01:26pm Thursday 09 July 2020

Exposure to "dirt" shows no effect on the development of asthma in children

“In an earlier study, we found that infants were exposed to high levels of endotoxin and allergens (mite and cockroach) in their daycare centers. Therefore, we were anxious to find out, through a birth cohort study, if infants from low income families with high risk of asthma might be protected from the development of the disease,” explained lead study author Vera E. V. Rullo, PhD.

In this cohort study, researchers in Brazil enrolled 104 newborns at birth. All of the children were from low-income families and were at high risk for asthma.

Allergen and endotoxin exposure, infection and breastfeeding were compared to the instances of persistent wheezing in the young children. Persistent wheezing was defined as ever wheezing treated with inhaled corticosteroids and beta-2 agonists in the past year. Also recorded were any infections of the upper or lower respiratory tract requiring antibiotics.

Additionally, dust samples were collected from the bedding and floor of the infants’ bedroom with testing for endotoxin content and major allergens done. An allergy test called ImmunoCAP® was used to determine serum IgE antibodies.

At 60 months, approximately 19% of the children had persistent wheezing. However, only respiratory infection in the first 12 months of life was found to be associated with it. Analysis showed that allergen and endotoxin exposure and exclusive breastfeeding for six months showed no effect in the development of asthma.

Sensitization to a species of house dust mite called D. Pteronyssinus was found in 27% of the children but this also had no association with persistent wheezing.

The AAAAI (www.aaaai.org) represents allergists, asthma specialists, clinical immunologists, allied health professionals and others with a special interest in the research and treatment of allergic and immunologic diseases. Established in 1943, the AAAAI has nearly 6,500 members in the United States, Canada and 60 other countries. To find an allergist/immunologist in your area, visit www.aaaai.org/physref.

Editor’s notes:

  • This study was presented during the 2010 Annual Meeting of the American Academy of Allergy, Asthma & Immunology (AAAAI) on February 26-March 2 in New Orleans. However, it does not necessarily reflect the policies or the opinions of the AAAAI.
  • A link to all abstracts presented at the Annual Meeting is available at annualmeeting.aaaai.org



Megan Brown
[email protected]
(414) 272-6071 (AAAAI executive office)

(504) 670-5113 (Press room, Ernest N. Morial Convention Center, February 26-March 2)

(Abstract: 224)

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