Effects of early intervention on dietary intake and its mediating role on cognitive functioning: a randomised controlled trial.

OBJECTIVE
To investigate the impact of an early intervention programme, Preparing for Life, on dietary intake between 12 and 36 months of age, and the mediating role played by diet on cognitive functioning.

DESIGN
A randomised controlled trial evaluation of a community-based home visiting programme. The intervention involved biweekly visits from mentors from pregnancy until age 5 years and parent training at age 2 years. Dietary intake was assessed at 12, 18, 24 and 36 months using an FFQ to calculate the proportion meeting dietary recommendations. Cognitive functioning was measured at 24 and 36 months. Treatment effects were estimated using conventional χ 2 tests, permutation testing, inverse probability weighting and the stepdown procedure. Mediation analysis examined the indirect effect of the intervention on cognitive functioning via its effect on dietary intake.

SETTING
Socio-economically disadvantaged communities in Dublin, Republic of Ireland.

SUBJECTS
Pregnant women (n 233) were assigned to the intervention (n 115) or control (n 118) group using an unconditional probability randomisation strategy.

RESULTS
Positive treatment effects were observed for meeting dietary recommendations for protein foods at 24 (OR=2·52) and 36 (OR=2·42) months, and all food groups at 24 (OR=3·92) months. There were no effects on grain, dairy, fruit and vegetable, or fatty/sugary food recommendations in most models. The conventional and more novel methods yielded similar results. Mediation analysis indicated that 13 % of the intervention's effect on cognitive functioning was mediated by 36-month protein food consumption.

CONCLUSIONS
The study demonstrates some potential to alter early childhood dietary patterns through community-based intervention programmes.