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Biomedical subjects

D Heederik

Publications and source records attributed to D Heederik.

At least 127 records · Page 7Linked to original sources
PubMed1992

Relations between occupation, smoking, lung function, and incidence and mortality of chronic non-specific lung disease: the Zutphen Study.

Information gathered in the "Zutphen study", the Dutch contribution to the Seven Countries Study was used for the present study. Follow up data from 1965 to 1 July 1985 were used. During this follow up, the morbidity state of the participants was verified at regular intervals. In 1965 lung function was measured by spirometry and the vital capacity (VC) and forced expiratory volume in one second (FEV1) were available. A complete set of data was available for 668 men. The occurrence of chronic non-specific lung disease (CNSLD) at a specific time was coded by one physician, using strict criteria. Information about the cause of death was obtained and coded by one physician in 1985. Occupation was coded and a distinction between blue and white collar workers was made. For the analysis of the relation between age, lung function, smoking habits, and occupational state with CNSLD incidence and mortality, proportional hazard models were used. Blue collar workers had a significantly raised risk for incidence of CNSLD only. The hazard ratio for blue v white collar workers with CNSLD mortality was 1.4 but not statistically significant. It was concluded that occupation is clearly related to incidence of CNSLD. There were indications that occupation is related to mortality from CNSLD. A reduced FEV1 was a strong predictor of both CNSLD incidence and mortality. It is noteworthy that small differences in age and height standardised lung function were significantly related to incidence of CNSLD, mortality from CNSLD, and total mortality. Although these differences in lung function have no direct clinical importance for the individual subject, they indicate a raised morbidity and mortality risk for the population.

Age Factors↗
PubMed1992

Dust- and endotoxin-related respiratory effects in the animal feed industry.

A cross-sectional study of 315 animal feed workers was undertaken in 14 animal feed mills in the Netherlands. Primary aims were to explore relationships between exposure to organic dust and respiratory symptoms and chronic lung function changes. The study comprised monitoring dust and endotoxin exposure, spirometric lung function measurements (FVC, FEV1, mean midexpiratory flow, and flow-volume parameters) and a questionnaire for respiratory symptoms. The exposure was measured in two periods, during spring and autumn. The average 8-h personal inspirable dust exposure was 9 mg/m3 grain dust (range, 0.2 to 150 mg/m3) and 25 ng/m3 endotoxin (range, 0.2 to 470 ng/m3) based on 530 personal dust measurements. On the basis of these measurements and the occupational history of the workers, the number of years "worked in dust" and an estimate of the cumulative dust and endotoxin exposure were calculated. The prevalence of most chronic respiratory symptoms tended to decrease with increasing years of exposure. The "healthy worker effect" is probably responsible for this finding. In general, a strong negative association between most of the exposure variables and lung function was found. The endotoxin exposure was more strongly related to decreases in lung function than the dust exposure. The estimated effects of an average (cumulative) endotoxin exposure on lung function were greater, with a higher statistical significance, than for an exposure to dust. These results suggest that endotoxin exposure is an important factor in the development of respiratory impairment. The lung function changes occur at endotoxin levels ranging from 0.2 to 470 ng/m3.

Adult↗
PubMed1991

Relationship of airborne endotoxin and bacteria levels in pig farms with the lung function and respiratory symptoms of farmers.

Previous studies have demonstrated a high prevalence of respiratory and other symptoms and a decrement in lung function among pig farm workers, although the relationships with specific agents present in the work environment remain obscure. This study was therefore undertaken to investigate the relationship between symptoms, lung function and airborne endotoxin, ammonia and dust levels in piggeries. Information on symptoms, lung function, endotoxin, ammonia and dust levels was available for 183 pig farmers who worked in 136 farms. For 62 farms information was present on the levels of bacteria and gram-negative bacteria. For these 62 farms, endotoxin exposure measurements were taken in more than one stable. In general, no significant correlations were found between lung function and chronic respiratory symptoms, or dust and ammonia levels. The endotoxin concentration in stables was negatively related to most lung function variables, but only for the subgroup of 62 farmers was a statistically significant relationship found between endoxtoxin exposure and FEV1. A borderline statistically significant and negative relationship was found between the endotoxin concentration and the FVC. Symptoms experienced during or shortly after work showed odds ratios larger than one with the levels of bacteria, gram-negative bacteria and endotoxin, indicating a positive relationship. No consistency in the relationship between symptoms and dust levels was found. The results suggest that endotoxins and (gram-negative) bacteria probably play an important role in the development of symptoms and lung function changes among pig farmers.

Adolescent↗
PubMed1990

Occupational exposure and 25-year incidence rate of non-specific lung disease: the Zutphen Study.

Information gathered in the Zutphen Study, the Dutch contribution to the Seven Countries Study that started in the 1960s, was used for the present study. In 1960 878 men participated in the physical examination and they were followed for 25 years until 1 July 1985. During this follow-up, their morbidity status was verified regularly. With this information the occurrence of chronic non-specific lung disease (CNSLD) at a specific time was coded by one physician, using strict criteria. The CNSLD diagnosis was based on the following criteria: episodes of respiratory symptoms such as regular cough and phlegm for longer than three months or episodes of wheezing and shortness of breath reported to the survey physician, or: diagnosis of CNSLD, including chronic bronchitis or emphysema by a clinical specialist. Occupation in 1960 was coded and used to generate specific occupational exposures with a Job Exposure Matrix. Because the exact time of diagnosis of CNSLD was known, incidence densities could be calculated. For 804 men a complete set of data was available. A Poisson regression analysis was used to analyse the relationships between the incidence density and independent variables like age, calendar period, occupation and specific occupational exposures. Blue collar workers had a significantly elevated incidence density ratio (IDR) compared to white collar workers (1.82, 95% confidence limits (CL): 1.35, 2.46). Subgroups of blue collar workers, wood and paper workers, textile workers, and tailors, construction workers and transport workers had significantly elevated IDRs also. Of the specific exposures heavy metals, mineral dust and adhesives had a significantly elevated IDR.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Relationship of airborne microorganisms with the lung function and leucocyte levels of workers with a history of humidifier fever.

An influenza-like illness appeared recently among workers in a plant processing synthetic yarn. A humidifier, a cold-water spraying system, was the suspected cause. Lung function changes over the day and week and changes in blood leucocytes were studied among the workers from the suspected department and two reference populations. Exposure to colony-forming units of bacteria and fungi and to endotoxins was also monitored. The workers from the suspected department had statistically significantly lower lung functions on the first workday of the week than the referents. Their blood leucocytes were also raised statistically significantly. The exposure to fungi, bacteria, and endotoxins differed significantly between the various departments, but the measured levels were low. It was concluded that the observed effects were suggestive of a "Monday morning fever" type of reaction and that adverse effects occurred at exposure levels lower than those found to date in the literature.

Air Microbiology↗
PubMed1989

Lung function of welders of zinc-coated mild steel: cross-sectional analysis and changes over five consecutive work shifts.

Spirometric lung-function measurements were conducted 5 days before and after the work shift of 11 welders of zinc-coated steel, ten nonwelders who were indirectly exposed to welding fumes, and 17 controls. The exposure to dust and zinc of all participants was monitored personally using PAS-6 samplers. Geometric mean concentrations for welders were 0.91 mg/m3 (dust) and 34.0 micrograms/m3 (zinc). Cross-sectional analysis of Monday morning values showed no differences in lung-function parameters between groups. However, the number of years the participants were engaged in welding was of borderline statistical significance and correlated negatively with values of FEV1 and FEV1/FVC. Changes in lung function over a work shift or a working week were not related to the exposure level.

Adult↗
PubMed1989

Potentially allergenic airborne particles in the vicinity of a yeast and penicillin production plant.

Potential health risks of exposure to emissions of a yeast and penicillin production plant were investigated by measuring viable particles and protein contents of particles in ambient air. The results showed a clear decrease of the downwind number of yeast colony-forming units with increasing distance from the source. Upwind the number of yeast colony-forming units was zero. Identification showed that nearly all yeast were of the species Saccharomices cerevisiae. Such a trend could not be found for the total number of colony-forming units (yeasts, molds, and bacteria) although the upwind concentration was slightly lower than the downwind concentration. The downwind protein concentration was significantly elevated compared to the upwind concentration.

Air Pollutants, Occupational↗
PubMed1989

Enumeration of viable fungi in occupational environments: a comparison of samplers and media.

The performance of sampling for fungi using four widely used microbiological air sampling devices and three broad spectrum media was compared in seven occupational settings. Total colony forming units counts ranged from 10 to 3700 CFU/m3. The sampling efficiencies of the Andersen N-6 sampler, slit sampler, and Reuter centrifugal air sampler (RCS) were comparable, whereas the SAS sampler underestimated CFU counts by approximately 50%. The correlation between the RCS results and the other three samplers used was lower compared to their mutual correlations. There were no large differences in performance of the three media tested: malt extract agar, dichloran glycerol (18) agar, and dichloran rose bengal chloramphenicol agar. Coefficients of variation of duplicate samples were large compared to commonly used methods for sampling dust and chemicals. It is concluded that the N-6 and slit sampler perform best, although RCS is useful in probes because it is easy to handle. The three media tested yielded similar results. Further testing of DG-18 is recommended, as it inhibits fast growing genera and, thus, counting colonies is easier.

Agar↗
PubMed1989

Chronic non-specific lung disease and occupational exposures estimated by means of a job exposure matrix: the Zutphen Study.

Information gathered in the Zutphen Study, the Dutch contribution to the Seven Countries Study that started in the 1960s, was used in this study. Of the 1266 men invited to take part in the 1985 survey, 939 (74%) participated. All participants were interviewed according to the BMRC chronic non-specific lung disease (CNSLD) questionnaire and medically examined for CNSLD complaints by a trained physician. The physician also filled in a questionnaire containing questions concerning previous treatments for asthma, bronchitis and emphysema. Exposures were generated by means of a job exposure matrix on the basis of the longest performed job and the gain and grouped into 12 exposure categories. A logistic regression analysis was performed using the occupational exposures as the sector of industry dependent variables in allowing for smoking habits, age and socioeconomic status. For the diagnosis by the physician and treatment for emphysema and or bronchitis, the strongest elevated odds ratios were found, indicating an adverse effect of the occupational exposures. In contrast, the variable 'ever treated for asthma' had odds ratios smaller than one with most of the exposure variables indicating a selection effect. In an analysis in which everyone who was ever treated for asthma was excluded an increase in the odds ratios compared with the first analysis was seen. The relationships between occupational exposures as generated by the job exposure matrix and CNSLD were stronger than those recently reported in the literature.

Aged↗
PubMed1989

Effects of exposure to dust in swine confinement buildings--a working group report.

Pulmonary and other symptoms among workers in swine confinement buildings were evaluated by an international working group. In several studies in five different countries a total of about 2000 workers has been studied in clinical and epidemiologic investigations. Symptoms indicative of acute and chronic airway inflammation were widespread, as were systemic reactions of organic dust toxic syndrome. The base-line, and across workshift, pulmonary function changes were moderate. There was no evidence that antigen-antibody reactions are important in the pathogenesis. Longitudinal studies are recommended to establish the relationship between acute and chronic symptoms and end stage disease.

Agricultural Workers' Diseases↗
PubMed1988

Weak associations in occupational epidemiology: adjustment for exposure estimation error.

Epidemiological studies often estimate the health effects of occupational exposures by multiple regression techniques. The standard theory of regression analysis is based on the assumption that the explanatory variables are known without error, and it has long been realised that departures from this assumption will lead to underestimation of the true regression coefficients. In reality, there may be considerable imprecision in the measurement of individuals' exposures to hazards in the workplace, but this is seldom taken into account in analyses. We therefore studied the effect of allowing for imprecision in the exposure estimate with more sophisticated statistical methods, using lung function data from a sample of 348 British miners exposed to mixed coal dust, over an eight-year period. Change in lung function over an eight-year period was regressed on cumulative dust exposure, weight, age and smoking habits. The error in the exposure estimation was assumed to be up to 30% of the total varience of the distribution of the exposure. Adjustment of the regression coefficients of lung function change on dust exposure for the estimation error using linear structural relationships increased the regression coefficient more than threefold compared with those calculated by standard regression analysis. The adjustment led to a change of the coefficients of age as well. The results indicate that a serious underestimation of the relation between lung function change and occupational exposure may occur, which might lead to false interpretations about the relative importance of the occupational exposure as a determinant of disease.

Adult↗
PubMed1987

Pulmonary function and intradermal tests in workers exposed to soft-paper dust.

A survey was carried out in the processing department of a paper mill, consisting of environmental and personal monitoring, a short questionnaire concerning chronic non-specific lung disease (CNSLD), spirometry, and intradermal tests. Spirometry was performed on Monday, Wednesday, and Friday. Exposures to paper dust regularly exceeded the Dutch Maximal Allowable Concentrations (MACs) for total and respirable dust. There were indications of a qualitatively different exposure to molds inside the mill in comparison with the outdoor air. A comparison between a group of workers exposed to paper dust and a control group showed significantly more persons with positive late and delayed intradermal test reactions in the exposed population. The analysis of the spirometric measurements after correction for differences between the groups in age, height, and smoking habits gave evidence of the existence of lower FEV1, MMEF, MEF50, and MEF25 among exposed workers with a positive immediate intradermal reaction on Friday. The same workers showed a decline in pulmonary function over the week compared with the controls. These changes suggest an obstructive airway reaction with an immunologic mechanism to dust exposure in a paper mill.

Humans↗
PubMed1987

Agreement between qualitative exposure estimates and quantitative exposure measurements.

A method for qualitative estimation of the exposure at task level was used and validated with actual measurements in five small factories. The results showed that occupational hygienists were in general the most successful estimators. Plant supervisors and workers handled the estimation method less successfully because of more misclassification of the tasks. The method resulted, in general, in a classification of tasks in four exposure categories ranging from no exposure to high exposure. The exposure categories correlated positively with mean concentrations, but showed overlapping exposure distributions. This resulted in misclassification of the exposure for individual workers when a relatively large interindividual variability in exposure levels within an exposure category was present. The results show that this method can be used for workplace exposure zoning, but that the usefulness of the estimates for epidemiological purposes is not clear-cut and depends strongly on the actual exposure characteristics within a workplace. A combination of the qualitative exposure estimation method together with assessment of the exposure levels by measurements makes a rearrangement of tasks or individual workers possible and could improve the validity of this method for epidemiological purposes.

Environmental Exposure↗