Perinatal factors and atopic disease in childhood.

BACKGROUND: Recent work has suggested possible linkages between perinatal factors and notably, head circumference and risks of subsequent atopic illness.

OBJECTIVE: To examine the linkages between perinatal factors and risks of atopic conditions in a birth cohort of New Zealand children studied to the age of 16.

METHODS: Measures of atopic illness including asthma, eczema, and other allergies were assessed prospectively during the course of a 16 year longitudinal study of a birth cohort of 1265 New Zealand children. In the initial stage of this research, measures of perinatal variables including birthweight, gestational age, head circumference and length at birth were obtained from hospital record data.

RESULTS: Children with head circumference at birth of 37 cm or greater had (unadjusted) odds of asthma that were 1.8 (P < 0.01) to 3.0 (P < 0.0001) times higher than the odds for children of lesser head circumference. However, risks of asthma were not related to other perinatal measures including birthweight, gestational age or length or ratios of these measures. There were no consistent associations between perinatal measures and other measures of childhood atopy including eczema, allergic rhinitis and other allergies. The associations between head circumference and asthma risks persisted when due allowance was made for potentially confounding social and perinatal factors.

CONCLUSIONS: It is concluded that large head circumference at birth may be associated with increased risks for the development of asthma. Possible explanations for the linkages between head circumference and asthma risks are considered.