Table 1

Inclusion and exclusion criteria of study

 Age and genderAge 25–58 years, female and male
 Symptom definition*(A) Self-reported symptoms attributed to indoor work environment (non-industrial workplaces) include (1) respiratory symptoms, and (2) symptoms in at least one of the other organ systems,
(B) Symptoms recurrently (1) occur in more than one indoor environment, or (2) continue despite measures at the workplace to solve the indoor air problem (eg, work arrangements and/or workplace reparations), and
(C) Symptoms are not adequately explained by medical reasons (symptoms are medically unexplained)†
 Symptom durationOnset of recurrent symptoms with disability of ≤3 years before the study
 WorkEmployed for ≥3 years before the study
 Sick leaveAt least 1 day of sick leave due to indoor air symptoms during the preceding 6 months
 LanguageFluent Finnish (writing/reading/speaking)
 Sick leave duration≥6 months of sick leave due to indoor air symptoms during the preceding 2 years and currently unable to work
 Changes in workChanges in work (eg, retirement, study leave, pregnancy, etc.) during the study
 Medical reasons†Some serious and/or acute untreated medical disease or illnesses:
  1. Somatic disease that explains the symptoms (eg, uncontrolled asthma, and/or disease causing disability)

  2. Psychiatric disorder (depression, moderate or severe; bipolar disorder; psychotic disorders; obsessive-compulsive disorders; eating disorders; and/or severe personality disorders)

  3. Alcohol and/or drug dependency or abuse

  4. Developmental disorders

 PsychotherapyPsychotherapy (current or ended during two preceding years)
 OtherPatient refusal; not actively participating in work life (retired or unemployed)
  • *IEI-criteria modified from Lacour et al.15

  • †Based on evaluation of occupational physician. Other criteria may also be evaluated by occupational health nurse.

  • IEI, idiopathic environment intolerance.