ESPE Yearbook of Paediatric Endocrinology

To read the full abstract: JAMA Pediatr 2018;172:1153–1160.

This paper describes a gene-environment interaction twin study in 925 UK families (1850 twins). The heritability of childhood BMI was calculated by comparing the concordance in BMI at mean age 4.1 years between monozygous and dizygous twins; heritability was much higher among more obesogenic households (h²=86%) compared to low risk households (h²=39%), as assessed by parent-reported food, physical activity, and media-related influences in the home.

In recent years, we have seen substantial advances in our understanding of the genetic basis of obesity, both severe early onset monogenic obesity with hyperphagia and also the more common susceptibility to overweight and ‘typical’ obesity. It is very important that, alongside these scientific advances, we promote a mature understanding of the role of genetics and heritability in health. One of the most common fallacies is the ‘deterministic’ idea; that having a genetic susceptibility to obesity means there is little you can do to avoid becoming obese. Conversely, the findings of the current study robustly show that carriers of genetic susceptibility to obesity have significantly more to gain by following a healthy lifestyle.

Specifically, the findings of this paper show the particular importance of a healthy home environment. It may be that this makes it more likely that healthy changes in an individual’s behaviour will occur, that the changes will be larger or possibly more sustained. However, this study was of young children, mean age 4.1 years, who may be more influenced by the home environment than older children and adults, whereas overweight and obesity common occurs in older age groups. Similar studies in such older populations are needed.