Risk factors of new-onset asthma in adults: a population-based international cohort study.
BACKGROUND
The occurrence of new-onset asthma during adulthood is common, but there is insufficient understanding of its determinants including the role of atopy.


OBJECTIVE
To assess the risk factors for the development of new-onset asthma in middle-aged adults and to compare them according to atopy.


METHODS
A longitudinal analysis of 9175 young adults who participated in two surveys of the European Community Respiratory Health Survey (ECRHS) conducted 9 years apart.


RESULTS
We observed 179 cases of new-onset asthma among 4588 participants who were free of asthma and reported at the beginning of the follow-up that they had never had asthma (4.5 per 1000 person-years). In a logistic regression, the following risk factors were found to increase the risk of new-onset asthma: female gender (OR: 1.97; 95% confidence interval (CI): 1.38, 2.81), bronchial hyperresponsiveness (3.25; 2.19, 4.83), atopy (1.55; 1.08, 2.21), FEV(1) < 100 % predicted (1.87; 1.34, 2.62), nasal allergy (1.98;1.39,2.84) and maternal asthma (1.91; 1.13; 3.21). Obesity, respiratory infections in early life and high-risk occupations increased the risk of new-onset asthma although we had limited power to confirm their role. Among the atopics, total IgE and sensitization to cat were independently related to the risk of new-onset asthma. The proportion of new-onset asthma attributable to atopy varied from 12% to 21%.


CONCLUSIONS
Adults reporting that they had never had asthma were at a substantial risk of new-onset asthma as a result of multiple independent risk factors including lung function. Atopy explains a small proportion of new-onset adult asthma.
Centre for Research in Environmental Epidemiology (CREAL), Barcelona. jmanto@creal.cat
J M
JM
Antó
J
J
Sunyer
X
X
Basagaña
R
R
Garcia-Esteban
I
I
Cerveri
R
R
de Marco
J
J
Heinrich
C
C
Janson
D
D
Jarvis
M
M
Kogevinas
N
N
Kuenzli
B
B
Leynaert
C
C
Svanes
M
M
Wjst
T
T
Gislason
P
P
Burney
D000328:Adult; D017668:Age of Onset; D000818:Animals; D001249:Asthma / Q000453:epidemiology / Q000209:etiology*; D016535:Bronchial Hyperreactivity / Q000150:complications* / Q000453:epidemiology; D002415:Cats / Q000276:immunology; D015331:Cohort Studies; D005060:Europe / Q000453:epidemiology; D005260:Female; D006306:Health Surveys; D006801:Humans; D006969:Hypersensitivity, Immediate / Q000150:complications* / Q000453:epidemiology / Q000209:etiology; D015994:Incidence; D008137:Longitudinal Studies; D008297:Male; D011159:Population Surveillance / Q000379:methods; D012129:Respiratory Function Tests; D012141:Respiratory Tract Infections / Q000150:complications / Q000453:epidemiology; D012307:Risk Factors; D055815:Young Adult