PubMed Health⌕ Search

Biomedical subjects

T Hallas

Publications and source records attributed to T Hallas.

9 recordsLinked to original sources
PubMed1990

Mite allergy and exposure to storage mites and house dust mites in farmers.

Sensitization to house dust mites, storage mites and other common inhalation allergens was studied in 144 farmers using SPT and RAST. The study population was selected from a random sample of 808 farmers and consisted of 47 persons who had declared themselves to suffer from asthma, 63 persons who had reported respiratory symptoms, and 34 healthy persons without respiratory symptoms. The most prevalent RAST was towards storage mites and was found in 17% of farmers who suffered from asthma and was estimated to occur in 5% of the random sample of farmers. A positive RAST to house dust mites was found in 17% of farmers who reported to suffer from asthma. Sensitization to pollens, animal dander and grain species was rare. A positive RAST to moulds was not found. There was a strong association between a positive RAST to house dust mites and a positive RAST to storage mites (odds ratio 21.0). A positive RAST to storage mites was significantly associated with living in a dwelling in the past which was recalled as damp (odds ratio 4.9). A high number of house dust mites was found in nearly all dwellings (median count 148 mites/0.1 g dust) and a high number of storage mites was found in some dwellings. This study suggests that in humid and temperate regions of Europe, allergy to storage mites in farmers is not caused exclusively by occupational exposure but damp housing conditions and indoor exposure to storage mites may also be important.

Agriculture↗
PubMed1989

Lung function and bronchial reactivity in farmers.

The purpose of this study was to evaluate the prevalence and type of lung function disorders in Danish farmers. Three samples of farmers were drawn from a group of unselected farmers who had participated in an epidemiological study. Group I (47 persons) was a sample of the 8% of all farmers who had reported that they had asthma; group II (63 persons) was a sample of the 28% of farmers who had had wheezing, shortness of breath, or cough without phlegm; and group III (34 persons) a sample of the farmers (64% of the total) who had no asthma and no respiratory symptoms. The farmers with symptoms (groups I and II) had low mean levels of FEV1 and high values for residual volume, whereas the symptomless farmers had normal lung function and no airways obstruction. The proportion of farmers with an FEV1 below the 95% confidence limit for predicted values was 43% in group I and 23% in group II; there were none in group III. Bronchial hyperreactivity to histamine occurred in 96% of asthmatic farmers, 67% of farmers with wheezing or shortness of breath, and 59% of symptomless farmers. A low level of FEV1 was associated with the number of years in pig farming and bronchial hyperreactivity in group II but not group I or III. Most of the bronchial hyperreactivity was explained in the multiple regression analysis by a low FEV1, though this was significant only for farmers in group II. Thus farmers who reported asthma, wheezing, shortness of breath, or a dry cough in general had airways obstruction with an increased residual volume, whereas symptomless farmers had normal lung function. Severe bronchial hyperreactivity was mostly explained by a diagnosis of asthma and poor lung function, though some farmers with normal lung function and no respiratory symptoms had increased bronchial reactivity.

Adult↗
PubMed1988

Respiratory symptoms in Danish farmers: an epidemiological study of risk factors.

An epidemiological study was performed with a self administered questionnaire in a representative sample of 1685 Danish farmers. The purpose of the study was to assess the prevalence of self reported asthma, wheezing during work, and symptoms of chronic bronchitis and to evaluate possible risk factors for the development of these symptoms. A response rate of 73.3% was obtained. The prevalence of asthma was 7.7% and of chronic bronchitis 23.6% in responders. The prevalence of asthma and chronic bronchitis increased from 3.6% and 17.9% in 31-50 year old farmers to 11.8% and 33.0% in 51-70 year old farmers, and from 5.5% and 17.5% in dairy farmers to 10.9% and 32.0% in pig farmers. A logistic regression analysis with correction for age and smoking habits confirmed that pig farming was a risk factor for asthma (odds ratio 2.03), chronic bronchitis (odds ratio 1.53), and wheezing during work (odds ratio 3.33).

Adult↗
PubMedDate not supplied

A one-year case study of farmers with storage mite allergy.

Four farmers with a positive bronchial challenge test to either L. destructor or T. putrescentiae had bronchial histamine challenge every second month during a year. In the same year, monthly samples of house dust, grain, straw and hay were analyzed for their content of house dust mites and storage mites. The exposure to house dust mites and storage mites differed between farmers. Significant changes in histamine reactivity were found, but no association with time of year or mite counts was observed.

Agriculture↗
PubMedDate not supplied

Storage mites as a cause of bronchial asthma in Denmark.

From October 1982 to July 1983, 133 consecutive patients complaining of allergic symptoms were prick-tested with three storage mites (Acarus siro, Lepidoglyphus destructor, Tyrophagus putrescentiae) and two housedust mites (Dermatophagoides pteronyssinus and Dermatophagoides farinae). A total of 60 patients (45%) had a positive prick-test for one or more of the storage mites. A mutual positive correlation was found between the prick-test results for the two house-dust mites as well as for the three storage mites. No significant correlation was found between house-dust mites and storage mites. Four cases of allergy to storage mites are presented. The diagnosis of storage mite allergy was based on the clinical history, prick-test, bronchial provocation test and the finding of storage mites in the environment of the patient. Our study suggests that allergies to storage mites could be rather frequent in the Danish population.

Adult↗