A genetic test could predict the odds of obesity, allowing for early interventions

One day one day can predict the risk of obesity of a child in adulthood, opening the way for early interventions.

Some genetic variants can affect the way a person’s body stores fat or make them more prone to overeating. Genetic variation can also predict to what extent one person will react to different weight loss drugs.

In a study published Monday in the journal Nature Medicine, more than 600 researchers from around the world worked together to compile genetic data of more than 5 million people – the most important and most diverse genetic data to date. They also used 23andme genetic data.

From the data set, the researchers were able to create what is called a polygenic risk score, which takes into account the genetic variants of a person who have been linked to a higher BMI in adulthood.

The score, the researchers said, could be used to predict the risk of obesity of a person as an adult – even before it is 5 years old.

“Childhood is the best time to intervene,” said the co-author of the Ruth Loos study, a professor at Novo Nordisk Foundation Center for Basic Metabolic Research at the University of Copenhagen. (Research carried out at the center is not influenced by the manufacturer of Novo Nordisk drugs, although some of the study authors have links with pharmaceutical societies that make weight loss drugs.)

The results come as obesity increases in the world. Obesity rates in adults have more than doubled in the world since 1990, and adolescent rates have quadrupled, according to the World Health Organization. About 16% of adults worldwide have obesity and the situation is worse in the United States, where more than 40% of adults have obesity, according to disease control centers and prevention statistics.

Twice as effective

The new test is not the first which predicts a person’s risk of obesity, but Loos and his team have shown that it was about twice as effective as the method that doctors are currently using to assess their patients. This polygenetic score can represent approximately 8.5% of the risk of a person to have a BMI raised in adulthood. The new score increased this to around 17.6%, at least in people with European ancestry.

“It is a fairly powerful risk indicator for obesity, but it always leaves a lot of things that are unknown,” said Dr. Roy Kim, pediatric endocrinologist at Cleveland Clinic Children’s who was not involved in research.

Based on this score, more than 80% of the risk of obesity of a person can be explained by other factors, as where they live, to what types of foods they have and how much they do.

The test was not as effective in predicting the risk of obesity in non-Europeans. He explained about 16% of the risk of having a high BMI among American Asian Americans, but only 2.2% in rural Ugandans.

About 70% of people whose data was included in the study were mainly European ancestry. About 14% were Hispanic and usually had a mixture of old ones. About 8% were of main origin in East Asia and just under 5% were of African predominance. These samples came mainly from the African-American people, who largely had mixed ancestors. Only 1.5% was mainly South Asian ancestry.

Loos said the new score is a big step forward, but that it is still a prototype. The next step is to collect more – and more diverse – data on people with African descent in particular to improve the way the score works for everyone, not just whites.

She said the score could offer an indicator – what blood pressure is for heart disease, for example – which could help predict the risk of developing obesity.

“Obesity is not only a question of genetics, so genetics alone can never predict obesity precisely,” said Loos. “For the general obesity that we see all over the world, we need other factors such as the lifestyle that must be part of the predictions.” Genetics plays a more important role in severe obesity, which means a BMI of more than 40, she added.

However, identifying the genetic risk of a person at the beginning of childhood and intervening early with lifestyle coaching could make a big difference, she said. Research has shown that around 55% of children with obesity then have obesity in adolescence and that around 80% of these people will have obesity in adulthood.

“Behavioral things are really important,” said Kim. “Their environment, their access to healthy foods, the possibilities of exercise, even their knowledge of healthy foods all affect the risk of a person.”

What is the importance of genetics, really?

Although studies on identical twins have shown that genetics can represent up to 80% of the reason why a person has obesity, lifestyle factors still play a huge role, Kim said.

“Even with the same genetic makeup, people can have different types of body,” he said. “From a very young age in my practice, we educate patients about the importance of eating protein -rich foods, a lot of fruits and vegetables and not too many refined carbohydrates.”

DRE Juliana Simonetti, co -director of the UTAH University of University Management Program has used genetic tests in adult patients for about five years. She said that understanding a person’s genes can help doctors better treat weight gain.

“Obesity is not homogeneous. We have different kinds and various presentations,” said Simonetti, who was not involved in the new study.

Simonetti uses a person’s genes to determine if a patient is fighting satiety or feeling full.

“They eat but do not feel full,” said Simonetti, adding that it is a disorder caused by genetic mutations affecting certain ways of the body. People who have these changes “tend to have a higher weight,” she said.

But such changes do not tell the whole genetic history of obesity, said Simonetti. The genes of which a person inherits from one or the other parent, even if they are not mutations, also determine how the body of a person stores weight or uses energy. Both can play a big role in the risk of obesity.

Genetic tests also begin to be able to determine to what extent certain weight loss drugs will work for a person, said Simonetti, but he added that it was only the beginning.

“We are talking about three of the 80 changes we can deal with,” she said. “We are improving, the more data we have, I hope we are going to do a better job to be more precise to understand the responses of the treatment.”