In a study published in the AAAAI’s journal, The Journal of Allergy and Clinical Immunology, researchers set out to find which inner-city environmental exposures positively or negatively affect the rate of asthma.
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Environmental exposures in early life appear to play an important role in the development of asthma, and children living in the inner-city are introduced to a unique set of exposures. In a study published in the AAAAI’s journal,
The Journal of Allergy and Clinical Immunology
, researchers set out to find which of those exposures positively or negatively affect the rate of asthma.
What they discovered is that exposures to certain allergens and bacteria are associated with a lower rate of asthma. More specifically, levels of cockroach, mouse and cat allergens in the home in the first few months of the child’s life were associated with a lower risk of wheezing symptoms at three years old. Many of those allergens are associated with certain bacteria. In the paper titled “Early-life home environment and the risk of developing asthma among inner-city children,” the goal of researchers was to examine the effect of allergens, the microbiome of homes, smoking, and maternal stress and depression levels on the rate of asthma and wheeze in children.
Dust samples were collected from over half of the children’s homes in order to profile the microbiome. Children with and without asthma had homes with similar amounts of microbial diversity. It was the types of bacteria present that had an association with asthma. Researchers identified 202 types of bacteria that were significantly more abundant in homes of children that developed asthma and 171 types present in homes of children who did not develop the disease.
“In the inner-city setting, indoor pests or pets and certain bacteria may provide biologic signals that promote normal lung and immunologic development,” said lead author George T. O’Connor, MD, MS. “These findings support that exposure to cockroach, mouse and cat allergens in infancy are associated with a lower rate of wheeze through age three.”
It was also found that tobacco smoke in the home as well as the stress and depression levels reported by mothers were factors associated with a higher risk of asthma. Levels of the biomarker cotinine, which indicates the presence of tobacco, in umbilical cord plasma was a significant predictor of asthma, while reported smoking by the mother and others in the household was not significant. Maternal stress and depression in the first three years of the child’s life were also significantly associated with the development of asthma at seven years old.
“To improve outcomes, the research suggests that primary prevention strategies for childhood asthma in low income, urban communities should probably not focus on home allergen reduction and that exposure to a broad variety of proteins in early life many have health benefits with respect to asthma,” said O’Connor. “Alternatively, interventions to reduce prenatal smoking and maternal stress and depression during pregnancy and infancy may hold promise for asthma prevention.”
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The American Academy of Allergy, Asthma & Immunology (AAAAI) 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 more than 7,000 members in the United States, Canada and 72 other countries. The
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