Child feeding indexes measuring adherence to New Zealand nutrition guidelines: Development and assessment

New Zealand (NZ) lacks nationally representative or generalisable information on the dietary intakes of pre‐schoolers. We used Growing Up in New Zealand cohort data to i) develop child feeding indexes (CFIs) based on National Food and Nutrition Guidelines for 2‐ and 4.5‐year‐olds; ii) describe the cohort adherence to the guidelines at 2 (n = 6046) and 4.5 years (n = 5889) and; iii) assess the CFIs’ convergent construct validity, by exploring associations with maternal sociodemographic and health behaviours and with child body mass index for age (BMI/age) and the waist‐to‐height ratio at 4.5 years. The CFIs scores ranged from 0 to 11, with 11 representing full adherence to the guidelines. Associations were tested using multiple linear regressions and Poisson regressions with robust variance (risk ratios [RR], 95% confidence intervals, 95% CI). The CFIs mean scores (SD) at 2 and 4.5 years were, respectively, 6.13 (1.21) and 6.22 (1.26) points. Maternal characteristics explained, respectively, 27.2% and 31.9% of the variation in the CFIs scores at 2 and 4.5 years. In the adjusted model at the 4.5‐year interview, in relation to girls ranked in the 5th quintile, those in the 2nd (RR, 95% CI: 1.48; 1.03; 1.24) and 4th (1.53; 1.05; 2.23) quintiles of the CFI were more likely to have BMI/age > +2z (World Health Organization growth standards) at 4.5 years. At 2 and 4.5 years, most children fell short of meeting national guidelines. The associations between the CFIs scores at both time points with maternal characteristics and with children's body size at 4.5 years were in the expected directions, confirming the CFIs’ convergent construct validity among NZ pre‐schoolers.