Breastfeeding Duration and Cardiometabolic Health during Adolescence: A Longitudinal Analysis.

OBJECTIVE: To investigate the longitudinal association between breastfeeding duration and cardiometabolic health, using repeated measures study design among children and adolescents. STUDY DESIGN: This study included 634 offsprings aged 10 to 21 years (52% female) from the Early Life Exposure in Mexico to Environmental Toxicants birth cohort followed up to four time points during adolescence. Breastfeeding duration was prospectively quantified using questionnaires during early childhood. Cardiometabolic risk factors, body composition, and weight-related biomarkers were assessed as outcomes during adolescent follow-up visits. Sex-stratified linear mixed-effects models were used to model the association between quartiles of breastfeeding duration and outcomes, adjusting for age and additional covariates. RESULTS: Median breastfeeding duration was 7 months (minimum = 0, maximum = 36). Boys in the second quartile (median breastfeeding = 5 months) had lower total fat mass % (ß (SE) -3.2 (1.5) P = .037), and higher lean mass % (3.1 (1.6) P = .049) and skeletal muscle mass % (1.8 (0.8) P = .031) compared with the reference group (median breastfeeding = 2 months). A positive linear trend between breastfeeding duration and trunk lean mass % (0.1 (0.04) P = .035) was found among girls. No association was found with other cardiometabolic indicators. CONCLUSION: Despite sex-specific associations of breastfeeding duration with body composition, there was a lack of substantial evidence for the protective effects of breastfeeding against impaired cardiometabolic health during adolescence among Mexican youth. Further longitudinal studies with a robust assessment of breastfeeding are recommended.

Individual and joint effects of prenatal PM2.5 and maternal stress on child temperament.

Prenatal fine particulate matter (PM2.5) and maternal psychological functioning have been associated with child cognitive outcomes, though their independent and joint impacts on earlier behavioral outcomes remains less studied. We used data from 382 mother-child pairs from a prospective birth cohort in Mexico City. Temperament was measured at 24 months using the Carey Toddler Temperament Scale (TTS). Exploratory factor analysis (EFA) was used to update the factor structure of the TTS. During pregnancy, mothers completed the Crisis in Family Systems-Revised, Edinburgh Depression Scale, pregnancy-specific anxiety scale, and the Perceived Stress Scale. Pregnancy PM2.5 was assessed using estimates from a satellite-based exposure model. We assessed the association between prenatal maternal stress and PM2.5 on temperament, in both independent and joint models. Quantile g-computation was used to estimate the joint associations. Models were adjusted for maternal age, SES, education, child sex, and child age. In EFA, we identified three temperament factors related to effortful control, extraversion, and negative affect. Our main results showed that higher levels of PM2.5 and several of the maternal psychological functioning measures were related to both effortful control and negative affect in the child, both individually and as a mixture. For instance, a one quartile increase in the prenatal mixture was associated with higher negative affect scores in the child (0.34, 95% CI: 0.16, 0.53). We observed modification of these associations by maternal SES, with associations seen only among lower SES participants for both effortful control (-0.45, 95% CI: -0.70, -0.20) and negative affect outcomes (0.60, 95% CI: 0.35, 0.85). Prenatal PM2.5 and maternal psychological functioning measures were associated with toddler temperament outcomes, providing evidence for impacts of chemical and non-chemical stressors on early child health.

Changes in depressive and anxiety symptoms during COVID-19 in children from the PROGRESS cohort.

BACKGROUND: We assessed associations between maternal stress, social support, and child resiliency during the COVID-19 pandemic in relation to changes in anxiety and depression symptoms in children in Mexico City. METHODS: Participants included 464 mother-child pairs from a longitudinal birth cohort in Mexico City. At ages 8-11 (pre-COVID, 2018-2019) and 9-12 (during COVID, May-Nov 2020) years, depressive symptoms were assessed using the child and parent-reported Children's Depressive Inventory. Anxiety symptoms were assessed using the child-reported Revised Manifest Anxiety Scale. Linear regression models were used to estimate associations between maternal stress, social support, and resiliency in relation to changes in depressive and anxiety symptoms. We additionally assessed outcomes using clinically relevant cut-points. Models were adjusted for child age and sex and maternal socioeconomic status and age. RESULTS: Higher continuous maternal stress levels during the COVID-19 pandemic were associated with increases in depressive symptoms (ß: 0.72; 95% CI: 0.12, 1.31), and higher odds of clinically relevant depressive and anxiety symptoms in the children. CONCLUSIONS: Maternal stress during the pandemic may increase mental health symptoms in pre-adolescent children. Additional studies are needed that examine the long-term pandemic-related impacts on mental health throughout the adolescent years. IMPACT: In this longitudinal cohort study of children in Mexico City, we observed that depressive symptoms were higher from before to during the pandemic. Maternal stress surrounding the pandemic may increase mental health symptoms in pre-adolescent children. Child resiliency may help to protect against pandemic-related stressors.

Prenatal Lead Exposure Is Associated with Reduced Abundance of Beneficial Gut Microbial Cliques in Late Childhood: An Investigation Using Microbial Co-Occurrence Analysis (MiCA).

Many analytical methods used in gut microbiome research focus on either single bacterial taxa or the whole microbiome, ignoring multibacteria relationships (microbial cliques). We present a novel analytical approach to identify microbial cliques within the gut microbiome of children at 9-11 years associated with prenatal lead (Pb) exposure. Data came from a subset of participants (n = 123) in the Programming Research in Obesity, Growth, Environment and Social Stressors cohort. Pb concentrations were measured in maternal whole blood from the second and third trimesters of pregnancy. Stool samples collected at 9-11 years old underwent metagenomic sequencing to assess the gut microbiome. Using a novel analytical approach, Microbial Co-occurrence Analysis (MiCA), we paired a machine learning algorithm with randomization-based inference to first identify microbial cliques that were predictive of prenatal Pb exposure and then estimate the association between prenatal Pb exposure and microbial clique abundance. With second-trimester Pb exposure, we identified a two-taxa microbial clique that included Bifidobacterium adolescentis and Ruminococcus callidus and a three-taxa clique that also included Prevotella clara. Increasing second-trimester Pb exposure was associated with significantly increased odds of having the two-taxa microbial clique below the median relative abundance (odds ratio (OR) = 1.03, 95% confidence interval (CI) [1.01-1.05]). Using a novel combination of machine learning and causal inference, MiCA identified a significant association between second-trimester Pb exposure and the reduced abundance of a probiotic microbial clique within the gut microbiome in late childhood.

Prenatal manganese biomarkers and operant test battery performance in Mexican children: Effect modification by child sex.

BACKGROUND: Manganese (Mn) is essential to healthy neurodevelopment, but both Mn deficiency and over-exposure have been linked to prefrontal cortex (PFC) impairments, the brain region that regulates cognitive and neurobehavioral processes responsible for spatial memory, learning, motivation, and time perception. These processes facilitated by attention, inhibitory control, working memory, and cognitive flexibility are often sexually dimorphic and complex, driven by multiple interconnected neurologic and cognitive domains. OBJECTIVE: We investigated the role of child sex as an effect modifier of the association between prenatal Mn exposure and performance in an operant testing battery (OTB) that assessed multiple cognitive and behavioral functional domains. METHODS: Children (N = 575) aged 6-8 years completed five OTB tasks. Blood and urinary Mn measurements were collected from mothers in the 2nd and 3rd trimesters. Multiple regression models estimated the association between Mn biomarkers at each trimester with OTB performance while adjusting for socio-demographic covariates. Covariate-adjusted weighted quantile sum (WQS) regression models were used to estimate the association of a Mn multi-media biomarker (MMB) mixture with OTB performance. Interaction terms were used to estimate modification effect by child sex. RESULTS: Higher blood Mn exposure was associated with better response rates (more motivation) on the progressive ratio task and higher overall accuracy on the delayed matching-to-sample task. In the WQS models, the MMB mixture was associated with better response rates (more motivation) on the progressive ratio task. Additionally, for the linear and WQS models, we observed a modification effect by child sex in the progressive ratio and delayed matching-to-sample tasks. Higher prenatal Mn biomarker levels were associated with improved task performance for girls and reduced performance in boys. CONCLUSION: Higher prenatal blood Mn concentrations and the MMB mixture predicted improved performance on two of five operant tasks. Higher prenatal Mn concentrations regulated executive functions in children in a sexually dimorphic manner. Higher prenatal Mn exposure is associated with improved performance on spatial memory and motivation tasks in girls, suggesting that Mn's nutritional role is sexually dimorphic, and should be considered when making dietary and/or environmental intervention recommendations.

Calcium supplementation and body mass index modify associations between prenatal phthalate exposure and perinatal bone ultrasound measures among pregnant women.

Phthalates have endocrine activity that may interfere with bone health, particularly during pregnancy and the early postpartum period, when bone resorption increases. We evaluated associations between prenatal phthalate exposure and perinatal bone health among 289 mothers in the ELEMENT birth cohort in Mexico City who were randomized upon recruitment to receive 1,200 mg daily calcium supplementation or placebo throughout pregnancy. Spot urine samples at up to three timepoints during pregnancy were assayed for 9 phthalate metabolites. Bone integrity was assessed by quantitative ultrasound speed of sound (SOS) measurements of the phalange and distal radius at 3, 6, and 8 months of pregnancy and 1, 3, 7, and 12 months postpartum. Geometric means of specific gravity-corrected phthalate concentrations were used as overall measures of prenatal exposure. Linear mixed effect models estimated associations between phthalate exposure and repeated perinatal bone SOS measures, adjusting for age, pre-pregnancy body mass index (BMI), education, parity, calcium supplementation, and month of pregnancy/postpartum. Effect modification by calcium supplementation and BMI were assessed in sensitivity analyses. An interquartile range increase in MEP and MiBP increased pregnancy phalange z-scores (ß: 0.11; 95%CI: 0.003, 0.31 and ß: 0.15; 95%CI: 0.00,0.42, respectively). Higher concentrations of several phthalate metabolites resulted in lower SOS measures among women who received calcium supplements (compared to placebo group) but higher SOS measures among women with a BMI≥25 (compared to BMI<25). These results suggest that phthalate exposure may interfere with bone remodeling during pregnancy, and that consideration of effect modifiers is paramount to fully understand the effects of environmental exposures on bone health.

Cross-sectional associations between phthalates, phenols, and parabens with metabolic syndrome risk during early-to-mid adolescence among a cohort of Mexican youth.

BACKGROUND: Epidemiological studies on children and adults have linked toxicants from plastics and personal care products to metabolic disruption. Yet, the impact of endocrine-disrupting chemicals (EDCs) on adolescent metabolic syndrome (MetS) risk during early and mid-adolescence is unclear. METHODS: To examine the links between exposure to EDCs and MetS risk and its components, cross-sectional data from 344 Mexican youth in early-to-mid adolescence (10-17 years) were analyzed. Urinary biomarker concentrations of phthalates, phenol, and paraben analytes were measured from a single spot urine sample collected in 2015; study personnel obtained anthropometric and metabolic measures. We examined associations between summary phthalates and metabolites, phenol, and paraben analytes with MetS risk z-scores using linear regression, adjusted for specific gravity, sex, age, pubertal status, smoking, alcohol intake, physical activity level, and screen time. As a secondary aim, mediation analysis was conducted to evaluate the role of hormones in the association between summary phthalates with lipids and MetS risk z-scores. RESULTS: The mean (SD) age was 13.2 (1.9) years, and 50.9% were female. Sex-stratified analyses revealed associations between summary phthalates and lipids ratio z-scores, including Σ DEHP [ß = 0.21 (95% CI: 0.04, 0.37; p < 0.01)], phthalates from plastic sources (Σ Plastic) [ß = 0.22 (95% CI: 0.05, 0.39; p < 0.01)], anti-androgenic phthalates (Σ AA) [ß = 0.22 (95% CI: 0.05, 0.39; p < 0.01)], and individual phthalate metabolites (MEHHP, MEOHP, and MECPP) among males. Among females, BPA [ß = 0.24 (95% CI: 0.03, 0.44; p < 0.05)] was positively associated with lipids ratio z-score and one phenol (2,5 DCP) [ß = 0.09 (95% CI: 0.01, 0.18); p < 0.05)] was associated with increased waist circumference z-score. Results showed no evidence of mediation by hormone concentrations in the association between summary phthalates with lipids ratio or MetS risk z-scores. CONCLUSION: Higher EDC exposure was positively associated with serum lipids during adolescence, particularly among males.

Plasma Fatty Acid Biomarkers of Dairy Consumption Are Associated with Sex-Dependent Effects on Metabolic Syndrome Components in Mexican Adolescents.

INTRODUCTION: During adolescence, dairy product intake has shown conflicting associations with metabolic syndrome (MetS) components, which are risk factors for cardiovascular disease (CVD). This study aims to investigate the association between plasma fatty acids (FAs) C15:0, C17:0, and t-C16:1n-7, as biomarkers of dairy intake, with MetS and its components in Mexican adolescents. METHODS: A sample of 311 participants from the Early Life Exposure in Mexico City to Environmental Toxicants (ELEMENT) cohort was included in this cross-sectional analysis. FA concentrations were measured in plasma as a percentage of total FA. We used quantile regression models stratified by sex to evaluate the association between FA quantiles and MetS components, adjusting for age, socioeconomic status (SES), sedentary behavior, BMI z-score, pubertal status, and energy intake. RESULTS: We found significant associations between dairy biomarkers and the median of MetS variables. In females, t-C16:1n-7 was associated with a decrease of 2.97 cm in WC (Q4 vs. Q1; 95% CI: -5.79, -0.16). In males, C15:0 was associated with an increase of 5.84 mm/Hg in SBP (Q4 vs. Q1; CI: 1.82, 9.85). For HDL-C, we observed opposite associations by sex. C15:0 in males was associated with decreased HDL-C (Q3 vs. Q1: ß = -4.23; 95% CI: -7.98, -0.48), while in females, C15:0 and t-C16:1n-7 were associated with increased HDL-C (Q3 vs. Q1: ß = 4.75; 95% CI: 0.68, 8.82 and Q4 vs. Q1: ß = 6.54; 95% CI: 2.01, 11.07), respectively. Additionally, in both sexes, different levels of C15:0, C17:0, and t-C16:1n-7 were associated with increased triglycerides (TG). CONCLUSION: Our results suggest that adolescent dairy intake may be associated in different directions with MetS components and that associations are sex-dependent.

Intoxicación infantil por plomo en México: otras fuentes de exposición más allá del barro vidriado (Ensanut 2022).

OBJETIVO: Describir y actualizar al año 2022 la prevalencia de intoxicación por plomo (Pb) en la población infantil de 1-4 años en México y describir fuentes de exposición ambiental, paraocupacional y uso de barro vidriado (BV). Material y métodos. Estudio en una muestra de menores que participaron en la Encuesta Nacional de Salud y Nutrición 2022 (Ensanut 2022). Se midió la concentración de plomo en sangre (PbS) capilar. Se aplicó un cuestionario para indagar sobre fuentes de exposición a Pb. RESULTADOS: Se midió PbS en 1 158 menores de 1-4 años. La prevalencia nacional de intoxicación por Pb (≥5.0 µg/dL) fue 16.8% (IC95%:13.6,20.5). La proporción de hogares que reportó exposición a una fuente exclusiva fue de 21.2, 17.7 y 7.4% para BV, exposición ambiental y paraocupacional, respectivamente. La prevalencia de intoxicación de los expuestos a una sola fuente fue 21.5%, y esta cifra aumenta a 24.2% entre quienes reportaron exposición combinada tres tipos de fuentes. Conclusión. La prevalencia nacional de intoxicación por plomo permaneció estable con respecto a lo reportado en la Ensanut 2018-19. El uso de BV es una fuente de exposición relevante, pero no es la única. Se identificó una contribución importante por exposición ambiental y, en menor medida, de exposición paraocupacional.

¿Agua para todos? La intermitencia en el suministro de agua en los hogares en México.

OBJETIVO: Medir el acceso a través de la intermitencia en el suministro de agua potable en hogares mexicanos. Material y métodos. A través de la Encuesta Nacional de Salud y Nutrición 2022 (Ensanut 2022), se recolectó información sobre intermitencia en días por semana y horas por día durante las últimas cuatro semanas y el suministro de agua durante el año para la temporada de mayor escasez. RESULTADOS: 31.5% de los hogares recibieron agua los siete días de la semana, las 24 horas del día. De estos, 17.4% no tuvo escasez en los últimos 12 meses. La intermitencia es más común entre hogares de las regiones en el sur del país y entre los más pobres. El 81% de las familias almacena agua y 16% almacena en contenedores portátiles como cubetas. Conclusión. En este artículo se presentan por primera vez patrones de intermitencia en el suministro de agua a nivel nacional en México. La gran mayoría de las familias no reciben agua de forma continua y tienen que almacenar agua. El almacenamiento podría disminuir la calidad del agua y la falta de confianza para su consumo con consecuencias para la salud. La conexión al sistema potable no refleja el acceso real de las familias al agua.

Contribución de diversas fuentes de exposición a la concentración de plomo en sangre en población infantil mexicana, Ensanut 2022.

OBJETIVO: Analizar la asociación entre fuentes de exposición al plomo (FEPb) y la concentración en sangre capilar (PbS) en menores de 1 a 4 años de edad a nivel nacional y regional, así como cuantificar la contribución relativa de las distintas FEPb. Material y métodos. Se utilizaron datos de la Encuesta Nacional de Salud y Nutrición (Ensanut 2022). Las FEPb consideradas fueron uso de loza de barro vidriada con plomo (LBVPb), residencia cercana a sitios contaminados y exposición paraocupacional. Se estimaron prevalencias de intoxicación (PbS ≥ 5.0 mg/dL) y medias geométricas de PbS. Se utilizaron modelos de regresión para PbS (escala logarítmica) y la descomposición Shapley-Owen de R2 para evaluar la contribución relativa de cada FEPb. RESULTADOS: Las FEPb estudiadas explican el 6% de la variabilidad de PbS a nivel nacional; de este, el 87.3% lo explica el uso de LBVPb, el 4.2% otras FEPb ambiental y 1.3% FEPb paraocupacionales. La contribución relativa del uso de LBVPb varía entre regiones, desde 38.1 a 76.8%. Algunas regiones destacan la FEPb ambiental, pero no paraocupacional. CONCLUSIONES: Los resultados confirman que el uso de LBVPb es la principal fuente de exposición reportada y sugieren que la población no identifica las principales FEPb documentadas hasta ahora.

Prenatal exposure to metals and concentration thereof in umbilical cord blood in a Mexico City cohort.

BACKGROUND: In Mexico, there is a paucity of evidence on the magnitude of prenatal exposure to metals. OBJECTIVE: To estimate the concentration of arsenic, cadmium, manganese and lead in umbilical cord blood (UCB) and its association with maternal blood concentrations during pregnancy and delivery. MATERIAL AND METHODS: Metal concentration in maternal blood was analyzed during pregnancy (n = 901), delivery (n = 732) and in UCB (n = 512) from participants of the PROGRESS cohort residing in Mexico City. The association between concentrations in UCB and maternal biomarkers was analyzed using generalized linear models, adjusted for relevant covariates. RESULTS: Mean concentrations (µg/L) of lead, arsenic and manganese in UCB were 27.14 (25.28-29.14), 0.77 (0.71-0.84) and 42.60 (40.45-44.83), respectively. Cadmium concentration could not be estimated because 86.2% of measurements were below the detection limit. Lead and manganese concentrations in UCB were significantly associated with maternal biomarkers during pregnancy and delivery; at delivery, association was only observed with arsenic. CONCLUSIONS: Prenatal exposure to toxic metals in sensitive periods of organogenesis shows a neglected public health problem. Biomonitoring of the population and establishment of regulations aimed at providing care to vulnerable populations is required.

ANTECEDENTES: En México es exigua la evidencia sobre la exposición prenatal a metales. OBJETIVO: Estimar la concentración de arsénico, cadmio, manganeso y plomo en sangre de cordón umbilical (SCU), y su asociación con las concentraciones en sangre materna durante el embarazo y parto. MATERIAL Y MÉTODOS: Se analizó la concentración de los metales en sangre materna durante el embarazo (n = 901), parto (n = 732) y en la SCU (n = 512) de participantes de la cohorte PROGRESS, residentes en la Ciudad de México. Se estimó la asociación entre la concentración en SCU y los biomarcadores maternos mediante modelos lineales generalizados, ajustados por covariables relevantes. RESULTADOS: La media (µg/L) de plomo, arsénico y manganeso en SCU fue 27.14 (25.28-29.14), 0.77 (0.71-0.84) y 42.60 (40.45-44.83), respectivamente. El valor del cadmio no se pudo estimar porque 86.2 % de las mediciones fueron inferiores al límite de detección. Las concentraciones de plomo y manganeso en SCU se asociaron significativamente a los biomarcadores maternos durante el embarazo y el parto; solo se observó asociación con arsénico en el parto. CONCLUSIONES: La exposición prenatal a metales tóxicos en periodos sensibles de la organogénesis evidencia un problema de salud pública desatendido. Se requiere un biomonitoreo poblacional y establecer regulación dirigida a proveer atención a población vulnerable.

Analysis of the burden of disease attributable to environmental risk factors in Mexico in the 1990-2021 period. Identification of advances, lags and emergencies.

BACKGROUND: It is estimated that environmental risk factors (ERF) were responsible for nine million deaths worldwide in 2019. OBJECTIVE: Using data from the Global Burden of Disease study, indicators of health loss associated with exposure to ERF in Mexico were analyzed. MATERIAL AND METHODS: Absolute numbers and population percentages of deaths and disability-adjusted life years (DALY) lost attributed to selected ERFs were analyzed at the national and state level and by sex, as well as age-standardized trends from 1990 to 2021. RESULTS: In 2021, ambient particulate matter pollution showed the highest mortality and DALYs lost attributed to selected ERFs (42.2 and 38.1% respectively), followed by lead exposure (20.6 and 13.4%) and low temperature (19.8 and 12.3%). Both indicators have decreased for all selected ERAs by different magnitudes between 1991 and 2021, except for high temperature. CONCLUSIONS: Despite decreases in the last 32 years, outdoor environment particulate matter showed the highest mortality and DALYs lost, followed by lead exposure. It is essential to strengthen air quality and lead exposure policies in Mexico.

ANTECEDENTES: Se estima que los factores de riesgo ambientales (FRA) fueron responsables en 2019 de nueve millones de muertes en el mundo. OBJETIVO: A partir de datos del estudio Global Burden of Disease, se analizaron indicadores de pérdida de salud asociada a la exposición a FRA en México. MATERIAL Y MÉTODOS: Se analizaron números absolutos y porcentajes poblacionales de muertes y años de vida saludable (AVISA) perdidos según sexo atribuidos a FRA seleccionados en los ámbitos nacional y estatal, así como las tendencias estandarizadas por edad de 1990 a 2021. RESULTADOS: En 2021, la contaminación por material particulado en ambiente exterior mostró la mayor mortalidad y AVISA perdidos por los FRA seleccionados (42.2 y 38.1 %, respectivamente), seguida de la exposición a plomo (20.6 y 13.4 %) y temperatura baja (19.8 y 12.3 %). Ambos indicadores han disminuido en todos los FRA seleccionados, en magnitudes diferentes entre 1991 y 2021, excepto la temperatura alta. CONCLUSIONES: A pesar de las disminuciones en los últimos 32 años, el material particulado en ambiente exterior mostró la mayor mortalidad y AVISA perdidos, seguido de la exposición a plomo. Es fundamental fortalecer las políticas de calidad del aire y exposición a plomo en México.

Dietary Exposure to Toxic Elements and the Health of Young Children: Methodological Considerations and Data Needs.

Concerns have been raised regarding toxic-element (arsenic, cadmium, lead, and mercury) contamination of commercially available infant foods around the world. Young children are vulnerable to the effects of toxic elements, based on higher absorption levels and potentially poorer detoxification capacities. Toxic-element exposures in early life exact high societal costs, but it is unclear how much dietary exposure to these elements contributes to adverse health outcomes. Well-designed epidemiological studies conducted in different geographical and socioeconomic contexts need to estimate dietary toxicant exposure in young children and to determine whether causal links exist between toxicants in children's diets and health outcomes. This commentary outlines the methodological considerations and data needs to advance such research.

Third-Trimester Maternal Dietary Patterns Are Associated with Sleep Health among Adolescent Offspring in a Mexico City Cohort.

BACKGROUND: Maternal diet during gestation has been linked to infant sleep; whether associations persist through adolescence is unknown. OBJECTIVES: We explored associations between trimester-specific maternal diet patterns and measures of sleep health among adolescent offspring in a Mexico City birth cohort. METHODS: Data from 310 mother-adolescent dyads were analyzed. Maternal diet patterns were identified by principal component analysis derived from FFQs collected during each trimester of pregnancy. Sleep duration, midpoint, and fragmentation were obtained from 7-d actigraphy data when adolescents were between 12 and 20 y old. Unstratified and sex-stratified association analyses were conducted using linear regression models, adjusted for potential confounders. RESULTS: Mean ± SD age of offspring was 15.1 ± 1.9 y, and 52.3% of the sample was female. Three diet patterns were identified during each trimester of pregnancy: the Prudent Diet (PD), high in lean proteins and vegetables; the Transitioning Mexican Diet (TMD), high in westernized foods; and the High Meat & Fat Diet (HMFD), high in meats and fat products. Mean ± SD sleep duration was 8.5 ± 1.5 h/night. Most associations were found in the third trimester. Specifically, PD maternal adherence was associated with shorter sleep duration among offspring (-0.57 h; 95% CI: -0.98, -0.16 h, in the highest tertile compared with the lowest) and earlier sleep midpoint among females (-0.77 h; 95% CI: -1.3, -0.26 h). Adherence to the HMFD and TMD was nonlinearly associated with less fragmented sleep, with the latter only evident among females. CONCLUSIONS: Findings indicate that maternal dietary patterns, especially during the third trimester of pregnancy, may have long-term impacts on offspring sleep.

Maternal anxiety during pregnancy and newborn epigenome-wide DNA methylation.

Maternal anxiety during pregnancy is associated with adverse foetal, neonatal, and child outcomes, but biological mechanisms remain unclear. Altered foetal DNA methylation (DNAm) has been proposed as a potential underlying mechanism. In the current study, we performed a meta-analysis to examine the associations between maternal anxiety, measured prospectively during pregnancy, and genome-wide DNAm from umbilical cord blood. Sixteen non-overlapping cohorts from 12 independent longitudinal studies of the Pregnancy And Childhood Epigenetics Consortium participated, resulting in a combined dataset of 7243 mother-child dyads. We examined prenatal anxiety in relation to genome-wide DNAm and differentially methylated regions. We observed no association between the general symptoms of anxiety during pregnancy or pregnancy-related anxiety, and DNAm at any of the CpG sites, after multiple-testing correction. Furthermore, we identify no differentially methylated regions associated with maternal anxiety. At the cohort-level, of the 21 associations observed in individual cohorts, none replicated consistently in the other cohorts. In conclusion, contrary to some previous studies proposing cord blood DNAm as a promising potential mechanism explaining the link between maternal anxiety during pregnancy and adverse outcomes in offspring, we found no consistent evidence for any robust associations between maternal anxiety and DNAm in cord blood. Larger studies and analysis of DNAm in other tissues may be needed to establish subtle or subgroup-specific associations between maternal anxiety and the foetal epigenome.

Sedentary patterns and cardiometabolic risk factors in Mexican children and adolescents: analysis of longitudinal data.

BACKGROUND: Sedentary behavior is a modifiable risk factor for cardiometabolic health; however, the assessment of total sedentary time may not capture youth's highly active and interrupted activity patterns. This study examined the associations between sedentary activity patterns and cardiometabolic risk factors among Mexican youth, who have a disproportionate burden of metabolic diseases, using a repeated measure design out of a longitudinal data. METHODS: 570 subjects in the Early Life Exposure in Mexico to ENvironmental Toxicants (ELEMENT) birth cohort, who were followed up to three-time points during adolescence, were included. Bout duration, and frequency and percentages of waking time spent in specific intensities of activity, were quantified using ActiGraph wGT3X-BT wrist accelerometers. Self-reported questionnaires were used to query the usual duration of different sedentary behaviors. Outcomes were fasting lipid profile, markers for glucose homeostasis, anthropometry, and blood pressure. Associations were modeled using linear mixed-effects models, and isotemporal substitution approach was additionally used to assess the effect of replacing objectively assessed sedentary activity with other activity intensities, adjusting for potential confounders. RESULTS: Each hour of self-reported screen-based time was positively associated with diastolic blood pressure (mm Hg) [ß = 0.30, 95% confidence interval (95% CI) = 0.10, 0.51], and an hour of other sedentary time was associated with log serum glucose (mg/dL) [ß = 0.01, 95% CI = 0.004, 0.017]. Substitution models showed that replacing 5% of sedentary time with moderate to vigorous physical activity (MVPA) was associated with lower waist circumference (cm) [ß = - 1.35, 95% CI = - 1.91, - 0.79] and log serum triglycerides (mg/dL) [ß = - 0.11, 95% CI = - 0.18, - 0.03]. Substituting one uninterrupted sedentary bout with light activity was associated with lower insulin (µIU/mL) [ß = - 0.06, 95% CI = - 0.10, - 0.02]. CONCLUSIONS: Sedentary time was associated with cardiometabolic risk factors in Mexican youth in a context-specific manner. Replacing sedentary time with higher intensities was associated with improvements in some cardiometabolic markers.

Prenatal maternal pesticide exposure in relation to sleep health of offspring during adolescence.

STUDY OBJECTIVES: The neurobiological processes involved in establishing sleep regulation are vulnerable to environmental exposures as early as seven weeks of gestation. Studies have linked in utero pesticide exposure to childhood sleep-disordered breathing. However, the impact of in utero pesticide exposure on the sleep health of adolescents remains unexplored. MATERIALS AND METHODS: Data from 137 mother-adolescent pairs from a Mexico City cohort were analyzed. We used maternal urinary 3-phenoxybenzoic acid (3-PBA, pyrethroid metabolite) and 3, 5, 6-trichloro-2-pyridinol (TCPy, chlorpyrifos metabolite) from trimester three to estimate in utero pesticide exposure. Among adolescents, we obtained repeated measures of objectively assessed sleep duration, midpoint, and fragmentation using wrist-actigraphy devices for 7 consecutive days in 2015 and 2017. Unstratified and sex-stratified associations between maternal urinary 3-PBA and TCPy and adolescent sleep measures were examined using generalized linear mixed models (GLMMs). We also examined the interactive effects of maternal pesticide exposure and offspring sex on sleep outcomes. RESULTS: 3-PBA and TCPy were detected in 44.4% and 93% of urine samples, respectively. Adjusted findings demonstrated that higher exposure to maternal TCPy was associated with longer sleep duration and later sleep timing. Findings from interaction tests between maternal pesticide exposure and offspring sex were not statistically significant, although adjusted sex-stratified findings showed that the association between TCPy with duration and midpoint was evident only among female offspring. To illustrate, those in the highest tertile of exposure had a 59 minute (95% CI: 12.2, 104.8) (p, trend = 0.004) longer sleep duration and a 0.6 hour (95% CI: 0.01, 1.3) (p, trend = 0.01) later sleep midpoint. We found no significant associations between 3-PBA and sleep outcomes. CONCLUSION: Within a cohort of mother-adolescent pairs, we found associations between maternal prenatal pesticide exposure and longer sleep duration and later sleep timing among adolescent offspring. Further, this association may be female-specific.

Association between prenatal metal exposure and adverse respiratory symptoms in childhood.

INTRODUCTION: Manganese and lead have been cross-sectionally associated with adverse respiratory outcomes in childhood but there is limited data on their combined effects starting in utero. We examined associations between in utero exposure to metals and childhood respiratory symptoms. METHODS: We assessed 633 mother-child dyads enrolled in the Programming Research in Obesity, Growth, Environment, and Social Stressors (PROGRESS) birth cohort in Mexico City. Blood manganese (BMn) and lead (BPb) were measured in mothers at 2nd and 3rd trimester. Ever wheeze, current wheeze and asthma diagnosis were ascertained at 4-5 and 6-7 year visits through the International Study of Asthma and Allergies in Childhood survey. Logistic mixed model regression was used to assess the association between prenatal metals and respiratory outcomes in children across the 4-5 and 6-7 year visits. Covariates included mother's age, education and asthma, environmental tobacco smoke, child's sex and assessment time. RESULTS: In adjusted models, higher 2nd trimester BPb had a significant association with elevated odds of ever wheeze (Odds Ratio (OR): 1.97, 95% CI: 1.05, 3.67). BMn at 2nd trimester was associated with decreased (OR: 0.06, 95% CI: 0.01, 0.35) odds of current wheeze. We did not find any statistically significant associations with 3rd trimester blood metals. CONCLUSION: Prenatal exposure to Pb was associated with higher odds of ever wheeze while Mn was negatively associated with odds of current wheeze. These findings underscore the need to consider prenatal metal exposure, including low exposure levels, in the study of adverse respiratory outcomes.

Early childhood fluoride exposure and preadolescent kidney function.

BACKGROUND: Early-life renal maturation is susceptible to nephrotoxic environmental chemicals. Given the widespread consumption of fluoride and the global obesity epidemic, our main aim was to determine whether childhood fluoride exposure adversely affects kidney function in preadolescence, and if adiposity status modifies this association. METHODS: Our study included 438 children from the PROGRESS cohort. Urinary fluoride (uF) was assessed at age 4 by diffusion analysis; outcomes studied included estimated glomerular filtration rate (eGFR), blood urea nitrogen (BUN), selected kidney proteins and blood pressure measured at age 8-12 years. We modeled the relationship between uF and outcomes, and adjusted for body mass index (BMI), age, sex, and socioeconomic status. RESULTS: The median uF concentration was 0.67 µg/mL. We observed null associations between 4-year uF and preadolescent eGFR, although effect estimates were in the expected inverse direction. A single unit increase in ln-transformed uF was associated with a 2.2 mL/min decrease in cystatin C-based eGFR (95% CI: 5.8, 1.4; p = 0.23). We observed no evidence of sex-specific effects or effect modification by BMI status. Although uF was not associated with BMI, among children with obesity, we observed an inverse association (ß: 4.8; 95% CI: 10.2, 0.6; p = 0.08) between uF and eGFR. CONCLUSIONS: Low-level fluoride exposure in early childhood was not associated with renal function in preadolescence. However, given the adverse outcomes of chronic fluoride consumption it is possible that the preadolescent age was too young to observe any effects. Longitudinal follow-up in this cohort and others is an important next step.