Annual average ambient particulate matter exposure estimates, measured home particulate matter, and hair nicotine are associated with respiratory outcomes in adults with asthma.

BACKGROUND: While exposure to outdoor particulate matter (PM) has been associated with poor asthma outcomes, few studies have investigated the combined effects of outdoor and indoor PM (including secondhand tobacco smoke). OBJECTIVE: To examine the associations between PM and asthma outcomes. METHODS: We analyzed data from a cohort of adults with asthma and rhinitis (n=302; 82% both conditions; 13% asthma only; 5% rhinitis alone) including measures of home PM, tobacco smoke exposure (hair nicotine and self-report), ambient PM from regional monitoring, distance to roadway, and season (wet or dry). The outcomes of interest were frequent respiratory symptoms and forced expiratory volume in 1 second (FEV1) below the lower limit of normal (NHANES reference values). Multivariable regression analyses examined the associations (Odds Ratio [OR] and 95% Confidence Interval [95%CI]) between exposures and these outcomes, adjusted by sociodemographic characteristics. RESULTS: In adjusted analyses of each exposure, the highest tertile of home PM and season of interview were associated with increased odds for more frequent respiratory symptoms (OR=1.64 95%CI: [1.00, 2.69] and OR=1.66 95%CI: [1.09, 2.51]). The highest tertile of hair nicotine was significantly associated with FEV1 below the lower limit of normal (OR=1.80 95%CI: [1.00, 3.25]). In a model including home PM, ambient PM, hair nicotine, and season, only two associations remained strong: hair nicotine with FEV1 below the lower limit of normal and season of measurement (dry, April-October) with increased respiratory symptoms (OR=1.85 95%CI: [1.00, 3.41] and OR=1.54 95%CI: [1.0, 2.37]). When that model was stratified by sex, the highest tertiles of ambient PM and hair nicotine were associated with FEV1 below the lower limit of normal among women (OR=2.23 95%CI: [1.08, 4.61] and OR=2.90 95%CI: [1.32, 6.38]), but not men. The highest tertile of hair nicotine was also associated with increased respiratory symptoms in women but not men (OR=2.38 95%CI: [1.26, 4.49]). When stratified by age, the middle quartile of ambient PM and the highest hair nicotine tertile were associated with increased respiratory symptoms (OR=2.07 95%CI: [1.01, 4.24] and OR=2.55 95%CI: [1.21, 5.36]) in those under 55 but not in the older stratum. CONCLUSIONS: Exposure to PM from both home and ambient sources is associated with increased symptoms and lower lung function in adults with asthma, although these associations vary by type of PM, the respiratory outcome studied, sex and age.

Higher environmental relative moldiness index values measured in homes of adults with asthma, rhinitis, or both conditions.

Higher values of the environmental relative moldiness index (ERMI), a DNA-based method for quantifying indoor molds, have been associated with asthma in children. In this study, settled dust samples were collected from the homes of adults with asthma, rhinitis, or both conditions (n=139 homes) in Northern California. The ERMI values for these samples were compared to those from dust collected in homes from the same geographic region randomly selected as part of the 2006 American Healthy Home Survey (n=44). The median ERMI value in homes of adult with airway disease (6) was significantly greater than median ERMI value (2) in the randomly selected homes (p<0.0001). In this study in Northern California, the homes of adults with asthma had ERMI values consistent with a heavier burden of indoor mold than that measured in other homes from the same region.

Solvent exposures and Parkinson disease risk in twins.

OBJECTIVE: Several case reports have linked solvent exposure to Parkinson disease (PD), but few studies have assessed associations with specific agents using an analytic epidemiologic design. We tested the hypothesis that exposure to specific solvents is associated with PD risk using a discordant twin pair design. METHODS: Ninety-nine twin pairs discordant for PD ascertained from the National Academy of Sciences/National Research Council World War II Veteran Twins Cohort were interviewed regarding lifetime occupations and hobbies using detailed job task-specific questionnaires. Exposures to 6 specific solvents selected a priori were estimated by expert raters unaware of case status. RESULTS: Ever exposure to trichloroethylene (TCE) was associated with significantly increased risk of PD (odds ratio [OR], 6.1; 95% confidence interval [CI] 1.2-33; p = 0.034), and exposure to perchloroethylene (PERC) and carbon tetrachloride (CCl(4) ) tended toward significance (respectively: OR, 10.5; 95% CI, 0.97-113; p = 0.053; OR, 2.3; 95% CI, 0.9-6.1; p = 0.088). Results were similar for estimates of exposure duration and cumulative lifetime exposure. INTERPRETATION: Exposure to specific solvents may increase risk of PD. TCE is the most common organic contaminant in groundwater, and PERC and CCl(4) are also ubiquitous in the environment. Our findings require replication in other populations with well-characterized exposures, but the potential public health implications are substantial.

Fungal chitin from asthma-associated home environments induces eosinophilic lung infiltration.

Development of asthma and allergic inflammation involves innate immunity, but the environmental contributions remain incompletely defined. Analysis of dust collected from the homes of asthmatic individuals revealed that the polysaccharide chitin is environmentally widespread and associated with ß-glucans, possibly from ubiquitous fungi. Cell wall preparations of Aspergillus isolated from house dust induced robust recruitment of eosinophils into mouse lung, an effect that was attenuated by enzymatic degradation of cell wall chitin and ß-glucans. Mice expressing constitutively active acidic mammalian chitinase in the lungs demonstrated a significant reduction in eosinophil infiltration after fungal challenge. Conversely, chitinase inhibition prolonged the duration of tissue eosinophilia. Thus, fungal chitin derived from home environments associated with asthma induces eosinophilic allergic inflammation in the lung, and mammalian chitinases, including acidic mammalian chitinase, limit this process.

Alpha-1-antitrypsin deficient man presenting with lung function decline associated with dust exposure: a case report.

INTRODUCTION: People with α1-antitrypsin deficiency are at increased risk for the development of chronic obstructive pulmonary disease. Previous retrospective epidemiologic studies have found that exposure to occupational dust among those with α1-antitrypsin deficiency is a risk factor at the group level for poorer lung function, but on an individual clinical basis, a causal attribution can be difficult to establish. CASE PRESENTATION: We describe the case of a 68-year-old Caucasian man with a 25 pack-year smoking history who presented with new-onset dyspnea on exertion in the setting of workplace dust exposure. During his evaluation, he was found to have α1-antitrypsin deficiency with evidence of development of pulmonary emphysema. Workplace spirometric monitoring over 10 years of surveillance for an on-the-job respirator fit program demonstrated a sharp downward slope in forced expiratory volume in one second, or FEV1, during his periods of most significant dust exposure, which was attenuated after discontinuation of his workplace exposure. CONCLUSION: Patients with α1-antitrypsin disease should be assessed for occupational exposures and closely monitored for work-accelerated progression of lung function decline. More generally, this case report supports the biological plausibility of occupationally associated chronic obstructive pulmonary disease, underscoring that work-associated pulmonary disease can be multi-factorial.

An integrated model of environmental factors in adult asthma lung function and disease severity: a cross-sectional study.

BACKGROUND: Diverse environmental exposures, studied separately, have been linked to health outcomes in adult asthma, but integrated multi-factorial effects have not been modeled. We sought to evaluate the contribution of combined social and physical environmental exposures to adult asthma lung function and disease severity. METHODS: Data on 176 subjects with asthma and/or rhinitis were collected via telephone interviews for sociodemographic factors and asthma severity (scored on a 0-28 point range). Dust, indoor air quality, antigen-specific IgE antibodies, and lung function (percent predicted FEV1) were assessed through home visits. Neighborhood socioeconomic status, proximity to traffic, land use, and ambient air quality data were linked to the individual-level data via residential geocoding. Multiple linear regression separately tested the explanatory power of five groups of environmental factors for the outcomes, percent predicted FEV1 and asthma severity. Final models retained all variables statistically associated (p < 0.20) with each of the two outcomes. RESULTS: Mean FEV1 was 85.0 +/- 18.6%; mean asthma severity score was 6.9 +/- 5.6. Of 29 variables screened, 13 were retained in the final model of FEV1 (R2 = 0.30; p < 0.001) and 15 for severity (R2 = 0.16; p < 0.001), including factors from each of the five groups. Adding FEV1 as an independent variable to the severity model further increased its explanatory power (R2 = 0.25). CONCLUSIONS: Multivariate models covering a range of individual and environmental factors explained nearly a third of FEV1 variability and, taking into account lung function, one quarter of variability in asthma severity. These data support an integrated approach to modeling adult asthma outcomes, including both the physical and the social environment.

Impact of the home indoor environment on adult asthma and rhinitis.

OBJECTIVE: We sought to study the combined effects of multiple home indoor environmental exposures in adult asthma and rhinitis. METHODS: We studied 226 adults with asthma and rhinitis by structured interviews and home assessments. Environmental factors included dust allergen, endotoxin and glucan concentrations, and indoor air quality (IAQ) variables. Outcomes included forced expiratory volume in 1 second (FEV1) percent predicted, Severity of Asthma Score (SAS), Short-Form (SF)-12 Physical Component Scale (PCS), and asthma Quality of Life (QOL) score. RESULTS: House dust-associated exposures together with limited IAQ variables were related to FEV1 % predicted (R = 0.24; P = 0.0001) and SAS (R = 0.18; P = 0.007). IAQ and limited dust variables were associated with SF-12 PCS (R = 0.15; P = 0.02), but not QOL (R = 0.13; P = 0.16). CONCLUSIONS: The home environment is strongly linked to lung function, health status, and disease severity in adult asthma and rhinitis.