Table 3

Relation between sibling number and mean age at onset of asthma or wheezy breathing for children with asthma

Mean age at onset of asthma or wheezy breathing in years
All childrenYoungest children of sibshipOldest children of sibshipPositive family history of asthmaNo family history of asthma
Only child2.40 (n = 115)2.11 (n = 70)2.80 (n = 40)
Children with 1 sibling2.26 (n = 655)2.07 (n = 316)2.43 (n = 339)2.19 (n = 461)2.48 (n = 179)
Children with 2 siblings2.20 (n = 441)2.23 (n = 156)2.35 (n = 115)2.11 (n = 329)2.46 (n = 110)
Children with 3 siblings2.16 (n = 207)2.18 (n = 62)2.12 (n = 26)2.01 (n = 162)2.79 (n = 42)
Children with 4 siblings1.90 (n = 60)1.61 (n = 18)1.50 (n = 2)1.80 (n = 49)2.10 (n = 10)
Children with ⩾ 5 siblings1.72 (n = 29)2.00 (n = 11)1.74 (n = 27)1.50 (n = 2)
p value of test for linear trend3-150 0.00930.900.110.01780.59
  • 3-150 There was no evidence to suggest that a non-linear model would have provided a substantially better fit.