Publications by authors named "Karen Huen"

Article Synopsis
  • Seasonal variations at birth can influence DNA methylation, which may affect health outcomes over a person’s lifetime.
  • A study involving multiple cohorts discovered specific DNA methylation patterns linked to different birth seasons, revealing 26 differentially methylated regions (DMRs) at birth and 32 in childhood.
  • Results suggested that geographic latitude plays a role in these associations, linking certain genes to conditions like schizophrenia and asthma, particularly in infants born in higher latitudes (≥50°N).
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Gestational age (GA) is an important determinant of child health and disease risk. Two epigenetic GA clocks have been developed using DNA methylation (DNAm) patterns in cord blood. We investigate the accuracy of GA clocks and determinants of epigenetic GA acceleration (GAA), a biomarker of biological ageing.

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Epigenome-wide association studies (EWAS) are widely implemented in epidemiology, and the Illumina HumanMethylationEPIC BeadChip (EPIC) DNA microarray is the most-used technology. Recently, next-generation sequencing (NGS)-based methods, which assess DNA methylation at single-base resolution, have become more affordable and technically feasible. While the content of microarray technology is fixed, NGS-based approaches, such as the Roche Nimblegen, SeqCap Epi Enrichment System (SeqCap), offer the flexibility of targeting most CpGs in a gene.

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  • Research shows that children exhibit sex-specific differences in disease prevalence, onset age, and susceptibility, potentially linked to DNA methylation variations.
  • A meta-analysis of 8438 newborns and 4268 older children found significant differences in DNA methylation at nearly 47,000 CpG sites, with males generally showing lower methylation than females.
  • The study identified additional methylation sites related to conditions like cancer and psychiatric disorders, emphasizing the role of DNA methylation in understanding health disparities between sexes.
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Smoking-associated DNA methylation (DNAm) signatures are reproducible among studies of mostly European descent, with mixed evidence if smoking accelerates epigenetic aging and its relationship to longevity. We evaluated smoking-associated DNAm signatures in the Costa Rican Study on Longevity and Healthy Aging (CRELES), including participants from the high longevity region of Nicoya. We measured genome-wide DNAm in leukocytes, tested Epigenetic Age Acceleration (EAA) from five clocks and estimates of telomere length (DNAmTL), and examined effect modification by the high longevity region.

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Cognitive skills are a strong predictor of a wide range of later life outcomes. Genetic and epigenetic associations across the genome explain some of the variation in general cognitive abilities in the general population and it is plausible that epigenetic associations might arise from prenatal environmental exposures and/or genetic variation early in life. We investigated the association between cord blood DNA methylation at birth and cognitive skills assessed in children from eight pregnancy cohorts within the Pregnancy And Childhood Epigenetics (PACE) Consortium across overall (total N = 2196), verbal (total N = 2206) and non-verbal cognitive scores (total N = 3300).

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Importance: Essential workers in agriculture and food production have been severely affected by the ongoing COVID-19 pandemic.

Objective: To identify risk factors associated with SARS-CoV-2 infection among farmworkers in California.

Design, Setting, And Participants: This cross-sectional study invited farmworkers in California's Salinas Valley (Monterey County) receiving transcription-mediated amplification (TMA) tests for SARS-CoV-2 infection at federally qualified community clinics and community sites to participate.

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Exposures to phthalates, parabens, and other phenols are often correlated due to their ubiquitous use in personal care products and plastics. Examining these compounds as a complex mixture may clarify inconsistent relationships between individual chemicals and childhood adiposity. Using data from the Center for the Health Assessment of Mothers and Children of Salinas (CHAMACOS) study, a longitudinal cohort of children in Salinas Valley, California ( = 309), we examined biomarkers of 11 phthalate metabolites and 9 phenols, including several parabens and bisphenol A, measured in maternal urine at two time points during pregnancy.

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During the ongoing coronavirus disease (COVID-19) pandemic, farmworkers in the United States are considered essential personnel and continue in-person work. We conducted prospective surveillance for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and antibody prevalence among farmworkers in Salinas Valley, California, during June 15-November 30, 2020. We observed 22.

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Article Synopsis
  • DNA methylation in childhood and adolescence shows significant correlations with body mass index (BMI), suggesting potential early indicators of obesity.
  • Analysis involved cord blood and whole blood measurements from up to 4,133 children in various studies, indicating the importance of age-specific patterns in dietary and physical health.
  • Findings reveal that as children age, the strength of the associations between DNA methylation and BMI increases, emphasizing the potential for using methylation patterns in obesity prevention strategies.
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Background: Preterm birth and shorter duration of pregnancy are associated with increased morbidity in neonatal and later life. As the epigenome is known to have an important role during fetal development, we investigated associations between gestational age and blood DNA methylation in children.

Methods: We performed meta-analysis of Illumina's HumanMethylation450-array associations between gestational age and cord blood DNA methylation in 3648 newborns from 17 cohorts without common pregnancy complications, induced delivery or caesarean section.

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Article Synopsis
  • Birthweight is linked to health outcomes throughout life, and DNA methylation may play a significant role, as shown in a meta-analysis involving 8,825 neonates.
  • The study identified 914 DNA methylation sites in neonatal blood associated with birthweight, revealing a weight difference from -183 to 178 grams per 10% increase in methylation.
  • Although some of the methylation changes related to birthweight were also seen in childhood, they did not persist into adulthood, suggesting the need for further research to clarify the causal relationships involved.
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Lipids play a role in many biological functions and the newly emerging field of lipidomics aims to characterize the varying classes of lipid molecules present in biological specimens. Animal models have shown associations between maternal dietary supplementation with fatty acids during pregnancy and epigenetic changes in their offspring, demonstrating a mechanism through which prenatal environment can affect outcomes in children; however, data on maternal lipid metabolite levels during pregnancy and newborn DNA methylation in humans are sparse. In this study, we assessed the relationship of maternal lipid metabolites measured in the blood from pregnant women with newborn DNA methylation profiles in the Center for the Health Assessment of Mothers and Children of Salinas cohort.

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Epigenetic mechanisms have emerged as an important pathway through which environmental exposures can affect health through the regulation of gene expression without changes in DNA sequence: microRNAs (miRNAs) are short non-coding RNAs that target protein-coding mRNAs, leading to post-transcriptional repression. They are involved in important physiologic processes, but little is known about how miRNA expression may change with age in children. We used an nCounter miRNA assay to assess the expression of 43 miRNAs in buffy coat samples collected from newborns ( = 121) and 7-year-old ( = 142) children.

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Objective: Little is known about the impact of the home environment on biomarkers of obesity, such as adipokines, in children. In this study, we examined the relationship of maternal depressive symptoms and potentially protective social factors, including maternal support and the home learning environment, with body mass index and adipokines.

Methods: Data were obtained from 326 Mexican American participants from the Center for the Health Assessment of Mothers and Children of Salinas cohort.

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Phthalates are known endocrine disruptors and found in almost all people with several associated adverse health outcomes reported in humans and animal models. Limited data are available on the relationship between exposure to endocrine disrupting chemicals and the human metabolome. We examined the relationship of metabolomic profiles in plasma and urine of 115 pregnant women with eleven urine phthalate metabolites measured at 26 weeks of gestation to identify potential biomarkers and relevant pathways.

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PON1 is a multifunctional enzyme involved in oxidative stress and detoxification of some organophosphate (OP) pesticides. It has been associated with nervous system diseases like Alzheimer's disease, amyotrophic lateral sclerosis, Parkinson's disease, and autism. We previously found that PON1 susceptible genotypes were associated with lower IQ scores in children.

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Background: 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin (TCDD) is proposed to interfere with fetal growth via altered activity of the aryl hydrocarbon receptor (protein: AHR; gene: AHR) pathway which regulates diverse biological and developmental processes including xenobiotic metabolism. Genetic variation in AHR is an important driver of susceptibility to low birthweight in children exposed to prenatal smoking, but less is known about these genetic interactions with TCDD, AHR's most potent xenobiotic ligand.

Methods: The Seveso Women's Health Study (SWHS), initiated in 1996, is a cohort of 981 Italian women exposed to TCDD from an industrial explosion in July 1976.

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Article Synopsis
  • * A study comparing DNA methylation data from both platforms using whole blood samples from newborns and 14-year-olds found high overall correlation between the two chips (r > 0.99), but some individual CpG sites showed lower correlations and notable differences in mean methylation between platforms.
  • * Differentially methylated positions between genders were consistently replicated across both platforms, suggesting their combined use in population studies is promising,
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Aim: Imprinted genes exhibit expression in a parent-of-origin-dependent manner and are critical for child development. Recent limited evidence suggests that prenatal exposure to phthalates, ubiquitous endocrine disruptors, can affect their epigenetic dysregulation.

Materials & Methods: We quantified DNA methylation of nine imprinted gene differentially methylated regions by pyrosequencing in 296 cord blood DNA samples in a Mexican-American cohort.

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Background: Maternal social environmental stressors during pregnancy are associated with adverse birth and child developmental outcomes, and epigenetics has been proposed as a possible mechanism for such relationships.

Methods: In a Mexican-American birth cohort of 241 maternal-infant pairs, cord blood samples were measured for repeat element DNA methylation ( and ). Linear mixed effects regression was used to model associations between indicators of the social environment (low household income and education, neighborhood-level characteristics) and repeat element methylation.

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Pre-pregnancy maternal obesity is associated with adverse offspring outcomes at birth and later in life. Individual studies have shown that epigenetic modifications such as DNA methylation could contribute. Within the Pregnancy and Childhood Epigenetics (PACE) Consortium, we meta-analysed the association between pre-pregnancy maternal BMI and methylation at over 450,000 sites in newborn blood DNA, across 19 cohorts (9,340 mother-newborn pairs).

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Epigenetic changes such as DNA methylation may be a molecular mechanism through which environmental exposures affect health. Phthalates are known endocrine disruptors with ubiquitous exposures in the general population including pregnant women, and they have been linked with a number of adverse health outcomes. We examined the association between in utero phthalate exposure and altered patterns of cord blood DNA methylation in 336 Mexican-American newborns.

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BackgroundAlthough experiments in animals suggest that phthalates may have obesogenic effects, studies on prenatal exposure in children show inconsistent results.MethodsWe measured urinary concentrations of 11 phthalate metabolites collected twice during pregnancy from mothers participating in the Center for the Health Assessment of Mothers and Children of Salinas (CHAMACOS) cohort study (N=345). Height, weight, waist circumference, and percent body fat were assessed in their children between 5 and 12 years of age.

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