Rhinoconjunctivitis in 5-year-old children: a population-based birth cohort study.
BACKGROUND
There is a paucity of data on the prevalence, risk factors and natural history of rhinitis in early childhood.


OBJECTIVE
Within the context of a whole-population birth cohort we investigated the prevalence of and risk factors for current rhinoconjunctivitis (CRC) at age 5 years.


METHODS
Children were followed prospectively to age 5 years [questionnaires (n = 815), skin testing (n = 717), specific immunoglobulin E (n = 478), lung function (n = 711), dry air challenge (n = 556)]. Endotoxin and allergen exposures were measured in dust samples.


RESULTS
The prevalence of rhinitis ever, current rhinitis and rhinoconjunctivitis was 28.2%, 26.1%, and 12.1%, respectively. Asthma, wheeze and eczema coexisted with CRC (P < or = 0.01). In a multivariate model, maternal asthma (OR 2.38, 95% CI: 1.30-4.38, P = 0.005), paternal hay fever (1.96, 1.11-3.46, P = 0.02) and sensitization to grass (3.46, 1.86-6.42, P < 0.001) and cat (2.42, 1.14-5.18, P = 0.02) remained significant and independent associates of CRC. Whilst almost half of children with CRC were nonatopic, there was little difference in risk factors between atopic and nonatopic CRC. Amongst children with current wheeze, the presence of concurrent CRC had no effect on either severity or frequency of wheezy episodes. There was no difference in specific airway resistance, forced expiratory volume in 1 second (FEV(1)) or airway reactivity between children with and without CRC after adjustment for the presence of wheeze.


CONCLUSIONS
Family history of allergic disease and sensitization to inhalant allergens are risk factors for rhinoconjunctivitis in preschool children. In this age group, there is no association between the presence of rhinoconjunctivitis and severity of wheeze, increased airway reactivity and reduced lung function.
Marinho
S
S
University of Manchester, Academic Division of Medicine and Surgery, University Hospital of South Manchester NHS Foundation Trust, Manchester, UK.
Simpson
A
A
Lowe
L
L
Kissen
P
P
Murray
C
C
Custovic
A
A
D000485:Allergens / Q000276:immunology; D001249:Asthma / Q000453:epidemiology / Q000276:immunology / Q000503:physiopathology; D001985:Bronchial Provocation Tests; D002675:Child, Preschool; D015331:Cohort Studies; D003231:Conjunctivitis / Q000453:epidemiology* / Q000276:immunology / Q000503:physiopathology; D004485:Eczema / Q000453:epidemiology; D004781:Environmental Exposure / Q000032:analysis; D005260:Female; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood / Q000276:immunology; D008297:Male; D012129:Respiratory Function Tests; D012135:Respiratory Sounds; D012220:Rhinitis / Q000453:epidemiology* / Q000276:immunology / Q000503:physiopathology; D012882:Skin Tests; D006113:United Kingdom / Q000453:epidemiology
D000485:Allergens; D007073:Immunoglobulin E