Abstract
Objective To examine the association between the time caregivers talk with their infants (mean age 8.77 months) and their communication, speech and language outcomes at 2 years (mean age 34.88 months).
Design Prospective longitudinal observational cohort study.
Setting The Growing Up In Australia: the Longitudinal Study of Australian Children.
Participants 5107 children, aged 3 to 19 months at the start of the study.
Main exposure The time caregivers talked to their infants, estimated from the caregivers’ reports in time-use diaries of the time infants were “being read a story, talked/sung to, sing/talk”.
Main outcome measures Expressive vocabulary complexity, expressive grammar (MacArthur-Bates Communicative Development Inventories-vocabulary and grammar scales) and communication (Communication Skills Scales) at 2 years.
Results Caregiver talking in infancy was associated with expressive vocabulary complexity and expressive grammar but not with communication in fully adjusted models. The regression coefficients for caregivers talking for up an hour to more than two hours were 5.26 (95% confidence interval of 2.6 to 7.9), 6.34 (3.1 to 9.6) and 6.34 (3.3 to 9.4) compared to caregivers who reported ‘no talking’. The odds ratio for caregivers talking for more than an hour for expressive grammar were 1.32 (1.02 to 1.71) and 1.48 (1.16 to 1.91) compared to caregivers who reported ‘no talking’.
Conclusions Caregivers talking to their infants for more than an hour a day have children whose expressive vocabulary complexity and expressive syntax is significantly superior to the children of caregivers who reported no talking.