Metalworking fluid-associated hypersensitivity pneumonitis: a workshop summary

A workshop discussing eight clusters of hypersensitivity pneumonitis in the automotive industry among metalworking fluid-exposed workers concluded that a risk exists for this granulomatous lung disease where water-based fluids are used and unusual microbial contaminants predominate. Strong candidates for microbial etiology are nontuberculous mycobacteria and fungi. Cases of hypersensitivity pneumonitis occur among cases with other work-related respiratory symptoms and chest diseases. Reversibility of disease has occurred in many cases with exposure cessation, allowing return to work to jobs without metalworking fluid exposures or, in some situations, to jobs without the same metalworking fluid exposures. Cases have been recognized with metalworking fluid exposures generally less than 0.5 mg/m3. The workshop participants identified knowledge gaps regarding risk factors, exposure-response relationships, intervention efficacy, and natural history, as well as surveillance needs to define the extent of the problem in this industry. In the absence of answers to these questions, guidance for prevention is necessarily limited.

Dampness and mold in the indoor environment: implications for asthma

This article presents epidemiologic findings pertinent to asthma and asthma-like symptoms in relation to exposure to dampness/mold in homes, schools, and workplaces. With regard to specific agents found in damp indoor environments that may play a role in asthma, it concentrates on mold (used synonymously with fungi) and includes some findings on bacteria. The literature on asthma in relation to dust mite or cockroach allergens is not addressed.

Comparative utilization of warm- and cool-season forages by cattle, sheep and goats

The quality of different classes of forage hay (C3, C4 grasses and legumes) was determined in intake and digestibility trials with mature cattle, sheep and goats. For all nine hays, DM and NDF digestibility by cattle and goats was higher (P less than .05) than by sheep, with no differences due to forage class. Cattle had a higher (P less than .01) DM intake than sheep or goats averaged across forage (92.6 vs 65.8 and 68.6 g/kg BW.75); hay intake was highest on legume, with no difference between C3 and C4 grasses. Mean NDF intake by cattle was greater than by sheep or goats (58.7 vs 39.6 and 42.6 g/kg BW.75); NDF intake for all animal species decreased in the order C4 grass greater than C3 grass greater than legume. Particle passage rates did not differ (P greater than .05) with forage class but were higher (P less than .02) for sheep and goats than for cattle. Prefeeding ruminal DM fill values, determined by emptying, were 10.6, 15.0 and 19.9 g/kg BW1.0 for alfalfa, orchardgrass and switchgrass hays fed to cattle, and 11.2, 11.3 and 16.5 g/kg BW1.0 for the same hays fed to sheep. Estimated turnover times for DM and NDF were shorter (P less than .05) for sheep than for cattle; DM turnover was longer for switchgrass than for alfalfa and orchardgrass, with no forage differences in NDF turnover between these two animal species. Results show that goats were superior to sheep in NDF digestion.

Building-related respiratory symptoms can be predicted with semi-quantitative indices of exposure to dampness and mold

Using a semi-quantitative mold exposure index, the National Institute for Occupational Safety and Health (NIOSH) investigated 13 college buildings to examine whether building-related respiratory symptoms among employees are associated with environmental exposure to mold and dampness in buildings. We collected data on upper and lower respiratory symptoms and their building-relatedness, and time spent in specific rooms with a self-administered questionnaires. Trained NIOSH industrial hygienists classified rooms for water stains, visible mold, mold odor, and moisture using semi-quantitative scales and then estimated individual exposure indices weighted by the time spent in specific rooms. The semi-quantitative exposure indices significantly predicted building-related respiratory symptoms, including wheeze [odds ratio (OR) = 2.3; 95% confidence interval (CI) = 1.1-4.5], chest tightness (OR = 2.2; 95% CI = 1.1-4.6), shortness of breath (OR = 2.7; 95% CI = 1.2-6.1), nasal (OR = 2.5; 95% CI = 1.3-4.7) and sinus (OR = 2.2; 95% CI = 1.2-4.1) symptoms, with exposure-response relationships. We found that conditions suggestive of indoor mold exposure at work were associated with building-related respiratory symptoms. Our findings suggest that observational semi-quantitative indices of exposure to dampness and mold can support action to prevent building-related respiratory diseases.

PRACTICAL IMPLICATIONS

Current air sampling methods have major limitations in assessing exposure to mold and other biological agents that may prevent the demonstration of associations of bioaerosol exposure with health. Our study demonstrates that semi-quantitative dampness/mold exposure indices, based solely on visual and olfactory observation and weighted by time spent in specific rooms, can predict existence of excessive building-related respiratory symptoms and diseases. Relative extent of water stains, visible mold, mold odor, or moisture can be used to prioritize remediation to reduce potential risk of building-related respiratory diseases. From a public health perspective, these observational findings justify action to correct water leaks and repair water damage in order to prevent building-related respiratory diseases. This approach can also be a basis for developing practical building-diagnostic tools for water-incursion.

Fungal and endotoxin measurements in dust associated with respiratory symptoms in a water-damaged office building

We investigated the associations of fungal and endotoxin levels in office dust with respiratory health in 888 (67% participation) occupants of a water-damaged building. We analyzed floor and chair dusts from 338 workstations for culturable fungi and endotoxin. Based on averages, we ranked each floor of the building as low, medium, or high for occupants' exposure to each of these agents. Multivariate logistic regression models for building-related symptoms included this ranking of fungi and endotoxin, age, gender, race, smoking status, and duration of occupancy. Using floor dust measures, we found significantly increased odds for lower respiratory symptoms [wheeze, chest tightness, attacks of shortness of breath, and attacks of cough: odds ratios (OR) = 1.7 (95% confidence interval (CI): 1.02-2.77) to 2.4 (95% CI: 1.29-4.59)], throat irritation [OR = 1.7, (95% CI: 1.06-2.82)], and rash/itchy skin [OR = 3.0, (95% CI: 1.47-6.19)] in the highest fungal exposure group compared to the lowest, with generally linear exposure-response relationships. Nonlinear relationships were observed for many of these symptoms and endotoxin in floor dust. Interaction models showed that endotoxin modified effects of fungi on respiratory symptoms. Our findings of exposure interactions and exposure-response relationships of fungal and endotoxin with increased risk of building-related symptoms contribute to an understanding of the role of microbial agents in building-related asthma and respiratory and systemic symptoms.

PRACTICAL IMPLICATIONS

Our demonstration of exposure-response relationships between measurements of fungi and/or endotoxin in floor dusts and building-related symptoms implies that microbial agents in floor dust may be a good surrogate measure for dampness-related bioaerosol exposure, considering that measurements of microbial agents in air often fail to demonstrate the associations between exposure and health. In addition, our finding that endotoxin exposure may change the effect of fungal exposure (and vice versa) on respiratory heath suggests that exposure to both fungi and endotoxin should be assessed in epidemiological investigations examining the effect of fungal or endotoxin exposure on respiratory health in indoor environments.

Evaluation of Brassicas in grazing systems for sheep: II. Blood composition and nutrient status

Blood composition of lambs grazing Brassicas and stockpiled grass or grass-clover pastures in the fall of 4 yr was monitored to assess possible effects of plant metabolites (e.g., glucosinolates, S-methyl cysteine sulfoxide) on health and performance. Serum thyroxine (T4) concentrations in lambs grazing Brassicas decreased upon initiation of grazing, with a subsequent recovery, and concentrations were increased by oral dosing with I or I+CuO. Serum triiodothyronine (T3) increased gradually with time and did not differ between lambs on Brassicas and on pasture at most time periods. In Exp. 3 and 4, T4 levels were lower in lambs grazing Tyfon chinese cabbage hybrid (Brassica rapa L. x B. pekinensis [Lour.] Rupr.) than in lambs on Forage Star hybrid turnip (B. rapa L.). Heinz body formation increased rapidly in lambs on Brassicas, with small decreases in packed cell volume (PCV); dosing with I+CuO reduced Heinz bodies in lambs on Tyfon and turnip pastures. In Exp. 2, I+CuO treatment increased liver Cu concentrations but had no effect on serum Cu. Serum cholesterol and urea N concentrations declined rapidly in lambs on Brassicas, with little change in lambs on stockpiled pastures. Decreases in serum triglycerides, and an increase in glucose concentration, were noted in Exp. 3 and 4 in lambs grazing Tyfon and Forage Star turnip. Although a number of differences related to plant composition were noted in blood of lambs grazing Brassica forages relative to stockpiled pastures, the changes did not seem sufficiently severe to affect animal performance.

Asthma and respiratory symptoms in hospital workers related to dampness and biological contaminants

The National Institute for Occupational Safety and Health investigated respiratory symptoms and asthma in relation to damp indoor environments in employees of two hospitals. A cluster of six work-related asthma cases from one hospital department, whose symptoms arose during a time of significant water incursions, led us to conduct a survey of respiratory health in 1171/1834 employees working in the sentinel cases hospital and a nearby hospital without known indoor environmental concerns. We carried out observational assessment of dampness, air, chair, and floor dust sampling for biological contaminants, and investigation of exposure-response associations for about 500 participants. Many participants with post-hire onset asthma reported diagnosis dates in a period of water incursions and renovations. Post-hire asthma and work-related lower respiratory symptoms were positively associated with the dampness score. Work-related lower respiratory symptoms showed monotonically increasing odds ratios with ergosterol, a marker of fungal biomass. Other fungal and bacterial indices, particle counts, cat allergen and latex allergen were associated with respiratory symptoms. Our data imply new-onset of asthma in relation to water damage, and indicate that work-related respiratory symptoms in hospital workers may be associated with diverse biological contaminants.

PRACTICAL IMPLICATIONS

In healthcare facilities with indoor dampness and microbial contamination, possible associations between such conditions and respiratory health effects should be considered. Good building maintenance and housekeeping procedures should lead to improvements in employee respiratory health.

Sarcoidosis, asthma, and asthma-like symptoms among occupants of a historically water-damaged office building

Sarcoidosis is a granulomatous disease of unknown etiology with evidence of association with exposure to microbial agents. In June 2006, we investigated a sarcoidosis cluster among office workers in a water-damaged building. In the course of the investigation, we became aware of a high rate of respiratory complaints including asthma and asthma-like symptoms. We conducted case finding for physician-diagnosed sarcoidosis and asthma and administered a health questionnaire survey and pulmonary function tests (PFTs) to consenting occupants. We compared prevalence ratios (PRs) to the Environmental Protection Agency's Building Assessment Survey and Evaluation study (BASE) and the National Health and Nutrition Examination Survey (NHANES). We identified six sarcoidosis cases. The current building prevalence is 2206 cases/100,000 population, elevated, compared with the US population range of <1-40 cases/100,000. Of current occupants, 77% (105) participated in the health questionnaire survey and 64% (87) in PFTs. Physician-diagnosed asthma was elevated, compared with the US adult population. Adult asthma incidence was 3.3/1000 person-years during the period before building occupancy and 11.5/1000 person-years during the period after building occupancy. Comparisons with US office workers (BASE) yielded elevated PRs for shortness of breath [PR, 9.6; 95% confidence interval (CI), 6.1-15.2], wheeze (PR, 9.1; 95% CI 5.6-14.6), and chest tightness (PR, 5.1; 95% CI 2.8-9.0). PFT results supported reports of respiratory symptoms and diagnoses. Based on our findings building occupants were relocated.

PRACTICAL IMPLICATIONS

The remission of occupational asthma caused by certain known antigens improves with early diagnosis and removal from exposure. As a suspected antigen-mediated disease, sarcoidosis might also benefit if affected persons are isolated from continued exposure. Our investigation identified a high prevalence of new-onset sarcoidosis, and asthma among workers of a water damaged building with a history of indoor environmental quality complaints. Removal of all individuals from such environments until completion of building diagnostics, environmental sampling and complete remediation is a prudent measure when feasible.

Occupational sensitization to soy allergens in workers at a processing facility

BACKGROUND

Exposure to soy antigens has been associated with asthma in community outbreaks and in some workplaces. Recently, 135 soy flake processing workers (SPWs) in a Tennessee facility were evaluated for immune reactivity to soy. Allergic sensitization to soy was common and was five times more prevalent than in health care worker controls (HCWs) with no known soy exposure.

OBJECTIVE

To characterize sensitization to soy allergens in SPWs.

METHODS

Sera that were positive to soy ImmunoCAP (n=27) were tested in IgE immunoblots. Wild-type (WT) and transgenic (TG) antigens were sequenced using nanoscale Ultra-Performance Liquid Chromatography Tandem Mass Spectrometry (nanoUPLC MS/MS). IgE reactivity towards 5-enolpyruvylshikimate-3-phosphate synthase (CP4-EPSP), a protein found in TG soy, was additionally investigated. De-identified sera from 50 HCWs were used as a control.

RESULTS

Immunoblotting of WT and TG soy flake extracts revealed IgE against multiple soy antigens with reactivity towards 48, 54, and 62 kDa bands being the most common. The prominent proteins that bound SPW IgE were identified by nanoUPLC MS/MS analysis to be the high molecular weight soybean storage proteins, β-conglycinin (Gly m 5), and Glycinin (Gly m 6). No specific IgE reactivity could be detected to lower molecular weight soy allergens, Gly m 1 and Gly m 2, in soybean hull (SH) extracts. IgE reactivity was comparable between WT and TG extracts; however, IgE antibodies to CP4-EPSP could not be detected.

CONCLUSIONS AND CLINICAL RELEVANCE

SPWs with specific IgE to soy reacted most commonly with higher molecular weight soybean storage proteins compared with the lower molecular weight SH allergens identified in community asthma studies. IgE reactivity was comparable between WT and TG soy extracts, while no IgE reactivity to CP4-EPSP was observed. High molecular weight soybean storage allergens, Gly m 5 and Gly m 6, may be respiratory sensitizers in occupational exposed SPWs.

Rhinosinusitis and mold as risk factors for asthma symptoms in occupants of a water-damaged building

Mold exposure in damp buildings is associated with both nasal symptoms and asthma development, but the progression of building-related (BR) rhinosinusitis symptoms to asthma is unstudied. We examined the risk of developing BR-asthma symptoms in relation to prior BR-rhinosinusitis symptoms and microbial exposure among occupants of a damp building. We conducted four cross-sectional health and environmental surveys among occupants of a 20-story water-damaged office building. We defined BR-rhinosinusitis symptom (N=131) and comparison (N=361) groups from participants' first questionnaire responses. We compared the odds for the development of BR-asthma symptoms between these two groups over the subsequent surveys, using logistic regression models adjusted for demographics, smoking, building tenure, and first-survey exposures to fungi, endotoxin, and ergosterol. The BR-rhinosinusitis symptom group had higher odds for developing BR-asthma symptoms [odds ratio (OR)=2.2; 95% confidence interval (CI)=1.3-3.6] in any subsequent survey compared to those without BR-rhinosinusitis symptoms. The BR-rhinosinusitis symptom group with higher fungal exposure within the building had an OR of 7.4 (95% CI=2.8-19.9) for developing BR-asthma symptoms, compared to the lower fungal exposure group without BR-rhinosinusitis symptoms. Our findings suggest that rhinosinusitis associated with occupancy of water-damaged buildings may be a sentinel for increased risk for asthma onset in such buildings.

PRACTICAL IMPLICATIONS

Exposure to mold is associated with the development of asthma in damp building occupants, and rhinitis is known to be a risk factor for asthma. However, there is little information about the degree of risk for the progression of rhinosinusitis to asthma owing to mold exposures in damp buildings. Our study of damp building occupants demonstrates that building-related (BR) rhinosinusitis symptoms were a risk factor for the development of BR asthma symptoms and that exposure to mold (fungi) or other dampness-related agents augments risk for the development of BR asthma symptoms among those with BR rhinosinusitis symptoms. Our findings suggest that occurrence of BR upper respiratory illness in water-damaged buildings may presage future endemic asthma.

Respiratory inflammatory responses among occupants of a water-damaged office building

The National Institute for Occupational Safety and Health (NIOSH) received a request for evaluation of a water-damaged office building which housed approximately 1300 employees. Workers reported respiratory conditions that they perceived to be building related. We hypothesized that these symptoms were associated with airways inflammation. To test this hypothesis, we assessed airways inflammation in employees using exhaled breath condensate (EBC) and the fraction of exhaled nitric oxide (FENO). In September 2001, a health questionnaire was offered to all employees. Based on this questionnaire, NIOSH invited 356 symptomatic and asymptomatic employees to participate in a medical survey. In June 2002, these employees were offered questionnaire, spirometry, methacholine challenge test, allergen skin prick testing, EBC and FENO. FENO or EBC were completed by 239 participants. As smoking is highly related to the measurements that we used in this study, we included only the 207 current non-smokers in the analyses. EBC interleukin-8 (IL-8) levels, but not nitrite, were significantly higher among workers with respiratory symptoms and in the physician-diagnosed asthmatic group. Of the analyses assessed, EBC IL-8 showed the most significant relationship with a number of symptoms and physician-diagnosed asthma.

PRACTICAL IMPLICATIONS

Implementation of exhaled breath condensate and exhaled nitric oxide in indoor air quality problems.

Observational scores of dampness and mold associated with measurements of microbial agents and moisture in three public schools

We examined associations between observational dampness scores and measurements of microbial agents and moisture in three public schools. A dampness score was created for each room from 4-point-scale scores (0-3) of water damage, water stains, visible mold, moldy odor, and wetness for each of 8 room components (ceiling, walls, windows, floor, ventilation, furniture, floor trench, and pipes), when present. We created mixed microbial exposure indices (MMEIs) for each of 121 rooms by summing decile ranks of 8 analytes (total culturable fungi; total, Gram-negative, and Gram-positive culturable bacteria; ergosterol; (1→3)-β-D-glucan; muramic acid; and endotoxin) in floor dust. We found significant (P ≤ 0.01) linear associations between the dampness score and culturable bacteria (total, Gram-positive, and Gram-negative) and the MMEIs. Rooms with dampness scores greater than 0.25 (median) had significantly (P < 0.05) higher levels of most microbial agents, MMEIs, and relative moisture content than those with lower scores (≤0.25). Rooms with reported recent water leaks had significantly (P < 0.05) higher dampness scores than those with historical or no reported water leaks. This study suggests that observational assessment of dampness and mold using a standardized form may be valuable for identifying and documenting water damage and associated microbial contamination.

Adverse respiratory outcomes associated with occupational exposures at a soy processing plant

This study aimed to characterise the relationship between adverse health outcomes and occupational risk factors among workers at a soy processing plant. A questionnaire, spirometry, methacholine challenge, immune testing and air sampling for dust and soy were offered. Prevalence ratios (PRs) of respiratory problems from comparisons with the US adult population were calculated. Soy-specific immunoglobulin (Ig)G and IgE among participants and healthcare worker controls were compared. Associations between health outcomes and potential explanatory variables were examined using logistic regression. 147 (52%) out of 281 employees, including 66 (70%) out of 94 production workers, participated. PRs were significantly elevated for wheeze, sinusitis, ever-asthma and current asthma. Participants had significantly higher mean concentrations of soy-specific IgG (97.9 mg·L(-1) versus 1.5 mg·L(-1)) and prevalence of soy-specific IgE (21% versus 4%) than controls. Participants with soy-specific IgE had three-fold greater odds of current asthma or asthma-like symptoms, and six-fold greater odds of work-related asthma-like symptoms; the latter additionally was associated with production work and higher peak dust exposures. Airways obstruction was associated with higher peak dust. Work-related sinusitis, nasal allergies and rash were associated with reported workplace mould exposure. Asthma and symptoms of asthma, but not other respiratory problems, were associated with immune reactivity to soy.

Use of surrogate markers of biological agents in air and settled dust samples to evaluate a water-damaged hospital

An environmental survey was conducted in two hospital buildings in Montana, one of which had historical water incursion on the top floors and higher prevalence of reported respiratory symptoms that improved when the occupants were away from work. We measured culturable fungi and bacteria, fungal spores, endotoxin, and sub-micron particles in air; and culturable fungi and bacteria, endotoxin, markers of fungi (extra-cellular polysaccharides specific for Penicillium/Aspergillus, ergosterol, and beta(1-->3) glucans) and cat allergen in chair and floor dusts. For the analytes measured in air, the correlation coefficients ranged from 0.43 to 0.78 (P < 0.05). In chair dust, beta(1-->3) glucan concentrations correlated with culturable fungi and ergosterol concentrations. We found that sub-micron particles and markers of microbiological agents, but not culturable microbiological agents, were significantly positively associated with the building that had both historical water damage and higher prevalence of reported respiratory symptoms. Chair dust measurements tended to be higher in the non-complaint building. These results suggest that air and floor dust measurements of marker compounds may be better indicators of current health risk in a water-damaged environment than chair dust measurements or measurements of culturable fungi or bacteria in air or settled dust.

PRACTICAL IMPLICATIONS

Detection and quantification of nonculture-based microbiological markers and/or agents of disease may be useful methods to assess microbial contamination and to more accurately evaluate microbial exposures in the indoor environment for exposure-response studies.

Bacteria in a water-damaged building: associations of actinomycetes and non-tuberculous mycobacteria with respiratory health in occupants

We examined microbial correlates of health outcomes in building occupants with a sarcoidosis cluster and excess asthma. We offered employees a questionnaire and pulmonary function testing and collected floor dust and liquid/sludge from drain tubing traps of heat pumps that were analyzed for various microbial agents. Forty-nine percent of participants reported any symptom reflecting possible granulomatous disease (shortness of breath on exertion, flu-like achiness, or fever and chills) weekly in the last 4 weeks. In multivariate regressions, thermophilic actinomycetes (median = 529 CFU/m² ) in dust were associated with FEV₁ /FVC [coefficient = -2.8 per interquartile range change, P = 0.02], percent predicted FEF_25-75% (coefficient = -12.9, P = 0.01), and any granulomatous disease-like symptom [odds ratio (OR) = 3.1, 95% confidence interval (CI) = 1.45-6.73]. Mycobacteria (median = 658 CFU/m² ) were positively associated with asthma symptoms (OR = 1.5, 95% CI = 0.97-2.43). Composite score (median = 11.5) of total bacteria from heat pumps was negatively associated with asthma (0.8, 0.71-1.00) and positively associated with FEV₁ /FVC (coefficient = 0.44, P = 0.095). Endotoxin (median score = 12.0) was negatively associated with two or more granulomatous disease-like symptoms (OR = 0.8, 95% CI = 0.67-0.98) and asthma (0.8, 0.67-0.96). Fungi or (1→3)-β-D-glucan in dust or heat pump traps was not associated with any health outcomes. Thermophilic actinomycetes and non-tuberculous mycobacteria may have played a role in the occupants' respiratory outcomes in this water-damaged building.

Evaluation of Brassicas in grazing systems for sheep: I. Quality of forage and animal performance

Four years of grazing trials were conducted with Brassica forages to evaluate their chemical composition and effect on ADG of fattening lambs and breeding ewes in late fall. Brassicas tested included kales (Brassica oleracea L. var. acephala DC), turnips (B. rapa L.), and a chinese cabbage hybrid (B. rapa L. x B. pekinensis [Lour.] Rupr.). Daily gains of lambs varied widely among years (19 to 330 g/d); ADG on Brassicas were, however, generally higher than on stockpiled Kentucky 31 tall fescue (Festuca arundinacea Schreb.) or orchardgrass (Dactylis glomerata L.)-red clover (Trifolium pratense L.) pastures grazed at the same time. In 1 yr, dietary supplementation of lambs grazing a hybrid turnip (Forage Star) with iodine and copper oxide needles improved (P < .05) ADG; however, there was no effect on gains in two later years. In 2 yr, lambs showed higher ADG on Tyfon chinese cabbage hybrid (241 and 330 g/d) than on Forage Star turnip (197 and 275 g/d) or stockpiled grass-clover (135 and 233 g/d), but yield of Tyfon was lower. Indications that supplementary hay improved ADG of lambs and ewes were not confirmed in the final year, in which hay increased (P < .05) ADG of lambs in the first 3 wk of grazing Brassicas but decreased gains later. Thyroid weights were increased (P < .01) consistently in all trials on Brassicas, but enlargement was modest and not related to ADG. Brassica forages provided high yields (5.6 to 10.5 t/ha) of DM in the late fall to early winter period, with high carrying capacity for sheep but large variability in ADG.

Respiratory morbidity and medical visits associated with dampness and air-conditioning in offices and homes

We used data from 4345 adult US residents who were part of a 2004 national random mail survey to investigate associations between dampness and air-conditioning (AC) in homes and offices, and health outcomes, sick leave due to respiratory symptoms and medical visits during the past 12 months. We identified from this group 1396 office workers employed in professional, executive, administrative, managerial or administrative support occupations. Office workers reporting home dampness had an elevated prevalence of nasal symptoms [prevalence ratio (PR) = 1.4, P = 0.01] and constitutional symptoms (PR = 1.3, P = 0.01) in the previous year. Office workers reporting workplace dampness had an elevated prevalence of sick leave attributed to respiratory symptoms (PR = 1.3, P = 0.04) in the previous year. Office workers with home AC were more likely to have visited a medical specialist in the previous year (PR = 1.3, P = 0.02). We did not find any statistically significant associations between workplace AC and any of the health outcomes. We estimated an annual cost of US$1.4 billion for excess respiratory-related sick leave among office workers with workplace dampness. Our study strengthens the evidence of a relationship between dampness and health effects, and highlights the resulting economic impact.

PRACTICAL IMPLICATIONS

This study adds to the literature on respiratory morbidity associated with home and office exposures to mold and dampness. Public health response to lessen these exposures will improve the health and well-being of residents and workers as well as diminish the economic burden of lost work time and medical costs.

Nutritive quality and palatability of switchgrass hays for sheep: effects of cultivar, nitrogen fertilization, and time of adaptation

Feeding and palatability trials were conducted with four cultivars (cv) of switchgrass (Panicum virgatum L.), fertilized at three levels of N (0, 75, or 150 kg of N/ha) in 2 yr. Wether sheep had ad libitum access to chopped hays, and intake, apparent digestibility, particle passage rates, and concentrations of blood metabolites were determined. Palatability was measured with mature sheep in cafeteria trials. Nitrogen fertilization did not affect (P > .05) DM digestibility (DMD) or DMI, but there was a year x N interaction (P < .01) for NDF digestibility. Dry matter digestibility values for combined years and N levels were 56.9, 54.4, 56.6, and 57.9% (P < .01) for Pathfinder, New Jersey 50, Kentucky 1625, and Trailblazer cv, respectively; mean DMI values were 60.4, 60.8, 57.7, and 64.0 g/kg BW.75 (year x cv, P < .01). An apparently greater quality of Trailblazer was masked by weed invasion of N-fertilized stands of this cv in yr 2, with changes in hay composition. Lambs adapted to hay diets with time; mean DMI for cv and N levels combined increased (P < .001) from 50.5 to 71.4 g/kg BW.75 between wk 2 and 3 and wk 10 and 11, with no change in DMD. Intakes of NDF increased from 37.6 to 55.6 g/kg BW.75, an increase of 48%. Marker (Yb) measurements indicated little change in particle passage rates with treatment. There were no major differences in blood composition, apart from increases in blood urea N, as a result of N fertilization. Cafeteria trials showed preference by sheep for Trailblazer and KY 1625 compared with NJ 50 and Pathfinder, with a N x cv interaction (P < .01). Trailblazer was preferred to KY 1625 in a two-choice situation (P < .01). Results show relatively small effects of cv and N fertilization on quality of switchgrass and indicate the need for a lengthy period of adaptation by sheep to the feeding of a warm-season grass.

Work-related peak flow and asthma symptoms in a damp building

BACKGROUND

Working in damp conditions is associated with asthma, but few studies have used objective testing to document work-related patterns.

AIMS

To describe the relationship of peak flow measurements to work-related asthma (WRA) symptoms and WRA among occupants in a damp office building.

METHODS

At the beginning of the study, all workers were offered a questionnaire and methacholine challenge testing. Participants were then instructed to perform serial spirometry using handheld spirometers five times per day over a 3 week period. Peak flow data were analysed using OASYS-2 software. We calculated the area between the curves (ABC score) using hours from waking. We considered a score >5.6 L/min/h to be indicative of a work-related pattern.

RESULTS

All 24 employees participated in the questionnaire. Seven participants (29%) reported physician-diagnosed asthma with onset after starting work in the building. Almost two-thirds (63%) of participants reported at least one lower respiratory symptom (LRS) occurring one or more times per week in the last 4 weeks. Twenty-two (92%) consented to participate in serial spirometry. Fourteen participants had adequate quality of serial spirometry, five of whom had ABC scores >5.6, ranging from 5.9-23.0. Of these five, two had airways responsiveness, three had current post-hire onset physician-diagnosed asthma and four reported work-related LRS.

CONCLUSIONS

We found evidence of work-related changes in serial peak flows among some occupants of an office building with a history of dampness. Serial peak flows may be a useful measure to determine WRA in office settings.

The Association of Airflow Obstruction with Occupational Exposures in a Sample of Rural Adults in Iowa

A recent article reported that occupational exposure to vapor-gas, dust, and fumes (VGDF) was more common in a sample of rural adults than in a sample of adults in urban settings. In another study of the same urban adults, airflow obstruction (AO) was associated with occupational VGDF and the combination of smoking and occupational exposure. The goal of the current study was to determine if similar associations were evident in the sample of rural adults. We analyzed enrollment data from the Keokuk County Rural Health Study (KCRHS), which investigated the health of rural residents in Iowa. We used the same methods as the study of urban adults. A job-exposure matrix (JEM) assigned an occupational VGDF exposure level based on each participants' last reported job. The health outcome was AO, defined as both the forced expiratory volume in one second (FEV1) and the FEV1/forced vital capacity (FVC) ratio < lower limit of normal. Of the 1699 KCRHS participants, 436 (25.7%) had high total VGDF occupational exposure, 661 (38.9%) had ever smoked cigarettes, and 110 (6.5%) had AO. The crude frequency of AO increased across the joint categories of smoking (never, ever) and high exposure (no, yes) (p < 0.05 for linear trend). After adjusting for potential confounders, AO was associated with high total occupational VGDF exposure only among smokers (OR = 1.81, 95% CI 1.002 to 3.26). In conclusion, the association of AO with occupational exposure in the current study of rural adults was similar to what was previously observed among urban adults.

Levels of microbial agents in floor dust during remediation of a water-damaged office building

We examined the effects of remediation on loads of culturable fungi in floor dust collected from a large water-damaged office building during four cross-sectional surveys (2002, 2004, 2005, and 2007, respectively). We created a binary remediation variable for each year for each sampled workstation using information on remediation associated with water damage obtained from building management and used generalized linear mixed-effects models. We found significantly lower levels of culturable total and hydrophilic fungi at remediated workstations than at non-remediated workstations in 2004 and 2005 after completion of major remediation. The remediation effect, however, disappeared in 2007. The fraction of hydrophilic to total fungal concentrations was lowest in 2004, increased in 2005, and was highest in 2007. Our results indicate that the 2003 remediation lowered dust indices of dampness temporarily, but remediation was incomplete, consistent with a building assessment report of water infiltration. This study demonstrates the utility of longitudinal evaluation of microbial indices during remediation of water damage in this building, in which elimination of sources of moisture was not fully addressed. Our findings indicate that the fraction of hydrophilic fungi derived from concentrations of fungal species may be a useful index for assessing the long-term effectiveness of remediation.

PRACTICAL IMPLICATIONS

This study demonstrates the utility of longitudinal evaluation of microbial indices during remediation of water damage in this building, in which elimination of sources of moisture was incomplete. Our findings indicate that the fraction of hydrophilic fungi derived from concentrations of fungal species may be a useful index for assessing the long-term effectiveness of remediation.

Gender differences in obesity-related cardiovascular disease risk factors among participants in a weight loss programme

Obesity is associated with increased cardiovascular disease risk factors in some, but not all, individuals, and blood pressure responses to weight loss are also heterogeneous. The purposes of this study are: (i) to assess associations among cardiovascular disease risk factors in obese individuals and (ii) to determine clinical predictors of a hypotensive response to weight loss. The study was undertaken in 155 consecutive patients enrolled in a weight loss programme. Individuals entering the programme were predominantly women and differences were found between men and women who joined the programme. Before weight loss, obese men exhibited higher cardiovascular disease risk factors (body mass indices, waist-to-hip ratios, systolic and diastolic blood pressures, serum glucose, and lower HDL cholesterol) than did women. However, among women, but not men, cardiovascular disease risk factors clustered in individuals with higher waist-to-hip ratios. Furthermore, in contrast to men, a higher waist-to-hip ratio in women was associated with a reduction in systolic blood pressure in response to weight loss. While it is possible that selection bias may explain gender differences among programme participants, and smaller numbers of men available for study may obscure associations in men, our data document that even at high levels of obesity, waist-to-hip ratios are associated with hypertension and a clustering of cardiovascular disease risk factors in women. We conclude that body fat distribution, as reflected in waist-to-hip ratios, may be a more robust risk factor in female than in male obese patients and that this risk factor extends to those women with high levels of obesity.

Treatment of spastic gait in cerebral palsy

The most common presentation of cerebral palsy is spastic diplegia, which in severe cases can impede nursing care and in less severe cases can impair a child's ability to move around with facility. A procedure has been developed to decrease spasticity in which there is selective section of portions of the dorsal roots L2-S2. In a series of such operations in 19 children with spastic diplegia, we were able to decrease their spasticity significantly with resultant improvement in motor function and self care. There were no significant complications and patient and family satisfaction was high. Our experiences further confirm existing evidence that this procedure is very helpful and highly recommended for selected children with spasticity due to cerebral palsy.