Simple formula can predict risk of childhood obesity at birth, study says

BMJ 2012; 345 doi: (Published 30 November 2012) Cite this as: BMJ 2012;345:e8166
  1. Susan Mayor
  1. 1London

A simple formula can predict a baby’s risk at birth of becoming obese later in childhood, show the results of a new study.1 The researchers suggest that the formula could be used to target families who would benefit most from efforts to prevent obesity.

The formula, which is available as an online calculator (, estimates the risk of obesity from the child’s birth weight, the body mass index (BMI) of the parents, the number of people in the household, the mother’s professional status, and whether she smoked during pregnancy.

An international research group developed the formula by using data collected in the Northern Finland Birth Cohort Studies, which prospectively followed 4032 people born in 1986 to assess factors at birth that correlated with obesity in childhood. These results showed that traditional risk factors, including parents’ BMI, birth weight, and social indicators, predicted obesity risk but that a genetic score that was based on polymorphisms associated with obesity added little further discrimination.

The group confirmed the formula’s accuracy in predicting childhood obesity in cohorts in Italy and the United States (area under the receiver operating curve for children’s obesity 0.78 (95% confidence interval 0.74 to 0.82), P<0.001). The 20% of children predicted by the formula to have the highest risk at birth accounted for 80% of the children who went on to become obese.

One of the study’s authors, Philippe Froguel, professor of genomic medicine at Imperial College London, said, “This test takes very little time, it doesn’t require any lab tests, and it doesn’t cost anything. All the data we use are well known risk factors for childhood obesity, but this is the first time they have been used together to predict from the time of birth the likelihood of a child becoming obese.”

Traditional approaches to managing obesity have had poor long term effectiveness, the research group pointed out. Therefore prevention was currently the most promising strategy for controlling the obesity epidemic. They suggest that efforts to prevent obesity should start as early as possible, because previous studies have shown a strong association between weight gain in early infancy and childhood obesity.

“Parents of newborns are particularly sensitive to information given about their child’s health,” the research group concluded, adding that parents found to have children at high risk of obesity might be more receptive to advice on prevention at this stage.


Cite this as: BMJ 2012;345:e8166