Sverre Vedal

Ambient Particles and Health: Lines that Divide

ISSN: 1096-2247 (Print) 2162-2906 (Online) Journal homepage: http://www.tandfonline.com/loi/uawm20 Ambient Particles and Health: Lines that Divide Sverre Vedal To cite this article: Sverre Vedal (1997) Ambient Particles and Health: Lines that Divide, Journal of the Air & Waste Management Association, 47:5, 551-581, DOI: 10.1080/10473289.1997.10463922 To link to this article: https://doi.org/10.1080/10473289.1997.10463922

Exposure of chronic obstructive pulmonary disease patients to particles: respiratory and cardiovascular health effects.

To examine hypotheses regarding air pollution health effects, we conducted an exploratory study to evaluate relationships between personal and ambient concentrations of particles with measures of cardiopulmonary health in a sample of patients with chronic obstructive pulmonary disease (COPD). Sixteen currently non-smoking COPD patients (mean age=74) residing in Vancouver were equipped with a particle (PM2.5) monitor for seven 24-h periods. Subjects underwent ambulatory heart monitoring, had their lung function and blood pressure (BP) measured, and recorded symptoms and medication use. Ambient PM2.5, PM10, sulfate, and gaseous pollutant concentrations were monitored at five sites within the study area. Although no associations between air pollution and lung function were statistically significant, an estimated effect of 3% and 1% declines in daily FEV1 change (ΔFEV1) for each 10 μg/m3 increase in ambient PM10 and PM2.5, respectively, was observed. Increases of 1 μg/m3 in personal or ambient sulfate were associated with 1.0% and 0.3% declines in ΔFEV1, respectively. Weak associations were observed between particle concentrations and increased supraventricular ectopic heartbeats and with decreased systolic BP. No consistent associations were observed between any particle metric and diastolic BP, heart rate, or heart rate variability (r-MSSD or SDNN), symptom severity, or bronchodilator use. Of the pollutants measured, ambient PM10 was most consistently associated with health parameters; the use of personal exposures did not improve the strength of any associations or lead to increased effect estimates.

Exposure of Chronic Obstructive Pulmonary Disease Patients to Particulate Matter: Relationships between Personal and Ambient Air Concentrations

ABSTRACT Most time-series studies of particulate air pollution and acute health outcomes assess exposure of the study population using fixed-site outdoor measurements. To address the issue of exposure misclassification, we evaluate the relationship between ambient particle concentrations and personal exposures of a population expected to be at risk of particle health effects. Sampling was conducted within the Vancouver metropolitan area during April-September 1998. Sixteen subjects (non-smoking, ages 54-86) with physician-diagnosed chronic obstructive pulmonary disease (COPD) wore personal PM2 5 monitors for seven 24-hr periods, randomly spaced approximately 1.5 weeks apart. Time-activity logs and dwelling characteristics data were also obtained for each subject. Daily 24-hr ambient PM10 and PM2.5 concentrations were measured at five fixed sites spaced throughout the study region. SO4 2-, which is found almost exclusively in the fine particle fraction and which does not have major indoor sources, was measured in all PM2 5 samples as an indicator of accumulation mode particu-late matter of ambient origin.

Symptoms and pulmonary function in western red cedar workers related to duration of employment and dust exposure

Measurements of total dust concentration were made in a western red cedar sawmill that employed 701 workers. Both area sampling and personal sampling of total dust were done over an 8-hr shift corresponding to job descriptions and locations to assign each worker an exposure level. A total of 652 (93%) of the workers completed a respiratory-occupational questionnaire and performed spirometry, of whom 334 were assigned an exposure level. Dust exposure ranged from undetectable to 6.0 mg/m3 with a median exposure level of 0.2 mg/m3. Only 10% of the workers with an assigned exposure level were exposed to more than 1.0 mg/m3. Work-related asthma, defined as symptoms of asthma which improved on days off work, was reported by 52 workers (8.0%) and was more prevalent after 10 or more yr of employment. Chronic cough, dyspnea, persistent wheeze, and physician-diagnosed asthma were unrelated to either work duration or exposure. Levels of forced vital capacity (FVC) and forced expiratory volume in 1 sec (FEV1.0) were lower with dust concentrations greater than 2.0 mg/m3, controlling for age and smoking; maximum mid-expiratory flow rate (FEF25-75%) and FEV1.0/FVC were unrelated to dust exposure concentration. Work-related symptoms of eye irritation were seen more commonly with exposure to dust concentrations of 3.0 mg/m3 or more. It is concluded that symptoms of work-related asthma in red cedar workers are more common after 10 yr of exposure, and that levels of pulmonary function are lower with higher wood dust exposures.

Peripheral leucocyte count and longitudinal decline in lung function.

A six year follow up study of 750 aluminium smelter workers was undertaken to evaluate the relationship between the leucocyte count at the start of the study and the rate of decline in lung function. An inverse relationship between the leucocyte count and the forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) was present cross sectionally irrespective of cigarette smoking habit. The initial leucocyte count was also significantly related to the mean annual decline in FEV1 in smokers (p = 0.04) but not in former smokers or those who had never smoked. These observations suggest that the leucocyte count is a factor influencing the annual decline in FEV1 in smokers.

Interpretation of Transbronchial Lung Biopsies from Lung Transplant Recipients:Inter- and Intraobserver Agreement

BACKGROUNDnTransbronchial lung biopsy results are crucial for the management of lung transplant recipients. Little information is available regarding the reliability and reproducibility of the interpretation of transbronchial lung biopsies.nnnOBJECTIVEnTo examine the inter-reader variability between two lung pathologists with expertise in lung transplantation.nnnMETHODSnFifty-nine transbronchial lung biopsy specimens were randomly selected. Active infection had been excluded in all cases. The original interpretations (as per the Lung Rejection Study Group) for acute rejection grade included 19 biopsies scored as A0 (none), 14 scored as A1 (minimal), 12 as A2 (mild), 11 as A3 (moderate) and three as A4 (severe). The pathologists worked independently without clinical information or knowledge of the original interpretation. The specimens were graded using the Lung Rejection Study Group criteria for acute rejection (grades A0 to A4), airway inflammation (grades B0 to B4) and bronchiolitis obliterans (C0 absent and C1 present). Between-reader agreement for each category was analyzed using a Kappa statistic.nnnRESULTSnBecause many transplant specialists initiate augmented immunosuppression with biopsy grades of A2 or higher, results for each reader were dichotomized as A0/A1 versus A2/A3/A4. Using this dichotomy, there was only moderate agreement (kappa 0.470, P < 0.001) between readers. For categories B and C, the results were dichotomized for the absence or presence of airway inflammation and bronchiolitis obliterans, respectively. The level of agreement between readers was fair for category B (kappa 0.333, P = 0.014) and poor for category C (kappa 0.166, P = 0.108). The intrareader agreement for acute rejection was substantial (kappa 0.795, P = 0.0001; kappa 0.676, P = 0.0001).nnnCONCLUSIONSnBecause the agreement between expert pathologists is only modest, optimum clinical decision-making requires that transbronchial lung biopsy results be used in an integrated clinical context.

Exposure misclassification and threshold concentrations in time series analyses of air pollution health effects.

Linear, no-threshold relationships are typically reported for time series studies of air pollution and mortality. Since regulatory standards and economic valuations typically assume some threshold level, we evaluated the fundamental question of the impact of exposure misclassification on the persistence of underlying personal-level thresholds when personal data are aggregated to the population level in the assessment of exposure-response relationships. As an example, we measured personal exposures to two particle metrics, PM2.5 and sulfate (SO4(2-)), for a sample of lung disease patients and compared these with exposures estimated from ambient measurements Previous work has shown that ambient:personal correlations for PM2.5 are much lower than for SO4(2-), suggesting that ambient PM2.5 measurements misclassify exposures to PM2.5. We then developed a method by which the measured:estimated exposure relationships for these patients were used to simulate personal exposures for a larger population and then to estimate individual-level mortality risks under different threshold assumptions. These individual risks were combined to obtain the population risk of death, thereby exhibiting the prominence (and the value) of the threshold in the relationship between risk and estimated exposure. Our results indicated that for poorly classified exposures (PM2.5 in this example) population-level thresholds were apparent at lower ambient concentrations than specified common personal thresholds, while for well-classified exposures (e.g., SO4(2-)), the apparent thresholds were similar to these underlying personal thresholds. These results demonstrate that surrogate metrics that are not highly correlated with personal exposures obscure the presence of thresholds in epidemiological studies of larger populations, while exposure indicators that are highly correlated with personal exposures can accurately reflect underlying personal thresholds.

Lymphocyte sub-populations in patients with allergic and non-allergic asthma

The subpopulations of peripheral blood lymphocytes were identified using monoclonal antibodies specific for T lymphocytes (T11 antibodies), B lymphocytes (B1 antibodies), helper/inducer T cells (T4 antibodies) and suppressor/cytotoxic cells (T8 antibodies). Ninety‐six subjects, including twenty‐five patients with allergic asthma, nineteen patients with non‐allergic asthma and fifty‐two controls without asthma, were studied. There was no significant difference in the lymphocyte subsets between the allergic and non‐allergic asthmatics. When comparing patients with asthma as a group with the controls, a decrease in the number of T8‐positive suppressor cells and therefore, an increase in the helper/suppressor cell ratio were demonstrated in the asthamtics. A relative deficiency of suppressor T cells may represent another immunological marker of bronchial asthma.

Health Effects of Air Pollution Due to Coal Combustion in the Chestnut Ridge Region of Pennsylvania: Cross-Section Survey of Children

A cross-sectional study of 4,071 children aged 6-11 yr of age from a rural region of Western Pennsylvania was conducted in spring of 1979. Standardized childrens questionnaires were distributed to the parents and returned by the children to school, where spirometry was performed. The region was divided into low-, moderate-, and high-pollution areas on the basis of the 1974-1978, 3-hr, 24-hr, and annual averages for sulfur dioxide (SO2). Seventeen monitoring stations in the region and a triangulation procedure were used to estimate centroid levels in each geographic residence area. After adjusting the respiratory symptom response outcomes and the pulmonary function levels for known predictors, no significant association was noted for level of SO2. However, the highest exposure categories were only slightly above the present annual and 24-hr National Air Quality Standards for SO2. We conclude that at levels of exposure to which these children were exposed, only by study of potentially sensitive subsets or measures of acute response would it be possible to detect respiratory outcomes associated with ambient air pollution.

Plicatic acid-specific IgE and nonspecific bronchial hyperresponsiveness in western red-cedar workers☆

In a cross-sectional survey of 652 workers in a western red-cedar sawmill, we obtained data on symptoms, pulmonary function, immediate skin reactivity to common allergens, nonspecific bronchial responsiveness, total IgE level, and sensitization to plicatic acid conjugated with human serum albumin as measured by RAST. Dust exposure was estimated by personal and area sampling for total dust during a work shift and cumulative exposure by duration of employment. Seven percent of the workers had an elevated RAST, and 20% had nonspecific bronchial hyperresponsiveness. Elevation in RAST was associated with bronchial hyperresponsiveness. Almost half (46%) of the workers with RAST elevation had bronchial hyperresponsiveness compared to 18% in workers with no RAST elevation. The association was unaffected by total IgE level or by limiting the analysis to workers without respiratory symptoms and was most apparent in younger workers. Bronchial hyperresponsiveness was associated with increased prevalence of respiratory symptoms as well as with lower levels of pulmonary function. The likelihood of bronchial hyperresponsiveness increased with increasing age but was unrelated to the dust-exposure concentration. RAST elevation was unrelated to employment duration or dust exposure and was not associated with an increased prevalence of symptoms or lower levels of pulmonary function independent of bronchial hyperresponsiveness. We conclude that plicatic acid-specific IgE and nonspecific bronchial hyperresponsiveness are associated in western red-cedar workers and that this association may reflect a causal connection.