Individuals are at high risk of obesity in the middle age if the parents were obese during the same stage, a new study revealed.

According to the study conducted by Norwegian researchers, people whose parents both experienced obesity in middle age are six times more likely to live with obesity during the same life stage. The risk of developing obesity triples when one parent is living with the condition.

"Previous research shows a strong association between parents' and their children's obesity status but few studies have investigated whether this intergenerational transmission of obesity continues past adolescence and into adulthood. We were interested in how parents' BMI is related to their offspring's BMI when the offspring is well into adulthood and has lived away from home for a long time," said lead researcher Mari Mikkelsen in a news release.

The findings of the study will published at the European Congress on Obesity (ECO 2024) conducted in Venice from May 12-15.

The research team used data from the Tromsø Study, an ongoing population-based health study. The study involved 2,068 groups, each consisting of parents and their offspring. The participants included people between 40 and 59 years old (middle age) during the seventh wave of the Tromsø Study in 2015-2016 and whose parents also participated in the Tromsø Study during its fourth wave in 1994-1995 when they were in the same age range.

The height and weight analysis indicated a strong association between the Body Mass Index (BMI) of the parents during their middle age and that of their offspring at the same age.

The BMI of the offspring increased by 0.8 units for every 4-unit increase in the mother's BMI and by 0.74 units for every 3.1-unit increase in the father's BMI.

The researchers also noticed significant connections between the obesity status of parents in middle age and that of their offspring at the same age.

"When both parents lived with obesity (BMI ≥ 30 kg/m2) in middle age, their offspring had six times higher odds of living with obesity themselves in middle age, than adults with both parents in the normal weight range (BMI 18.5-24.9 kg/m2). The odds were also raised when only one parent lived with obesity. When only the mother lived with obesity, the offspring had 3.44 times higher odds of living with obesity themselves. The corresponding number for fathers was 3.74," the news release stated.

Several factors could contribute to shared obesity status between parents and their children. While genes could be one possibility, some studies also suggest that the children tend to pick up dietary and exercise habits from parents particularly when they live together, resulting in a similar BMI status, researchers explained.

"It can't be established from our analyses whether this is due to genes or environment but we are most likely looking at a combination of the two. Whatever the explanation, our finding that obesity that is transmitted between generations can persist well into adulthood underlines the importance of treating and preventing obesity, a condition that contributes significantly to ill health and premature death. It also lays the foundation for research into factors that influence the intergenerational transmission of obesity and that can be targeted to prevent offspring from spending their whole life affected by obesity," the researchers wrote.