Table 2 Incidence proportions (%) and adjusted* relative risks with 95% CI for wheeze, lower respiratory tract infections (LRTIs) and hospitalisations for LRTIs up to 18 months of age according to prenatal exposure to folic acid supplements for children born in 2000–2005
Folic acid supplements in pregnancyWheeze, 6–18 monthsLRTI, 0–18 monthsLRTI hospitalised, 0–18 months
Before week 12After week 12n%aRR (95% CI)%aRR (95%CI)%aRR (95%CI)
NoYes443139.51.01 (0.96 to 1.07)16.0%0.97 (0.88 to 1.08)3.8%0.92 (0.73 to 1.15)
YesNo714541.01.07 (1.03 to 1.12)17.3%1.10 (1.01 to 1.20)5.0%1.28 (1.07 to 1.53)
YesYes13 66641.21.07 (1.02 to 1.12)16.8%1.07 (0.98 to 1.16)4.2%1.08 (0.90 to 1.29)
  • *Adjusted for other vitamin supplements and cod liver oil in pregnancy, vitamin supplements and cod liver oil at 6 months of age, and for maternal age, maternal atopy, maternal smoking in pregnancy, maternal educational level, postnatal parental smoking, sex, parity, birth weight, season born, breast feeding and type of day care.

  • aRR, adjusted relative risk; LRTI, lower respiratory tract infection.