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Severe childhood obesity can cut life expectancy in half

Severe childhood obesity can drastically reduce life expectancy, cutting it nearly in half. A recent global study has provided detailed insights into how the age of onset, severity, and duration of childhood obesity affect long-term health and life expectancy.

Long-term impact of childhood obesity

New research presented at the European Congress on Obesity (ECO) in Venice, Italy, has quantified the impact of different aspects of childhood obesity on long-term health for the first time.

The study, conducted by stradoo GmbH, a life sciences consultancy in Munich, Germany, was supported by Rhythm Pharmaceuticals. The project was led by Dr. Urs Wiedemann and his colleagues from universities and hospitals across Europe and the United States.

The experts found that the earlier a child develops obesity, the more severe the long-term effects. For instance, a child living with severe obesity at age four, who does not lose weight, has a life expectancy of just 39 years – about half the average life expectancy.

The findings in detail

“While it’s widely accepted that childhood obesity increases the risk of cardiovascular disease and related conditions such as type 2 diabetes (T2D), and that it can reduce life expectancy, evidence on the size of the impact has been patchy,” said Dr. Wiedemann.

“A better understanding of the precise magnitude of the long-term consequences and the factors that drive them could help inform prevention policies and approaches to treatment, as well as improve health and lengthen life.”

The researchers created an early onset obesity model. This model estimates the effect of childhood obesity on cardiovascular disease and related conditions like T2D, as well as life expectancy.

Four key variables were included: age of obesity onset, obesity duration, irreversible risk accumulation (a measure of irreversible health effects even after weight loss), and severity of obesity.

Critical factors

The severity of childhood obesity was measured using BMI Z-scores, which indicate how much an individual’s BMI deviates from the norm for their age and sex.

For example, a four-year-old boy with a BMI Z-score of 3.5, indicating severe obesity, has a life expectancy of just 39 years if he does not lose weight.

Data for the model came from 50 existing clinical studies on obesity and related comorbidities, involving over 10 million participants worldwide. Approximately 2.7 million of these individuals were between two and 29 years of age.

The risks of severe childhood obesity

The model shows that earlier onset and more severe childhood obesity elevate the likelihood of developing related health issues later in life.

For example, a child with a BMI Z-score of 3.5 at age four has a 27% likelihood of developing type 2 diabetes by age 25 and a 45% chance by age 35. In contrast, a child with a BMI Z-score of 2 at age four has a 6.5% chance of developing type 2 diabetes by age 25 and 22% by age 35.

Higher BMI Z-scores at an early age also lead to a lower life expectancy. For instance, a BMI Z-score of 2 at age four without subsequent weight reduction reduces life expectancy from about 80 years to 65 years. The life expectancy drops further to 50 years for a BMI Z-score of 2.5 and 39 years for a BMI Z-score of 3.5.

Implications for early weight loss

Comparisons with other studies and expert opinions confirmed the model’s accuracy. Furthermore, the model also demonstrated the positive impact of weight loss on life expectancy and long-term health.

For example, a child with severe early onset obesity (BMI Z-score of 4 at age four) has a life expectancy of 37 years and a 55% risk of developing T2D by age 35. If the child loses weight, reducing the BMI Z-score to 2 by age six, life expectancy increases to 64 years, and the risk of T2D drops to 29 percent.

“The early onset obesity model shows that weight reduction has a striking effect on life expectancy and comorbidity risk, especially when weight is lost early in life,” said Dr. Wiedemann.

Addressing childhood obesity

The model has some limitations. It does not account for the causes of obesity, genetic risk factors, ethnic or sex differences, or the interactions between different co-morbidities.

“The impact of childhood obesity on life expectancy is profound. It is clear that childhood obesity should be considered a life-threatening disease. It is vital that treatment isn’t put off until the development of type 2 diabetes, high blood pressure, or other ‘warning signs’ but starts early. Early diagnosis should and can improve quality and length of life,” concluded Dr. Wiedemann.


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