**2.1. Definition**

Obesity is an important pediatric public health problem associated with risk of complications in childhood and increased morbidity and mortality throughout life. Overweight and obesity predispose people to noncommunicable diseases such as heart disease, diabetes mellitus, musculoskeletal and psychological disorders and certain types of cancer [1].

Without intervention, obese infants and young children will likely continue to be obese during childhood, adolescence and adulthood [1–3].

The methodological problem of inconsistency between criteria of childhood obesity classification is a major obstacle in studying global trends for younger age group. The body mass index [BMI: weight (kg)/height (m)<sup>2</sup> ] is the parameter used for the screening of overweight and obesity in childhood because it is easy to determine, it tends to correlate well with body fat, and it has been widely used in adults to define obesity. It decreases until the period called "adiposity rebound" when body fat is at the lowest level (between 3 and 7 years) and after then BMI increases again until the adulthood [4, 5].

The child's BMI must be plotted on nationally recommended BMI—for age charts. The classification of overweight and obesity varies among guidelines, such as those from Centre for Disease Control (CDC), International Obesity Task Force (IOTF) and World Health Organization (WHO).

For example, in UK (IOTF BMI values) the cut off points for and are the BMI >91st and >98th percentile, respectively.

The definition of overweight and obesity using BMI percentiles in the USA: children aged 2 years and older with a BMI between the 85th and 95th percentile is overweight, and those with a BMI greater than the 95th percentile for a specific age and sex subgroup are obese [4–6].

According to WHO, for children aged between 5 and 19 years, overweight is >2 standard deviations and obesity is defined as a BMI-for-age >1 standard deviation, above the WHO growth reference median [1].

The IOTF BMI values represent standard international references that allow the screening of adiposity in children and adolescents worldwide under the same criterion, without variations depending on geographic, social and secular trends [5].

#### **2.2. Epidemiological data**

Currently, the prevalence of obesity among children and adolescents and related complications is considered one of the most important nutritional problem globally. The obesity epidemic among children is the result of excess energy intake and inadequate energy expenditure [2]. The prevalence of childhood overweight and obesity has increased worldwide in recent decades, and the numbers of those affected continue to rise at an alarming rate [6].

In recent years, the epidemiology of overweight and obesity is well described in many European countries and the data showed the increasing trends in the prevalence of childhood obesity. The current prevalence of childhood obesity is ten times higher than it was in the 1970s [5].

**2. Nosologic framework of obesity in children and adolescent**

musculoskeletal and psychological disorders and certain types of cancer [1].

ing childhood, adolescence and adulthood [1–3].

then BMI increases again until the adulthood [4, 5].

depending on geographic, social and secular trends [5].

index [BMI: weight (kg)/height (m)<sup>2</sup>

98 Adiposity - Epidemiology and Treatment Modalities

Organization (WHO).

percentile, respectively.

growth reference median [1].

**2.2. Epidemiological data**

obese [4–6].

Obesity is an important pediatric public health problem associated with risk of complications in childhood and increased morbidity and mortality throughout life. Overweight and obesity predispose people to noncommunicable diseases such as heart disease, diabetes mellitus,

Without intervention, obese infants and young children will likely continue to be obese dur-

The methodological problem of inconsistency between criteria of childhood obesity classification is a major obstacle in studying global trends for younger age group. The body mass

and obesity in childhood because it is easy to determine, it tends to correlate well with body fat, and it has been widely used in adults to define obesity. It decreases until the period called "adiposity rebound" when body fat is at the lowest level (between 3 and 7 years) and after

The child's BMI must be plotted on nationally recommended BMI—for age charts. The classification of overweight and obesity varies among guidelines, such as those from Centre for Disease Control (CDC), International Obesity Task Force (IOTF) and World Health

For example, in UK (IOTF BMI values) the cut off points for and are the BMI >91st and >98th

The definition of overweight and obesity using BMI percentiles in the USA: children aged 2 years and older with a BMI between the 85th and 95th percentile is overweight, and those with a BMI greater than the 95th percentile for a specific age and sex subgroup are

According to WHO, for children aged between 5 and 19 years, overweight is >2 standard deviations and obesity is defined as a BMI-for-age >1 standard deviation, above the WHO

The IOTF BMI values represent standard international references that allow the screening of adiposity in children and adolescents worldwide under the same criterion, without variations

Currently, the prevalence of obesity among children and adolescents and related complications is considered one of the most important nutritional problem globally. The obesity epidemic among children is the result of excess energy intake and inadequate energy expenditure [2]. The prevalence of childhood overweight and obesity has increased worldwide in recent decades, and the numbers of those affected continue to rise at an alarming rate [6].

] is the parameter used for the screening of overweight

**2.1. Definition**

The incidence of overweight and obesity increased progressively from infancy through adolescence [5, 6]. High prevalence of obesity in 0- to 6-year-old children is warning signs and risk for increased rates of obesity in adolescence and adulthood reported.

North America and some countries in Europe have shown consistent year-on-year increases in prevalence of overweight (20–30%) and obesity (5–15%), although recent surveys indicate that the rising trends are easing, with a plateau in prevalence levels shown since around 2005 [6].

Children's risk of obesity varies by age and sex groups, ethnic/racial groups, socioeconomic status, geographic and rural/urban regions. The key reason for the variations is due to the considerable socioeconomic and lifestyle differences and the differences in differing criteria for obesity and overweight definition [4, 7].

Several countries of Southern Europe appear to be showing high prevalence of childhood obesity (20–35%) in the Italy, Greece, Malta, Portugal and Spain. The highest levels of overweight and obesity were in Southern Italy (30.1 and 33.1% in preschool boys and, respectively, girls) and in various regions of Spain (29.4% in both sexes, increasing to 32.6% among children aged 7- to 10-year old), followed by Greece (19.1 and 23.6% in boys and, respectively, girls) [7–9]. Children and adolescents residing in countries surrounding the Mediterranean Sea show the highest rates ranging from 20 to 40%, too [7]. Studies concerning obesity with regard to its prevalence in Portugal reported a rate of overweight in children under the age of 6 years, 13.6% in boys and 20.4% in girls, and, obesity varied between 6.5% in boys and 6.9%, respectively, in girls [10]. The very high prevalence of childhood obesity in Mediterranean countries could be secondary to lifestyle changes (switching from a healthy Mediterranean diet to a fast food type of diet and lower physical activity levels) [7].

In children and adolescents residing the Scandinavian countries and Central Western European countries, the prevalence of overweight and obesity is far lower (10–20%). Scandinavian countries have the lowest prevalence of obesity in all age groups, except Finland which reported the prevalence of overweight and obesity in school children of 23.6 and 19.1% for boys and, respectively, girls [7, 11]. It is important to note that among preschool children, the highest prevalence rates of overweight and obesity were in Ireland (26 and 29% in boys and, respectively, girls), United Kingdom (24.1 and 21.4% in boys and, respectively, girls). In school children, the prevalence of overweight and obesity has increased to 32.7% and, respectively, 29.2% in 2007 the United Kingdom [7]. In developed countries, an increasing number of studies suggest that children of lower-income families are vulnerable to becoming obese, possibly due to poor dietary habits and limited opportunities for physical activity [7, 12]. In the UK, the prevalence of overweight and obesity in 11- to 12-year-old children was 25%, with higher rates in girls (29%) and students from lower socioeconomic backgrounds (31%), and the highest rates was observed in black girls (38%) [13].

Data from Eastern European countries indicate the prevalence rate is smaller (15%), but rising. In Lithuania, the Russian Federation, Slovakia and Poland, the overweight and obesity prevalence ranges from 8.46 to 15.8% in children aged 6–12 years. It is likely that the huge economic burden and the associated poverty following the political transition in the 1990s may have contributed to the relatively low obesity prevalence in Eastern Europe [7].
