Prevalence and maternal determinants of early and late introduction of complementary foods: results from the Growing up in New Zealand cohort study.

A nationally generalisable cohort (n=5770, 7-12-month-old children) was used to determine prevalence of non-timely (early/late) introduction of complementary food and core food groups and associations with maternal sociodemographic and health behaviours in New Zealand (NZ).Variables describing maternal characteristics and infant food introduction were sourced, respectively, from interviews completed antenatally and during late infancy. The NZ Infant Feeding Guidelines were used to define early (<4 months) and late (≥7 months) food introduction. Associations were examined using multivariable multinomial regression, presented as adjusted relative risk ratios (RRR) and 95% confidence intervals (CI).Complementary food introduction was early for 40.2% and late for 3.2%. The prevalence's of early food group introduction were: fruit/vegetables (23.8%), breads/cereals (36.3%), iron-rich foods (34.1%); and of late were: meat/meat alternatives (45.9%), dairy products (46.2%), fruits/vegetables (9.9%).Compared to infants with timely food introduction, risk of early food introduction was increased for infants: breastfed <6 months (RRR=2.52; 95%CI 2.19-2.90); whose mothers were <30 years old (1.69; 1.46-1.94), had a diploma/trade certificate versus tertiary education (1.39; 1.14-1.70), of Māori versus European ethnicity (1.40; 1.12-1.75), or smoked during pregnancy (1.88; 1.44-2.46).Risk of late food introduction decreased for infants breastfed <6 months (0.47; 0-2.7-0.80) and increased for infants whose mothers had secondary versus tertiary education (2.04; 1.16-3.60), were of Asian versus European ethnicity (2.22; 1.35-3.63), or did not attend childbirth preparation classes (2.23; 1.24-4.01).Non-timely food introduction, specifically early food introduction, is prevalent in NZ. Interventions to improve food introduction timeliness should be ethnic-specific and support longer breastfeeding.