Table 3

Adjusted odds ratios* (95% confidence intervals) for eczema and hay fever by potential risk factors in combined cohorts (n=15 564)

Hay feverEczema
Birth weight (g)
2001-25001.49 (0.90 to 2.46)1.08 (0.43 to 2.70)
2501-30001.53 (0.96 to 2.45)1.39 (0.60 to 3.22)
>30001.47 (0.93 to 2.34)1.37 (0.60 to 3.13)
Test for trendP >0.70P >0.35
Birth order
20.70 (0.63 to 0.77)0.81 (0.68 to 0.98)
30.53 (0.46 to 0.61)0.74 (0.57 to 0.95)
40.41 (0.33 to 0.50)0.82 (0.59 to 1.14)
>50.35 (0.27 to 0.44)0.66 (0.45 to 0.98)
Test for trendP <0.001P<0.05
Maternal age (years)
20-241.23 (1.01 to 1.49)1.14 (0.81 to 1.60)
25-291.50 (1.23 to 1.83)1.28 (0.90 to 1.82)
30-341.67 (1.35 to 2.08)1.28 (0.87 to 1.89)
35-391.60 (1.24 to 2.07)1.11 (0.70 to 1.76)
>401.61 (1.10 to 2.35)0.80 (0.37 to 1.72)
Test for trendP <0.001P >0.65
Duration of breast feeding
<1 month1.09 (0.97 to 1.22)0.99 (0.80 to 1.23)
>1 month1.20 (1.08 to 1.33)1.25 (1.04 to 1.50)
Test for trendP <0.001P < 0.05
Maternal smoking during pregnancy
Yes0.87 (0.79 to 0.95)0.94 (0.80 to 1.11)
Test for heterogeneityP <0.01P >0.45
Father's social class at birth14 15
II0.84 (0.69 to 1.04)0.90 (0.61 to 1.31)
IIINM0.89 (0.73 to 1.10)1.06 (0.72 to 1.55)
IIIM0.72 (0.60 to 0.87)0.90 (0.64 to 1.27)
IV0.60 (0.48 to 0.75)0.94 (0.64 to 1.40)
V0.60 (0.47 to 0.77)1.08 (0.70 to 1.68
Test for trendP < 0.001P > 0.80
  • * Odds ratios are adjusted for cohort, sex, and all other factors in table and are calculated relative to baseline categories (birth weight <=2000 g, birth order=1, maternal age < 20, duration of breast feeding=never, maternal smoking during pregnancy=no, father's social class at birth=I).