In 2025, our country will receive nationally recorded growth curves for children and young people for the first time in its history.
disorders can be identified more quickly and treatments improved.
Who is how tall and when? Growth charts are important tools for assessing the development and health of children.
Image Source / Getty
It took a long time, too long. But now the time has finally come: Switzerland is getting new growth curves for children and adolescents. In 2025, the Swiss Pediatric Society will make the data published in 2019 by the Pediatric Endocrinology Center Zurich (PEZZ) available nationally. This will be supplemented by new data from French-speaking Switzerland and Ticino. This will mean that Switzerland will have its own nationally collected growth and weight curves for the first time in history.
Growth curves are important tools for assessing the development and health of children. After birth, height, weight and head circumference are therefore measured regularly. A child’s growth can then be compared with the norm values in the corresponding age group. This allows parents to see in which percentile their child is growing, whether it is one of the taller or shorter ones. If a child grows along the 30th percentile, this means that 30 percent of their peers are smaller and 70 percent are taller.
Between their 2nd and 10th birthdays, children should always grow in roughly the same percentile channel. If a child suddenly moves away from this path, this can indicate illness. The third percentile is crucial here: if a child falls below this, doctors take notice.
When assessing such borderline cases, it is important which standard values are used. In Switzerland, until 2011, the growth curves that the Zurich pediatrician Andrea Prader from the Zurich Children’s Hospital had collected based on 274 girls and boys born in the Zurich area between 1954 and 1956 were used. The Prader curves received worldwide recognition at the time. However, most European countries now have their own national growth curves, particularly for the ages between 5 and 18 years.
The ominous third percentile
In 2011, the Swiss Society of Pediatrics, now known as Pediatrics Switzerland, decided to replace the Prader curves with international data from the World Health Organization (WHO). Since then, data collected between 1997 and 2003 in Brazil, Ghana, India, Norway, Oman and the USA have been used for the first five years of life. For years 5 to 18, measurements from American children from the 1950s to the 1970s are used. The curves introduced in 2011 were therefore not really up to date.
Urs Eiholzer, head of PEZZ and Andrea Prader’s last student, has long pointed out this problem. In 2016, he criticized the fact that the international curves did not adequately reflect the growth of children in Switzerland, as children in this country are significantly larger than the WHO curves indicate. As a result, growth disorders could be overlooked or even missed, he fears.
“Usually, pediatricians only become suspicious when a child falls below the third percentile,” explains Eiholzer. From the age of 4, however, the third percentile of the WHO curve differs from the growth of children in Switzerland by up to 4 centimeters. So it takes longer to recognize that a child is growing too slowly. “The child may then not grow as tall as it would have if the disorder had been discovered earlier and treated with the appropriate therapies,” he says.
This affects children with celiac disease, for example. Celiac disease weakens growth and the children fall off their curve. But pediatricians often only take a closer look when they fall below the third percentile and refer them to a specialist for further evaluation. “If a pediatrician uses the international curves, he may react two or three years late,” says Eiholzer.
Up to a third of children with growth-impairing diseases are not diagnosed using the international curves or are diagnosed too late, a Danish study“The time window for growth is limited. What is not solved between the ages of 5 and 15 cannot be undone,” says Chris Fritz, research associate at PEZZ.
“Over the years, we have certainly seen dozens of children who have lost 10, 15 or even 20 centimeters of their final height because the doctors recognized the problem too late,” says Eiholzer. In addition to celiac disease, growth disorders also occur in children who are born too small, so-called SGA children, or in girls with Turner syndrome. In this congenital disease, one of the two X chromosomes is completely or partially missing.
But there could also be problems at the upper end of the curves, namely with the weight curves, says Eiholzer. “Using the international curves leads to overdiagnosis of obesity in Swiss children.”
Why did it take so long?
It is obvious that regionally collected data is better than international data. In Europe, hardly any country relies on the WHO data for children aged 5 to 18. In 2016, Urs Eiholzer decided to collect new data for Switzerland. Within two years, PEZZ collected data from 30,000 children between the ages of 0 and 20.
In 2019, the results were published in the renowned journal «Annals of Human Biology»They show, for example, that the Swiss have only grown one centimeter taller in the last fifty years, that children today reach puberty six months earlier and that they have not really gotten fatter. “The obesity among children is almost exclusively due to migration from southeastern Europe,” he says. This means that prevention campaigns need to be much more specifically targeted at the risk groups.
In principle, the WHO curves could have been replaced with those of the PEZZ as early as 2019. In 2020, However, a group of experts from Pediatrics Switzerland is in favour of continuing to use the growth curves that have been in use since 2011 for the time being.
Pediatrics Switzerland was primarily concerned about the lack of representativeness of the PEZZ data. This was because it was collected primarily in the Zurich region and in central and eastern Switzerland. It is known from recruit surveys that people in French-speaking Switzerland and German-speaking Switzerland grow at practically the same rate.
But the inclusion of all parts of the country is very important, says Oskar Jenni, head of developmental pediatrics at the University Children’s Hospital Zurich, who also speaks as a representative of Pediatrics Switzerland. “When it comes to the question of which curves should be used in Switzerland, one must therefore take into account not only scientific but also political aspects. It requires complete acceptance by all those involved in our multilingual country.”
Regular monitoring
After several years of back and forth, Pediatrics Switzerland and PEZZ have now reached a contractual agreement. Data collection will be expanded to include Ticino and French-speaking Switzerland, and the additional data will be integrated into PEZZ’s growth curves. The methodology is exactly the same as that used to collect data for the 2019 study. The work in Ticino has already been completed, and in French-speaking Switzerland the data should be available by the end of the year and integrated into the existing data sets.
Pediatrics Switzerland is responsible for recommending growth curves. “The publication of the new curves is not yet planned in detail,” says Oskar Jenni. However, according to the contract, they should be available in 2025. If the data from western Switzerland is not available by the end of 2024, Eiholzer’s growth curves from 2019 will automatically come into force unchanged.
The new growth curves are intended to prevent overdiagnosis and underdiagnosis as much as possible and to ensure the well-being of children. One thing is certain: Switzerland will never again be able to get new growth curves so cheaply. This is because they were largely financed by the privately financed PEZZ. “We recognize the great effort that PEZZ has put into collecting data in recent years,” says Jenni. “We are happy. This work is not trivial, it is expensive and time-consuming.”
In the future, the official body of pediatricians does not want to repeat the mistakes of the past. “We do not want to remain inactive for decades after the introduction of the new curves,” says Jenni. With regular monitoring of the curves, we will be able to identify more quickly what is needed to best support the health of children. “Digitalization will play into our hands here, so that the growth curves can be updated more easily,” says Jenni.
An article from the «»
