Göran Stridh

Nasal hyperreactivity among teachers in a school with a long history of moisture problems.

Upper airway symptoms have frequently been reported in people working or residing in damp buildings. However, little information has been available on objective pathophysiologic findings in relation to these environments. Twenty-eight teachers, who had worked for at least five years in a recently renovated school that had had severe moisture problems for years, were randomly selected for this study. Eighteen teachers, who had worked in another school that had no moisture problems, were randomly selected to serve as the control group. Although remedial measures had been taken, an increase in the prevalence of mucous membrane irritations was still reported by the teachers in the target school. We used a nasal challenge test with three concentrations of histamine (1, 2 and 4 mg/mL). Recordings of swelling of the nasal mucosa were made with rhinostereometry, a very accurate optical non-invasive method. The growth curves of mucosal swelling induced by the three concentrations of histamine differed significantly between the two groups (p < 0.01). The frequencies of atopy, evaluated with the skin-prick test, were almost identical in both groups. The study indicates that long-term exposure to indoor environments with moisture problems may contribute to mucosal hyperreactivity of the upper airways. Such hyperreactivity also seems to persist for at least one year after remedial measures have been taken.

Effects on human eyes caused by experimental exposures to office dust with and without addition of aldehydes or glucan

UNLABELLED Thirty-six volunteers (in three susceptibility groups: 11 subjects were non-allergic with nasal histamine hypersensitivity, 13 were non-allergic with normal sensitivity, and 12 were pollen allergic with or without nasal hypersensitivity) were exposed for three and a half hours in a climate chamber. Each subject was exposed to clean air (dust 45 +/- 38 microg/m(3) total suspended particle, TSP), house dust at 357 +/- 180 microg/m(3) TSP, house dust 382 +/- 175 microg/m(3) TSP with added glucan (50 ng/m(3)) and house dust 394 +/- 168 microg/m(3) TSP with added aldehydes corresponding to a gaseous phase of 300 microg/m(3) in the air. The study was explorative by nature. No significant effects of exposures as such were seen on break-up time, conjunctival epithelial damage score and Trolox Equivalent Antioxidant Capacity (TEAC) in tear film and subjective ratings. However, in TEAC a significant different time course was seen during exposures to aldehyde-containing dust indicating a subacute and late response to the exposures. Perceived eye irritation increased significantly during exposures to normal dust. The perception ratings were highly correlated, whereas no correlation was found between the subjective responses and the objective measurements. PRACTICAL IMPLICATIONS The findings indicate that measurement effects on the eyes are rather insensitive measures of short time effects of office dust exposures.

Dose-Response Study of Formaldehyde on Nasal Mucosa Swelling. A Study on Residents with Nasal Distress at Home

Despite great effort, it has been difficult to demonstrate in an objective way any impact of sick building environment on affected individuals. The aim of this study was to learn whether or not it is possible with rhinostereometry to register changes in the nasal mucosa swelling at exposure to formaldehyde in concentrations 0–0.174 mg/m3. Seven persons, non-allergic, otherwise healthy, and with a history of nasal distress in their homes, participated in the study. Six healthy persons, without nose problems, were controls. Each person was exposed to formaldehyde in different concentrations during two hours in a climate chamber. Increased swelling was recorded al the two highest concentrations (0.073 and 0.174 mg/m3) in the symptomatic group. The control group did not show any mucosal swelling. It was possible to demonstrate an increased mucosal swelling that must be attributed to exposure to formaldehyde. This was possible at formaldehyde concentrations close to the (0.125 mg/m3) upper limit for indoor climate recommended by the World Health Organization (WHO). The study model can be considered useful for further investigations of the impact on the individual from other airborne irritants connected to sick building environments.

Nasal hyperresponders and atopic subjects report different symptom intensity to air quality : a climate chamber study

UNLABELLED Short-term exposure to dust and dust added with beta-(1,3)-d-glucan or aldehydes may cause sensory reactions. In random order, we exposed 36 volunteers in a climate chamber to clean air, office dust, dust with glucan, and dust with aldehydes. Three groups of subjects were exposed, eleven were non-atopic with nasal histamine hyperreactivity, 13 were non-atopic, and 12 were atopic. Subjective ratings of symptoms and general health were registered four times during four 6-h exposure sessions. Six symptom intensity indices were constructed. The nasal hyperreactive group had a high and time-dependent increase of mucous membrane irritations, whereas the atopic group had a low and stable rate of irritations with exposure time, close to the reference group (P = 0.02 for differences between the groups with respect to time under exposure for Weak Inflammatory Responses and P = 0.05 for Irritative Body Perception, significance mainly because of the nasal hyperreactive group). Exposure to dust, with or without glucan or aldehydes, showed increased discomfort measured by the index for Constant Indoor Climate, and dust with glucan had a similar effect for the index for Lower Respiratory Effects. For Psychological and Neurological Effects these were dependent on group affiliation, thus preventing a uniform statement of exposure effects for all three investigated groups. PRACTICAL IMPLICATIONS Opportunities for identifying persons with high or low sensitivity to low-level exposures are important in preventive medicine and will reduce intra-group variability and thus increase the power of experimental and epidemiological studies searching for correlations between exposures and health effects. The contrast between nasal hyperreactive on one side and atopic and reference subjects on the other side is particularly important. The atopic group indicated a non-homogenous reaction depending on their hyperreactive status, a finding that could be important but needs further confirmation.

Nasal mucosal histamine reactivity among young students and teachers, having no or prolonged exposure to a deteriorated indoor climate.

Background: In a study performed in the spring of 1995, we found a significantly greater nasal mucosal histamine reactivity among teachers, who had worked for several years in a recently renovated moisture‐damaged school, than in those in a control school. In the present study we investigated the students who begun their high‐school studies at both schools in the autumn of 1995 and compared them with the teachers as regards mucosal reactivity, atopy and symptoms.