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J Kongerud

Publications and source records attributed to J Kongerud.

69 records · Page 4Linked to original sources
PubMed1992

Bronchial responsiveness and work-related asthma in aluminium potroom workers: effect of removal from exposure.

Twelve subjects relocated from aluminium potrooms due to work-related asthma were followed up for 2-27 months (median 23 months). Repeated post-relocation examinations (numbering 3-7, median 6) of methacholine challenge, forced expiratory volume in one second (FEV1), eosinophil cell count and respiratory symptoms were carried out at regular intervals. At the time of relocation, bronchial hyperresponsiveness (provoking concentration producing a 20% fall in FEV1 (PC20) less than or equal to 8.0 mg.ml-1) was found in eight of the subjects. During the follow-up period a twofold increase in PC20 was found in 7 of the 8 subjects who had PC20 less than 8.0 mg.ml-1 at the time of relocation. There was an improvement of symptoms but no improvement in FEV1 or decrease of eosinophils during the follow-up examinations.

Adult↗
PubMed1991

[Do we have an asthma epidemic?].

The number of persons hospitalized for asthma and mortality from asthma have both shown an increasing tendency in many countries over the last few years. In Norway, 1.4% of the respondents in the 1975 Health Survey conducted by the Central Bureau of Statistics claimed to suffer from asthma. The corresponding number in 1985 was 2.4%. The prevalence of asthma was higher among subjects in rural than in urban communities. There are many sources of error linked to the studies discussed in this paper. Nevertheless, there are certain indications of a real increase in the prevalence of asthma, and analytical studies into the possible causes of this disease should be conducted.

Adolescent↗
PubMed1991

The influence of the helmet respirator on peak flow rate in aluminum potroom.

The efficiency of the Racal Airstream helmet respirator in improving peak expiratory flow rates (PEFR) and symptoms (dyspnea, wheezing, and cough) in aluminum potroom workers with respiratory complaints was assessed in 19 workers. Peak expiratory flow readings and symptom recording from a 2-week working period with use of the respirator were compared with a period when the 3M 9906 disposable mask was used. The study was designed as a randomized, parallel, cross-over study with five or six daily measurements of PEFR and daily symptom recording. A significant number of workers (15) had a higher mean peak flow in the helmet period than in the nonhelmet period (p less than 0.01); symptoms did not improve significantly in the helmet period. Objective evidence of respiratory protection was observed for the group of workers as a whole, but the effect on symptoms as well as individual effect on peak flow was minor in the majority of the workers.

Adult↗
PubMed1991

A longitudinal study of respiratory symptoms in aluminum potroom workers.

The influence of occupational work exposure and host factors on the incidence of dyspnea and wheezing as reported in questionnaires was examined in 1,301 new employees in aluminum electrolytic potrooms. The incidence appeared to decrease after 2 yr of exposure, and the estimated probability of development of symptoms was nearly 20% after 4 yr. A total of 105 subjects developed dyspnea and wheezing. Of 78 symptomatic subjects who were interviewed, 76% experienced improvement or absence of symptoms when off work. In 523 subjects who were assigned to specific levels of exposure at the end of follow-up, a dose-response gradient was found between the development of symptoms and fluoride exposure. Increased risk with increasing amounts of tobacco was also observed, but childhood allergy and a family history of asthma were not significantly related to the outcome variable. We conclude that both total fluoride exposure and smoking are related to asthmatic symptoms in potroom workers, and the suggestion of a dose-response gradient was found for both variables. However, a causal relationship between fluorides and symptoms should be investigated further by specific bronchial provocation testing and by research for specific antibodies and other immunologic markers.

Adult↗
PubMed1991

Methacholine responsiveness, respiratory symptoms and pulmonary function in aluminum potroom workers.

The relationship between nonspecific bronchial reactivity and work-related asthmatic symptoms was examined in a cross-sectional study of 337 aluminium potroom workers by a shortened method of continuous methacholine nebulization. The provocative concentration producing a 20% fall in forced expiratory volume in one second (FEV1) (PC20) was less than or equal to 8 mg.ml-1 (hyperresponsiveness) in 17 workers (5%), whilst minor responsiveness (8 mg.ml-1 less than PC20 less than 32 mg.ml-1) was present in 24 subjects (7%). The prevalence of work-related asthmatic symptoms was 9%. Female sex, ex-smoker and airflow limitation were significant predictors of methacholine responsiveness (p less than 0.05). In a multiple logistic regression analysis the odds ratios (OR) for work-related asthmatic symptoms was 10.8 (95% confidence interval: 2.9-40.6) for hyperresponsiveness and 4.4 (95% confidence interval: 1.2-16.4) for minor responsiveness. The sensitivity, specificity and predictivity of PC20 less than 32 mg.ml-1 for work-related asthmatic symptoms were 35, 92 and 35%, respectively, whilst the agreement, when adjusted for the by chance expectation, was 0.27 (95% confidence interval: 0.10-0.54). Although a significant association was found between bronchial reactivity and work-related asthmatic symptoms, the usefulness of the methacholine test as a tool for detection of work-related asthmatic symptoms appears to be of limited value due to its low sensitivity.

Adult↗
PubMed1990

Respiratory symptoms and lung function of aluminum potroom workers.

The association of occupational exposure with respiratory disease and lung function was examined in a cross-sectional study of 1805 aluminum potroom workers. Work-related asthmatic symptoms occurred in 15% of the workers with an exposure of 10 years or more and in 8% of the workers who had been employed less than five years. In a multiple logistic regression analysis an odds ratio (OR) of 3.4 [95% confidence interval (95% CI) 2.1-5.8] for work-related asthmatic symptoms was estimated for long versus short duration of employment. Airflow limitation was also significantly related to years of exposure (OR 2.6, 95% CI 1.7-3.9). Current occupational exposure and the occurrence of respiratory symptoms were not significantly associated. The results suggest that exposure to air pollutants in the primary aluminum industry may lead to the development of asthmatic symptoms, as well as to reduced respiratory function.

Adult↗
PubMed1989

Questionnaire reliability and validity for aluminum potroom workers.

As a part of a study on the respiratory symptoms of aluminum potroom workers, the reliability of a self-administered questionnaire and an interview questionnaire was studied with the use of 261 and 49 employees, respectively. The validity of the self-administered questionnaire (134 persons examined) and the interview questionnaire (90 persons examined) was assessed in a comparison of the statements with the case histories. The reliability of the self-administered questionnaire was fairly high, the kappa coefficient ranging from 0.58 to 0.83, while the reliability of the interview questionnaire varied from -0.03 to 0.45. The same pattern was present with regard to validity, as the self-administered questionnaire showed the highest mean sensitivity, specificity, and agreement in a comparison with the case histories. The self-administered questionnaire seemed to discriminate well between symptomatic and asymptomatic individuals, whereas supplemental information about symptoms, as obtained by a standardized interview questionnaire, appeared to be less valid.

Adult↗
PubMed1989

Room temperature influences output from the Wright jet nebulizer.

Standardization of the solute output from the Wright nebulizer is necessary in nonspecific bronchial challenge to obtain reproducible results. Airflow and driving pressure are known determinants of the output. In an epidemiological study, in which day-to-day variations in room temperature occurred, we found the reproducibility of the output from a Wright nebulizer to be outside the range of acceptance. We have, therefore, examined to what extent ambient temperature and humidity might influence the output from three Wright nebulizers. The solute output was linearly correlated not only to flow (r = 0.98) and driving pressure (r = 0.90) but also to room temperature (r = 0.96). The mean output increased approximately 23% when room temperature was increased from 19 to 24 degrees C. This is equivalent to an increase in airflow of more than one litre. Ambient humidity did not influence the nebulizer output. When temperature was included in the calibration procedure, the coefficient of variation of the output decreased from 5 to 2%. This emphasizes the need for calibration of the Wright nebulizer with regard to ambient temperature as well as to airflow and pressure, especially in epidemiological field studies in which large variations of temperature are likely to occur.

Bronchodilator Agents↗
PubMed1981

Aging, cigarette smoking and oral theophylline requirement.

In a prospective study in 73 patients with obstructive pulmonary disease, aged 63.5 +/- 13.5 years (SD), it was found that theophylline dose, cigarette smoking and age were all significant determinants of the steady-state trough plasma theophylline level during oral administration of the drug. As the predictive efficiency of the three factors combined amounted only to 25%, firm dosage recommendations cannot be made. Even among elderly patients, tobacco smokers had significantly lower plasma concentrations of theophylline. It is suggested that in order to obtain trough plasma concentrations of 50 mumol/l (approximately equal to 9 micrograms/ml), a non-smoking 50 year-old patient would require 9.8 mg/kg/day of oral theophylline, the dose increasing to 14.2 mg/kg/day in smokers of the same age. These doses should probably be reduced by 15-20% in 75 year-old patients.

Administration, Oral↗
PubMedDate not supplied

Respiratory disorders in aluminium potroom workers.

Epidemiological studies of aluminum potroom workers have been in progress in Norway since 1986. The occurrence of work-related asthmatic symptoms and their determinants were studied. Work-related asthmatic symptoms and airflow limitation were closely associated with duration of potroom employment. A significant relationship between current fluoride exposure and work-related asthmatic symptoms was observed in a smaller, cross-sectional population where a detailed exposure classification was carried out. A similar association and also a dose-response gradient was found in a longitudinal study of new employees. The existence of occupational asthma in aluminium potroom workers was confirmed by characteristic patterns of repeated peak flow measurements supported by changes in methacholine responsiveness in workers with suspected work-related asthma. Current smoking as a risk factor for work-related asthmatic symptoms was observed both in cross-sectional and in longitudinal investigations. Similarly to current fluoride exposure, a dose-response gradient was demonstrated in the association between work-related asthmatic symptoms and current amount of tobacco smoked. Allergy was not shown to be a determinant of work-related asthmatic symptoms in any part of the investigation. A family history of asthma and previous occupational exposure may have had some influence on the risk of developing symptoms but the findings were inconsistent and probably of minor importance. Methacholine challenge seemed inappropriate for the screening of aluminium potroom workers in order to detect work-related asthmatic symptoms, but was closely correlated to the severity of symptoms.(ABSTRACT TRUNCATED AT 250 WORDS)

Aluminum↗