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OBESITY AS AN INTERGENERATIONAL PROBLEM: Evidence of the big impact of parents’ bodyweight on children’s bodyweight

  • Published Date: April 2014

OBESITY AS AN INTERGENERATIONAL PROBLEM: Evidence of the big impact of parents’ bodyweight on children’s bodyweight

If a child has obese parents, then he or she is over 50% more likely to suffer from obesity as an adult. Equally, if you are a thin person with a thin partner, then your children are unlikely to become obese. These are among the findings of research by Professor Peter Dolton and Mimi Xiao, to be presented at the Royal Economic Society’s 2014 annual conference.

 

Analysing data over time for six countries, including the UK, the United States, China and Indonesia, their study of the ‘intergenerational transmission of adiposity’ finds that:

 

·          Around half of a child’s weight is determined by their parents – including both genetic and environmental factors – with children who have obese parents being up to 50% more likely to suffer from obesity as adults.

 

·          On average, fathers and mothers each separately account for around 20% of the child’s Body Mass Index (BMI), so the joint effect of the family and its associated genetic make-up accounts for around 40% of the child’s likely BMI.

 

·          The strength of this intergenerational relationship, for the average child, is constant and very comparable across countries.

 

·          The results are stronger for fatter children; parents’ influence is up to double for the fattest children what it is for the thinnest children.

 

·          For obese children, where both parents are obese, over 50% of the children’s tendency to obesity may be predetermined by parental factors and not amenable to dietary or other interventions.

 

The authors comment:

 

‘The implications of these results could have far-reaching consequences for child obesity and the effectiveness of possible interventions; it puts the emphasis on parents in the family to understand how obesity in their children is determined.

 

‘Especially for fat children, much of the damage is done at the beginning of their lives. By the time they are adults, it is already too late for a fat child to become a thin adult, overcoming their inherited legacy by dint of their own dieting and lifestyle decisions.’

 

More…

 

Using data on six countries, including the UK, the United States, China and Indonesia, across time, this study finds that how fat we are is largely determined by how fat our parents are.

 

The researchers’ estimate of the ‘intergenerational elasticity of adiposity’ is 0.2 per parent. This means that 20% of our Body Mass Index (BMI), on average, is determined by each of our parents. The study finds that the strength of this intergenerational relationship, for the average child, is constant and very comparable across countries.

 

The researchers also find that the results are stronger for fatter children. The implications of these results could have far-reaching consequences for child obesity and the effectiveness of possible interventions.

 

The first finding is that the intergenerational transmission of BMI is constant and comparable across time and countries. This suggests that a significant fraction of the child’s BMI is determined by the biological process that operates via both genetic and environmental channels within the family.

 

On average, father and mother each separately account for around 20% of the child’s BMI, so the joint effect of the family and its associated genetic make-up accounts for around 40% of the child’s likely BMI.

 

The second major finding is that this intergenerational transmission mechanism varies across the distribution of children’s BMI. Most specifically, it is up to double for the fattest children what it is for the thinnest children.

 

Over 30% of the fattest child’s BMI is determined by the mother and 25% by the father. Hence, jointly they account for over 50% of the fattest child’s likely BMI. In contrast, the corresponding fraction is only around 30% for the thinnest child.

 

Thus, for obese children, where both parents are obese, over 50% of the children’s tendency to obesity may be predetermined by parental factors and non-amenable to dietary or other interventions.

 

The implication of this research is that it puts the emphasis on parents in the family to understand how obesity in their children is determined. Specifically, we need to look no further than the simple biological process of inheritance from parents to child and what happens to the child when they are very young, to explain a large fraction of what they become – as fat or thin adults.

 

The adiposity of the child relates directly to what goes on inside the family – it terms of healthy habits and family diet. Especially for fat children, much of the damage is done at the beginning of their lives. By the time they are adults, it is already too late for a fat child to become a thin adult, overcoming their inherited legacy by dint of their own dieting and lifestyle decisions.

 

These findings also have implications for public health measures addressed at tackling the growing worldwide epidemic of childhood obesity. It is remarkable that these results apply to both the most developed nation on earth and to the least developed.

 

The findings suggest that if a child has obese parents, then he or she is over 50% more likely to suffer from obesity as an adult. Equally, if you are a thin person with a thin partner, then your children are unlikely to become obese.

 

ENDS

 

 

Notes for editors:

‘The Intergenerational Transmission of Adiposity across Countries’ by Peter Dolton and Mimi Xiao

 

For further information, contact:

Mimi Xiao: mx31@ sussex.ac.uk

Romesh Vaitilingam: romesh@vaitilingam.com, +44 7768 661095