Children with overweight have an increased risk of developing many diseases as adults, including type 2 diabetes, cardiovascular disease and various types of cancer. New research adds chronic kidney disease to the diseases associated with overweight in childhood. The leading author says that understanding the possible long-term effects of children living with overweight is important.
Adults with overweight have an increased risk of developing chronic kidney disease.
Researchers have long known about this association, but new research shows that overweight in childhood also increases the risk of developing chronic kidney disease in adulthood.
The study also shows that the association is independent of type 2 diabetes, which is a strong risk factor for chronic kidney disease.
According to the leading author of the study, the results emphasise the importance of preventing overweight in childhood, since this can have lifelong negative effects on their health.
“We were surprised by how strong the associations are, and actually, the associations are evident already with body mass index (BMI) trajectories slightly above-average. Chronic kidney disease is a serious disease that is increasing in prevalence and causes many deaths. As more and more children develop overweight, this may increase the number of people who will later develop chronic kidney disease,” explains Julie Aarestrup, PhD and Researcher in the Lifecourse Epidemiology Group at the Center for Clinical Research and Prevention, Bispebjerg and Frederiksberg Hospital, Copenhagen.
The research has been published in PLoS Medicine.
Investigated height and weight of 300,000 children
Since previous studies have found that some children with obesity already have kidney complications, the new study hypothesised that overweight and obesity in childhood may also be associated with chronic kidney disease in adulthood.
To investigate this possible association, the researchers used a large database with data on almost 300,000 children from the Copenhagen School Health Records Register.
The data set contains height and weight measurements of school-aged children in Copenhagen born between 1930 and 1987. The children were measured and weighed up to 12 times at ages 6–15 years.
The researchers used the data to create BMI trajectories for each child and divided them into the following BMI trajectories: below-average, average, above-average, overweight and obesity.
The researchers then linked the data from the school health examinations with data from the Danish National Patient Register, which contains information about all hospital admissions and examinations in Denmark, including those related to chronic kidney disease.
Surprisingly strong association
In the study population, 5,986 men and 3,903 women developed chronic kidney disease during the study period.
A total of 997 men and 543 women developed end-stage kidney disease requiring dialysis or transplantation.
Compared with people who had an average BMI trajectory in childhood, men with an obesity BMI trajectory at school ages had a 39% increased risk of developing chronic kidney disease. For women, the figure was 54%.
According to Julie Aarestrup, the association was surprisingly strong.
“We have carried out similar studies for cardiovascular disease, cancer and diabetes, and the association between obesity in childhood and the risk of developing chronic kidney disease is among the strongest we have seen,” she says.
The researchers adjusted their analysis for adult-onset type 2 diabetes, which is strongly associated with developing chronic kidney disease, but the association remained very strong. According to Julie Aarestrup, this indicates that obesity in childhood can be a risk factor for developing chronic kidney disease in adulthood, independent of type 2 diabetes.
Risk increases with childhood BMI trajectories slightly above average
The researchers also examined more absolute figures for the risk of developing chronic kidney disease for children with an obesity trajectory.
As an example, men aged 65 years who had an obesity BMI trajectory in childhood have a 3% likelihood of developing chronic kidney disease over the following 10 years.
Three per cent may sound minor, but if these men also have type 2 diabetes, the risk rises to 11%.
“Chronic kidney disease has few established early-life risk factors, but we found that overweight and obesity in childhood is one. In addition, we found that the higher the BMI trajectory, the higher the risk, and that the risk is already evident at a BMI trajectory slightly above average. Our findings may help to earlier identify those with a greater risk of later developing chronic kidney disease, so that fewer people develop this disease in the future,” concludes Julie Aarestrup.