Hallo,
Spinnifex hat folgendes geschrieben::
.. die wahrscheinlichkeit, dass sich leute eine allergie holen steigt mit der häufigkeit der kontakte...
Kannst Du diese Aussage irgendwie belegen? Gibt es dafür schon Beweise?
Dazu gibt es Untersuchungen. Je nachdem, an welcher Art der Atopie man leidet ( Typ1 zb. bei Asthma oder Typ 4 bei Kontaktexzem ) mag es vielleicht so vorkommen, dass man auf wiederholten Kontakt mit dem Allergen eine heftigere Immunreaktion zeigt, was daran liegt, dass der Körper durch den wiederholten Kontakt mit dem Allergen schneller reagiert.
ABER: Die Wahrscheinlichkeit, eine Allergie zu bekommen
SINKT mit der Häufigkeit der Kontake.
Das kann man z.B. hier nachlesen:
Four-year incidence of allergic sensitization among schoolchildren in a community where allergy to cat and dog dominates sensitization: report from the Obstructive Lung Disease in Northern Sweden Study Group.
Ronmark E, Perzanowski M, Platts-Mills T, Lundback B; Obstructive Lung Disease in Northern Sweden Study Group.
Department of Medicine, Sunderby Central Hospital of Norrbotten, Lulea, Sweden.
BACKGROUND: Exposure to high levels of cat allergen might prevent sensitization. OBJECTIVE: We sought to measure the incidence of allergic sensitization among schoolchildren living in a dust mite- and cockroach-free environment and the associated risk factors. METHODS: In 1996, a longitudinal cohort was established in northern Sweden, including 2454 children aged 7 to 8 years. Children were skin tested, and the testing was repeated 4 years later. Questionnaires were completed yearly. Participation was 88% both in 1996 and 2000. RESULTS: The prevalence of positive skin test results increased from 20.6% at age 7 and 8 years to 30.4% at age 11 and 12 years, a cumulative incidence of 13.8%, and was significantly higher among boys. The incidence was highest for cat (6.0%), timothy grass (5.9%), dog (4.9%), and birch (3.6%). A family history of allergy was the major risk factor for both a positive skin test response at age 7 and 8 years (odds ratio [OR], 1.69; 95% CI, 1.36-2.10) and for development of a positive skin test response over the next 4 years (OR, 1.67; 95% CI, 1.23-2.28). A significant inverse association between cat and dog ownership and the prevalence of type 1 allergy was found, particularly for those children who had lived with a cat both before age 7 and 8 years and during the next 4 years (OR, 0.44; 95% CI, 0.31-0.61). A similar pattern, although not significant, was found for incident cases. CONCLUSION: The high incidence of type 1 allergy at this age was similar to reports from communities with mite and cockroach allergen. Despite cat and dog being the most common allergens of sensitization, keeping these animals at home was not associated with an increased risk for sensitization.
oder auch hier:
Effect of cat and dog ownership on sensitization and development of asthma among preteenage children.
Perzanowski MS, Ronmark E, Platts-Mills TA, Lundback B.
OLIN Studies, Department of Medicine, Sunderby Central Hospital of Norrbotten, Lulea, Sweden.
[email protected]
An inverse relationship has been proposed between exposure to high quantities of cat allergen at home and both asthma and cat allergy. First- and second-grade children from Lulea, Kiruna, and Pitea, Sweden participated in an asthma questionnaire study (n = 3,431) and incidence was evaluated over the next 3 years. Skin testing was performed on the children in Lulea and Kiruna (n = 2,149). The strongest risk factor for incident cases of asthma was Type 1 allergy (relative risk [RR], 4.9 [2.9-8.4]), followed by a family history of asthma (RR, 2.83 [1.8-4.5]). Living with a cat was inversely related both to having a positive skin test to cat (RR, 0.62 [0.47-0.83]) and incidence of physician-diagnosed asthma (RR, 0.49 [0.28-0.83]). This effect on incident asthma was most pronounced among the children with a family history of asthma (RR, 0.25 [0.08-0.80]). The evidence also suggests that many of the children exposed to cats at home can develop an immune response that does not include immunoglobulin E. Weaker protective trends were seen with dog ownership. The traditional thinking that not owning cats can provide protection against developing allergy and asthma among those with a family history of allergy needs to be re-evaluated. In a community where cat sensitization was strongly associated with asthma, owning a cat was protective against both prevalent and incident asthma.
oder da:
Exposure to dogs and cats in the first year of life and risk of allergic sensitization at 6 to 7 years of age.
Ownby DR, Johnson CC, Peterson EL.
Section of Allergy and Immunology, Department of Pediatrics, BG-1019, Medical College of Georgia, Augusta, GA 30912-3790, USA.
[email protected]
CONTEXT: Childhood asthma is strongly associated with allergic sensitization. Studies have suggested that animal exposure during infancy reduces subsequent allergic sensitization. OBJECTIVE: To evaluate the relationship between dog and cat exposure in the first year of life and allergic sensitization at 6 to 7 years of age. DESIGN, SETTING, AND SUBJECTS: Prospective birth cohort study of healthy, full-term infants enrolled in a health maintenance organization in suburban Detroit, Mich, who were born between April 15, 1987, and August 31, 1989, and followed up yearly to a mean age of 6.7 years. Of 835 children initially in the study at birth, 474 (57%) completed follow-up evaluations at age 6 to 7 years. MAIN OUTCOME MEASURES: Atopy, defined as any skin prick test positivity to 6 common aeroallergens (dust mites [Dermatophagoides farinae, D pteronyssinus], dog, cat, short ragweed [Ambrosia artemisiifolia], and blue grass [Poa pratensis]); seroatopy, defined as any positive allergen-specific IgE test result for the same 6 allergens or for Alternaria species. RESULTS: The prevalence of any skin prick test positivity (atopy) at age 6 to 7 years was 33.6% with no dog or cat exposure in the first year of life, 34.3% with exposure to 1 dog or cat, and 15.4% with exposure to 2 or more dogs or cats (P =.005). The prevalence of any positive allergen-specific IgE test result (seroatopy) was 38.5% with no dog or cat exposure, 41.2% with exposure to 1 dog or cat, and 17.9% with exposure to 2 or more dogs or cats (P =.003). After adjustment for cord serum IgE concentration, sex, older siblings, parental smoking, parental asthma, bedroom dust mite allergen levels at 2 years, and current dog and cat ownership, exposure to 2 or more dogs or cats in the first year of life was associated with a significantly lower risk of atopy (adjusted odds ratio, 0.23; 95% confidence interval, 0.09-0.60) and seroatopy (adjusted odds ratio, 0.33; 95% confidence interval, 0.13-0.83). CONCLUSION: Exposure to 2 or more dogs or cats in the first year of life may reduce subsequent risk of allergic sensitization to multiple allergens during childhood.
Grüße,
Philipp
