Abstract:
Background: Research on infant feeding tends to focus on discrete practices, making it difficult to summarize this critical period to reflect the whole infant diet simultaneously. We aimed to create an infant feeding index (IFI) which measures overall adherence to the New Zealand Ministry of Health Food and Nutrition guidelines for infants, and investigate associations between index scores and socio-demographic characteristics. Methods: Data on 6435 infants were collected in the Growing Up in New Zealand study at the antenatal, 6-week, 9-month and 31-month interviews. Based in statements in the Ministry of Health guidelines, the IFI encompassed indicators of: breastfeeding, age of food introduction and food intake at 9-months of age (using a food frequency questionnaire). The IFI has a maximum of 100 points and contains 4 equally-weighted domains (Breastfeeding; Introduction to solids; Eating a variety of foods and; Appropriate foods and drinks). Associations of the child and mother characteristics with the IFI scores were examined using a multiple linear regression model (p < 0.05). Results: The IFI median (interquartile range) score was 70.0 points [56.87; 82.50]. The lower the level of maternal education and age of the mother, the lower the IFI score. Infants of mothers of Māori, Asian, Pacific and other ethnicities scored, respectively, 7.8, 6.6, 5.0 and 2.6 less points on the IFI in comparison with European mothers. Infants living in more deprived neighbourhoods (NZDep deciles 5–10), whose mothers did not have a partner during pregnancy, and did not attend childbirth preparation classes also had lower scores on the IFI in comparison with reference groups. Conclusions: This is the first IFI created in NZ using data that is generalizable to all NZ births from 2007-2010. Socio-economic inequalities in overall adherence to the infant feeding guidelines call for interventions that aim to reduce inequalities during infancy in NZ.