To quantify the mediating role of childhood diets in the relationship between maternal diets prior to pregnancy and childhood behavioural disorders.

The Healthy Eating Index score was constructed using a semi-quantitative and validated 101-item FFQ. We assessed childhood behavioural disorders using the Strengths and Difficulties Questionnaire. Three dietary patterns were identified using principal component analysis to explore childhood dietary patterns (high fats and sugar; prudent diets; and diary). A causal inference framework for mediation analysis was used to quantify the mediating role of childhood diets in the association between pre-pregnancy diets and the risk of offspring behavioural problems.

This is a national representative population-based survey which covers all Australian citizens and permanent residents in Australia.

We included 1448 mother–child pairs from the Australian Longitudinal Study on Women’s Health and its sub-study mothers and their children’s health.

We found a 20 % of the total effect of the poor adherence to pre-pregnancy diet quality on the risk of offspring behavioural problems was mediated through childhood high consumptions of fats and sugar. No clear mediating effect through prudent and diary childhood diets was observed.

This study suggests that childhood high fats and sugar consumption may contribute to the total effects of the pre-pregnancy diets on the risk of childhood behavioural problems.