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Biomedical subjects

H W Glindmeyer

Publications and source records attributed to H W Glindmeyer.

At least 19 recordsLinked to original sources
PubMed1995

Blue-collar normative spirometric values for Caucasian and African-American men and women aged 18 to 65.

Normative spirometric values were derived from 5,042 white (of mainly European ancestry) and black (of mainly African ancestry) men and women paper plant workers who are never-smokers, with no respiratory symptoms or diagnoses and no history of occupational exposure to fibrogenic dusts or irritant chemicals. This cohort was selected from a much larger population under long-term respiratory surveillance (n > 50,000 at 50 plants). Standardized equipment, procedures, and data reduction methods complied with ATS recommendations. Data were collected by the medical departments of the participating companies as part of their routine health surveillance, and the graphic and numeric test results were transmitted to the Tulane University Section of Environmental Medicine for centralized quality assurance, interpretation, and archiving. The large numbers allow derivation of gender- and race-specific reference values. Lower limits of normal were derived and depend upon residual variation and any changes in variation with age. The results indicate that polynomial regression equations provide a significantly better fit than linear regressions with breakpoints. In addition to being more biologically plausible, the polynomial model more closely matches observed longitudinal changes in lung function with age. The age range of the cohort, 18 to 65, provides a regression that more closely matches the observed values in this range, because it does not include "supernormal" elderly survivors, which can lessen the slope of the regression and artifactually increase the predicted values of 50 to 65 yr olds. The regression equations derived for black men and women do not support the use of a single race adjustment (0.85 or 0.88) for all age, sex, height, and spirometric test parameter combinations. These race- and gender-specific regression equations, with their respective lower limits of normal, should improve the detection and quantification of adverse health effects in working individuals and populations.

Adolescent↗
PubMed1992

Abnormal lung function in polyurethane foam producers. Weak relationship to toluene diisocyanate exposures.

Exposures to toluene diisocyanate (TDI) were studied for effects on respiratory health of workers in two plants manufacturing polyurethane foams. Intensive personal monitoring was used to characterize job exposures. Of 4,845 12-min personal samples, 9% exceeded 5 ppb and 1% exceeded 20 ppb. Initial questionnaire and spirometry were obtained in 386 workers (88.7% of target population). Current smoking was associated with lower mean FEV1 and FEF25-75, but percent predicted (% pred) means were normal in all smoking categories. Multiple regression showed significant adverse effects of cumulative TDI exposure on initial level of FVC and FEV1 of current smokers, and an effect at borderline significance (p less than 0.063) on FEF25-75 over all smoking categories. Logistic regression showed that chronic bronchitis was more prevalent among those with higher cumulative exposures, after controlling for smoking, age, and sex. Methacholine (MCh) reactivity was associated with reduced airway function, -8.5% pred for FEV1 and -20.0% pred for FEF25-75. In 227 with adequate follow-up, the slopes of annual change were abnormal, for example, FEV1 of -67 ml/yr in current and -53 ml/yr in never smokers. Men had worse FEV1 declines than did women, -71 ml/yr versus -43 ml/yr. TDI exposure, lifetime or concurrent, had no significant effect on slopes, despite its demonstrated effects on initial level of lung function and on prevalence of chronic bronchitis.

Adult↗
PubMed1991

Exposure-related declines in the lung function of cotton textile workers. Relationship to current workplace standards.

To evaluate the effectiveness of the current workplace standards in preventing chronic health effects from cotton dust exposure, a 5-yr longitudinal study of a large multimill population of cotton textile and synthetic process workers, employed at a major U.S. textile company, was conducted. To control for and assess the effect of type of work area on annual change in lung function, we limited the analysis to those 1,817 subjects who, throughout their textile work history at the company, worked exclusively in cotton yarn manufacturing or slashing and weaving, or in synthetic textile mills. The expected effect of smoking on average annual change in lung function was demonstrated for both cotton and synthetic workers. Despite lower overall dust exposure, cotton yarn workers exhibited steeper annual declines in lung function than did workers in slashing and weaving; this difference persisted within each smoking category, indicating a dust potency effect. There were mill differences in annual change in lung function among cotton workers, potentially masking an exposure effect. A smoking-work area interaction persisted after adjusting for mill differences, with the largest annual declines observed in cotton yarn workers who smoke. A significant dose-response relationship was seen in cotton yarn manufacturing between annual declines in FEV1, FVC, and FEF25-75 and average exposure by mill, and the larger declines were found in mills using the highest percentage and lowest grade of cotton. Synthetic textile workers had larger declines than did cotton textile workers, which were not explained by smoking or duration of employment. Unrecognized and unmeasured causative exposures or selection bias could explain this result.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Progression of asbestos effects: a prospective longitudinal study of chest radiographs and lung function.

From an original prospective cohort of 244 current and ex-workers in two asbestos cement plants, longitudinal radiographic data covering ten years were available for 165 and lung function data covering about six years for 150. Estimates of average and cumulative dust exposure were available for each participant, all men. Radiographic progression (onset or worsening) was assessed by comparing earliest and latest films side by side. Annual changes in lung function were computed by fitting regression lines to all the data points. Small opacities (ILO category 1/0 or higher) were found in 16% of initial films, and progression of small opacities occurred in 13% of film pairs. Average and cumulative dust exposure were each significant determinants of the initial presence of small opacities, and were determinants of the progression of both parenchymal and pleural abnormalities. There was greater likelihood of progression if an abnormality was initially present, and a greater likelihood of progression in the plant that had systematic use of some crocidolite. Initial levels of lung function were related to smoking, exposure to dust, and initial radiographic status. Mean annual declines in lung function were modest (FVC-0.017 l/y, FEV1-0.020 l/y) and were related to smoking but not exposure to dust, initial radiographic status, or radiographic progression. Both plants used mainly chrysotile asbestos and exposure levels declined severalfold after 1960. Our findings suggest a waning effect of the larger remote dust exposures on recent annual change in lung function. This accords with human and experimental pathology data showing the relatively low resistance of chrysotile fibres to chemical alteration and clearance.

Adult↗
PubMed1989

Role of inhalation challenge testing in the diagnosis of isocyanate-induced asthma.

Results of isocyanate challenge tests performed on 63 workers referred with a diagnosis of probable isocyanate asthma between 1974 and 1988 were reviewed. Thirty (48 percent) had an acute episode of asthma with a greater than 20 percent decline in FEV1 following subirritant exposure to isocyanates. No difference in the frequency or type of respiratory complaints between isocyanate reactors and nonreactors was found. No differences in lung function results were present when comparing smoking and ex-smoking reactors and nonreactors. In never-smokers with complaints consistent with isocyanate-induced asthma, the presence of obstructive lung disease increased the likelihood that isocyanate-induced asthma was present. Bronchial responsiveness to methacholine occurred in nearly all isocyanate reactors but predicted isocyanate-induced asthma in only 68 percent of the workers. In nearly all cases of challenge-confirmed toluene diisocyanate (TDI)-induced asthma, a 15-min exposure to 20 ppb of the commercial TDI mixture (80:20 2,4:2,6) provoked asthma. Conversely, in the absence of an asthmatic response following exposure to this dose for this duration, a second exposure at this concentration for a longer time would be reasonable to confirm the absence of isocyanate-induced asthma. Among workers employed in the production of polyurethane foam and confirmed to have TDI-induced asthma by inhalation challenge to the different TDI isomers, there appeared to be increased airway reactivity to the 2,6 isomer. This may have relevance to the frequency and intensity of respiratory symptoms that workers with TDI-induced asthma develop in differing industrial settings.

Adult↗
PubMed1988

Contributing factors to sandblasters' silicosis: inadequate respiratory protection equipment and standards.

National concordance standards for respiratory protection during abrasive blasting have existed for more than 50 years; however, these standards have not kept pace with advances in blast equipment, have not provided realistic estimates of expected protection in the workplace, and have been misused by manufacturers and distributors of respiratory protective equipment who have assured, through sales literature, that the equipment is acceptable for conditions under which they have never been tested. This situation has contributed to exposure of sandblasters to hazardous levels of respirable free silica, and is reviewed here to prevent a continuation of the incompatibility of these and other standards for respiratory protection with the actual exposures to various noxious inhalants in the workplace.

Humans↗
PubMed1987

Spirometry: quantitative test criteria and test acceptability.

Quantitative test criteria have been developed to assess the acceptability of spirometric tracings. Most automated spirometers have been programmed with the criteria in order to assist in data collection. These instruments compare computed parameters from the collected tracings with the criteria and, after 3 acceptable FVC maneuvers have been collected, print out a statement indicating that "tests meet acceptability criteria." Technicians, nurses, and even their medical supervisors are beginning to rely on these statements as assuring overall test quality. However, a review of actual curves indicates that unacceptable results can be obtained from tests that comply with these standards. Although quantitative test criteria are a positive step toward quality assurance, they should be treated as they were developed, as "minimum" criteria. All curves should be inspected for visible defects, especially if the results are used to follow subjects longitudinally.

Forced Expiratory Volume↗
PubMed1987

Useful and extraneous variability in longitudinal assessment of lung function.

Longitudinal measurement is increasingly used to quantify the effects of recent and ongoing influences on lung function, whether treatments of groups of patients, or exposures of working or community populations. The variability in an estimate, eg, mean annual change in FEV1, comes from two sources; variability from true differences in annual change among individuals (called signal), and variability from measurement error (called noise). Signal is useful variability, potentially relatable to explanatory variables, and noise is extraneous. Assuming the variance of true differences remains constant, any increase in noise produces a calculable fall in the proportion of signal in the total observation, which fall we term "signal decay". This is not a function of the number of individuals, which influences rather the statistical power to determine that observed differences are not likely from chance alone. Imprecision in the estimation of individuals' rates of change is a major source of signal decay. Within practical limits, this can be compensated for by increasing the length of the study. Higher rates of subject attrition cause signal decay, in addition to loss of statistical power and susceptibility to survivor bias. Increasing the frequency of testing, within a study of constant length, has little effect on signal and noise, but interval testing protects against secular bias and minimizes data loss from subject attrition.

Adult↗
PubMed1986

Absence of hyperresponsiveness to methacholine in a worker with methylene diphenyl diisocyanate (MDI)-induced asthma.

A 29-year-old man had a persuasive history of respiratory illness following exposures to methylene diphenyl diisocyanate (MDI). He was evaluated by measuring bronchial reactivity to methacholine, both before and after controlled laboratory exposures to MDI. Despite evidence of progressive declines in FEV1 with increasing (but subirritant) doses of MDI on three consecutive days, there was no bronchial hyperresponsiveness to methacholine, before or after MDI challenge. We conclude that the absence of nonspecific bronchial hyperresponsiveness does not exclude the possibility of isocyanate asthma. In the face of a compelling history, a negative result of methacholine challenge should not deter observation or laboratory testing for specific respiratory allergy to these chemicals.

Adult↗
PubMed1982

Lung function consequences of exposure and hypersensitivity in workers who process green coffee beans.

Three hundred seventy-two workers were examined at two coffee processing plants in New Orleans. Workplace dust concentrations were relatively low, and respiratory symptom prevalences were not different in various areas of the plants. After controlling for other variables, men with lengthy employment and exposure to dust of green (unroasted) coffee had lower mean residual FEV1 values (regression coefficient, -0.011 L/yr employed, p less than 0.05). Similarly, workers with serum IgE antibodies to green coffee beans had lower mean residual FEV1 (-0.244 L, p less than 0.05). Each effect remained significant after controlling for the other. In a subset that included all workers exposed to green coffee, acute changes in expiratory flow rates were not related to differences in exposure. The finding of adverse impacts of exposure and sensitization, in a work force relatively free of overt asthma, has important implications for worker health protection.

Adult↗
PubMed1982

Noncomparability of longitudinally and cross-sectionally determined annual change in spirometry.

Annual decline in lung function determined longitudinally is often compared with predicted decline determined cross-sectionally. To test this comparison, spirometric data were collected 5 times over 5 yr from 52 adult male Caucasians. The age regression coefficient for FEV1 and FVC, determined cross-sectionally at each visit, was more than twice the longitudinal annual change computed from the same data as the mean of the slopes of each subject's regression lines. The discrepancy persisted even when the first visit was deleted to reduce learning effects on longitudinal estimates. This discrepancy may be partly explained by the sensitivity of cross-sectional analyses to past noxious influences, whereas longitudinal analyses are sensitive only to influences that continue to affect annual decline during the study period. We also found historical evidence of an increase in height-specific VC, which would artifactually steepen cross-sectionally determined regression lines. Thus, observed longitudinal changes of study cohorts should be compared with control longitudinal data.

Adult↗
PubMed1982

Five-year longitudinal study of workers employed in a new toluene diisocyanate manufacturing plant.

The respiratory health of 277 workers in a new toluene diisocyanate (TDI) manufacturing plant was studied prospectively during 5 yr of exposure. Personal TDI monitors were used to continuously measure peak and 8-h time-weighted average (TWA) concentrations in over 2,000 samples. Longitudinal change in pulmonary function was assessed in 223 men in whom 3 or more data points allowed construction of individual slopes of annual change. Regression of annual change on smoking (pack-years), atopic status, and cumulative TDI exposure dichotomized at 68.2 parts per billion (ppb) months into low and high exposure groups showed significant effects of smoking on spirometric tests and lung volumes. After adjusting for pack-years of smoking, the 74 men in the high cumulative TDI exposure category had significantly larger declines in FEV1, %FEV, and FEF25--75% than did the 149 men in the low category. Annual change in FEV1 was then examined in 6 smoking-exposure categories: in never smokers, average annual decline was 38 ml/yr greater in those with higher cumulative TDI exposure. Current and previous cigarette smokers did not show this effect of cumulative TDI exposure. Analysis of FEV1 change by time above 20 ppb TDI yielded a similar result in never smokers, a 24 ml/yr excess average decline attributable to longer time above 20 ppb. In current cigarette smokers, those with longer time above 20 ppb had excess decline of 18 ml/yr (42 versus 24 ml/yr). our low and high cumulative exposure groups spent 2 and 15%, respectively, of their working time above 5 ppb TDI. The different health effects observed in these groups supports the NIOSH-recommended standard of 5 ppb TDI as an 8-h TWA.

Adult↗
PubMed1982

A compact computer printer for quality control spirometric data collection.

A new microcomputer, the Datamite III, was tested with a standardized group of known physiologic spirometric inputs. These test inputs were developed by the National Institute for Occupational Safety and Health, and are recommended by the Association for Advancement of Medical Instruments. They exhibit a wide range of flows and volumes along with initial and terminal hesitation in order to test, under the most severe conditions, all aspects of automated data collection, such as initiation and termination thresholds, sampling rate, back extrapolation logic and data reduction. For all measured spirometric parameters, the accuracy of the Datamite III in computing data from these curves was well within all published requirements. Correlation coefficients of 1.000 were obtained between computed and delivered values for forced expiratory volume at 1s (FEV1), forced vital capacity (FVC), FEV1/FVC, and forced expiratory flow between 25% and 75% of the FVC (FEF25-75). In addition, the Datamite III provides maximum technician support for enhanced quality control through unique program features.

Computers↗
PubMed1980

Interaction of atopy and exposure to cotton dust in the bronchoconstrictor response.

A survey of 255 workers in four cottonseed crushing mills included a respiratory health questionnaire, allergy skin testing, and measurements of lung function over the Monday working shift. Atopy was defined as having two or more positive weal reactions to common inhalant antigens. Categories of exposure to dust were based on the stage of milling, and one category contained workers with continuous exposure to cotton dust derived from linters, the cotton fibres adherent to cottonseed. Atopy and exposure to dust were found to have significant interaction: large mean declines in FEV1 and FEF 25-75 occurred only in the workers exposed to linter dust who were also atopic. Skin-testing surveys in cotton textile mills have concentrated on specific cotton antigen reactivity and its first-order relations to symptoms. Our results indicate a need to identify atopic workers, and to search for interactions between atopy and other variables that may influence acute changes in expiratory flow rates.

Adult↗
PubMed1978

A comparison of the Jones and Stead-Wells spirometers.

A comparison was made between the noncounterweighted Jones and Stead-Wells spirometers, and "conversion factors" were determined for the forced expiratory volume in one second (FEV1) and the forced vital capacity (FVC). A cross-sectional study produced a high correlation between the instruments for these two measurements, yielding quadratic and linear regression equations ("conversion factors") for FEV1 and FVC, respectively. Standard deviations of measurements were similar for both spirometers. Results from a longitudinal study agreed with the "conversion factors" predicted from the cross-sectional study; however, significant day-to-day variability was observed by both spirometers. Neither spirometer met all of the technical recommendations proposed by the Committees on Environmental Health and Respiratory Physiology of the American College of Chest Physicians; however, the Stead-Wells water-sealed spirometer complied more often than the Jones waterless spirometer (Pulmonor). In addition, the open-circuit procedure used for the Jones spirometer required more corrdination in the subject than did the closed-circuit procedure employed in this study for the Stead-Wells spirometer; however, with application of the "conversion factors," both instruments, yield comparable data and prove adequate for spirometric studies.

Forced Expiratory Flow Rates↗