Several studies have suggested that very low birthweight (VLBW < 1500 g) is
associated with increased rates of respiratory problems in childhood and t
hat the presence of chronic lung disease further increases the risk. We aim
ed to assess rates of asthma at 7-8 years of age in a national cohort of VL
BW infants born in 1986 and for whom perinatal data were available. Two hun
dred ninety-nine former VLBW children (96% of surviving children living in
New Zealand) were assessed at a home visit. Parents were asked a comprehens
ive questionnaire, including three questions aimed at assessing morbidity f
rom asthma: I)was the child diagnosed as having asthma before age 7 years;
2) was the child still experiencing asthma at the age of 7 years; and 3) wa
s the child prescribed daily medication for asthma at the age of 7 years.
Overall. 50% of the cohort had been diagnosed with asthma before age 7, com
pared with 27% of a sample of New Zealand children assessed contemporaneous
ly in an international study; 32% had asthma at age 7, and 11% were taking
daily medication. All three categories of asthma were associated with a fam
ily history of asthma, but there was no association with any perinatal fact
ors. A diagnosis of asthma before age 7 was more likely when the mother smo
ked in pregnancy (P < 0.005) and currently smoked (P < 0.01), and trended s
o when parents lacked high school qualifications and in Maori or Pacific Is
land families (P< 0.10). In contrast, daily medication was more frequent wh
en parents had educational qualifications and in non-Maori or Pacific Islan
d families (P < 0.05). On multiple logistic regression, a family history of
asthma was a significant predictor for any and current asthma (P < 0.001)
and daily medication (P < 0.05); maternal smoking in pregnancy was a signif
icant predictor for any asthma (P < 0.05); and non-Maori or Pacific Island
ethnicity was a significant predictor for asthma treatment (P < 0.05).
We conclude that rates of childhood asthma are high in this VLBW cohort, bu
t the high prevalence appears to be unrelated to perinatal factors, includi
ng respiratory morbidity. There are suggestions that social factors contrib
ute to both asthma risk and treatment. Pediatr Pulmonol, 2000; 30:291-296,
(C) 2000 Wiley-Liss, Inc.