TY - JOUR T1 - Review: evidence does not support an association between allergen levels and risk for asthma JF - Evidence Based Medicine JO - Evid Based Med SP - 27 LP - 27 DO - 10.1136/ebm.6.1.27 VL - 6 IS - 1 A2 - , Y1 - 2001/01/01 UR - http://ebm.bmj.com/content/6/1/27.abstract N2 - (2000) Thorax 55, 424. Pearce N, Douwes J, Beasley R.. Is allergen exposure the major primary cause of asthma?. May;. :. –31.OpenUrlAbstract/FREE Full Text
 
 QUESTION: Is allergen exposure the major primary cause of asthma? Medline search (from 1980). English language studies were selected if they were longitudinal or cross sectional studies of the relation between allergens and asthma. The review focused on primary causation studies that reported the amount of allergen exposure. Studies that used bronchial hyperresponsiveness in the definition of asthma were excluded. Studies of selected populations were used when no information from population based studies was available. Data were extracted on age, allergen levels, asthma prevalence, definition of asthma, and population attributable risk. Results are reported for longitudinal studies only. No population based studies were found on the relation between allergen exposure during infancy and asthma risk after the age of 6 years. In 1 randomised controlled trial, 160 infants with a family history of atopy were allocated to prophylaxis (avoidance of house dust mite allergen and allergenic food) or no … ER -