Early obesity prevention - polish contribution to european projects

Wczesna profilaktyka otyłości - udział Polski w projektach Unii Europejskiej

Dariusz Gruszfeld 1, Piotr Socha2, Magdalena Hajduczek3, Zbigniew Kułaga4, Jerzy Socha2
1Klinika Patologii i Intensywnej Terapii Noworodka Instytutu „Pomnik-Centrum Zdrowia Dziecka”
Head: prof. A. Dobrzańska
2Klinika Gastroenterologii, Hepatologii i Immunologii Instytutu „Pomnik-Centrum Zdrowia Dziecka”
Head: prof. J. Ryżko
3Faculty of Psychology, University of Warsaw
Dean: prof. E. Czerniawska
4Public Health Division The Children’s Memorial Health Institute, Warsaw
Head of Division: Z. Kułaga, MD

* Acknowledgments. The OLAF study was supported by a grant from Iceland, Liechtenstein and Norway through the EEA Financial Mechanism and the Norwegian Financial Mechanism, and the Ministry of Science and Higher Education of Poland; grant number: PL0080.


Abstract

Poland faces the same problem of obesity epidemics as other European countries. Polish contribution to the EU research projects concerning overweight and obesity is a direct consequence of recognition of this problem and scientific activity of Polish researchers. At present time early prevention seems to be the only effective approach to decrease obesity and obesity-related chronic diseases in adulthood. Three studies described here consider early prevention of obesity – by decreasing protein intake in infancy (CHOP and EARNEST study) or by behavioural approach in preschoolers (TOYBOX). The Children’s Memorial Health Institute is participating in all these projects as a recruiting centre of the subjects studied and as a central laboratory for the CHOP and EARNEST studies. The CHOP study proved in a randomized trial that high protein intake in infancy increases the risk of obesity. The results of the CHOP studies have already indicated the need for protein reduction in infant formulas. This was reduced to 1.8 g/100kcal in the 2006 EU Directive. The results from the TOYBOX project which was started in 2010 have not yet been published.

Key words: childhood obesity, obesity prophylaxis, international multicentre studies, Poland

Streszczenie
W Polsce, podobnie jak w innych krajach europejskich pojawia sie narastajacy problem ”epidemii” otyłosci. Polscy badacze biora aktywny udział w wieloosrodkowych, miedzynarodowych projektach dotyczacych nadwagi i otyłosc . Wczesna profilaktyka wydaje sie byc obecnie jedynym skutecznym sposobem zapobiegania otyłosci oraz zwiazanych z nia pózniejszych chorób. W artykule opisano 3 badania zajmujace sie wczesna prewencja otyłosci – przez ograniczenie ilosci białka w diecie niemowlat (Projekt CHOP i EARNEST) lub modyfikacje zachowan zywieniowych dzieci w wieku przedszkolnym (TOYBOX). Instytut „Pomnik-Centrum Zdrowia Dziecka” bierze udział we wszystkich wymienionych projektach jako osrodek rekrutujacy oraz jako laboratorium centralne w przypadku projektu EARNEST i CHOP. Rezultaty badania CHOP potwierdziły zasadnosc ograniczania zawartosci białka w powszechnie stosowanych mieszankach dla niemowlat. W zaleceniach Dyrektywy UE z 2006 r. została ona ograniczona do 1,8 g/100 kcal. Wyniki projektu TOYBOX, rozpoczetego w 2010 roku nie sa jeszcze opublikowane.

Słowa kluczowe: otyłość dziecięca, profilaktyka otyłości, międzynarodowe badania wieloośrodkowe, Polska

INTRODUCTION
In recent years researchers have reported an alarming increase of the prevalence of childhood obesity in the world (1, 2). This trend can also be seen in Europe (3, 4) including Poland (5, 6). Rising prevalence of childhood obesity represents an increasingly recognized public health problem (7) due to the fact that obesity in early life is associated with severe short and long term health consequences and that it inuences young people’s psychosocial development (8). Moreover, obesity and related diseases, once developed, are dicult and costly to cure. (1, 5, 7). Therefore, overweight children are more likely to stay overweight or become obese in adulthood (phenomenon known as tracking overweight and obesity from early childhood to adolescence and adulthood) (7, 9) with all the consequences of this condition. This is why early prevention seems to be the only eective approach to decrease obesity and obesityrelated chronic diseases later in adulthood. The critical periods for determining the obesity risk seem to be infancy or early childhood (preschooler age) and three European Projects were devoted to those time windows. The Childhood Obesity Programme (CHOP) and Early Nutrition Programming Project, EARNEST, investigate the early dietary intervention in infancy on later obesity risk. The Toybox Project aims at behavioural approach in preschoolers to change life style and inhibit overweight development.

Polish studies on overweight and obesity in young children
So far, few studies on the prevalence of paediatric obesity have been conducted in Europe (4) and particularly in Poland (6) in comparison to investigations related to adults and adolescents obesity (7), for example the recent publications of Jodkowska et al (2007, 2010) referring to a narrow group of teenagers aged 1315 years (10, 11). According to Wang and Lobstein (2006) this is related mainly to a methodological problem of inconsistency between intraand intercountry classications of childhood obesity (3, 12, 13). The amount of published information on preschool children in Poland is substantially smaller than for other age groups (13). Therefore, the data for two groups of children preschool children and early school children – is presented below.

Preschool children
Krawczynski et al. (2001) present data of the prevalence of overweight and obesity among children and teenagers (aged 318) living in Poznan (Poland) (14). The sample consists of 35 788 children, including 492 girls and 452 boys aged 3-6. Denition of overweight and obesity was based on Poznan BMI references. Overweight was diagnosed for BMI in the range of 90-97 centile and obesity for BMI over 97 centile for age and sex. The frequency of overweight and obesity showed sex dierences. The prevalence of overweight in the girls group ranged from 2.9% to 7% in age 3-6 years. With regard to obesity, the prevalence in this group ranged from 3.7% to 10.1%. Such high prevalence of obesity was observed also in the age range of 11-13 years. In the boys group the prevalence of overweight ranged from 0% to 11.1% in the age range 3-6 years. Prevalence of obesity among boys range from 3.1% to 14.4% in the youngest group (3-6 years).
In the household survey conducted by the National Food and Nutrition Institute in 2000, 269 children 1-6 years-of-age were investigated (143 boys) (15). Szponar et al. applied overweight and obesity denition based on Warsaw BMI reference. Overweight was diagnosed when BMI ranged 90-97 centile and obesity when it was over 97 centile for age and sex. In the case of girls both overweight and obesity were more frequent in children aged 13 compared to children aged 46 (9.1 vs 2.4 and 11.4 vs 8.5, overweight and obesity, respectively). In the case of boys overweight was more frequent among 1-3 yearsofage compared to 46 yearsofage (12.3 vs 10.3) but obesity was more frequent in the older group (7.7 vs 11.5, boys aged 1-3 and 4-6, respectively).
In 2004-2007 Bielecka-Jasiocha et al. conducted an investigation of 302 overweight and obese children aged 1.5 to 18 years who were patients of the Department of Paediatrics and Endocrinology (16). The youngest group (i.e. under 6 years) accounted for 7% of all girls and 5.6% of all boys and displayed the highest levels of obesity.
Mastalerz-Migas et al. reported in 2008 the prevalence of overweight and obesity among preschool aged children in Opole (17). There were 253 children aged 36 recruited into the study. The denition of overweight and obesity was the same as in the case of Szponar et al study (15) i.e. based on Warsaw BMI reference. Overall overweight including obesity prevalence was 18.5%. Overweight and obesity were more frequent in boys compared to girls. At the age of four years 15% of children were overweight, at the age of ve years 17%, and at the age of six years 8%. Obesity was present in 10%, 9% and 8%, at the ages four, ve years and six years, respectively. The authors did not report overweight and obesity prevalence for age of 3 years.
The aim of Mazur et al. study was to assess the prevalence of overweight and obesity in preschool children from Rzeszow region (Poland) (13). The sample consisted of 302 girls and 274 boys in preschool age (3-6 years). International Obesity Task Force criteria were used for diagnosis of overweight and obesity. The study showed that overweight was present in 9.1% of girls and 9.9% of boys and the prevalence of obesity was 7.2% and 8.4% for girls and boys, respectively. Moreover, the researchers demonstrate that 3 years old boys were signicantly more overweight than the girls of the same age. Nevertheless, when obesity was taken into account there was a signicantly higher prevalence of obesity in 3 years old girls, while girls aged 5-6 presented lower obesity prevalence than boys of the same age.
Figure 1 facilitates a comparative analysis of data related to preschool children obesity and overweight obtained during 2001-2008. Overall, the prevalence of obesity among girls and boys did not exceed respectively 9% and 13% and the prevalence of overweight reached its maximum respectively at 10% and 12.4%. Only the data of overweight prevalence among girls vary dramatically between studies covering specific region and the country at large (respectively from 6.1% to 10% in regional studies and 2.4% in the country-wide study). ere are two possible reasons for this. One is that regional studies overestimated the prevalence of overweight and another is that country-wide study underestimated its prevalence. Further study should be performed to estimate current levels of prevalence of obesity and overweight.
In 2010 Cattaneo et al. combined available information on prevalence and time trends of overweight and obesity among pre-school children in the European Union (3). Although the comparison was problematic because of dierent definitions and methods of data collection and analysis, authors compared data from European countries including Poland. Poland presented the highest prevalence of overweight among 2 years old children (26%). In contrast, in a group of 3 and 4 years old children the prevalence of overweight in Poland ranks as one of the lowest (respectively 4.9% and 10.4%). is striking difference may be due to a low sample size (particularly at age 2 years), but it is not assessable because standard errors of the rates are not provided. Prevalence of obesity showed similar levels (4.0%) across all European countries (with an exception of Spain). Among children between 3 and 4 years the prevalence of obesity slightly increased from 12.2% to 12.5%. Prevalence of obesity among Polish children between 3 and 4 years is one of the highest in Europe. The bottom line of the study indicates that the levels of overweight and obesity prevalence among Polish children between 2-4 years – relative to other European countries – may be worrying.

Early school children
In 2007 Chrzanowska et al. published a study which aimed to examine the changes in prevalence of overweight and obesity, using International Obesity Task Force criteria, in three cohorts of children and youth (7-18 years old) living in Cracow (Poland) in 1971, 1983 and 2000 (18). e study showed that rates of overweight and obesity of 1971 (7.5% among boys and 6.5% among girls) doubled respectively to 15.2% and 11.8% in the year 2000. What is interesting, the greatest increases in prevalence occurred in the youngest age groups: 7-12 years for boys and 7-10 years for girls.
In the same year Matusik, Malecka-Tendera and Klimek described a study on randomly selected representative sample of 7-9-year-old Polish children (N=2916; 1445 girls; 1471 boys) which was performed in 2001 (12). at investigation aimed at assessing the frequency of obesity, overweight and underweight in the study group by using a population specific definition as compared to the Polish, French, United States and International Obesity Task Force references. The study evidenced that the choice of definition has a significant effect on estimated prevalence. According to Polish, French, U.S. and IOTF references overweight (including obesity) was found in respectively 12.1%, 14.3%, 20.7% and 15.4% of children. Finally, the investigation indicates a trend of decreasing overweight and increasing underweight with respect to age classes.
Recent data (2007-2009) presenting the prevalence of overweight and obesity among Polish school-aged children were collected in the course of the population-representative OLAF study (PL0080) (19). This study, which was conducted to elaborate blood pressure reference ranges for Polish children and adolescents, provide also data for updated growth references for Polish school-aged children and adolescents. According to Kułaga et al. the prevalence of overweight among school-age children aged 7 to 10 years, ranged respectively from 12.9% to 17.0% for girls and from 14.0% to 16.8% for boys, while the prevalence of obesity in this age groups ranged respectively 2.7% to 4.5% for girls and 5.2% to 5.9% for boys.
In 2007 Jarosz, Rychlik and Respondek analyzed the results of a country-wide representative research conducted based on “Household Food Consumption and Anthropometric Survey”. These analysis showed that 15-20% of Polish children and adolescents suer from excessive body weight and 4% of them are obese. Moreover, the prevalence of overweight and obesity changes with age. Excessive body weight was most frequent in the youngest age group, as the incidence of excessive body weight, and especially obesity, fell with age (5).
The analysis of results of dierent Polish studies as well as a comparison with other European countries shows a great need for further examinations and systematic control of prevalence of obesity and overweight among both Poland’s and Europe’s youngest population. This is due to the lack of longitudinal studies, limited sample size or conducting previous studies at local level. It causes hampered possibility to reliably assess lifestyle and nutritional determinants of overweight and obesity and problems with evaluation of the eects of the prevention programmes. Reporting overweight and obesity rates together with their (rates’) standard errors is also postulated for sake of more precise reasoning.

CHOP AND EARNEST
EU Childhood Obesity Programme (CHOP) started in 2002 and was finished in 2005. It was coordinated by Professor Berthold Koletzko from Ludwig Maximilian University of Munich and in Poland by Children’s Memorial Health Institute in Warsaw, with two departments involved: Neonatal Department and Gastroenterology, Hepatology and Immunology Department. The idea of the project was based on earlier findings that breast feeding had long-term benefits for obesity risk in later life (20, 21). Based on epidemiological evidence and results of animal studies, it has been hypothesized that the lower protein supply with breast milk than with infant formula, may play a causal role for this protective long-term eect. Therefore, the Research Programme “Childhood Obesity: Early Programming by Infant Nutrition?” investigated whether the protein/fat ratio in infant formula and complementary feeds affects rates of growth, energy expenditure and other markers of later obesity risk. Almost 1700 infants have been recruited in 5 European countries (Belgium, Germany, Italy, Poland and Spain) and most of them were followed up to the age of 2 years. In addition to anthropometric variables also a number of biological variables, diet, lifestyle and energy expenditure were determined.
The results of EU Childhood Obesity Programme (acronym: CHOP) indicate that infant formulas with lower protein content bring metabolic and endocrine benefits, as well as body growth rates closer to breastfed babies (22). The further follow-up of the children as part of EARNEST will indicate whether these changes are associated with lower risk of childhood obesity at a later age.
Aer 2 years, the infants fed the lower protein formula were the same length but weighed slightly less than the infants fed the higher protein formula and were more alike to the group of breast fed infants. Their weight-forlength and body mass index were significantly less than those fed with higher protein formulas. The dierences in weight, weight for length and BMI persisted, even aer the intervention had finished and the children went onto similar diets. As there were no significant dierences in length between the groups, it is likely that the dierences in weight for length and BMI are due to differences in body fat. Whether these small differences in weight and BMI develop into significant differences in the rates of obesity between the groups remains to be seen (Fig. 2). The results from EU Childhood Obesity Programme showing the different growth trajectories of formula fed and breast-fed infants lend support for the new 2006 WHO growth charts.
These are based on the growth patterns of healthy breast-fed babies. The previous 1990 charts were based on a mixed group of breast and formula fed babies and were actually a description of how infants did grow, rather than how they should grow. The current WHO standards are derived from the Multicentre Growth Reference Study which measured the growth of around 8500 infants from six countries across the globe (WHO Multicentre Growth Reference Study Group) (23). The study included only full-term healthy children who had been exclusively breast fed for at least 4 months and partially breast fed for a year and weaning onto solid foods started by 6 months. The children’s growth was followed up for 5 years and the study found that the growth patterns of these children were similar in all countries. The standards produced from this study are therefore applicable to infants from all racial backgrounds. Results from EU Childhood Obesity Programme also have implications for the protein content of infant formulas. The companies manufacturing infant formulas have now a direct proof from a randomized, controlled human trial that reduced protein content in the infant formula results in a growth pattern more similar to breast-fed babies.
The protein content of infant formulas has al ready been reduced quite substantially over the years but further reductions are likely. The protein content of formulas was as high as 4 g/100 kcal in the 1970s and came down to around 3 g/100 kcal in the 1980s as concerns about adequacy of protein intake were lessened. These concerns have been replaced by concerns about excessive intakes. The minimum protein content recommended in the 1991 Infant and Follow-on Formula Directive was 2.25 g/100 kcal and this was reduced to 1.8 g/100 kcal in the 2006 Directive. The WHO have also reduced their recommendations of the safe level of prote in intake for infants less than 12 months of age from their 1985 report (24). Those for infants aged up to one month were reduced by about 20%.
The study also tested the hypothesis that a higher protein intake in healthy infants modifies kidney growth and function. Infants on high protein diet showed larger kidney volumes at 6 months. It was associated with higher values of serum-urea and urea/creatinine ratio. The results indicate that high protein formula increases kidney growth in the first 6 months of life (25). The anthropometric data supports the major hypothesis of the CHOP project, but the mechanisms of programming are not very clear. Within this study we also examined the inuence of protein intake in infancy on serum amino acids, insulin and the IGF-1 axis. Biochemical and endocrine parameters were determined at the age of 6 months. As expected, most of the amino acid concentrations increased in the high protein group, particularly branched chain amino acids among essential amino acids. With increase of amino acids also total and free IGF-1 were significantly higher, which was also accompanied by increase of urine C-peptide/creatinine ratio as an indicator of insulin secretion. We concluded that higher protein intake stimulates the IGF axis and insulin release in infancy.
The Early Nutrition Programming Project, EARNEST, (www.metabolic-programming.org, FOOD-CT-2005-007036) is an EC funded research programme that addresses the issue of early nutritional programming of later health. It was supported by the EC Sixth Framework Programme for Research and Technical Development. The project started in 2005 and ended in 2010. It was coordinated by Professor Berthold Koletzko of the Children’s Hospital, Ludwig- Maximilians-Uni versität, Munich, Germany.
The EARNEST Research Consortium is a multidisciplinary team of scientists from 16 EU countries, mostly the leaders in their areas. The project includes:
- experimental studies in humans – randomised controlled trials in mothers and infants,
- prospective observational studies,
- animal studies – including physiological studies, cell culture models and molecular techniques.
Evidence for early nutritional programming has come from all above types of studies. There are considerable benefits from adopting an approach that combines the strengths of these dierent types of study. This is why EARNEST was designed to cover dierent fields of activities which fit one to the others and have a common direction. We can identify several themes inside the project. Theme 1 investigated early nutritional programming of adult disease risk in humans by following up previously well-conducted randomised controlled trials of specific nutrition interventions in pregnancy and infancy and measuring disease markers in childhood and early adulthood. The follow up of the CHOP cohort was included in Theme 1- we continue observation of those children up to the age of 6 years (2005-2010) as one of activities inside Theme 1 (work package 1.2.2) to investigate the eect of the intervention, and of the anticipated associated variations in growth rates, on body composition and cardiovascular risk factors. each study visit, detailed anthropometry was performed and blood pressure was measured. Children’s food habits, nutrient intake, and physical activity levels were assessed by interviews and accelerometers. Several biochemical parameters were controlled and body composition by bioelectric impedance was estimated. The result should be available soon.
At each study visit, detailed anthropometry was performed and blood pressure was measured. Children’s food habits, nutrient intake, and physical activity levels were assessed by interviews and accelerometers. Several biochemical parameters were controlled and body composition by bioelectric impedance was estimated. The result should be available soon.

Toybox
In recent years behavioural research on nutrition and physical activity has started to develop. We try to understand why people eat difierent food products and why energy intake increases in spite of hormonal regulators. Physical activity seems to be equally important in weight control and it decreases in spite of efforts to stimulate individuals and populations to have active life style. It seems that the critical period to inuence life style is far before adulthood and even school children do not respond to dietary and life style advice. Many studies also indicate early childhood and preschool period to determine later risk of obesity. An early adiposity rebound was described to be associated with an increased risk of overweight. It is inversely associated with bone age, and reects accelerated growth (26). According to another study early rebound is associated with increased depositions of fat in middle childhood, and risks associated with early rebound persist at least until early adulthood (27).
Unfortunately, no extensive research concerning prevention of obesity was performed in preschooler age. Toybox project aims at conducting the behavioural research in this age group based on evaluated and developed strategies that may inuence behaviour. The major idea is to develop new behavioural models that could be applied on a European scale.
Any intervention aiming to prevent childhood obesity early in life should primarily aim to support the development of healthy habits and target parental behaviours (Fig. 3). A cost-effective approach could be the school setting. It enables access to large populations of children and parents. This kind of intervention must, however, involve regulations and national policies. The project aims at testing a school health promotion programme which will further indicate changes of regulations and policies.

CONCLUSIONS
Poland faces the same problems of obesity epidemics as other European countries and Polish contribution to the EU research projects concerning overweight and obesity is a direct consequence of recognition of those problems and scientic activity of Polish researchers. The Children’s Memorial Health Institute contributed actively to the three European Projects on obesity: CHOP, EARNEST and TOYBOX. The results of the CHOP project indicate the role of protein in programming of obesity risk. Based on these results protein content in infant formulas was decreased. Literature search performed within the TOYBOX project allowed to identify current knowledge on nutrition and physical activity in preschoolers in Poland. The ongoing intervention study will dene the role of intervention programmes in kindergartens to decrease obesity risk. In general, results of the studies have practical applications and may inuence regulations and policies of European countries including Poland.

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Adres do korespondencji / Address for correspondence:
Piotr Socha
Al. Dzieci Polskich 20, 04730
Warszawa, Poland
tel: (+48 22) 8157384
fax: (+48 22) 8157382
[email protected]