The Urban Environment and Childhood Asthma (URECA) birth cohort study: design, methods, and study population.
BACKGROUND
The incidence and morbidity of wheezing illnesses and childhood asthma is especially high in poor urban areas. This paper describes the study design, methods, and population of the Urban Environment and Childhood Asthma (URECA) study, which was established to investigate the immunologic causes of asthma among inner-city children.


RESULTS
URECA is an observational prospective study that enrolled pregnant women in central urban areas of Baltimore, Boston, New York City, and St. Louis and is following their offspring from birth through age 7 years. The birth cohort consists of 560 inner-city children who have at least one parent with an allergic disease or asthma, and all families live in areas in which at least 20% of the population has incomes below the poverty line. In addition, 49 inner-city children with no parental history of allergies or asthma were enrolled. The primary hypothesis is that specific urban exposures in early life promote a unique pattern of immune development (impaired antiviral and increased Th2 responses) that increases the risk of recurrent wheezing and allergic sensitization in early childhood, and of asthma by age 7 years. To track immune development, cytokine responses of blood mononuclear cells stimulated ex vivo are measured at birth and then annually. Environmental assessments include allergen and endotoxin levels in house dust, pre- and postnatal maternal stress, and indoor air nicotine and nitrogen dioxide. Nasal mucous samples are collected from the children during respiratory illnesses and analyzed for respiratory viruses. The complex interactions between environmental exposures and immune development will be assessed with respect to recurrent wheeze at age 3 years and asthma at age 7 years.


CONCLUSIONS
The overall goal of the URECA study is to develop a better understanding of how specific urban exposures affect immune development to promote wheezing illnesses and asthma.
University of Wisconsin School of Medicine and Public Health, Madison, WI, USA. gern@medicine.wisc.edu
James E
JE
Gern
Cynthia M
CM
Visness
Peter J
PJ
Gergen
Robert A
RA
Wood
Gordon R
GR
Bloomberg
George T
GT
O'Connor
Meyer
M
Kattan
Hugh A
HA
Sampson
Frank R
FR
Witter
Megan T
MT
Sandel
Wayne G
WG
Shreffler
Rosalind J
RJ
Wright
Samuel J
SJ
Arbes
William W
WW
Busse
D001249:Asthma / Q000453:epidemiology* / Q000276:immunology; D002648:Child; D015331:Cohort Studies; D004777:Environment; D005260:Female; D006801:Humans; D015994:Incidence; D007231:Infant, Newborn; D008297:Male; D009017:Morbidity; D017063:Outcome Assessment, Health Care / Q000379:methods*; D011247:Pregnancy; D011446:Prospective Studies; D012107:Research Design; D012307:Risk Factors; D014505:Urban Population