title: Mercury and psychosocial stress exposure interact to predict maternal diurnal cortisol during pregnancy.
abstract: BACKGROUND
  Disrupted maternal prenatal cortisol production influences offspring development. Factors influencing the hypothalamic-pituitary-adrenal axis include social (e.g., stressful life events) and physical/chemical (e.g., toxic metals) pollutants. Mercury (Hg) is a common contaminant of fish and exposure is widespread in the US. No prior study has examined the joint associations of stress and mercury with maternal cortisol profiles in pregnancy.
  
  
  OBJECTIVE
  To investigate potential synergistic influences of prenatal stress and Hg exposures on diurnal cortisol in pregnant women.
  
  
  METHODS
  Analyses included 732 women (aged 27.4 ± 5.6 years) from a Mexico City pregnancy cohort. Participants collected saliva samples on two consecutive days (mean 19.52 ± 3.00 weeks gestation) and reported life stressors over the past 6 months. Hg was assessed in toe nail clippings collected during pregnancy.
  
  
  RESULTS
  There were no main effects of Hg or psychosocial stress exposure on diurnal cortisol (ps > .20) but strong evidence of interaction effects on cortisol slope (interaction B = .006, SE = .003, p = .034) and cortisol at times 1 and 2 (interaction B = -.071, SE = .028, p = .013; B = -.078, SE = .032, p = .014). Women above the median for Hg and psychosocial stress exposure experienced a blunted morning cortisol response compared to women exposed to higher stress but lower Hg levels.
  
  
  CONCLUSIONS
  Social and physical environmental factors interact to alter aspects of maternal diurnal cortisol during pregnancy. Research focusing solely on either domain may miss synergistic influences with potentially important consequences to the offspring.
authors.affiliation: Department of Pediatrics, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1198, New York, NY, 10029, USA. hannah.schreier@mssm.edu.
authors.forename: Hannah M C
authors.initials: HM
authors.lastname: Schreier
authors.affiliation: Department of Preventive Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA. leon.hsu@mssm.edu.
authors.forename: Hsiao-Hsien
authors.initials: HH
authors.lastname: Hsu
authors.affiliation: Department of Preventive Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA. chitra.amarasiriwardena@mssm.edu.
authors.forename: Chitra
authors.initials: C
authors.lastname: Amarasiriwardena
authors.affiliation: Department of Biostatistics, Harvard School of Public Health, Boston, MA, USA. bacoull@gmail.com.|Department of Environmental Health, Harvard School of Public Health, Boston, MA, USA. bacoull@gmail.com.
authors.forename: Brent A
authors.initials: BA
authors.lastname: Coull
authors.affiliation: Division of Research on Public Health, National Institute of Perinatology, Mexico City, Mexico. lschnaas@hotmail.com.
authors.forename: Lourdes
authors.initials: L
authors.lastname: Schnaas
authors.affiliation: Center for Evaluation Research and Surveys, National Institute of Public Health, Cuernavaca, Morelos, Mexico. mmtellez@insp.mx.
authors.forename: Martha María
authors.initials: MM
authors.lastname: Téllez-Rojo
authors.affiliation: Center for Research in Nutrition and Health, National Institute of Public Health, Cuernavaca, Morelos, Mexico. mtamayo@mail.harvard.edu.
authors.forename: Marcela
authors.initials: M
authors.lastname: Tamayo y Ortiz
authors.affiliation: Department of Pediatrics, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1198, New York, NY, 10029, USA. rosalind.wright@mssm.edu.
authors.forename: Rosalind J
authors.initials: RJ
authors.lastname: Wright
authors.affiliation: Department of Preventive Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA. robert.wright@mssm.edu.
authors.forename: Robert O
authors.initials: RO
authors.lastname: Wright
mesh_terms: D000328:Adult; D002940:Circadian Rhythm; D015331:Cohort Studies; D004781:Environmental Exposure; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000378:metabolism*; D008628:Mercury / Q000378:metabolism*; D008800:Mexico / Q000453:epidemiology; D009262:Nails / Q000737:chemistry; D011247:Pregnancy; D012463:Saliva / Q000737:chemistry; D013315:Stress, Psychological / Q000453:epidemiology* / Q000209:etiology; D055815:Young Adult
chemical_list: D008628:Mercury; D006854:Hydrocortisone