The main findings of this study are that the percentage of overweight and obesity in children and adolescents in our population is high compared to previous studies, and that overweight and obesity in children and adolescents is independently and negatively associated with cardiac morphology and function parameters measured by echocardiography.
In the study by Sánchez-Cruz et al.  the prevalence of childhood overweight is 26% and that of childhood obesity is 12.6%. Data from the recently published ENPE study show a prevalence of childhood obesity of 10.3% . The percentage of overweight in our sample was 26.9% and the percentage of obesity was 23.1%, higher than that reported in previous population-based studies in Spain. These findings could be correlated with a heterogeneous distribution of obesity in the different areas of our country. The enKid study , designed to assess the dietary and nutritional habits of children and young people, reported that the Canary Islands and Andalusia had the highest rates of childhood obesity. These data are consistent with the high rates of overweight and obesity in our study.
Furthermore, the results of our study show that higher BMI in childhood is independently associated with increased ventricular wall thickness and LV mass, as well as with increased LV size in both diastolic and systolic volumes. Similarly, higher BMI is associated with increased size of both atria, right ventricle and ascending thoracic aorta. Regarding LV systolic function, the overweight and obese groups of children and adolescents had a lower ejection fraction compared to the normal weight group, and increased BMI was independently associated with decreased LVEF with acceptable goodness-of-fit.
Previous studies have described a relationship between childhood obesity and increased left ventricular mass and altered diastolic parameters. The group of Saltijeral et al , describes an increase in LV size and LV wall thickness in the childhood obesity group compared to the control group. Mangner et al  describe LV and left atrial enlargement and worse diastolic function in obese children and adolescents. Dias et al , agree with previous studies in that adolescents with obesity showed an increase in left ventricular thickness and size. In this respect, our results are in line with those of previous studies published on this topic.
However, these previous studies were case-control studies with small samples, and only the study by Saltijeral et al. was conducted in our setting. In this respect, our study provides relevant information from a large, randomly selected sample of a rural Spanish child population. Furthermore, none of these studies reported a significant worsening of LVEF in the obese group, nor an independent relationship of BMI with worsening LVEF.
Based on our results, in childhood obesity we observed an adaptation of the LV by dilation and hypertrophy, in a similar way that is reported in adult obesity, and it may be related to the increase in cardiac output needed to meet the metabolic demands. Our group is concerned about the high prevalence of childhood overweight and obesity, as well as the structural and functional changes observed in the cardiac cavities of overweight and obese children and adolescents, leading to an increased cardiac chamber size and an impaired LV systolic and diastolic function. Although these structural and functional changes are far from clinical significance, it is likely that these changes, present an early age, may persist over time, and should be considered as incipient changes for the development of obesity cardiomyopathy in adulthood.
It has been described that therapeutic intervention on obesity in adulthood and the reduction of BMI is accompanied by significant structural improvements, even reaching complete normalisation of the cardiac structure . Extrapolating this information to children, this research group considers that therapeutic intervention on childhood obesity would set a great precedent in the primary prevention of cardiovascular events in this population risk group.
As a main limitation of the study, our group considers that, being designed as a cross-sectional study, it does not really allow us to assess whether these structural changes can be maintained over time into adulthood. Similarly, it does not allow us to assess whether an intervention on obesity in childhood could reverse the structural and functional changes observed. Further sample follow-up or obesity intervention studies would be needed to answer these questions. On the other hand, it is a study carried out in a specific population in southern Spain and may be the results, at least in terms of prevalence of childhood obesity, may not be extrapolated to other regions.