title: Negative affect is associated with development and persistence of chemical intolerance: a prospective population-based study.
abstract: OBJECTIVE
  Chemical intolerance (CI) is characterised by negative health effects attributed to a heightened responsiveness to common airborne chemicals. This longitudinal study explored the hypothesised role of negative affect in the development and persistence of CI in a general population.
  
  
  METHODS
  A general population sample aged 19 to 72 years was examined in 2006-2008 and again in 2011-2012. Longitudinal data on CI were analysed with the purpose of examining baseline negative affect as a risk factor for having developed CI at 5-year follow-up and for reporting persistent CI. Participants were classified as reporting no signs of CI, having symptoms of CI and as being a likely CI case based on self-reported reactions to 11 common chemical exposures, symptoms related to chemical exposures and daily life adjustments attributed to reactions when exposed to chemicals.
  
  
  RESULTS
  A total of 69.4% of the participants who had reported CI at baseline also reported CI at follow-up. In participants with no baseline CI, 15.5% reported CI at follow-up and 18.1% reported symptoms related to chemicals but no daily life adjustments. Baseline negative affect was positively and statistically significantly associated with both development and persistence of CI.
  
  
  CONCLUSIONS
  Initial reports of CI were found to be persistent over time, and a considerable proportion of the participants with no CI at baseline reported having developed CI after 5 years. The positive association between negative affect and CI at the 5-year follow-up supports negative affect as a possible risk factor for CI.
authors.affiliation: The Research Centre for Prevention and Health, Capital Region, Copenhagen, Denmark. Electronic address: sine.skovbjerg.jakobsen@regionh.dk.
authors.forename: Sine
authors.initials: S
authors.lastname: Skovbjerg
authors.affiliation: Section of Biostatistics, Department of Public Health, University of Copenhagen, Denmark.
authors.forename: Karl Bang
authors.initials: KB
authors.lastname: Christensen
authors.affiliation: The Research Centre for Prevention and Health, Capital Region, Copenhagen, Denmark.
authors.forename: Jeanette Frost
authors.initials: JF
authors.lastname: Ebstrup
authors.affiliation: The Research Centre for Prevention and Health, Capital Region, Copenhagen, Denmark; Department of Clinical Experimental Research, Copenhagen University Hospital Glostrup, Denmark; Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark.
authors.forename: Allan
authors.initials: A
authors.lastname: Linneberg
authors.affiliation: Unit for Psychooncology and Health Psychology, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: Robert
authors.initials: R
authors.lastname: Zachariae
authors.affiliation: The Allergy Clinic, Copenhagen University Hospital, Gentofte, Copenhagen, Denmark.
authors.forename: Jesper
authors.initials: J
authors.lastname: Elberling
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D018777:Multiple Chemical Sensitivity / Q000523:psychology*; D009341:Negativism; D011446:Prospective Studies; D012307:Risk Factors; D057566:Self Report; D012917:Social Adjustment
keywords: Chemical intolerance; Epidemiology; Longitudinal study; Multiple chemical sensitivity; Negative affect