August 1, 2016

expert reaction to study looking at BMI and incidence of heart attacks, type 2 diabetes and death in identical twins

The contribution of genetics and obesity to cardiovascular disease, type 2 diabetes and death is evaluated in a paper published in JAMA Internal Medicine. Through their analysis of monozygotic twins with varying body mass indexes (BMI) the researchers report that higher BMI was not associated with increased risk of heart attack or death but was associated with the onset of diabetes.

Dr Elizabeth Robertson, Director of Research, Diabetes UK, said:

“Obesity is a well-known risk factor of Type 2 diabetes with obese people approximately seven times more likely to develop the condition; but it’s not the only one. Genetics and other factors such as age or ethnicity also play a role. Comparing twins who share identical genes is a particularly elegant way of untangling genetics from other risk factors; and the stark connection between BMI and the risk of Type 2 diabetes found here is expected.

“With all studies of this nature, we have to be careful not to imply that something causes a condition just because there’s a relationship between the two, or to oversimplify complex risk calculations. While it’s very interesting that this study didn’t find an association between BMI and cardiovascular disease or mortality, the evidence linking the underlying biology of obesity to the development of cardiovascular disease is relatively strong. We would be interested to see the findings here being explored further, using other obesity measurements alongside BMI. BMI is designed to be used on a population level and doesn’t account for other signs of obesity such as weight circumference, muscle mass, or the build-up of fatty deposits inside the body.

“While we are very much focused on promoting weight loss and preventing weight gain as a means to reduce the prevalence of Type 2 diabetes, we believe that further research is needed before we send a potentially confusing message that the same isn’t required to protect against cardiovascular disease or mortality.”

‘Risks of myocardial infarction, death, and diabetes in identical twin pairs with different body mass indexes’ by Peter Nordström et al. published in JAMA Internal Medicine UK time on Monday 1 August 2016. 

Declared interests

None received