Grain dust and the lungs.

Grain dust is composed of a large number of materials, including various types of grain and their disintegration products, silica, fungi, insects and mites. The clinical syndromes described in relation to exposure to grain dust are chronic bronchitis, grain dust asthma, extrinsic allergic alveolitis, grain fever and silo-filler''s lung. Rhinitis and conjunctivitis are also common in grain workers. While the concentration and the quality of dust influence the frequency and the type of clinical syndrome in grain workers, host factors are also important. Of the latter, smoking is the most important factor influencing the frequency of chronic bronchitis. The role of atopy and of bronchial hyperreactivity in grain dust asthma has yet to be assessed. Several well designed studies are currently being carried out in North America not only to delineate the frequency of the respiratory abnormalities, the pathogenetic mechanisms and the host factors, but also to establish a meaningful threshold limit concentration for grain dust.     

House dust mite-related respiratory allergies and probiotics: a narrative review

The socio-economic burden of allergic respiratory conditions on continental Europe is even higher than that of mainstream diseases, such as diabetes and cardiovascular disease, as allergic rhinitis alone accounts for billions of Euros in healthcare expenses across Europe. House dust mites (HDM) are one of the most common triggers behind allergic rhinitis and asthma. The role of probiotics in the treatment and prevention of some allergic conditions, such as atopic dermatitis, is already well recognized, whereas evidence about their efficacy in patients with respiratory allergies—while increasing—is still limited. Here the current evidence for the use of probiotics in patients with allergic rhinitis and/or asthma is discussed.     

Grain sorghum dust increases macromolecular efflux from the in situ nasal mucosa

The purpose of this study was to determine whether an aqueousextract of grain sorghum dust increases macromolecular efflux from thenasal mucosa in vivo and, if so, whether this response is mediated, inpart, by substance P. Suffusion of grain sorghum dust extract on the insitu nasal mucosa of anesthetized hamsters elicits a significantincrease in clearance of fluorescein isothiocyanate-labeled dextran(FITC-dextran; mol mass, 70 kDa; P < 0.05). This response is significantly attenuated byCP-96345 and RP-67580, two selective, but structurally distinct,nonpeptide neurokinin 1 (substance P)-receptor antagonists, but not byCP-96344, the2R,3Renantiomer of CP-96345 (P < 0.05). CP-96345 has no significant effects on adenosine-induced increase in clearance of FITC-dextran from the insitu nasal mucosa. CP-96345 and RP-67580, but not CP-96344, significantly attenuate substance P-induced increases in clearance ofFITC-dextran from the in situ nasal mucosa(P < 0.05). Collectively, these datasuggest that grain sorghum dust elicits neurogenic plasma exudationfrom the in situ nasal mucosa.

     

North African dust intrusions and increased risk of respiratory diseases in Southern Portugal

International Journal of Biometeorology - The study of dust intrusions in Portugal is still a subject on which little investigation has been made, especially in terms of their effects. Thus, this...     

African desert dust in the Caribbean atmosphere: Microbiology and public health

Air samples collected on St. John in the U.S.Virgin Islands were screened for the presenceof viable bacteria and fungi to determine ifthe number of cultivatable microbes in theatmosphere differed between ``clear atmosphericconditions' and ``African dust-events.' Resultsindicate that during ``African dust-events,' thenumbers of cultivatable airborne microorganismscan be 2 to 3 times that found during ``clearatmospheric conditions.' Direct microbialcounts of air samples using an epifluorescentmicroscopy assay demonstrated that during an``African dust-event,' bacteria-like andvirus-like particle counts were approximatelyone log greater than during ``clear atmosphericconditions.' Bacteria-like particles exhibitingautofluoresence, a trait of phototrophs, wereonly detected during an ``African dust-event.'     

Ozone, air pollution, and respiratory health.

Of the outdoor air pollutants regulated by the Clean Air Act of 1970 (and recently revised in 1990), ozone has been the one pollutant most difficult to control within the federal standards. The known human health effects are all on the respiratory system. At concentrations of ozone which occur during summer air-pollution episodes in many urban metropolitan areas of the United States, a portion of the healthy population is likely to experience symptoms and reversible effects on lung function, particularly if exercising heavily outdoors. More prolonged increase in airway responsiveness and the presence of inflammatory cells and mediators in the airway lining fluid may also result from these naturally occurring exposures. Serial exposures to peak levels of ozone on several consecutive days are more characteristic of pollution episodes in the Northeast United States and may be associated with recurrent symptoms. No "high-risk" or more sensitive group has been found, in contrast to the case of sulfur dioxide, to which asthmatics are more susceptible than normals. The occurrence of multiple exposure episodes within a single year over many years in some areas of California has led to studies looking for chronic effects of ozone exposure on the lung. To date, no conclusive studies have been reported, although further work is under way. Much of what we know about the effects of this gas on the lung are based on controlled exposures to pure gas within an environmental exposure laboratory. Interactions between substances which commonly co-occur in air-pollution episodes are also under investigation.     

Controlled trial of respiratory health worker visiting patients with chronic respiratory disability.

Seventy five patients with chronic respiratory disability were randomised to a group visited by a respiratory health worker (42) or control group (33). The first group was visited monthly by a respiratory nurse, who gave education and support. The effect of the intervention was assessed in terms of quality of life (by questionnaires), the number and duration of admissions to hospital, and the number of deaths. The questionnaires on quality of life showed no changes in either group during the study, but nearly all of the group visited by a respiratory health worker said that they valued the visits and wished them to continue. Their knowledge about their condition also improved compared with that of the controls. The duration of stay in hospital for respiratory reasons in the group visited by a respiratory health worker was longer than that of control patients. This was explained by their being scored as more ill than the controls on admission. Fewer patients died in the group visited by a respiratory health worker than in the control group (p = 0.11). The patients in the group visited by respiratory health workers may have survived longer because they sought help rather than dying at home. If confirmed this could have implications for the cost of their care.     

Occupational exposure and respiratory health of workers at small scale industries

Certain occupations like welding, painting, and vehicle repairing are associated with regular exposure to dust, exhausts, fuels, fumes, PM, and vapors of welding, solvents, and paint. Many studies have proved a reduction in lung functions due to exposure to these agents. The present study aims to assess and compare respiratory symptoms and pulmonary functions among exposed and non-exposed persons as well as suggests controls respectively. A cross-sectional case study was carried out among small scale industry workers having matched demographic and anthropometric parameters. Medical Research Council (MRC) questionnaire and Micro Direct computerized automated spirometer were used for recording respiratory ailments and pulmonary function tests (PFT) respectively. The percentages of mechanics, welders and painters were 40.9, 31.8, and 27.3 respectively. The highest reported respiratory symptom was chest tightness and whistling among exposed (22.7%) and unexposed (10%). Among study exposed cases, the occupational exposure was found as often (22.7%), sometimes (68.2%) and never (9.1%) while the reported use of airway protection (masks) was very low. Overall respiratory health of the exposed versus controls was reported as excellent (54.5% vs 73.4%), good (27.3% vs 23.3%) and average (18.2% vs 3.3%) respectively. The exposed group on contrary to control one has decreased mean values for FEV1 (3.12 vs 3.50), FVC (4.12 vs 4.43), FEV1/ FVC % (79.60 vs 80.79) and PEF (414.77 vs 523.16). The present study reveals that exposed workers are at increased risk of developing respiratory symptoms and decreased pulmonary functions as compared to unexposed. Such exposure research studies are instrumental in health status evaluation of workers. However, this area has been neglected by the researchers in Saudi Arabia. It is, thus, strongly recommended to carry out prospective studies to substantiate the study results including large sample size, background pollutants concentrations and biological monitoring. Control strategies should be adopted to reduce the vapor concentration in the ambient air, protect and promote respiratory health of workers.     

Road traffic and adverse effects on respiratory health in children.

OBJECTIVES--To examine whether road traffic in a big city has a direct effect on pulmonary function and respiratory symptoms in children. DESIGN--Cross sectional study. SETTING--Of all 7445 fourth grade children (aged 9-11 years) in Munich, 6537 were examined. Of the children with German nationality and the same residence during the past five years and known exposure data, 4678 questionnaires and 4320 pulmonary function tests could be analysed. MAIN OUTCOME MEASURES--Variables of pulmonary function by forced expiration and respiratory symptoms reported in a questionnaire; census data on car traffic collected in the school district. RESULTS--Density of car traffic ranged from 7000 to 125,000 cars per 24 hours. Multiple regression analysis of peak expiratory flow showed a significant decrease of 0.71% (95% confidence interval 1.08% to 0.33%) per increase of 25,000 cars daily passing through the school district on the main road. Maximum expiratory flow when 25% vital capacity had been expired was decreased by 0.68% (1.11% to 0.25%). In contrast, response to cold air challenge was not increased. The adjusted odds ratio for the cumulative prevalence of recurrent wheezing with the same exposure was 1.08 (1.01 to 1.16). Cumulative prevalence of recurrent dyspnoea was increased, with an odds ratio of 1.10 (1.00 to 1.20). Lifetime prevalence of asthma (odds ratio 1.04; 0.89 to 1.21) and recurrent bronchitis (1.05; 0.98 to 1.12) were not significantly increased. CONCLUSIONS--High rates of road traffic diminish forced expiratory flow and increase respiratory symptoms in children.     

The role of the local microbial ecosystem in respiratory health and disease

Respiratory tract infections are a major global health concern, accounting for high morbidity and mortality, especially in young children and elderly individuals. Traditionally, highly common bacterial respiratory tract infections, including otitis media and pneumonia, were thought to be caused by a limited number of pathogens including Streptococcus pneumoniae and Haemophilus influenzae. However, these pathogens are also frequently observed commensal residents of the upper respiratory tract (URT) and form—together with harmless commensal bacteria, viruses and fungi—intricate ecological networks, collectively known as the ‘microbiome’. Analogous to the gut microbiome, the respiratory microbiome at equilibrium is thought to be beneficial to the host by priming the immune system and providing colonization resistance, while an imbalanced ecosystem might predispose to bacterial overgrowth and development of respiratory infections. We postulate that specific ecological perturbations of the bacterial communities in the URT can occur in response to various lifestyle or environmental effectors, leading to diminished colonization resistance, loss of containment of newly acquired or resident pathogens, preluding bacterial overgrowth, ultimately resulting in local or systemic bacterial infections. Here, we review the current body of literature regarding niche-specific upper respiratory microbiota profiles within human hosts and the changes occurring within these profiles that are associated with respiratory infections.     

Oral health and history of respiratory tract infection in frail institutionalised elders

Objectives: The purpose of this study was to look for a relationship between history of respiratory tract infection (RTI) and oral health in very old subjects. Setting and Subjects: 302 frail elders (mean age: 85 years) living in a medical care facility were examined by one dentist. Outcome Measures: The incidence of RTI over 1 year had been recorded along with markers of nutritional status and degree of dependency. The oral examination comprised an evaluation of hygiene, quality of prostheses and the prevalence of caries, periodontal disease and mucosal disorders. Results: One third (33%) of the subjects had experienced at least one episode of RTI and a fifth (19%) had visited the dentist in emergency. The incidence of RTI had been greater among dentate subjects and those who came to the dentist in emergency. The dentate subjects with a history of RTI had higher plaque score (P=0.02). Half (49%) of the subjects had oral disorders that could develop in a dental emergency and these subjects had had a higher risk of RTI (relative risk: 1.9, 95% confidence interval: 1.1–3.9). The presence of selected oral disorders associated with low serum albumin increased the relative risk of having had RTI to 3.2 (1.5–6.7). The association between presence of actual oral health problems and previous experience of RTI was more noticeable in those who had poor general health or were more debilitated. Conclusions: The present study suggests that poor oral hygiene and the presence of potential emergency could be major risk factors for RTI among the frail elderly.     

Impact of a waste disposal site on adult respiratory health

Introduction. This study evaluated the impact of the presence of a dump on respiratory health in adults older than 50 years of age, living in its area of influence. Materials and methods. A cohort study was conducted with 313 adults older than 50 years of age living near the Navarro Dump (Cali, Colombia) and compared with 359 adults in an unexposed area. Each was examined monthly during a 6 month period to compare the incidence of respiratory symptoms and alterations in peak expiratory flow. Results. Exposure to the Navarro Dump was associated with occurrence of respiratory symptoms (odds ratio=1.25, 95% C.I. 1.01-1.56), in particular with mild respiratory symptoms (odds ratio=1.28, 95% C.I. 0.98-1.66). This result was obtained after adjusting for age, sex, education level, humidity, health insurance, comorbidity, smoking and previous occupational exposure. A higher recurrence of symptoms was found in adults in the area of exposure (correlation coefficient=0.29, 95% C.I. 0.23-0.33, p<0.001) and a significant reduction in the lung function defined by peak expiratory flow; the average decrease was15.2 L/min (95% C.I. -30.2 to +0.22). Conclusion. Independent of potential confounding factors, the respiratory health of adults exposed to the Navarro Dump was affected and exhibited an increased occurrence and recurrence of mild respiratory symptoms as well as decreased lung function.     

Short-term effect of dust storms on the risk of mortality due to respiratory, cardiovascular and all-causes in Kuwait

This study aimed to investigate the impact of dust storms on short-term mortality in Kuwait. We analyzed respiratory and cardiovascular mortality as well as all-cause mortality in relation to dust storm events over a 5-year study period, using data obtained through a population-based retrospective ecological time series study. Dust storm days were identified when the national daily average of PM₁₀ exceeded 200 μg/m³. Generalized additive models with Poisson link were used to estimate the relative risk (RR) of age-stratified daily mortality associated with dust events, after adjusting for potential confounders including weather variables and long-term trends. There was no significant association between dust storm events and same-day respiratory mortality (RR = 0.96; 95 %CI 0.88–1.04), cardiovascular mortality (RR = 0.98; 95 %CI 0.96–1.012) or all-cause mortality (RR = 0.99; 95 %CI 0.97–1.00). Overall our findings suggest that local dust, that most likely originates from crustal materials, has little impact on short-term respiratory, cardiovascular or all-cause mortality.