Phenotyping asthma, rhinitis and eczema in MeDALL population-based birth cohorts: an allergic comorbidity cluster.
BACKGROUND
Asthma, rhinitis and eczema often co-occur in children, but their interrelationships at the population level have been poorly addressed. We assessed co-occurrence of childhood asthma, rhinitis and eczema using unsupervised statistical techniques.


METHODS
We included 17 209 children at 4 years and 14 585 at 8 years from seven European population-based birth cohorts (MeDALL project). At each age period, children were grouped, using partitioning cluster analysis, according to the distribution of 23 variables covering symptoms 'ever' and 'in the last 12 months', doctor diagnosis, age of onset and treatments of asthma, rhinitis and eczema; immunoglobulin E sensitization; weight; and height. We tested the sensitivity of our estimates to subject and variable selections, and to different statistical approaches, including latent class analysis and self-organizing maps.


RESULTS
Two groups were identified as the optimal way to cluster the data at both age periods and in all sensitivity analyses. The first (reference) group at 4 and 8 years (including 70% and 79% of children, respectively) was characterized by a low prevalence of symptoms and sensitization, whereas the second (symptomatic) group exhibited more frequent symptoms and sensitization. Ninety-nine percentage of children with comorbidities (co-occurrence of asthma, rhinitis and/or eczema) were included in the symptomatic group at both ages. The children's characteristics in both groups were consistent in all sensitivity analyses.


CONCLUSIONS
At 4 and 8 years, at the population level, asthma, rhinitis and eczema can be classified together as an allergic comorbidity cluster. Future research including time-repeated assessments and biological data will help understanding the interrelationships between these diseases.
Centre for Research in Environmental Epidemiology (CREAL), Barcelona, Spain.|CIBER Epidemiología y Salud Pública (CIBERESP), Barcelona, Spain.|Departament de Ciències Experimentals i de la Salut, Universitat Pompeu Fabra, Barcelona, Spain.
J
J
Garcia-Aymerich
Centre for Research in Environmental Epidemiology (CREAL), Barcelona, Spain.|CIBER Epidemiología y Salud Pública (CIBERESP), Barcelona, Spain.|Departament de Ciències Experimentals i de la Salut, Universitat Pompeu Fabra, Barcelona, Spain.
M
M
Benet
VIB Inflammation Research Center and Department of Respiratory Medicine, Ghent University, Ghent, Belgium.
Y
Y
Saeys
Centre for Research in Environmental Epidemiology (CREAL), Barcelona, Spain.|CIBER Epidemiología y Salud Pública (CIBERESP), Barcelona, Spain.|Departament de Ciències Experimentals i de la Salut, Universitat Pompeu Fabra, Barcelona, Spain.|IMIM (Hospital del Mar Research Institute), Barcelona, Spain.
M
M
Pinart
Centre for Research in Environmental Epidemiology (CREAL), Barcelona, Spain.|CIBER Epidemiología y Salud Pública (CIBERESP), Barcelona, Spain.|Departament de Ciències Experimentals i de la Salut, Universitat Pompeu Fabra, Barcelona, Spain.
X
X
Basagaña
Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, the Netherlands.
H A
HA
Smit
Inserm, U823, Institut Albert Bonniot, Team of Environmental Epidemiology Applied to Reproduction and Respiratory Health, Grenoble, France.|Université Joseph Fourier, Grenoble, France.
V
V
Siroux
Groupe Hospitalier Trousseau-La Roche-Guyon, Centre de l'Asthme et des Allergies, APHP, Université Paris 6, Paris, France.
J
J
Just
Department of Public Health and Biostatistics, EA 4064, Paris Descartes University, Paris, France.|Paris Municipal Department of Social Action, Childhood, and Health, Paris, France.
I
I
Momas
Department of Public Health and Biostatistics, EA 4064, Paris Descartes University, Paris, France.|Paris Municipal Department of Social Action, Childhood, and Health, Paris, France.
F
F
Rancière
Institute of Social Medicine, Epidemiology and Health Economics, Charité - Universitätsmedizin Berlin, Berlin, Germany.|Institute of Clinical Epidemiology and Biometry, University of Wuerzburg, Wuerzburg, Germany.
T
T
Keil
Institute of Social Medicine, Epidemiology and Health Economics, Charité - Universitätsmedizin Berlin, Berlin, Germany.
C
C
Hohmann
Department of Pediatrics, Charité - Universitätsmedizin Berlin, Berlin, Germany.
S
S
Lau
Department of Pediatrics, Charité - Universitätsmedizin Berlin, Berlin, Germany.
U
U
Wahn
Institute of Epidemiology I, Helmholtz Zentrum, Munich, Germany.
J
J
Heinrich
Institute of Epidemiology I, Helmholtz Zentrum, Munich, Germany.
C G
CG
Tischer
Department of Biomedical and Neuromotor Sciences, Alma Mater Studiorum - University of Bologna, Bologna, Italy.
M P
MP
Fantini
Department of Biomedical and Neuromotor Sciences, Alma Mater Studiorum - University of Bologna, Bologna, Italy.
J
J
Lenzi
Department of Epidemiology, Lazio Regional Health Service, Rome, Italy.
D
D
Porta
Pediatric Pulmonology and Pediatric Allergology, GRIAC Research Institute, Beatrix Children's Hospital, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands.
G H
GH
Koppelman
Department of Pulmonology, GRIAC Research Institute, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands.
D S
DS
Postma
Department of Pediatrics, Research Institute, Marien-Hospital Wesel, Wesel, Germany.
D
D
Berdel
Division of Pediatric Gastroenterology and Hepatology, Dr von Haunersches Kinderspital, Ludwig-Maximilians-University of Munich, Munich, Germany.
S
S
Koletzko
Department of Epidemiology, GRIAC Research Institute, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands.
M
M
Kerkhof
Institute for Risk Assessment Sciences, Utrecht University, Utrecht, the Netherlands.
U
U
Gehring
Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden.|Sach's Children's Hospital, Stockholm, Sweden.
M
M
Wickman
Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden.|Sach's Children's Hospital, Stockholm, Sweden.
E
E
Melén
Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden.|Sach's Children's Hospital, Stockholm, Sweden.
J
J
Hallberg
Department of Dermatology and Allergy Centre, Odense University Hospital, Odense, Denmark.
C
C
Bindslev-Jensen
Department of Dermatology and Allergy Centre, Odense University Hospital, Odense, Denmark.
E
E
Eller
Department of Dermatology and Allergy Centre, Odense University Hospital, Odense, Denmark.
I
I
Kull
Department of Paediatrics, Oslo University Hospital and University of Oslo, Oslo, Norway.
K C
KC
Lødrup Carlsen
Department of Paediatrics, Oslo University Hospital and University of Oslo, Oslo, Norway.
K-H
KH
Carlsen
VIB Inflammation Research Center and Department of Respiratory Medicine, Ghent University, Ghent, Belgium.
B N
BN
Lambrecht
Centre for Research in Environmental Epidemiology (CREAL), Barcelona, Spain.|CIBER Epidemiología y Salud Pública (CIBERESP), Barcelona, Spain.|Departament de Ciències Experimentals i de la Salut, Universitat Pompeu Fabra, Barcelona, Spain.|IMIM (Hospital del Mar Research Institute), Barcelona, Spain.|National School of Public Health, Athens, Greece.
M
M
Kogevinas
Centre for Research in Environmental Epidemiology (CREAL), Barcelona, Spain.|CIBER Epidemiología y Salud Pública (CIBERESP), Barcelona, Spain.|Departament de Ciències Experimentals i de la Salut, Universitat Pompeu Fabra, Barcelona, Spain.|IMIM (Hospital del Mar Research Institute), Barcelona, Spain.
J
J
Sunyer
Inserm (Institut National de la Santé et de la Recherche Médicale), CESP (Centre de recherche en Épidémiologie et Santé des Populations), U1018, Respiratory and Environmental Epidemiology Team, Villejuif, France.|UMRS 1018, Université Paris Sud 11, Villejuif, France.
F
F
Kauffmann
Hôpital Arnaud de Villeneuve, University Hospital of Montpellier, Montpellier, France.
J
J
Bousquet
Centre for Research in Environmental Epidemiology (CREAL), Barcelona, Spain.|CIBER Epidemiología y Salud Pública (CIBERESP), Barcelona, Spain.|Departament de Ciències Experimentals i de la Salut, Universitat Pompeu Fabra, Barcelona, Spain.|IMIM (Hospital del Mar Research Institute), Barcelona, Spain.
J M
JM
Antó
D017677:Age Distribution; D001249:Asthma / Q000453:epidemiology* / Q000235:genetics / Q000276:immunology*; D002648:Child; D002675:Child, Preschool; D016000:Cluster Analysis; D015331:Cohort Studies; D015897:Comorbidity; D003430:Cross-Sectional Studies; D004485:Eczema / Q000453:epidemiology* / Q000235:genetics / Q000276:immunology*; D005060:Europe / Q000453:epidemiology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D038622:Internationality; D008297:Male; D010641:Phenotype; D015995:Prevalence; D065631:Rhinitis, Allergic / Q000453:epidemiology* / Q000235:genetics / Q000276:immunology*; D012720:Severity of Illness Index; D017678:Sex Distribution
allergy; asthma; cluster analysis; eczema; rhinitis