Understanding the dynamics of childhood body fat - the mediating effect of dietary patterns and eating behaviors

Summary:

Obesity is the result of complex interactions between genetic, behavioural and social factors [1]. Although obesity status has beensomewhat reduced to a clear and simple unbalance between energy intake and expenditure, important underline mechanisms relatedwith appetite and satiety could exert their influence and regulate, at the long-term, body weight [2]. An early assessment ofbehavioural traits that confer susceptibility to an obesogenic environment could identify children with high-risk appetitecharacteristics, who have an increased likelihood of becoming obese in the future [3-6].

 

This project, using a longitudinal approach, will provide a better understanding of diet-related influences (expressed in differentdimensions: food patterns, eating behaviours and early parental feeding practices) on factors related with appetite and body fat inchildren, from a life-course approach. It could offer insights into tackling the obesogenic environment, and promises to shed light therelationship of diet with childhood obesity. Until now, most studies have approached these dimensions individually withoutinterconnections between them, and most studies on children have a cross-sectional design.

 

This project aims to re-evaluate children enrolled as part of the Generation XXI birth cohort that has included prospectively bothmothers and their children since birth (8666 children and their mothers were enrolled during 2005-2006 at five level III maternityunits of Porto) until 4 years-old. The re-evaluation of these children at 7 years of age will allow understanding how food habits changefrom pre-school to school-aged children and influence the dynamics of childhood body fat. The current project has 5 specificobjectives to be attained: i) to define dietary patterns at two time frames (4 and 7 years of age), evaluate their stability over timeand early determinants (e.g. birth weight, breastfeeding, prepregnancy maternal body mass index); ii) to evaluate if food patterns(dietary patterns and meals’ structure) of 4 year-old children are associated with eating behaviours related with appetite (e.g. satietyresponsiveness and food cues responsiveness) at 7 years of age; iii) to understand the effect of parental feeding practices at 4 years(namely a higher parental control over children’s intake) on eating behaviours related with appetite and body fat at 7 years; iv) toestimate the clustering effect of food patterns and physical activity established at 4 years on body fat and metabolic factors, such asinsulin, leptin and blood lipids at 7 years; v) to evaluate neonatal determinants (e.g. leptin measured in umbilical cord blood) ofadiposity signals (such as leptin and insulin) and body fat at 7 years.

 

We expect to re-evaluate 3000 children with complete information on both food records and body composition at 4 years of age. Theavailability of prior evaluations of these children brings an important contribution to this project and assures comparability of data andthe performance of longitudinal analyses. Different dimensions of food habits will be approached: i) dietary patterns (defined by factoranalysis or latent class analysis); ii) structure of meals (number of eating episodes, meal time span and snacking); iii) child eatingbehaviours (evaluated by 5 sub-scales of the Children’s Eating Behaviour Questionnaire designed to assess aspects of children’sappetite, already validated and adapted to Portuguese children). Body weight and height, waist circumference and body composition(fat mass and free fat mass, obtained by tetrapolar bioimpedance) of 7 year-old children will be also obtained. A fasting venous bloodsample will be drawn from all children, after parent’s agreement, to perform measurements of glucose, insulin, leptin and lipids ’profile.

 

The accomplishment of the projects’ aims is, at some extent, guaranteed by a sustained knowledge of researchers on the main topicsof this project, as well as by them large experience in methodological aspects related with cohort studies. The project also intends topromote the improvement of human resources on both technical and scientific aspects, supporting the development of post-graduation theses, writing of manuscripts, and presentation of the final results at national and international meetings and to thegeneral public through the lay press. The project will also promote an exchange of ideas with external consultants, recognized asexpertises in this area of research, namely with involvement in the network of birth cohorts in Europe.