Study links wealth and obesity

Research into the link between national income, inequality and body size reveals more adolescent girls are obese in wealthier countries.

The University of Auckland study, led by Associate Professor Rinki Murphy, looked at 200,000 children in 36 countries including New Zealand, Australia and Britain.

It analysed height and weight data from over 77,000 children aged 6-7 and over 205,000 adolescents aged 13 or 14, from 19 and 36 different countries, respectively.

It found obesity rates differed by either the gross national index or the Gini index.

Young people from countries with a higher gross national index had a higher median BMI compared with those from less wealthy countries.

Adolescent girls from these places with higher income inequality had both a greater median BMI and a less skewed BMI distribution.

Commentary from Murphy acknowledged low nutrition was the likely explanation for greater numbers of underweight children in states with a lower national income.

However, the prevalence of calorie-dense foods and a decreased need for physical activity was likely to be common in both richer and poorer countries.

This could potentially affect young people in both high and low GNI countries, Murphy said.

Other factors could include genes and environmental explanations.

Murphy said more research was needed into why greater income inequality within societies was linked with greater body mass index of adolescent girls. — Alice Peacock