Table 5 Summary of main associations with age at infection

Associated with earlier infection

White British

• household size^c

• breastfeeding >6m^b [16, 32, 42]

• formal childcare in 1st yr^b [32]

• not owner-occupied household^b [11]

• informal childcare <1165 hrs^c

• birth order^b [18]

Pakistani

• breastfeeding^b

• mother born outside UK/Ireland ^c

• bedroom sharing in 1st yr^b [21]

• birth order^b

Associated with later infection

White British

-

• mother/baby activities in 1st yr^a

-

Pakistani

• birth order^a

• travel outside Europe in 1st yr*^b

-

• maternal age^a