Asthma phenotypes and lung function up to 16 years of age-the BAMSE cohort.

BACKGROUND: Asthma is a disease affecting many locations throughout the airway. Most studies have used spirometry as the primary assessment of airway obstruction, a method that may be less sensitive in regard to peripheral airway obstruction. The aim of this study was to elucidate the associations between asthma phenotypes based on age of onset and duration of symptoms, and (i) spirometry and (ii) small airway involvement measured by impulse oscillometry (IOS) in adolescence. METHODS: Children and adolescents taking part in BAMSE, a prospective birth cohort study, performed spirometry at 8 and 16 years and IOS at 16 years of age. Based on data collected in questionnaires, children were categorized into the following groups: 'never asthma', 'early transient asthma', 'early persistent asthma', and 'late onset asthma'. RESULTS: Compared with the never asthma group, all asthma groups were associated with lower FEV1 at 16 years of age (early transient-119 ml, 95% confidence interval -204 to -34; early persistent-410 ml, 95%CI -533; -287; and late onset-148 ml, 95%CI -237; -58). Between 8 and 16 years, significantly less increase in FEV1 was observed in the early persistent and late onset groups. The small airway index 'R5-20 ' was significantly associated with active asthma at 16 years, but not transient asthma. CONCLUSIONS: All asthma phenotypes studied were negatively associated with FEV1 in adolescence. IOS measurements indicated that active asthma could be associated with small airway impairments. These results provide new insights into the physiology underlying wheezing phenotypes based on age of onset and duration of disease.

Dispersion of horse allergen from stables and areas with horses into homes.

BACKGROUND/AIM: To protect susceptible subjects from exposure to horse allergen, a Swedish national report recommended a distance of at least 500 m between homes and stables and other areas with horses. The aim of this project was to study indoor and outdoor levels of horse allergen in relation to distance from stables and horse tracks. METHODS: Indoor and outdoor samples were collected with Petri dishes at 49 sites in different housing areas and near to a track for trotting horses. In the apartments, Petri dishes were placed on a bookshelf in the living room at a height of approximately 1.5 m. Outdoors, cages containing Petri dishes were attached to tree branches at various distances from the horse track. RESULTS: Six of 45 indoor samples had detectable levels of horse allergen, 3 of those despite the fact that no family member had had any contact with horses, and 16 of 26 outdoor samples were positive. Outdoors, allergen levels drop quickly when the distance from stables or horses increases. Further, the allergen level found at a distance of 45 m from a horse track was around 1% of the allergen level found at 1 m from the track. CONCLUSIONS: Allergens dispersed from horses decline rapidly outdoors and are barely found indoors in homes. We support the view that indirect exposure to horses such as exposure from clothing of horse riders, should be taken into account when measures to protect susceptible people from undesired exposure to horse allergens are taken.