| Group | Number of CCP sheets handled per day | % Respondents with symptoms |
|---|---|---|
| 1 | <100 | 57.6 |
| 2 | 100–250 | 66.7 |
| 3 | 250–1,000 | 93.5 |
| 4 | >1,000 | 100 |
Source: Sondergard [1981] as cited by Murray [1991] and Olsen and Mrrck [1985].
The authors suggested that mass psychosis was an unlikely explanation for their findings since an exposure-response relationship was identified—not the all or nothing response expected with mass psychosis. The authors also suggested that mass psychosis was inconsistent with the fact that no relationship existed between the age of the workers and the number of complaints: they would expect younger workers to have the weakest ties to the company and thus to be more likely to report symptoms. In rejecting mass psychosis as an explanation for their findings, the authors suggested that some component of the paper was responsible for the observed symptoms.
Göthe et al. 1981 and Norbäck et al. 1983b. Göthe et al. [1981] and Norbäck et al. [1983b] presented findings about the frequency of respiratory symptoms in three groups of Swedish patients:
- Group A: 19 patients referred to the Clinic of Occupational Medicine at South Hospital
- Group B: 38 patients at the Karolinska Clinic of Occupational Dermatology
- Group C: a random sample of 22 patients with no CCP exposure
The patients in Groups A and B were referred during the period January 1976 to October 1980 because of health problems associated with occupational handling of CCP. However, because the authors did not describe the population from which the patients were referred, population prevalence rates could not be calculated. Among patients with health complaints from handling CCP, roughly half reported irritative symptoms involving the eyes or upper respiratory tract, and 11% (Group A) to 28% (Group B) experienced nasal catarrh or congestion. In the unexposed group (Group C), 14% experienced ocular or upper respiratory irritation, and there were no cases of nasal catarrh or congestion. The difference in incidence between the exposed groups (A and B) and the unexposed group (C) was statistically significant (P<0.01) for eye and upper respiratory irritation. The elevated incidence of nasal catarrh or congestion was statistically significant (P<0.01) in Group B but not in Group A relative to the unexposed Group C. Symptoms such as headache, fatigue, nausea, and a metallic taste in the mouth occurred at a low rate (1% to 9%), with no statistically demonstrable correlation with the type of exposure or the volume of CCP handled. The results in Table 4-7 contrast patients in a high-exposure group (≥150 sheets per day) with those in a low-exposure group
