significantly increase the risk of overweight and obesity with a dose-response relationship, particularly in girls. While limiting the exposure of PAEs products, the determination of exposure limit of plasticizer should be further strengthened.

Modification of the association by sex between the prenatal exposure to di(2-ethylhexyl) phthalate and fat percentage in a cohort of Mexicans schoolchildren

INTRODUCTION

Children's overweight and obesity are global public health problems, children with obesity have grater obesity risk as adults, thus leading to develop cardiometabolic diseases. Previous studies have found positive and significant associations between the exposure to phthalates and body mass index and body composition.

OBJECTIVE

To evaluate the modification of the association by sex between DEHP exposure during pregnancy and the percentage of body fat in a cohort of Mexican schoolchildren.

MATERIAL AND METHODS

The sample was comprised by children which had previously participated in a POSGRAD longitudinal study. A subsample of 190 mother-children binomials were included. Mothers' DEHP concentrations and its metabolites had been measured in the second trimester of pregnancy: Mono-2-ethylhexyl phthalate (MEHP), Mono-2-ethyl-5-carboxypentyl phthalate (MECPP), Mono-2-ethyl-5-hidroxyhexyl phthalate (MEHHP), and Mono-2-ethyl-5-oxohexyl phthalate (MEOHP). The children's adipose mass was measured at age 8, 9, and 10. Longitudinal data were analyzed using the mixed effects linear regression model, with intercept and random slope, adjusted by important confounders and stratified by sex.

RESULTS

We found a differentiated effect by sex, the exposure to DEHP during pregnancy significantly increases the adipose mass in boys. The average increase was 0.058% (p = 0.02) for every 1% variation in MECPP; 0.047% (p = 0.04) in MEHHP; 0.051% (p = 0.03) in MEOHP, and 0.066% (p = 0.007) in MECPP.

CONCLUSIONS

The results suggest an effect differentiated by sex; with boys being the main ones affected by the prenatal exposure to phthalates. However, we cannot rule out effects in girls.

Exposure to endocrine-disrupting compounds such as phthalates and bisphenol A is associated with an increased risk for obesity

Increasing evidence from epidemiological, animal and in vitro studies suggests that the increased production of synthetic chemicals that interfere with the proper functioning of the hormonal system, so-called endocrine-disrupting compounds (EDCs), might be involved in the development and rapid spread of obesity, coined the obesity epidemic. Recent findings have demonstrated that EDCs may interfere with hormonal receptors that regulate adipogenesis and metabolic pathways. Furthermore, prenatal exposure to EDCs has been shown to influence the metabolism of the developing embryo through epigenetic mechanisms and to promote obesity in subsequent generations. In this Review, we discuss the potential impact of bisphenol A (BPA) and phthalate-based plasticizers on obesity and obesity-related metabolic disorders. Special emphasis is given to the obesogenic effects of prenatal exposure and strategies for identifying, regulating, and replacing EDCs.

Prenatal exposure to phthalate esters and its impact on child development

Endocrine disruptive chemicals (EDCs) cause adverse health effects through interaction with endocrine systems. They are classified by chemical structure, effects on specific endocrine systems, their bioaccumulation and/or persistence in the environment, and/or clinically observable effects. In industrial nations, people are exposed to complex mixtures of many different substances all of which may have multiple and deleterious effects upon the individual. The clinical importance of epigenetic changes caused by the action of EDCs during vulnerable phases of development is currently unclear but of particular relevance. Epidemiological studies are criticized because reproducibility is not always guaranteed. Nevertheless, they remain the method of choice for the development and analysis of suitable model systems. Positive associations, despite of sometimes conflicting results, are the key in the selection of factors that can then be analyzed in model systems in an unbiased way. This article reports EDC-caused effects in the fields of growth and metabolism, neurocognitive development and sexual development and reproduction focusing mainly on phthalates and their metabolites. However, research will have to focus on the interactions of different EDCs and their consequences of prenatal and early life exposure.

Developmental origins of metabolic diseases

Almost 2 billion adults in the world are overweight, and more than half of them are classified as obese, while nearly one-third of children globally experience poor growth and development. Given the vast amount of knowledge that has been gleaned from decades of research on growth and development, a number of questions remain as to why the world is now in the midst of a global epidemic of obesity accompanied by the "double burden of malnutrition," where overweight coexists with underweight and micronutrient deficiencies. This challenge to the human condition can be attributed to nutritional and environmental exposures during pregnancy that may program a fetus to have a higher risk of chronic diseases in adulthood. To explore this concept, frequently called the developmental origins of health and disease (DOHaD), this review considers a host of factors and physiological mechanisms that drive a fetus or child toward a higher risk of obesity, fatty liver disease, hypertension, and/or type 2 diabetes (T2D). To that end, this review explores the epidemiology of DOHaD with discussions focused on adaptations to human energetics, placental development, dysmetabolism, and key environmental exposures that act to promote chronic diseases in adulthood. These areas are complementary and additive in understanding how providing the best conditions for optimal growth can create the best possible conditions for lifelong health. Moreover, understanding both physiological as well as epigenetic and molecular mechanisms for DOHaD is vital to most fully address the global issues of obesity and other chronic diseases.

Exposure to obesogenic endocrine disrupting chemicals and obesity among youth of Latino or Hispanic origin in the United States and Latin America: A lifecourse perspective

Following a 2019 workshop led by the Center for Global Health Studies at the Fogarty International Center on the topic of childhood obesity prevention and research synergies transpiring from cross-border collaborations, we convened a group of experts in the United States and Latin America to conduct a narrative review of the epidemiological literature on the role of obesogenic endocrine disrupting chemicals (EDCs) in the etiology of childhood obesity among Latino youth in the United States and Latin America. In addition to summarizing and synthesizing results from research on this topic published within the last decade, we place the findings within a lifecourse biobehavioral framework to aid in identification of unique exposure-outcome relationships driven by both biological and behavioral research, identify inconsistencies and deficiencies in current literature, and discuss the role of policy regulations, all with the goal of identifying viable avenues for prevention of early life obesity in Latino/Hispanic populations.

Associations between pesticide mixtures applied near home during pregnancy and early childhood with adolescent behavioral and emotional problems in the CHAMACOS study

Supplemental Digital Content is available in the text.

Studies suggest that exposure to pesticides during pregnancy and early childhood is associated with adverse child neurodevelopment. Research to date has focused primarily on exposure to single pesticides or pesticide classes in isolation; there are little data on the effect of exposure to pesticide mixtures on child and adolescent neurodevelopment.

Associations between Prenatal Exposure to Phthalates and Timing of Menarche and Growth and Adiposity into Adulthood: A Twenty-Years Birth Cohort Study

Phthalates are ubiquitous environmental chemicals with endocrine disrupting properties and potentially obesogenic effects. We hypothesised that antenatal phthalate exposure may influence growth and adiposity patterns in girls through childhood into adolescence. Among 1342 Raine Study singleton females, 462 had maternal serum and at least one outcome available up to 20 years of age. Individuals’ maternal serum collected at 18 and 34 weeks gestation was pooled and analyzed for concentrations of 32 metabolites of 15 phthalate diesters. Cox regression and linear models were used to determine associations between maternal phthalate levels and age at menarche, change in height and weight z-scores between birth and two years, height from birth to 20 years, BMI from two to 20 years, deviation from mid-parental height at age 20 and DEXA scan measures at age 20. Weak negative associations were detected with some phthalate metabolites and change in height and weight z-score during infancy. Weak positive associations between some of the high molecular weight phthalate metabolites and height z-score were detected during childhood. While still within the normal range, age at menarche was slightly delayed in girls with higher prenatal exposure to the higher molecular weight phthalate metabolites. We derived some associations between prenatal phthalate exposure with early growth patterns and age at menarche.

The influence of prenatal exposure to phthalates on subsequent male growth and body composition in adolescence

Phthalates are ubiquitous environmental chemicals with predominantly anti-androgenic, and potentially obesogenic effects. We hypothesised that antenatal phthalate exposure may influence subsequent boy's growth and body composition through childhood and adolescence. Among 1399 singleton males from the Raine Study, 410 had maternal serum and at least one height, BMI or DEXA outcome available after birth and up to 20 years of age. Maternal serum collected at 18 and 34 weeks' gestation was pooled, and analyzed for concentrations of 32 metabolites of 15 phthalate diesters. Their serum concentrations were categorized into undetectable/detectable levels or tertiles. Linear mixed models were used to determine associations between maternal serum phthalate levels and longitudinal height and body mass index (BMI) z-scores in boys from birth to 20 years of age (n = 250 and n = 295 respectively). Linear regression was used to determine associations between maternal phthalate levels and deviation from mid-parental height (n = 177) and DEXA scan outcomes (n = 191) at the 20 year follow-up. Weak positive associations of participants height z-score increase were detected with exposure to some phthalate metabolites in particular to the lower molecular weight phthalate metabolites. Less consistent findings, by mixed model analyses, were detected for BMI and body composition, by dual energy X-ray absorptiometry (DEXA), with some positive associations of phthalate metabolites with BMI and some negative associations with DEXA fat tissue measures, although no consistent findings were evident. In conclusion, we derived some associations of childhood growth with prenatal phthalate exposure, particularly with respect to the lower molecular weight phthalate metabolites.

Plasticizers and Cardiovascular Health: Role of Adipose Tissue Dysfunction

Since the 1950s, the production of plastics has increased 200-fold, reaching 360 million tonnes in 2019. Plasticizers, additives that modify the flexibility and rigidity of the product, are ingested as they migrate into food and beverages. Human exposure is continuous and widespread; between 75 and 97% of urine samples contain detectable levels of bisphenols and phthalates, the most common plasticizers. Concern over the toxicity of plasticizers arose in the late 1990s, largely focused around adverse developmental and reproductive effects. More recently, many studies have demonstrated that exposure to plasticizers increases the risk for obesity, type 2 diabetes, and cardiovascular disease (CVD). In the 2000s, many governments including Canada, the United States and European countries restricted the use of certain plasticizers in products targeted towards infants and children. Resultant consumer pressure motivated manufacturers to substitute plasticizers with analogues, which have been marketed as safe. However, data on the effects of these new substitutes are limited and data available to-date suggest that many exhibit similar properties to the chemicals they replaced. The adverse effects of plasticizers have largely been attributed to their endocrine disrupting properties, which modulate hormone signaling. Adipose tissue has been well-documented to be a target of the disrupting effects of both bisphenols and phthalates. Since adipose tissue function is a key determinant of cardiovascular health, adverse effects of plasticizers on adipocyte signaling and function may underlie their link to cardiovascular disease. Herein, we discuss the current evidence linking bisphenols and phthalates to obesity and CVD and consider how documented impacts of these plasticizers on adipocyte function may contribute to the development of CVD.

Prenatal maternal phthalate exposures and child lipid and adipokine levels at age six: A study from the PROGRESS cohort of Mexico City

BACKGROUND

Prenatal phthalate exposures may affect processes that underlie offspring cardiometabolic health, but findings from studies examining these associations are conflicting. We examined associations between biomarkers of phthalate exposures during pregnancy with child lipid and adipokine levels.

METHODS

Data were from 463 mother-child pairs in the PROGRESS cohort of Mexico City. We quantified 15 phthalate metabolites in 2nd and 3rd trimester maternal urine samples and created an average pregnancy measure using the geometric mean. We evaluated the 15 metabolites as nine biomarkers, including four metabolite molar sums. We measured fasting serum triglycerides, non-HDL cholesterol, leptin, and adiponectin in children at the six-year follow-up visit (mean = 6.8 years). We estimated associations using linear regression, Bayesian kernel machine regression (BKMR), and weighted quantile sum (WQS) and assessed effect modification by sex.

RESULTS

In BKMR and WQS models, higher concentrations of the total mixture of phthalate biomarkers were associated with lower triglycerides (β = -3.7% [-6.5, -0.78] per 1 unit increase in WQS biomarker index) and non-HDL cholesterol (β = -2.0 [-3.7, -0.25] ng/ml per increase in WQS biomarker index). Associations between individual biomarkers and child outcomes were largely null. We observed some evidence of effect modification by child sex for mono-3-carboxypropyl phthalate (β = 19.4% [1.26, 40.7] per doubling of phthalate) and monobenzyl phthalate (β = -7.6% [-14.4, -0.23]) in girls for adiponectin.

CONCLUSIONS

Individual prenatal phthalate biomarkers were not associated with child lipid or adipokine levels. Contrary to our hypothesis, the total phthalate mixture was associated with lower child triglycerides and non-HDL cholesterol.

Life-Time Environmental Chemical Exposure and Obesity: Review of Epidemiological Studies Using Human Biomonitoring Methods

The exponential global increase in the incidence of obesity may be partly attributable to environmental chemical (EC) exposure. Humans are constantly exposed to ECs, primarily through environmental components. This review compiled human epidemiological study findings of associations between blood and/or urinary exposure levels of ECs and anthropometric overweight and obesity indices. The findings reveal research gaps that should be addressed. We searched MEDLINE (PubMed) for full text English articles published in 2006-2020 using the keywords "environmental exposure" and "obesity". A total of 821 articles were retrieved; 102 reported relationships between environmental exposure and obesity indices. ECs were the predominantly studied environmental exposure compounds. The ECs were grouped into phenols, phthalates, and persistent organic pollutants (POPs) to evaluate obesogenic roles. In total, 106 articles meeting the inclusion criteria were summarized after an additional search by each group of EC combined with obesity in the PubMed and Scopus databases. Dose-dependent positive associations between bisphenol A (BPA) and various obesity indices were revealed. Both individual and summed di(2-ethylhexyl) phthalate (DEHP) and non-DEHP metabolites showed inconsistent associations with overweight and obesity indices, although mono-butyl phthalate (MBP), mono-ethyl phthalate (MEP), and mono-benzyl phthalate (MBzP) seem to have obesogenic roles in adolescents, adults, and the elderly. Maternal exposure levels of individual POP metabolites or congeners showed inconsistent associations, whereas dichlorodiphenyldichloroethylene (DDE) and perfluorooctanoic acid (PFOA) were positively associated with obesity indices. There was insufficient evidence of associations between early childhood EC exposure and the subsequent development of overweight and obesity in late childhood. Overall, human evidence explicitly reveals the consistent obesogenic roles of BPA, DDE, and PFOA, but inconsistent roles of phthalate metabolites and other POPs. Further prospective studies may yield deeper insights into the overall scenario.

Short- and long-term effects of perinatal phthalate exposures on metabolic pathways in the mouse liver

Phthalates have been demonstrated to interfere with metabolism, presumably by interacting with peroxisome proliferator-activated receptors (PPARs). However, mechanisms linking developmental phthalate exposures to long-term metabolic effects have not yet been elucidated. We investigated the hypothesis that developmental phthalate exposure has long-lasting impacts on PPAR target gene expression and DNA methylation to influence hepatic metabolic profiles across the life course. We utilized an established longitudinal mouse model of perinatal exposures to diethylhexyl phthalate and diisononyl phthalate, and a mixture of diethylhexyl phthalate+diisononyl phthalate. Exposure was through the diet and spanned from 2 weeks before mating until weaning at postnatal day 21 (PND21). Liver tissue was analyzed from the offspring of exposed and control mice at PND21 and in another cohort of exposed and control mice at 10 months of age. RNA-seq and pathway enrichment analyses indicated that acetyl-CoA metabolic processes were altered in diisononyl phthalate-exposed female livers at both PND21 and 10 months (FDR = 0.0018). Within the pathway, all 13 significant genes were potential PPAR target genes. Promoter DNA methylation was altered at three candidate genes, but persistent effects were only observed for Fasn. Targeted metabolomics indicated that phthalate-exposed females had decreased acetyl-CoA at PND21 and increased acetyl-CoA and acylcarnitines at 10 months. Together, our data suggested that perinatal phthalate exposures were associated with short- and long-term activation of PPAR target genes, which manifested as increased fatty acid production in early postnatal life and increased fatty acid oxidation in adulthood. This presents a novel molecular pathway linking developmental phthalate exposures and metabolic health outcomes.

Phthalate Exposure, Adolescent Health, and the Need for Primary Prevention

Phthalates, a class of endocrine-disrupting chemicals, are used widely in many consumer products, and exposure can interfere with a range of hormonal functions during early life. These disruptions may alter development during late childhood and adolescence. This article discusses the potential effects of phthalate exposure on adiposity, puberty, and neurodevelopment during late childhood and adolescence. It also highlights studies of behavioral interventions to reduce phthalate exposures and the roles of health care professionals and policy makers in preventing phthalate exposure.

Simple and rapid analysis of phthalate esters in marine sediment using ultrasound-assisted extraction combined with gas purge microsyringe extraction followed by GC-MS

Phthalate esters (PAEs) are a class of the emerging pollutants that pose a potential environmental threat to marine ecosystems. In this study, a simple analytical method using ultrasound-assisted extraction combined with gas purges microsyringe extraction (GP-MSE) coupled with GC-MS was utilized for the reliable and rapid determination of PAEs in different types of marine sediment. The analytical results showed that the method exhibited excellent reproducibility, linear responses, and detection limits, which verified the suitability of the method for the determination of PAEs in marine sediment. This approach requires minimal reagents, solvents, and sample pretreatment procedures as well as a short analysis time; thus, procedural blanks can be kept to a minimum. This method was demonstrated to be a highly efficient and sensitive quantitative analytical method for the simple detection of PAEs in marine sediment.

Phthalates in the diet of Mexican children of school age. Risk analysis

Phthalates are widely used as plasticizers, additives, or solvents. Its extensive use has generated environmental and food contamination, which implies continuous population exposure. The aim of this work was to determine the probability of health risk of Mexican children exposed to phthalates through the consumption of contaminated food. A survey was applied to 384 Mexican school-age children (between 6 and 12 years old), to find out the type of food they eat most frequently, based on this, a research was made to know the concentration of phthalates contained in these foods. The daily intake had been calculated with the concentration of phthalates reported in food, obtaining: DEHP (19.50 μg/kg body weight/day), DnBP (5.52 μg/kg body weight/day) y for DEP (1.12 μg/kg body weight/day). The hazard index (HI) for DEP y DEHP was 0.49 to 42.5 for internal organs damage reported. HI for reproductive health damage due to exposure to DnBT and DEHP was of 0.04 to 5.58, so that there is a high probability that children's health is at risk. Therefore, it is necessary to a quantitative analysis of phthalates in food consumed in Latin American countries and establish the TDI of phthalates especially, to DEHP, which was obtained the higher HI.

Fetal exposure to phthalates and bisphenols and childhood general and organ fat. A population-based prospective cohort study

OBJECTIVES

Fetal exposure to phthalates and bisphenols might have long-lasting effects on growth and fat development. Not much is known about the effects on general and organ fat development in childhood. We assessed the associations of fetal exposure to phthalates and bisphenols with general and organ fat measures in school-aged children.

METHODS

In a population-based, prospective cohort study among 1128 mother-child pairs, we measured maternal urinary phthalate metabolites and bisphenol concentrations in first, second, and third trimester. Offspring body mass index, fat mass index by dual-energy X-ray absorptiometry, and visceral and pericardial fat indices and liver fat fraction were measured by magnetic resonance imaging at 10 years.

RESULTS

After adjustment for confounders and correction for multiple testing, an interquartile range increase in first trimester phthalic acid concentrations remained associated with a 0.14 (95% confidence interval: 0.05, 0.22) standard deviation score increase in pericardial fat index. We also observed tendencies for associations of higher maternal low molecular weight phthalate urinary concentrations in second trimester with childhood pericardial fat index, but these were not significant after adjustment for multiple testing. High molecular weight phthalate, di-2-ethylhexyl phthalate, and di-n-octyl phthalate concentrations were not associated with childhood outcomes. Maternal urinary bisphenol concentrations were not associated with childhood adiposity.

CONCLUSIONS

Maternal first trimester phthalic acid concentrations are associated with increased childhood pericardial fat index at 10 years of age, whereas maternal bisphenol concentrations are not associated with childhood adiposity. We did not find significant sex-specific effects. These findings should be considered as hypothesis generating and need further replication and identification of underlying mechanisms.

Prenatal maternal organophosphorus pesticide exposures, paraoxonase 1, and childhood adiposity in the Mount Sinai Children's Environmental Health Study

BACKGROUND

Animal studies suggest that organophosphorus pesticides (OPs) may be environmental obesogens. While prenatal OP exposures have been associated with altered infant glucose metabolism, associations with pediatric adiposity remain unknown.

METHODS

We summed concentrations of three dimethylphosphate (∑DMP) and three diethylphosphate (∑DEP) metabolites of OPs measured in third trimester spot urine samples collected from pregnant women enrolled in New York City, 1998-2002. We measured percent fat mass using bio-electrical impedance analysis and calculated age- and sex-standardized body mass index (BMI) z-scores from anthropometric measurements collected at approximately 4, 6, and 7-9 years of age (166 children, 333 observations). We assessed covariate-adjusted associations of OPs with repeated adiposity measures using linear mixed models and evaluated effect measure modification (EMM) by sex and paroxonase (PON) 1 -108C/T and Q192R polymorphisms measured in maternal peripheral blood samples.

RESULTS

The geometric mean urinary concentration of ∑DMP metabolites (29.9 nmol/L, IQR: 105.2 nmol/L) was higher than ∑DEP metabolites (8.8 nmol/L, IQR: 31.2 nmol/L). Adjusted associations were null, with differences in fat mass per 10-fold increase in prenatal ∑DMP and ∑DEP concentrations of 0.7% (95% CI: -0.6, 2.0) and 0.8% (95% CI: -0.4, 2.0), respectively. Maternal PON1-108C/T polymorphisms modified relationships of prenatal ∑DMP with percent fat mass (EMM p-value = 0.18) and ∑DEP with BMI z-scores (EMM p-value = 0.12). For example, ∑DMP was modestly associated with increased percent fat mass among children of mothers with the at-risk CT or TT genotype (β = 1.2%, 95% CI: -0.6, 3.0) but not among those whose mothers had the CC genotype (β = -0.4%, 95% CI: -2.4, 1.5). Associations were not modified by sex or maternal PON1 Q192R polymorphisms.

CONCLUSIONS

We observed little evidence of a relationship between prenatal OP exposures and child adiposity, although there was some suggestion of increased risk among offspring of mothers who were slow OP metabolizers. Larger studies are warranted to further evaluate possible associations of prenatal OP exposures with child adiposity and differences by maternal PON1 genotype, which regulates OP metabolism and may increase susceptibility to exposure.

Using three statistical methods to analyze the association between exposure to 9 compounds and obesity in children and adolescents: NHANES 2005-2010

BACKGROUND

Various risk factors influence obesity differently, and environmental endocrine disruption may increase the occurrence of obesity. However, most of the previous studies have considered only a unitary exposure or a set of similar exposures instead of mixed exposures, which entail complicated interactions. We utilized three statistical models to evaluate the correlations between mixed chemicals to analyze the association between 9 different chemical exposures and obesity in children and adolescents.

METHODS

We fitted the generalized linear regression, weighted quantile sum (WQS) regression, and Bayesian kernel machine regression (BKMR) to analyze the association between the mixed exposures and obesity in the participants aged 6-19 in the National Health and Nutrition Examination Survey (NHANES) 2005-2010.

RESULTS

In the multivariable logistic regression model, 2,5-dichlorophenol (2,5-DCP) (OR (95% CI): 1.25 (1.11, 1.40)), monoethyl phthalate (MEP) (OR (95% CI): 1.28 (1.04, 1.58)), and mono-isobutyl phthalate (MiBP) (OR (95% CI): 1.42 (1.07, 1.89)) were found to be positively associated with obesity, while methylparaben (MeP) (OR (95% CI): 0.80 (0.68, 0.94)) was negatively associated with obesity. In the multivariable linear regression, MEP was found to be positively associated with the body mass index (BMI) z-score (β (95% CI): 0.12 (0.02, 0.21)). In the WQS regression model, the WQS index had a significant association (OR (95% CI): 1.48 (1.16, 1.89)) with the outcome in the obesity model, in which 2,5-DCP (weighted 0.41), bisphenol A (BPA) (weighted 0.17) and MEP (weighted 0.14) all had relatively high weights. In the BKMR model, despite no statistically significant difference in the overall association between the chemical mixtures and the outcome (obesity or BMI z-score), there was nonetheless an increasing trend. 2,5-DCP and MEP were found to be positively associated with the outcome (obesity or BMI z-score), while fixing other chemicals at their median concentrations.

CONCLUSION

Comparing the three statistical models, we found that 2,5-DCP and MEP may play an important role in obesity. Considering the advantages and disadvantages of the three statistical models, our study confirms the necessity to combine different statistical models on obesity when dealing with mixed exposures.