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Biomedical subjects

D A Enarson

Publications and source records attributed to D A Enarson.

At least 19 recordsLinked to original sources
PubMed1992

Five cross-sectional studies of grain elevator workers.

Five cross-sectional studies were conducted on grain workers in all the terminal elevators in British Columbia, Canada, at 3-year intervals from 1976 to 1988. Civic workers were studied in the same manner as a referent group. The studies consisted of questionnaires, spirometry using the same spirometers, allergy skin tests, and measurement of dust concentration by personal sampling. Although the dust concentration in the elevators was reduced progressively over the years, grain workers had more respiratory symptoms and lower lung function compared with the civic workers in each of the five cross-sectional studies. Exposure to grain dust was associated with significant reduction in forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC) but not in maximal midexpiratory flow rate or FEV1/FVC, suggesting reduction in volume which may be due to lesions in the lung parenchyma or in the small airways. Cigarette smoking was associated with significant reduction in FEV1, maximal midexpiratory flow rate, and FEV1/FVC due to airflow obstruction, but had no influence on FVC. Workers who took part in all five surveys tended to be a "healthier" selected group, but the grain workers still had lower lung function compared with the civic workers. This study confirmed previous findings that grain dust has adverse effects on the lungs. Cross-sectional study of the grain elevator workers proved to be a consistent and useful method to evaluate occupational health hazards.

Adult↗
PubMed1992

Deaths in tuberculosis patients in British Columbia, 1980-1984.

Records of all 1884 newly notified tuberculosis cases, over the 5-year period 1980-1984 in British Columbia, Canada, were reviewed and 201 deaths were identified, including 48 diagnosed only after death, and 153 who died while on treatment; 56 of unrelated causes, 67 in whom tuberculosis was a contributing cause, and 30 in whom it was the principal cause. Significant predictors of death while on treatment (specific to tuberculosis) were the extent of disease, history of previous disease and sputum smear-positive for acid-fast organisms. Significant predictors of failure of diagnosis, in patients who died, were the presence of disseminated disease and the absence of a history of previous disease. The presenting features were not different in those dying, in whom the diagnosis was made before, as compared with after, death. The most frequent mode of death due to tuberculosis was respiratory failure, followed by multiple organ system failure and haemoptysis. The case fatality rate was low (1.6%) and did not change over 10 years. One-half of patients whose death was due to tuberculosis were diagnosed only after death and this had not changed over 10 years. We conclude that death due to tuberculosis is uncommon in patients while on treatment and that the main reason for death due to tuberculosis is that some patients are not diagnosed, and therefore not treated, before they die of the disease.

Adult↗
PubMed1992

An estimate of the future size of the tuberculosis problem in sub-Saharan Africa resulting from HIV infection.

The impact of the human immunodeficiency virus (HIV) on tuberculosis is well documented. Its effect in populations with a high proportion of dually infected individuals is likely to be significant. Sub-Saharan Africa is one such region and to better document the effect of HIV infection on tuberculosis there we developed a mathematical model to predict the likely extra numbers of tuberculosis cases due to it. A mathematical model was developed using a variety of scenarios giving a range of risks for the period 1980-2000. The four scenarios included (1) a low rate of 1% risk of tuberculosis infection in year 0 (1980) with 45% tuberculosis infection prevalence, and an HIV prevalence of 2% in 1989; (2) a 2% risk of tuberculosis infection in year 0 with 60% tuberculosis infection prevalence, and a 2% HIV prevalence in 1989; (3) a 2% risk of tuberculosis infection in year 0 with 60% tuberculosis infection prevalence, and a 10% HIV prevalence in 1989; and (4) a 2% risk of tuberculosis infection in year 0 with 60% tuberculosis infection prevalence and a 20% HIV prevalence in 1989. Under scenarios 1 and 2, a 50-60% increase in smear-positive rates in the subpopulation (15-45 years old) is predicted for the year 2000, under scenario 3, smear-positive rates in the subpopulation in the year 2000 are expected to increase four-fold from the 1980 baseline. Under scenario 4, a 10-fold increase in smear-positive rates in 2000 is expected in the subpopulation. Under this scenario, total disease will have increased 12-fold in the subpopulation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Tuberculosis among institutionalized elderly in Alberta, Canada.

Previous studies in the US have suggested that the risk of tuberculosis is increased among elderly residents of nursing homes. This registry-based study determined and compared the tuberculosis incidence rate for the elderly in nursing homes and community dwellings in Alberta, Canada, over the 5-year period 1979-1983. Rate ratios (RR) using the community elderly rate as baseline, were estimated for all notified cases and for culture positive cases only. Adjustment was made for the variables age, sex, and ethnicity. The nursing home elderly in Alberta did not have an increased risk of tuberculosis: adjusted RR = 1.09, 95% CI : 0.38-1.80.

Aged↗
PubMed1992

Adrenocortical function in patients investigated for active tuberculosis.

Previous reports have identified adrenal insufficiency in groups of patients with active pulmonary tuberculosis. To investigate this possibility, serum cortisol levels were measured in consecutive patients admitted to the hospital for investigation of active tuberculosis. Blood was drawn for cortisol determination promptly at the time of hospital admission, in the morning and afternoon before commencing chemotherapy for the suspected tuberculosis, and before the diagnosis was confirmed. Thirty-seven patients were assessed; 19 of these patients were subsequently proven to have active pulmonary tuberculosis, six had pulmonary disease caused by mycobacteria other than tuberculosis, and 12 had radiologic appearance indicating tuberculosis, accompanied by a significant tuberculin skin reaction but with negative sputum cultures and no change in roentgenographic appearance during the course of treatment. In evaluating the adrenocortical function, the morning and afternoon serum cortisol level was measured and the diurnal change in serum cortisol level (the difference between afternoon and morning levels) was calculated. There was no association of either morning cortisol levels or diurnal change in cortisol levels with age, gender, or race. There was no difference among the three groups in either cortisol determination. Although difference in morning cortisol levels between those with extensive as compared with limited disease was not statistically significant (p = 0.349 from analysis of variance), there was a significantly decreased diurnal change in cortisol levels in those with extensive disease as compared with those with limited disease (+2.7 +/- 188.3 vs -259.1 +/- 177.1). We conclude that patients in our hospital with active pulmonary tuberculosis do not exhibit decreased adrenocortical function as compared with groups of patients without active pulmonary tuberculosis.

Adrenal Cortex↗
PubMed1992

A statistical chronicle of tuberculosis in Canada: Part I. From the era of sanatorium treatment to the present.

This report marks over 50 years of publication by Statistics Canada of annual reports on tuberculosis statistics. These years have witnessed what has been described as a conquest of tuberculosis in Canada. To quote George Jasper Wherrett in The Miracle of the Empty Beds: One hundred years ago the word consumption (as tuberculosis was then called) struck horror in human hearts. Today, in the western world, it barely evokes any emotion save a too easy surprise that it still exists. This statistical chronicle of tuberculosis in Canada is divided into two parts. Part I: From the Era of Sanatorium Treatment to the Present pulls together data from yellowed-with-age reports on tuberculosis and vital statistics, historical accounts and modern computer files, to document the changes in tuberculosis incidence and mortality over past decades to the present. Part II: Risk Today and Control takes a closer look at those most vulnerable to contracting tuberculosis. It also looks at the future, the need for maintaining and, indeed, strengthening vigilance, and the work yet to be done to eradicate tuberculosis in Canada. The fight against tuberculosis is far from over.

Adolescent↗
PubMed1992

A statistical chronicle of tuberculosis in Canada: Part II. Risk today and control.

This report marks over 50 years of publication by Statistics Canada of annual reports on Tuberculosis Statistics. These years have witnessed what has been described as a conquest of tuberculosis in Canada. To quote George Jasper Wherrett in the Miracle of the Empty Beds: One hundred years ago the word consumption (as tuberculosis was then called) struck horror in human hearts. Today, in the western world, it barely evokes any emotion save a too easy surprise that it still exists. This statistical chronicle of tuberculosis in Canada is divided into two parts. Part I: From the Era of Sanatorium Treatment to the Present pulls together data from yellowed-with-age reports on tuberculosis and vital statistics, historical accounts, and modern computer files, to document the changes in tuberculosis incidence and mortality over past decades to the present. Part II: Risk Today and Control takes a closer look at those most vulnerable to contracting tuberculosis. It also looks at the future, the need for maintaining and, indeed, strengthening vigilance, and the work yet to be done to eradicate tuberculosis in Canada. The fight against tuberculosis is far from over.

Acquired Immunodeficiency Syndrome↗
PubMed1991

DNA adducts in bronchial biopsies.

To investigate the feasibility of measuring DNA-carcinogen adducts in the lungs of non-surgical patients, endobronchial biopsies were obtained from 78 patients undergoing routine diagnostic bronchoscopy. Lung cancer was present in 37 (47%) of the patients. DNA was isolated from the tissues and analyzed by HPLC- or nuclease-PI-enriched 32P-postlabelling, using procedures selective for aromatic adducts. Chromatograms from all 28 current smokers showed a distinctive diagonal adduct zone which was present in only 24 of 40 ex-smokers and 4 of 10 lifetime non-smokers. Adduct levels and chromatographic patterns were similar in bronchial tissue from different lobes of the lung, in bronchial and alveolar tissue, and in tumor and non-tumor bronchial tissue taken from the same subject. Bronchial DNA adduct levels were strongly associated with cigarette smoking status and dropped rapidly after smoking ceased. Higher levels of DNA adducts seen in the lung-cancer patients were mainly due to cigarette smoking. Frequent alcohol intake was the only dietary factor associated with higher levels of bronchial DNA adducts. We conclude that the level of bronchial DNA adducts is strongly associated with cigarette-smoking history and with alcohol intake, but is not associated with lung cancer independently from its relation to smoking. The results indicate the feasibility of using 32P-postlabelling to detect and quantitate genetic damage in bronchial biopsy specimens.

Aged↗
PubMed1991

First-aid reports of acute chlorine gassing among pulpmill workers as predictors of lung health consequences.

Workers in pulpmills can be exposed to a multitude of gases hazardous to respiratory function, the most common of which is chlorine gas. First-aid reports of acute gas overexposure incidents ("gassings") over an 8 year period were used to generate exposure data on a group of pulpmill workers whose respiratory function had been studied cross-sectionally in 1981 and 1988. Three hundred forty-eight incidents representing 174 workers were identified, 78% of these being treated solely by the first-aid attendant with the administration of O2 and cough suppression medication. Among 316 workers tested during a 1988 respiratory health survey, 78 had at least one chlorine or chlorine dioxide "gassing" incident. There was a significant decrease in the FEV1/FVC ratio (p less than .05) as well as increased risk for workplace associated chest symptoms in this group with at least one "gassing" incident. In an age- and smoking-matched analysis, among workers tested both in 1981 and 1988, there was a greater decline in FEV2/FVC ratio and MMF (p less than .05) in the "gassed" group than in the nonexposed group over the 7 year period of observation. These results emphasize the need for worker protection against accidental chlorine gas exposures.

Analysis of Variance↗
PubMed1991

Tuberculosis in recent Asian immigrants to British Columbia, Canada: 1982-1985.

The prevalence and incidence of active tuberculosis among 21,959 recently arrived (1982-1985) immigrants from 7 selected Asian countries into British Columbia (BC), Canada, were reviewed. Among these newly arrived immigrants, 1173 (5.3%) were judged to have inactive tuberculosis at the immigration examination in their country of origin. In this subgroup, 14 of 932 (1.5%) were found to have active tuberculosis at the initial examination after arrival in Canada. Subsequently, 7 further cases arose in this group of inactive cases giving an average annual incidence rate of 0.33% over the 4-year period of study. Only 3 of these 21 cases had had previous antituberculosis chemotherapy. The remaining 20,786 recent immigrants with normal X-rays at the immigration examination contributed 30 cases during the next 4 years--an average annual incidence rate of 0.08% or 8 times the comparable rate for BC (0.01%). The limitations of the immigration screening process are illustrated and the value of early surveillance of immigrants designated as having inactive tuberculosis is underlined. The apparent failure to exclude active disease prior to the arrival of these immigrants is one factor elevating the incidence of active tuberculosis in the first few years after arrival in the host country. Other factors include the relatively high prevalence of inactive tuberculosis among the immigrants from certain countries and their high rate of early relapse after entry, especially in those not previously treated. Such immigrants should be considered for chemoprophylaxis immediately after entry.

Asia↗
PubMed1991

Lung health consequences of reported accidental chlorine gas exposures among pulpmill workers.

The long-term consequences of accidental chlorine gas exposure have been investigated, mainly in the community setting, among persons exposed as a result of a nearby chlorine spill. This circumstance is not analogous to the more frequent chlorine or chlorine dioxide gas overexposures that occur commonly in pulpmills over a background of a low level of gas exposure. To investigate the respiratory health consequences of these accidental exposures ("chlorine gassing") in the industrial setting, we carried out a cross-sectional respiratory health survey among workers at a British Columbia coastal pulpmill and a nearby rail maintenance yard. A greater proportion of pulpmill workers were unavailable for study because of illness (10.5% versus 2.4% in the railyard, p less than 0.01). Procedures involved simple spirometry, respiratory symptom assessment, and measurement of average levels of air contaminants. Average chlorine levels in the pulpmill were below 1 ppm; however, 60% of the pulpmill workers reported one or more accidental "chlorine gassing" incidents. Pulpmill workers who reported being "gassed" were significantly more likely to report wheezing on occasion than were other pulpmill workers and railyard workers (rate for these three groups: nonsmokers: 8, 2, 1%; ex-smokers: 17, 11, 7%; current smokers: 42, 21, 19%; p less than 0.05). No significant lung function differences were found between the overall pulpmill group and the railyard workers; however, nonsmoking and formerly smoking pulpmill workers who reported being "gassed" had significantly lower average midmaximal flow rate and FEV1/FVC ratio than did their counterparts in the remainder of the pulpmill population (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Accidents, Occupational↗
PubMed1991

Relationship between tuberculin reactivity and hepatitis B virus infection in the Northwest Territories.

Of 370 NWT Inuit or Dene who were HBsAg-positive, only 31 had HBeAg. Persons who were PPD negative were 6.2 times more likely to be HBeAg-positive than those who were PPD positive, but this inverse association applied only to those 30 years of age. We further analyzed a group of 3,378 Inuit whose status was known for HBV serologic markers and PPD reactivity. Overall, a significantly greater proportion (76.2%) of HBsAg positives were PPD reactive in comparison to those positive for anti-HBs (67.2%) or who had no HBV markers (43.2%). For persons 30 years of age who were positive for HBsAg or anti-HBs there was no significant difference between the proportions with PPD reactivity but a significantly smaller proportion of PPD reactivity was found in the no marker group. Among persons 30 years of age, the proportions of those who were PPD reactive were statistically equivalent across all three HBV marker groups. We conclude that patterns of HBV infection in NWT are random with respect to tuberculin reactivity resulting from either exposure to M. tuberculosis or administration of BCG vaccine.

Adolescent↗
PubMed1991

Principles of IUATLD collaborative tuberculosis progammes.

The success of IUATLD-assisted National Tuberculosis Programme developed by Dr. Karel Styblo is dependent on a number of important principles. The most important step is the organization of the basic components of the National Tuberculosis Programme. This first step requires 1) a political commitment on the part of the Government, 2) a secure supply of drugs and materials, including a reserve stock, 3) a network of microscopy centres with a system of quality control and 4) proper recording and reporting of cases. These conditions can result in significant improvement in case-finding and treatment results but rarely results in a cure rate of smear-positive cases in excess of 55 per cent. To obtain the levels of cure necessary to achieve an epidemiologic impact, it is necessary to employ short-course chemotherapy. Additional conditions must be met for this to be successful: 1) adequate supervision of drug-taking in the initial intensive phase, 2) proper training of staff prior to commencement of the treatment and 3) step-wise introduction throughout the country. Several factors may adversely affect the outcome of treatment programmes. These are drug resistance, a high rate of relapse and HIV infection. To date, the IUATLD-assisted programmes have shown sustained success.

Humans↗
PubMed1991

Relationship between severity of rheumatoid arthritis and serum alpha 1-antitrypsin.

We determined serum alpha 1-antitrypsin phenotypes and levels in 281 patients with classical or definite rheumatoid arthritis (RA). The prevalence of the MZ phenotype in our patients with RA was not increased, as there were only 3 MZ cases (1.1% of all cases and 1.4% of seropositive cases) compared to the 3% prevalence in controls. The FM phenotype was detected in 6 cases, a prevalence rate of 2.1%, significantly higher than in controls (prevalence less than 0.4%). Increased serum levels of alpha 1-antitrypsin were independently associated (p less than 0.01) with the presence of wrist joint erosions and the use of gold and/or penicillamine for treatment; this association may represent a serum antitrypsin response to more severe disease.

Adult↗
PubMed1991

Tuberculosis elimination in the countries of Europe and other industrialized countries.

The working group summarized the conclusions of the workshop with the intention of providing a guide for the preparation of national plans for tuberculosis elimination. The basic strategies that appear consistently effective are: 1. Direct government responsibility for diagnosis, treatment and prevention of tuberculosis (the government is responsible by law for assuring that tuberculosis is identified early, and that cure of the patients is achieved). 2. Maintenance (or development) of properly designed disease surveillance and a programme monitoring system. 3. Availability of specialized tuberculosis personnel at regional and provincial level, responsible for close monitoring of the diagnostic skills and patient prioritization in general health institutions. Regarding research it was felt that no immediate practical applications of new techniques in the diagnosis of mycobacterial diseases, in treatment, or in vaccination can be recommended, but that further basic research in the field of mycobacteria should be pursued and supported.

Communicable Disease Control↗
PubMed1990

Methacholine responsiveness among working populations. Relationship to smoking and airway caliber.

It has been suggested that the development of bronchial hyperresponsiveness (BHR) in some smokers may be an intermediate event in the progression to chronic obstructive pulmonary disease in this group. If this is true, prevalence data on BHR in a general population should show an independent association between BHR and smoking status. To test this, we analyzed BHR to inhaled methacholine in 654 white men without known asthma, in relation to smoking, skin-test reactivity, type of work (office versus industrial), and indicators of baseline airway caliber (FEV1 % predicted and FEV1/FVC). BHR was measured in the traditional way (PC20) and as the slope of FEV1 versus the methacholine concentration (linear scale). A PC20 of less than 16 mg/ml was considered "responsive" for analyses of this outcome. We found that although a positive skin test, smoking, and being an industrial worker all appeared to be significant predictors of increased BHR (p less than 0.05), once FEV1 (% predicted) and FEV1/FVC% were taken into account, none of these variables alone remained significantly associated with BHR. The strongest predictors of BHR were prechallenge FEV1 and FEV1/FVC (both p less than 0.01). The combination of smoking, atopy, and work groups, which identified a small subgroup of atopic smokers who were office workers, also remained significantly associated with increased BHR. We also used a regression model that allowed for comparison of predictors for BHR between the most responsive subset of the population (n = 84) and the remainder of the study population.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗