New Delhi: Researchers have said that a person’s body mass index (BMI) can be explained genetically, as they found that children have a 77 per cent chance of being obese at the age of 17 if their parents were obese at the same age. A team of researchers, including those from Tel Aviv University, used data from over 1.3 million people recorded between 1986 and 2018 during screening before mandatory military service in Israel.

The BMI of the children at age 17 was compared with the BMI of both their parents when they were the same age. Data was available for 24 per cent of the over 4.45 lakh children included in the analysis.

“The prevalence of overweight or obesity among offspring of children under three whose both parents had a healthy BMI was 15.4 percent, and this proportion increased to 76.6 percent when both parents were obese,” the authors wrote in the study published in the Journal of the American Medical Association (JAMA) Network Open.

The researchers also found a correlation between the average of the father’s and mother’s BMI and their child’s BMI and estimated that BMI is 39 percent genetic. The correlation between father-son BMI was found to be 0.273, indicating that the father’s BMI may have up to a 27 percent influence on the son’s BMI.

In addition, the authors found a stronger association between the BMI of mothers and daughters than between mothers and sons. Obese mothers have already been linked with a higher chance of daughters developing the condition, compared with obese fathers.

The authors said that, therefore, these results underline the role of genetic and environmental factors as well as gender-specific influences on the heritability of BMI.