A population based approach to obesity

Another reason for taking a population based approach to obesity

Increasing rates of childhood obesity

Strong genetic influences on

childhood BMI (meta analysis heritability

estimate 75%)

Stronger argument for a population

approach

Increasing overweight in children around the world (Foresight 2007)

Tom Fowler, [email protected]

If individuals differences are mainly explained by genetic factors, addressing the obesity epidemic by targeting high risk groups alone, i.e. trying to reducing individual differences, is likely to prove problematic. Interventions which focus on shifting the population mean are likely not only to have the largest effect but also be most effective. .

Clear, focussed message• Obesity is one of the main public health challenges facing both the world

and the UK• An area that still causes debate is the apparent discrepancy between

findings showing an important genetic aetiology for BMI and the increase in BMI over the last several years which must be environmental.

• This slide is based on work and preliminary findings from a meta analysis of twin studies looking at a number of different age groups in which I am collaborating, however as this work is still preliminary the heritability estimate quoted is from the published study by Silventoinen et al 2009

• Genetic studies focus on explaining individual differences, i.e. Why one person differs from another with regard to BMI

• The factors implicated in the overall rise in BMI scores (Foresight report) are societal, i.e. What has caused the change over time are environmental factors that affect the whole

• The main message of this work is that a) obesity levels are rising, b) genetic factors are largely implicated in the aetiology of BMI, c) these are not conflicting findings but actually complementary and d) given the genetic influences on BMI, and the difficultly likely to be involved in addressing this, approaches that seek to reduce individual differences, by targeting risk groups, may have difficulty in achieving their aims. As such the genetic aetiology adds to the argument that there is a need to focus societal interventions that affect the whole population


Pleasing to the eye• The slide includes a number of complex concepts, however it breaks down

the issues into 3 steps to get the concepts across.• The slide also uses visual representations of the key issues, i.e. It uses a

graphical representation of increasing rates of obesity to both demonstrate the change of a relatively short (evolutionarily) time period and that this is an important issue.

• It also uses the iconic symbol of the double helix to instantly clarify that the slide is considering genetic effects.


Has clear potential to help a decision be made

• Reducing the levels of obesity is a key public health aim• In responding to this issue it is easy for policy makers to focus on targeted

solutions as this appears to be a more concrete response (the population paradox at policy level)

• This work provides another argument as to why the focus should be on population based interventions


Demonstrates a Public Health competency

• Currently this work relates to mainly academic PH competencies, but it is hoped that when published it will be able to add to the evidence based used to make more service based decisions.

• Specific academic competencies addressed include:– Formulating a specific public health research question– interpret a meta analysis– Identify the potential for misleading findings from different research methods

and how to avoid them– Draw appropriate conclusions and make recomendtions


Health & Medicine

A population based approach to obesity