Table 4 Relative mortality rate, according to their age at transfer separately for high and low social class of their adoptive father

Low social class

At birth

1 (reference)

1 (reference)

1 (reference)

1 (reference)

1–5 months

1.09 (0.98–1.21)

1.09 (0.97–1.22)

0.93 (0.65–1.32)

1·07 (0·61–1·90)

6–23 months

1.11 (1.00–1.23)

1.11 (0.98–1.24)

0.94 (0.66–1.33)

1·21 (0·69–2·13)

2–7 years

1.06 (0.92–1.21)

0.91 (0.78–1.05)

1.50 (1.01–2.23)

2·15 (1·16–3·97)

Overall effect

0.27

0.02

0.06

0·06

Test for trend^a

–

–

0.005

0·02

High social class

At birth

1 (reference)

1 (reference)

1 (reference)

1 (reference)

1–5 months

1.11 (0.94–1.31)

1.21 (1.01–1.45)

1.07 (0.66–1.74)

1.08 (0.57–2.05)

6–23 months

1.27 (1.09–1.48)

1.27 (1.07–1.51)

1.19 (0.74–1.90)

1.14 (0.61–2.14)

2–7 years

1.20 (1.00–1.43)

1.13 (0.93–1.38)

0.97 (0.54–1.74)

1.17 (0.55–2.50)

Overall effect

0.02

0.05

0.84

0.97

Test for trend^a

–

–

0.26

0.05

High versus low social class^b

Transfer at birth

0.91 (0.78–1.06)

0.88 (0.74–1.04)

1.00 (0.64–1.57)

1.62 (0.85–3.11)

Test for modifying effect

0.36

0.33

0.22

0.53