Clinical Findings in Subjects with Workplace Moisture Damage Related Symptoms

Indoor air quality problems are considered important health risk worldwide and in Finland, they have caused public concern about permanent health deterioration. In epidemiological studies, it has been observed that indoor moisture damage (MD) exposure is associated with respiratory health effects, such as upper respiratory tract symptoms, the development of asthma and asthma deterioration. These studies have mainly focused on children’s risk of asthma and other respiratory tract symptoms and on exposure at home or in schools. Some previous research has also established a temporal relationship between workplace MD exposure and asthma and rhinitis symptoms. However, due to a lack of clinical research, there has been a gap in knowledge at the individual level about the conditions and findings that underlie MD-associated symptoms when asthma, rhinosinusitis, or other symptom explanatory illnesses are not found.

The aim of this thesis was to describe the patient characteristics, the prevalence of different symptoms, and the clinical findings in secondary healthcare, among patients with workplace MD-associated respiratory tract or voice symptoms. The special interest was in improving the differential diagnostics among asthma, laryngeal findings, and multiple chemical sensitivity (MCS). Comprehensive clinical tests were used to diagnose respiratory tract illnesses. The findings of laboratory and allergy tests from the study patients were compared to those of the symptomless subjects. The frequency of MCS among the study patients was assessed with a questionnaire and compared to MCS prevalence in a control population randomly selected by the Finnish Population Information System.

The final study population consisted of 99 patients. Regarding workplace associated symptoms, 99% of the patients reported hoarseness or loss of voice, 85% reported a runny or stuffy nose, 92% reported coughing, and 86% reported dyspnoea. New-onset asthma with a temporal association with workplace MD exposure was diagnosed in one-third of the study patients. Laryngeal dysfunction was found in one-third and organic laryngeal changes in 22% of the patients, and these were common among patients both with and without asthma. Of the patients, 11% had chronic rhinosinusitis but none were diagnosed with acute bacterial rhinosinusitis.

Allergic sensitization was equally common in the study patients as in the 48 symptomless subjects. Minor clinically insignificant differences in blood counts were seen in the comparison between the study patients and the symptomless subjects. Among the study patients, elevated neutrophil counts were found in 19% with and 2% without asthma (p=0.003). The levels of CRP and ESR were low, and the study patients’ FeNO, total IgE, and allergic sensitization were not increased compared to the symptomless subjects indicating a low probability of inflammatory processes or infections explaining the symptoms. Other serious illnesses such as hypersensitivity pneumonitis were not found.

The study patients had high scores significantly more often in chemical intolerance (39% vs. 23%, p=0.001) indicating a higher degree of MCS than among the population controls. Additionally, symptom severity (60% vs. 27%, p < 0.001) and life impact (53% vs. 20%, p < 0.001) with MCS were perceived as more significant among the study patients than among the population controls. Among the study patients, asthma, chronic rhinosinusitis, laryngeal problems, and allergic sensitization were not associated with the presence of MCS.

In conclusion, laryngeal findings were rather common among patients with workplace MD-associated respiratory tract or voice symptoms. Thus, proper differential diagnostics with lung function testing and investigations of the larynx and its function are recommended, in cases of prolonged workplace MD- associated respiratory tract or voice symptoms. Regarding upper respiratory tract symptoms, it is recommended to pay attention to the differential diagnosis between acute and chronic sinusitis. There were no basic laboratory or allergy test results characteristic of this patient group. However, inflammatory processes should still be excluded with basic laboratory tests, although the use of allergy tests does not seem necessary when the symptoms are clearly workplace associated. MCS was common among these patients, and it considerably affected their everyday life. MCS should be considered as a possible explanatory factor for MD-associated symptoms.