title: Pop, heavy metal and the blues: secondary analysis of persistent organic pollutants (POP), heavy metals and depressive symptoms in the NHANES National Epidemiological Survey.
abstract: OBJECTIVE
  Persistent environmental pollutants, including heavy metals and persistent organic pollutants (POPs), have a ubiquitous presence. Many of these pollutants affect neurobiological processes, either accidentally or by design. The aim of this study was to explore the associations between assayed measures of POPs and heavy metals and depressive symptoms. We hypothesised that higher levels of pollutants and metals would be associated with depressive symptoms.
  
  
  METHODS
  National Health and Nutrition Examination Survey (NHANES).
  
  
  METHODS
  A total of 15 140 eligible people were included across the three examined waves of NHANES.
  
  
  METHODS
  Depressive symptoms were assessed using the nine-item version of the Patient Health Questionnaire (PHQ-9), using a cut-off point of 9/10 as likely depression cases. Organic pollutants and heavy metals, including cadmium, lead and mercury, as well as polyfluorinated compounds (PFCs), pesticides, phenols and phthalates, were measured in blood or urine.
  
  
  RESULTS
  Higher cadmium was positively associated with depression (adjusted Prevalence Ratios (PR)=1.48, 95% CI 1.16 to 1.90). Higher levels of mercury were negatively associated with depression (adjusted PR=0.62, 95% CI 0.50 to 0.78), and mercury was associated with increased fish consumption (n=5500, r=0.366, p<0.001). In addition, several PFCs (perfluorooctanoic acid, perfluorohexane sulfonic acid, perfluorodecanoic acid and perfluorononanoic acid) were negatively associated with the prevalence of depression.
  
  
  CONCLUSIONS
  Cadmium was associated with an increased likelihood of depression. Contrary to hypotheses, many of persistent environmental pollutants were not associated or negatively associated with depression. While the inverse association between mercury and depressive symptoms may be explained by a protective role for fish consumption, the negative associations with other pollutants remains unclear. This exploratory study suggests the need for further investigation of the role of various agents and classes of agents in the pathophysiology of depression.
authors.affiliation: IMPACT Strategic Research Centre, School of Medicine, Deakin University, Geelong, Australia Orygen Youth Health Research Centre, Centre for Youth Mental Health, University of Melbourne, Parkville, Victoria, Australia Barwon Health and the Geelong Clinic, Swanston Centre, Geelong, Victoria, Australia Florey Institute for Neuroscience and Mental Health, Parkville, Australia Department of Psychiatry, University of Melbourne, Parkville, Australia.
authors.forename: Michael
authors.initials: M
authors.lastname: Berk
authors.affiliation: IMPACT Strategic Research Centre, School of Medicine, Deakin University, Geelong, Australia Department of Psychiatry, University of Melbourne, Parkville, Australia.
authors.forename: Lana J
authors.initials: LJ
authors.lastname: Williams
authors.affiliation: Departments of Psychiatry and Pharmacology, University of Toronto, Ontario, Canada Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada.
authors.forename: Ana C
authors.initials: AC
authors.lastname: Andreazza
authors.affiliation: IMPACT Strategic Research Centre, School of Medicine, Deakin University, Geelong, Australia Department of Medicine, NorthWest Academic Centre, The University of Melbourne, St Albans, Victoria, Australia.
authors.forename: Julie A
authors.initials: JA
authors.lastname: Pasco
authors.affiliation: IMPACT Strategic Research Centre, School of Medicine, Deakin University, Geelong, Australia Barwon Health and the Geelong Clinic, Swanston Centre, Geelong, Victoria, Australia Department of Psychiatry, University of Melbourne, Parkville, Australia.
authors.forename: Seetal
authors.initials: S
authors.lastname: Dodd
authors.affiliation: IMPACT Strategic Research Centre, School of Medicine, Deakin University, Geelong, Australia Department of Psychiatry, University of Melbourne, Parkville, Australia.
authors.forename: Felice N
authors.initials: FN
authors.lastname: Jacka
authors.affiliation: IMPACT Strategic Research Centre, School of Medicine, Deakin University, Geelong, Australia Barwon Health and the Geelong Clinic, Swanston Centre, Geelong, Victoria, Australia.
authors.forename: Steven
authors.initials: S
authors.lastname: Moylan
authors.affiliation: Laboratory Services Branch, Ontario Ministry of the Environment, Toronto, Ontario, Canada.
authors.forename: Eric J
authors.initials: EJ
authors.lastname: Reiner
authors.affiliation: National Institute for Translational Medicine, Hospital de Clinicas de Porto Alegre, Porto Alegre, Brazil.
authors.forename: Pedro V S
authors.initials: PV
authors.lastname: Magalhaes
mesh_terms: D000328:Adult; D003863:Depression / Q000139:chemically induced*; D004785:Environmental Pollutants / Q000009:adverse effects* / Q000032:analysis; D062665:Epidemiological Monitoring; D005260:Female; D006306:Health Surveys; D006801:Humans; D008297:Male; D019216:Metals, Heavy / Q000009:adverse effects* / Q000032:analysis; D008875:Middle Aged; D009930:Organic Chemicals / Q000009:adverse effects* / Q000032:analysis
chemical_list: D004785:Environmental Pollutants; D019216:Metals, Heavy; D009930:Organic Chemicals
keywords: MENTAL HEALTH