Allergens, indoor house dust

It is desirable to collect as many different matrices from each study participant as is feasible and to process them with consideration of both immediately planned analyses of biomarkers and future uses. For example, several Children s Environmental Health Centers obtained urine, peripheral blood, cord blood, breast milk, meconium, saliva, hair, placental tissue, infant formula, indoor and outdoor air, and house dust from longitudinal birth cohort studies (Eskenazi et al. 2005). The centers have analyzed concentrations of numerous compounds in those biologic and environmental samples, such as pesticides, phthalates, mercury, lead, cotinine, polycyclic aromatic hydrocarbone (PAHs), PAH-DNA adducts, allergens, endotoxin, antioxidant micronutrients, cholinesterase, and thyroid hormones. Most centers also banked samples for future analyses. 

Airway hyperresponsiveness in children is mostly associated with airway inflammation due to IgE sensitisation [63-65]. Chronic asthma is mainly associated with sensitisation to indoor allergens (house dust mites, animal dander, cockroaches etc), which are more important than the outdoor allergens, probably because of the time spent indoors [2, 66, 67]. Several studies have demonstrated a relationship (in a dose-dependent manner) between exposure and presence of IgE antibody [68-71], as well as a clear association between presence of IgE antibody and development of asthma [65, 70-78]. However, no significant direct association between early exposure to indoor allergens and development of asthma up to the age of 7 years was found in a recent study [72]. Importantly, such an association should only be expected as regards allergic asthma. A dose-response relationship between exposure to house dust mites and development and severity of asthma has been demonstrated [74, 75]. Other longitudinal studies have shown that sensitisation to house dust mites and animal dander antedate, and are a risk factor for development of asthma in children [65, 71, 78, 79]. 

Patients with asthma, rhinoconjunctivitis or eczema who are allergic to indoor allergens such as house dust mites, cockroaches and animal danders should eliminate or reduce the exposure to improve symptom control and prevent exacerbations (A-B). 

Indoor allergens usually are present perennially most important among these are house dust mite fecal proteins, animal dander, cockroaches, and certain mold species. Dust mite levels are on the rise, possibly due to the improved construction of energy-efficient homes and offices that result in reduced ventilation and increased humidity, use of wall-to-wall carpeting, and the popularity of cool water detergents and cold water washing. ... 

Several factors are affecting asthma including environmental and individual factors. There is seasonal variability in asthma in autumn, it is increased, while in summer, it is minimum in the United States (Silverman et ah, 2003). The reasons for these variations include increased exposure to allergens such as pollen, house dust mites, and mould spores among yoimger generation and in adults it may be increased influenza or other respiratory tract infections (Riccioni et ah, 2001). Moreover, cigarette smoke is one of the most common asthmatic reasons. Both indoor and outdoor air pollutants may also increase asthma. Inhalation of toxic vapors from industrial fumes, bleach sulfur, or smoke from fire or tobacco may also affect asthma (Just et ah, 2002). 

Those studies conducted to date establish a basis for control of lead, pesticides, PAHs, PCBs, and allergens in indoor air and house dust. Track-in and accumulation of pollutants in rugs is an important source of exposure for children lead in dust is the major source of lead for most toddlers. The established benefits from reduced exposure to lead and allergens justify public education to reduce dust from track-in and inside sources as well as pollutants in indoor air. Action to control lead and allergens will reduce exposure to other pollutants in house dust and indoor air. It is possible that a nonregulatory education and outreach program with emphasis on public participation and pollution prevention will be more effective in the home than use of regulations and other traditional methods of pollution control. 

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