Professional Education

  • Doctor of Philosophy, University of California, Berkeley, Environmental Health Sciences & Designated Emphasis in Computational and Genomic Biology (2022)
  • Master of Public Health, University of California, Berkeley, Environmental Health Sciences (2019)
  • Bachelor of Science, University of California, Davis, Environmental Toxicology & Minor in Communication (2016)

Stanford Advisors

All Publications

  • Infant Feeding Practices and Metal Concentrations in Children's Blood. JAMA network open Smith, A. R., Thilakaratne, R., Lin, P. D., Rifas-Shiman, S. L., Hivert, M., Oken, E., Cardenas, A. 2023; 6 (12): e2348230


    This cohort study assesses the association between 4 infant feeding practices and concentrations of 8 nonessential and 7 essential metals in red blood cells.

    View details for DOI 10.1001/jamanetworkopen.2023.48230

    View details for PubMedID 38109115

  • Associations between prenatal blood metals and vitamins and cord blood peptide hormone concentrations ENVIRONMENTAL EPIDEMIOLOGY Smith, A. R., Lin, P. D., Rifas-Shiman, S. L., Switkowski, K. M., Fleisch, A. F., Wright, R. O., Coull, B., Oken, E., Hivert, M., Cardenas, A. 2023; 7 (6)
  • The prenatal environment and its influence on maternal and child mitochondrial DNA copy number and methylation: A review of the literature. Environmental research Smith, A. R., Hinojosa Briseno, A., Picard, M., Cardenas, A. 2023; 227: 115798


    Mitochondrial DNA (mtDNA) is sensitive to environmental stressors and associated with human health. We reviewed epidemiological literature examining associations between prenatal environmental, dietary, and social exposures and alterations in maternal/child mtDNA copy number (mtDNAcn) and mtDNA methylation. Evidence exists that prenatal maternal exposures are associated with alterations in mtDNAcn for air pollution, chemicals (e.g. metals), cigarette smoke, human immunodeficiency virus (HIV) infection and treatment. Evidence for their associations with mtDNA methylation was limited. Given its potential implications as a disease pathway biomarker, studies with sufficient biological specificity should examine the long-term implications of prenatal and early-life mtDNA alterations in response to prenatal exposures.

    View details for DOI 10.1016/j.envres.2023.115798

    View details for PubMedID 37001851

  • Associations of Prenatal First Trimester Essential and Nonessential Metal Mixtures with Body Size and Adiposity in Childhood. Epidemiology (Cambridge, Mass.) Smith, A. R., Lin, P. D., Rifas-Shiman, S. L., Wright, R. O., Coull, B., Hivert, M. F., Hubbard, A., Oken, E., Cardenas, A. 2023; 34 (1): 80-89


    Prenatal nonessential metals may contribute to postnatal adiposity, whereas essential metals may have metabolic benefits. We evaluated joint and individual associations between prenatal metals and childhood adiposity.We measured concentrations of six nonessential (arsenic, barium, cadmium, cesium, lead, and mercury) and four essential (magnesium, manganese, selenium, and zinc) metals in first trimester maternal blood from a prebirth cohort. We collected anthropometric measures in early childhood, mid-childhood, and early adolescence including subscapular+tricep skinfold thickness (mm) (N = 715-859), waist circumference (cm) (N = 717-882), and body mass index (BMI) (z-score) (N = 716-875). We measured adiposity in mid-childhood and early adolescence using bone densitometry total- and trunk- fat mass index (kg/m2) (N = 511-599). We estimated associations using adjusted quantile g-computation and linear regression.The nonessential metal mixture was associated with higher total (β = 0.07, 95% CI = 0.01, 0.12) and trunk fat mass index (β = 0.12, CI = 0.02, 0.22), waist circumference (β = 0.01, CI = 0.00, 0.01), and BMI (β = 0.24, CI = 0.07, 0.41) in mid-childhood, and total fat mass index (β = 0.07, CI = 0.01, 0.14), and BMI (β = 0.19, CI = 0.02, 0.37) in early adolescence. The essential metal mixture was associated with lower early adolescence total-(β = -0.11, CI = -0.17, -0.04) and trunk- fat mass index (β = -0.13, CI = -0.21, -0.05), subscapular+tricep skinfold thickness (β = -0.02, CI = -0.03, -0.00), waist circumference (β = -0.003, CI = -0.01, -0.00), and BMI (β = -0.16, CI = -0.28, -0.04). Cadmium and cesium were individually associated with childhood adiposity at different timepoints.Prenatal first-trimester essential metals were associated with lower childhood adiposity, whereas nonessential metals were associated with higher adiposity into adolescence.

    View details for DOI 10.1097/EDE.0000000000001560

    View details for PubMedID 36455248

  • Comparison of DNA methylation measurements from EPIC BeadChip and SeqCap targeted bisulphite sequencing in PON1 and nine additional candidate genes EPIGENETICS Khodasevich, D., Smith, A. R., Huen, K., Eskenazi, B., Cardenas, A., Holland, N. 2022: 1-12


    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. With the current usage of microarrays and emerging NGS-based technologies, it is important to establish whether data generated from the two platforms are comparable. We harnessed 112 samples from the Center for the Health Assessment of Mothers and Children of Salinas (CHAMACOS) birth cohort study and compared DNA methylation between the EPIC microarray and SeqCap for PON1 and nine additional candidate genes, by evaluating epigenomic coverage and correlations. We conducted multivariable linear regression and principal component analyses to assess the ability of the EPIC array and SeqCap to detect biological differences in gene methylation by the PON1-108 single nucleotide polymorphism. We found an overall high concordance (r = 0.84) between SeqCap and EPIC DNA methylation, among highly methylated and minimally methylated regions. However, substantial disagreement was present between the two methods in moderately methylated regions, with SeqCap measurements exhibiting greater within-site variation. Additionally, SeqCap did not capture PON1 SNP associated differences in DNA methylation that were evident with the EPIC array. Our findings indicate that microarrays perform well for analysing DNA methylation in large cohort studies but with limited coverage.

    View details for DOI 10.1080/15592294.2022.2091818

    View details for Web of Science ID 000820075200001

    View details for PubMedID 35786310

  • Dietary intake and household exposures as predictors of urinary concentrations of high molecular weight phthalates and bisphenol A in a cohort of adolescents. Journal of exposure science & environmental epidemiology Smith, A. R., Kogut, K. R., Parra, K., Bradman, A., Holland, N., Harley, K. G. 2022; 32 (1): 37-47


    Phthalates and bisphenol A (BPA) are endocrine disrupting chemicals used in consumer products, building materials, and food processing and packaging materials. They are associated with adverse health outcomes, especially when exposure occurs during heightened windows of susceptibility.We evaluated the relationship between housing and dietary characteristics and the concentration of several high-molecular-weight (HMW) phthalate metabolites and BPA in a cohort of Latina adolescents.We collected information on recent food consumption and housing characteristics and quantified the concentration of HMW phthalate and BPA metabolites in urine collected at two different time points. We used generalized estimating equations (GEE) to assess predictors of each metabolite.No significant associations were observed between housing and dietary characteristics and metabolites of di(2-ethylhexyl) phthalate (DEHP) or BPA. In contrast, higher urinary monobenzyl phthalate (MBzP) concentration was associated with living in a home with vinyl or linoleum flooring (66.7% change, p-value <0.01), while higher urinary mono(3-carboxypropyl) phthalate (MCPP) concentration was associated with recent consumption of coffee (47.2% change, p-value <0.01), and fast food (30.3% change, p-value <0.05).These findings may be useful in targeting interventions that reduce phthalate uptake in young adults.

    View details for DOI 10.1038/s41370-021-00305-9

    View details for PubMedID 33619365

    View details for PubMedCentralID PMC8380263

  • Prospective Associations of Early Pregnancy Metal Mixtures with Mitochondria DNA Copy Number and Telomere Length in Maternal and Cord Blood ENVIRONMENTAL HEALTH PERSPECTIVES Smith, A. R., Lin, P. D., Rifas-Shiman, S. L., Rahman, M. L., Gold, D. R., Baccarelli, A. A., Henn, B., Amarasiriwardena, C., Wright, R. O., Coull, B., Hivert, M., Oken, E., Cardenas, A. 2021; 129 (11): 117007


    Metal exposure during pregnancy influences maternal and child health. Oxidative stress and inflammation may mediate adverse effects of heavy metals, whereas essential metals may act as antioxidants. Mitochondrial DNA is a prime target for metal-induced oxidative damage. Telomere dysfunction is attributed to imbalances between reactive oxidant species and antioxidants.We evaluated individual and joint associations of prenatal metals with mitochondrial DNA copy number (mtDNAcn) and telomere length (TL) in maternal and cord blood as biomarkers of inflammation and oxidative stress.We measured six nonessential metals (arsenic, barium, cadmium, cesium, lead, mercury) and four essential metals (magnesium, manganese, selenium, zinc) in first-trimester maternal red blood cells in Project Viva, a U.S. prebirth cohort. We measured relative mtDNAcn (n=898) and TL (n=893) in second-trimester maternal blood and mtDNAcn (n=419) and TL (n=408) in cord blood. We used multivariable linear regression and quantile g-computation to estimate associations between prenatal metals and the biomarkers. We used generalized additive models and Bayesian kernel machine regression to examine nonlinearity and interactions.A 2-fold increase in maternal magnesium was associated with lower maternal [β=-0.07, 95% confidence interval (CI): -0.10, -0.01] and cord blood (β=-0.08, 95% CI: -0.20, -0.01) mtDNAcn. Lead was associated with higher maternal mtDNAcn (β=0.04, 95% CI: 0.01, 0.06). Selenium was associated with longer cord blood TL (β=0.30, 95% CI: 0.01 0.50). An association was observed between the nonessential metal mixture and higher maternal mtDNAcn (β=0.04, 95% CI: 0.01, 0.07). There was a nonlinear relationship between cord blood mtDNAcn and magnesium; maternal mtDNAcn and barium, lead, and mercury; and maternal TL and barium.Maternal exposure to metals such as lead, magnesium, and selenium was associated with mtDNAcn and TL in maternal second trimester and cord blood. Future work will evaluate whether these biomarkers are associated with child health.

    View details for DOI 10.1289/EHP9294

    View details for Web of Science ID 000726754800012

    View details for PubMedID 34797165

    View details for PubMedCentralID PMC8604047

  • Cannabis Exposure During Critical Windows of Development: Epigenetic and Molecular Pathways Implicated in Neuropsychiatric Disease CURRENT ENVIRONMENTAL HEALTH REPORTS Smith, A., Kaufman, F., Sandy, M. S., Cardenas, A. 2020; 7 (3): 325-342


    Cannabis exposure during critical windows of development may have intergenerational physiological consequences disrupting epigenetic programming and marks. This review examines the literature relating to pre-gestational and prenatal cannabinoid exposure and its effect on genes and molecular pathways related to the development of psychiatric disease.Developmental cannabis exposure alters epigenetic processes with functional gene consequences. These include potentially heritable alterations in genes and molecular pathways critical for brain development and associated with autism spectrum disorder (ASD), attention deficit hyperactivity disorder (ADHD), schizophrenia, addiction, and other psychiatric diseases. Cannabis consumption and mental health illness in adolescents and young adults are increasing in the United States (U.S.), and recent studies suggest that cannabis consumption during critical periods of brain development could contribute to mental health illness through epigenetic mechanisms. These findings warrant future studies and consideration by regulators and health communicators.

    View details for DOI 10.1007/s40572-020-00275-4

    View details for Web of Science ID 000538169400001

    View details for PubMedID 32441004

    View details for PubMedCentralID PMC7458902