Childhood overweight is not a judgement: if your weight is normal by age 20, your risk of heart attack does not increase

If body weight returns to normal before adulthood, the heart, according to new data, does not practically "remember" the increased childhood BMI. This is the conclusion reached by scientists at the University of Gothenburg.

What the study showed

It is well known that overweight and obese children on average have a higher risk of heart attack in the future. But until now, it has been unclear whether this risk can be markedly reduced if weight can be normalised before adulthood.

A new study published in JAMA Pediatrics has tried to answer this question.

The study analysed data from more than 103,000 people born between 1945 and 1968.

• Height and weight in childhood were taken from the school health service of the city of Gothenburg.

• The data were linked to national registers that record cases of myocardial infarction in adulthood.

Key findings

The scientists compared weight in childhood (7-8 years old) and young adulthood (around 20 years old), and then compared this with the risk of heart attack.

The following picture emerged:

• Overweight in both childhood and young adulthood → increased risk of heart attack in adulthood.

• Normal weight in both childhood and youth → baseline (low) risk.

• Was overweight at age 7-8, but weight normalised by age 20 →

  • the risk of heart attack is the same as for people of normal weight in both childhood and youth;

  • i.e. childhood overweight itself did not leave a "cardiovascular footprint" if corrected in time.

Pros:

• People who were overweight in their 20s had an increased risk of heart attack regardless of,

  • whether they were already overweight as children

  • or whether they were overweight at puberty.

And an unexpected detail:

• those who gained excess weight specifically during adolescence had a higher risk of heart attack than those who had been overweight since childhood.

"This study does not directly answer the question of why being overweight starting during puberty is associated with a greater risk," notes professor and physician Claes Ohlsson (Claes Ohlsson). - We hypothesise that changes in sex hormones during puberty play an important role, and we are now working on this hypothesis."

Why it's important

"This study emphasises the importance of early detection and correction of overweight," says co-author of the paper, physician and researcher Rebecca Bramsved.

The authors draw several important conclusions:

• Childhood overweight is not a verdict if the weight manages to normalise before young adulthood.

• Overweight around the age of 20 is especially critical - both "long-standing" and acquired during adolescence.

• Prevention of cardiovascular diseases, according to the researchers, should begin in childhood:

  • controlling weight and eating habits,

  • support physical activity,

  • early interventions if weight is outside the normal range.

"Our results confirm once again: prevention of cardiovascular disease in adults should really start in childhood," emphasises Professor and physician Jenny Kindblom, one of the co-authors.