Table 4 Associations between caesarean section and chronic asthma from the ages of 3 to 8 years
Number of events(chronic asthma)HRAdjusted* HR (95% CI)p Value
All11.1 (348)1.891.77 (1.29 to 2.43)<0.001
Non-allergic parents8.3 (124)1.541.30 (0.74 to 2.28)0.36
Only one allergic parent14.5 (168)1.871.81 (1.14 to 2.88)0.01
Two allergic parents21.1 (56)3.012.72 (1.28 to 5.78)0.01
  • The hazard ratio (HR) is for the children born by caesarean section compared with children born by vaginal delivery.

  • *Adjusted for gender, birth weight, breastfeeding, maternal education and maternal body mass index (and for parental allergy status in the analysis of the total study population).