Asthma: Sensitisation to indoor allergens and primary prevention in infancy
Başlık:
Asthma: Sensitisation to indoor allergens and primary prevention in infancy
Yazar:
Custovic, Adnan, author.
ISBN:
9780438043367
Yazar Ek Girişi:
Fiziksel Tanımlama:
1 electronic resource (451 pages)
Genel Not:
Source: Dissertation Abstracts International, Volume: 76-08C.
Özet:
Introduction: Prevalence of asthma is increasing, and the disease places enormous demands on health care services. It is essential to devise methods of primary prevention. Aims: To design a primary prevention study using allergen avoidance, it was essential to investigate the sources, aerodynamics and particle size distribution of allergens (mite cat and dog) in homes and in public places. Results: Airborne pet allergens are readily measured in houses with pets (and in a quarter of the homes without pets), and ~25% of airborne Fel d 1 and Can f 1 is associated with small particles (<5 mum). Cat and dog allergens are detectable in most dust reservoirs in public places. The passive exposure in homes without pets and in public places may be important. Conclusions: This research has provided the basic evidence for a Primary Prevention programme and enabled establishing of a prospective primary prevention study using environmental manipulation. Primary Prevention programme: Early exposure to mite allergens may be critical for primary sensitisation. Reducing exposure may offer a realistic chance for primary prevention. Methods: Parents were screened at 'Booking' ante-natal visits. The prevalence of atopy and the risk factors for asthma and allergic disorders (logistic regression) were investigated in women and their partners who completed the questionnaire and underwent skin testing. Children were allocated to risk groups according to parental atopic status. Group A (high- risk, both parents atopic, no pets) was entered into a prospective, prenatally randomised study investigating whether living in a low allergen environment reduces the risk of asthma and atopic diseases. Infants were randomly allocated to dust mite allergen avoidance (Active group) or no intervention (Control group). Avoidance measures comprised; a) mite-proof covers for parental bed; b) high filtration vacuum cleaner; c) vinyl flooring in infants' bedroom; d) new cot and carrycot mattress encased in mite-proof material; e) Benzyl-benzoate applied on carpets and soft furniture; f) bed linen hot washed weekly; g) washable soft toys. Dust samples from homes were collected between 10th and 14th week of pregnancy, immediately after birth, and then at 6 months and 1 year of age and Der p 1 levels determined by ELISA. Group B comprised of "High risk" infants with pets in the home, and Group C of "Low risk" infants (Both parents SPT negative). Signs and symptoms suggestive of atopic disease have been recorded at the follow-up clinic visit at 1 year of age. The relative risk (R) and 95% Cl were calculated and the outcome probabilities for different risk groups of children in relation to the High risk Control group were estimated. Results: In 5687 adult subjects there was a very high (48.2%) prevalence of atopy, and 9.7% of subjects had a diagnosis of asthma. In a multivariate regression analysis sensitisation to dust mite, cat, dog and mixed grasses were all independently associated with asthma. The odds ratios for asthma increased with the increasing number of positive skin tests (2 allergens - OR 3.9, 3 allergens - OR 6.9, all 4 allergens OR 9.8). Dog ownership and current smoking were significantly and directly associated with asthma. The strongest independent associate of eczema was sensitisation to dog. The prevalence of hay fever in was high (20.6%), and in the multivariate analysis the association between sensitisation to pollen and hay fever was extremely strong (OR 13.6, 95% Cl 11.3-16.3). The total amount of Der p 1 recovered at 1 year of age was 29-fold (95% Cl 15.1-56.7 fold) higher in the control than in the active group. A total of 517 infants were reviewed at 1 year of age (133 Active group, 118 Control group, 140 Group B and 126 Group C). The estimates of relative risks for the whole range of respiratory symptoms during first year of life for infants in the Active group were consistently lower compared to the Control group. The most marked differences were in the risk ratios for: severe wheeze with shortness of breath-R=0.44, 95% Cl 0.197 to 0.999, p<0.05; prescribed medication for the treatment of wheezy attacks-R=0.58, 95% Cl 0.356 to 0.952, p<0.05; wheezing after vigorous playing, crying or exertion-R = 0.177, 95% Cl 0.04 to 0.794, p<0.05). Conclusions: Although very encouraging, these early results are not conclusive, since they relate to infant wheeze, and these differences may, or may not persist as follow-up continues.
Notlar:
School code: 1543
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Yer Numarası | Demirbaş Numarası | Shelf Location | Lokasyon / Statüsü / İade Tarihi |
---|---|---|---|
XX(684273.1) | 684273-1001 | Proquest E-Tez Koleksiyonu | Arıyor... |
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