Social inequalities in early nutrition and health : from observation to prevention – NUT-PREV

Strong social inequalities in health exist in high income countries for chronic diseases associated with diet and lifestyles. As early as infancy, children from disadvantaged families are breastfed less often, display suboptimal diets, along with a higher risk of later overweight and obesity. Although the cost of food accounts for a portion of the disparities, factors related to the environmental (availability and accessibility of food supplies) and the socio-cultural setting (e.g., knowledge, social norms and beliefs) also play an important role. Growing knowledge about the developmental origins of health and disease (DOHaD) reinforces the importance of promoting healthful diet and feeding practices during pregnancy and the first 2 years of life. However, interventions targeting early risk factors for obesity in the most vulnerable families are rare.

The overarching aim of the current project is to increase knowledge about the socioeconomic and cultural factors associated with diet in families (mothers, fathers and young children), not only in the general population (WP1), but also among disadvantaged families (WP2, WP3), which are sparsely represented in epidemiological studies. A further objective is to translate this knowledge into the on-going ECAIL multi-component intervention, aimed at promoting a healthy diet and optimal growth in disadvantaged young children (WP3).

Based on the ELFE birth cohort, WP1 aims to assess if maternal and paternal diets mediate the respective associations between maternal and paternal socioeconomic positions and their children’s diets at ages 9 months and 2 years. Whether each parent’s diet is associated with their child’s diet, independent of parental socioeconomic position, has not been established and is a question of interest for obesity prevention, as their diets are likely to be more amenable to change than their socioeconomic position.

In WP2, based on the ENFAMS cross-sectional survey, we will describe the proportion of mothers who initiated breastfeeding and the distribution of breastfeeding durations in homeless families in shelters in 2013, in the greater Paris area. We will study the associations of maternal socioeconomic and cultural factors with breastfeeding, and test the hypothesis that breastfeeding is associated with a lower risk of overweight. Knowledge from WP2 will inform future public health interventions directed at these particularly vulnerable, culturally and socially diverse, populations.

The ECAIL randomised controlled trial (WP3) has been co-constructed with stakeholders involved in an existing programme (namely, MALIN) based on an innovative and sustainable partnership between non-governmental organisations and participants from the public and private sectors. It includes a nutritional educational component that seeks to build knowledge, skills and social support in feeding practices (including breastfeeding) at the individual level (social cognitive theory); and at a more structural level, it provides fresh fruit and vegetable baskets at a reduced price starting in pregnancy, along with vouchers for baby food/follow-on formula from 6 to 24 months. Now that it has launched, we aim to continue the implementation of the ECAIL trial and to include in its assessment a qualitative component that will contribute to a better understanding of how, why and for whom the programme does and does not work. This will enrich the process evaluation of this complex intervention, in a framework addressing the relations between implementation, mechanisms and context. The co-construction of the ECAIL trial with some key participants of the MALIN programme is valuable for promoting the transfer and sharing of knowledge (translational research). More generally, the unique experience acquired in the field of the ECAIL intervention will allow us to make progress on the issues of identifying, recruiting, and following up vulnerable and hard-to-reach families.