“Asthma, allergy and particulates from home. Is important country?”
10/02/2016
There are still big questions about the role of the environment in the origin of asthma and allergy. Experts consider perinatal age a crucial period in the development and maturation of our immune system. Previous studies have pointed that, in rural areas, exposure to biological particles present in house dust is associated with a lower chance of developing asthma and allergies in childhood. However, other studies have found that this relationship is opposite in metropolitan areas, while in suburban areas it remains inconsistent. The fact that the follow-up periods in all these researches have been relatively short, have not allowed assessing late onset of symptoms.
European study with newborns from suburban areas of Spain, The Netherlands and Germany was conducted. In the study, measures of biomolecules present in household dust of the newborns were taken during pregnancy of the mothers. After more than 10 years of follow-up, no associations were observed between concentrations of any of the substances evaluated and atopic reactions. However, endotoxins associated with the development of asthma during childhood. The main surprise was that the pattern varied substantially across countries; while in The Netherlands the risk of developing asthma at 6 years almost doubled, no significant results were found in the German cohort. An inverse relationship in the Spanish sample was found: babies exposed to higher concentrations of endotoxin had a 60{3effe4377b6f02be2524d084f7d03914ac32a2b62c0a056ca3444e58c1f10d0b} risk reduction of developing asthma at age 10 years compared to non-exposed children.
The effects of early exposure to microbes on asthma in children living in suburban areas remain unclear, and the differences observed between countries deserve further consideration.
Reference: Tischer C, Casas L, Wouters IM, Doekes G, Garcia-Esteban R, Gehring U, Hyvärinen A, Oldenwening M, Kerkhof M, Sunyer J, Standl M, Thiering E, Torrent M, Heinrich J; the HITEA study group. Early exposure to bio-contaminants and asthma up to 10 years of age: results of the HITEA study. Eur Respir J. 2015; 45(2): 328-337.