Prematurity at birth reduces the long-term risk of atopy.
BACKGROUND
Antigen exposure in early life has long-lasting effects on atopic sensitization. Thus the predisposition to atopy of children born preterm can be assumed to differ from that of children born at term.


OBJECTIVE
The aim of this study was to evaluate the association between premature birth and atopy.


METHODS
At an outpatient clinic, we examined 2 groups of 10-year-old children, 72 who were born preterm (birth weight < 1500 g) and 65 who were born at term (birth weight > 2500 g). The atopy data were collected with a questionnaire, by performing skin prick testing, and by measuring the serum total IgE level, 3 allergen-specific IgE levels, the eosinophil cationic protein level, and the blood eosinophil level. The data on perinatal and neonatal events affecting the preterm children were collected from the hospital records.


RESULTS
By the age of 10 years, the children born preterm had significantly less atopy than the children born at term: 15% versus 31% of children in the 2 groups were defined as having had obvious atopy (P = .03, odds ratio 0.41, 95% CI 0.18-0.93). The mean value of total IgE level was significantly higher in the term group, 74 kU/L versus 41 kU/L (P = .02). By skin prick testing, the children born at term had positive reactions 2 to 3 times more often; 37% versus 17% of children in the groups had at least 1 positive reaction (P = .007).


CONCLUSIONS
Our data show that prematurity at birth is linked with a decreased long-term risk of atopic sensitization.
Siltanen
M
M
Hospital for Children and Adolescents, University of Helsinki, Finland.
Kajosaari
M
M
Pohjavuori
M
M
Savilahti
E
E
D005260:Female; D006801:Humans; D006969:Hypersensitivity, Immediate / Q000453:epidemiology*; D007231:Infant, Newborn; D007234:Infant, Premature / Q000502:physiology*; D019102:Infant, Very Low Birth Weight / Q000502:physiology; D008297:Male; D012307:Risk Factors; D013997:Time Factors