By comparing symptoms in the first 2 years and in the last year, new
onset of a specific symptom was calculated as the presence of the symptom
in the last year but absent during the first 2 years of life. The variable
‘any onset’ was calculated as onset of at least one the 3 symptoms
(wheeze, rhinitis and eczema). The remission of a specific symptom
was defined as presence of the symptom during the first 2 years of life
but absence of the symptom in the last year. The variable ‘complete remission’
was defined as having at least one of the 3 symptoms (wheeze,
rhinitis and eczema) in the first 2 years of life but having none of the
symptoms in the last year