Overweight and Obesity Prevalence and Physical Activity among Moscow Schoolchildren

15067 Moscow school-age children and adolescents (6-17 years o ld, 7760 boys, and 7307 girls) were examined. From age of 1013 years old numbers of girls with underweight growth up to twice. In boys group number of schoolchildren with underweight was just the same. Instead of girls, number of boys with underweight was stable. Number of girls with overweight (without obesity) was higher 20% of population except age 16-17 years old. Peak number of girls with obesity registered in age 8-14 years old. In age 11, 13-14 years old number of g irls with overweight was higher than 25%. Number of boys with overweight (without obesity) was some lower then number of girls; it also was near 20% of populations. The highest levels of overweight were registered in age 12-13 years old. Boys’ physical development demonstrated to be ahead such of girls. The flexib ility of the boys was reduced in comparison with girls. At the same time the boys had the best indicators of physical development and coordination of movements. With age significantly increased physical performance of school children: it was increasing in flexib ility, in improving speed of visual-motor reaction.


Introduction
Control and management of functional reserves and psychophysical human health will always be relevant and highly complex scientific and practical problems. After generation of the population follows each other in a relatively short time scales even in the life o f one man. In this sense, one lost to improve the recovery of children and adolescents five years or a maximu m of ten years already wrapped almost hopelessly lost in the valeological sense generation. Thus, it is important to maintain the health of children for schooling, because after it ended they still need to either further study or work act ivity [1], [2], [3].
Long-term trend of deteriorating health of children and youth entails a subsequent decrease in health in all age groups, and further affects the quality of manpower, the reproduction of generations. Since the early 1990's trend towards worsening indicators of health, in particular, an increase of psychosomatic disease of adolescents and youth, esp ecially in g raduat ion classes o f majo r cit ies and industrial cit ies. In 2008 nu mber of children with chronic diseases increases on 4.7% co mpared with 1998. The mass screening of students found that among healthy children can be attributed only 34% of the studied, with high risk of developing ch ronic d isease and severe funct ional vio lat ions can be attributed most (52%) examined children [3].
During the school time the nu mber of children with myopia increases 5 times, disorders of the locomotor apparatus increases in 1,5 times, diseases of the nervous system increases in 2 times. 33% o f youths who were released fro m service in the Armed Forces have mental disorders. 77% o f students are at high level of influence of pollutants and 68% have high levels of CO 2 . In these children there is the heavy breathing, shortness of breath, dry cough, and rhinitis are mo re likely than other students. Children affected by high levels of CO 2 are mo re vulnerab le nasopharynx than their peers, they were 3.5 times higher at risk of nocturnal dry cough and a 2-fold h igher risks the development of rh initis [1], [3].
During puberty there are changes at all levels, especially in the bio logical, as well as psychologically and socially, changing the intensity of physiological processes, hormones, function of organs. Skeletal gro wth is faster than the development of muscle tissue, hence the awkwardness, disproportionately, the angularity of the figures. In girls there was increasing fat mass by 10-20%, which is subjectively experienced by them very difficult. Heart volume is increased puberty twice, wh ile there are significant variat ions in blood pressure, often upwards, frequent headaches. Doctors often put adolescents diagnosed: vasoneurosis [1].
The propose of this work was to study physical activity and overweight among Moscow schoolchildren.

Material and Methods
School-age child ren and adolescents were examined (2010-2011). Beforehand, written info rmed consent was signed by parents confirming participation of their children in that investigation. The work was approved by local ethical committee of Moscow State University of Med icine and Dentistry.
Totally we include in investigation 15067 Moscow schoolchildren fro m all Moscow regions, 7760 were boys and 7307 were g irls. Height and weight data were obtained fro m part icipants (6-17 years old). BMI (body mass index) was calculated for each of data pair. Derived data was analysed according to the World Health Organizat ion growth charts, for gender and age (at the children last birthday) [4]. Participants were considered to be obese if their BMI was ≥ 95 percentile. Overweight was defined if the person had a BMI < 95 and ≥ 75 percentile. Those with a BMI ≥ 25 and < 75 percentile were considered to be the normal weight group. And those with BM I < 25 percentile considered to be the group with underweight. We applied a median index fo r the overall age groups' assessment.
Further examination including waist circu mference and hip circu mference, and skinfold th ickness measurement were done. Skinfolds were measured in three standard points: triceps (TSF), subscapular (SSF), abdominal (ASF). TSF was assessed in the upper third of the upper arm's back (posterior) surface. SSF was assessed at the end of the lower (inferior) angle of the shoulder-blade (scapula). A SF was done on umbilicus level along the midclav icular line. Those anthropometric data proved classification of schoolchildren in groups with underweight, normal weight, overweight or obesity due to individual proportions of body due to international reco mmendations [4], [5].
We measured blood pressure (BP) and heart rate (HR) before and after physical activity. With the help of spirometer we measured lung capacity (LC).
We performed the following functional tests: motor coordination (determined in the test by throwing at the wall and catching the batted ball fro m a d istance of 3 meters), the timed inspiratory capacity (breath holding at inspiration in the sitting position), flexibility (in cm belo w the floor level). Evaluated the physical perfo rmance as pushups and press (number of times within 30 seconds). Using a co mputerized program calculates the index of physical health (IPH) [2].
Usual daily physical activity was detected using Russian version of IPAQ questionary as it early described [6].
Statistics included the Student's T-test, Wilco xon-Mann-Whitney U test and F-Test. Pearson chi-square analysis and standard adjusted residuals calculated to determine samp le characteristics. Also we used correlat ion and regression analysis [7]

Results
Nu mber o f g irls with underweight was about 5% in population (Fig 1). Fro m age of 10-13 years old nu mbers of girls with underweight growth up to twice. In boys group number of schoolchildren with underweight was just the same. In stead of girls, nu mber of boys with underweight was stable (Fig 2). Only in age 14 years old we saw increasing number of boys with underweight.
Nu mber of girls with overweight (without obesity) was higher 20% of population except age 16-17 years old. Peak number of girls with obesity registered in age 8-14 years old. In age 11, 13-14 years old number of girls with overweight was higher then 25%. Nu mber of boys with overweight (without obesity) was some lower then number of girls; it also was near 20% of populations. The highest levels of overweight were registered in age 12-13 years old.
Nu mber of g irls with obesity is g rowing up fro m age 6 to 9 years old. In age 9-11 years old girls' population we demonstrated the highest levels of obesity prevalence (about 18%). Nu mber of girls with obesity decreases fro m 11 to 17 years old. In 16-17 years old number of girls with obesity is lower than 5% of population. Nu mber of boys with obesity is growing up fro m 6 till 11 years old. In age of 11 years old number of boys with obesity is higher (28%) then those in girls. In age 11-17 years old number of boys with obesity decreases.
Boys 14-17 years old had significantly higher BM I than girls of the same age (Table 1). This led to an increase in systolic and diastolic blood pressure reduction alone, which may indicate the existence of boys' imbalance regulation of the cardiovascular system. The flexib ility of the boys was reduced in comparison with girls. At the same t ime the boys had the best indicators of physical development and coordination of movements. Therefore, the index of physical health in boys was higher than in girls. With increasing age significantly increased physical performance of school children, increased flexibility, improved speed of visual-motor react ion (Table 2). This indicates that the processes of normal physiological maturity. At the same time, with age there was a significant increase in BMI. This may indicate an increase in the proportion of people overweight in the group of older students than younger. It is known that overweight is a risk factor for chronic noncommunicable d iseases. Therefore, despite the increase in the IPH, a group of older students may have a greater risk of developing card iovascular and other diseases. In particular, this can indirectly indicate no significant differences in the index of physical develop ment in schoolchildren 16 and 17 years.  We have shown that BMI in addit ion to age and sex is the main factor affecting the health of schoolchildren. Students with normal body weight had a higher IPH than those with insufficient or excess body weight (Table 3). Those with normal body weight were more flexible, better at squeezing out the exercises. Change in body weight compared to normal was significantly increased heart rate, blood pressure, systolic and diastolic b lood pressure.  When we analysed usual physical activity, it was demonstrated prevalence of hypodynamia among schoolchildren with obesity ( Table 4, 5). In general we can speak about high-level prevalence of hypodynamia and adynamia among schoolchildren. At least 1 / 3 of respondents have adynamia. Only 1 / 3 of schoolchildren have optimal physical activity. Detailed analysis of schoolchildren's physical activ ity demonstrated that (Table 6) boys have higher mean number of vigorous physical activity and its duration than girls. For boys it corresponds to that minimal level o f physical activity which is reco mmended by WHO. For girls it is lo wer then recommended. Usual duration of walking for male was also higher than for those female. But both for male and female schoolchildren it is higher than it is given minimu m by WHO. Boys had lower time of sitting during the day. At least there were not found any gender differences between moderate physical activit ies.

Discussion
Obesity in children and adolescents has become one of the most globally challenging med ical p roblems over the past decades [8], [9], [10]. It is acknowledged that several serious consequences of excess weight occur in adults with the most common being cardio-vascular diseases and glucose metabolism disorders [11]. To the present it has also been demonstrated that different deviations fro m a healthy condition have been observed [9], [12]. Another unfavourable consequence related to childhood obesity is that there is a strong tendency for the continuation of obesity in adulthood [9], [13]. That is why public health specialists today predict a pessimistic mo rbid ity and mortality expectation for future decades of adults [8].
Childhood obesity has become an epidemic on a world wide scale [10] and it continues to increase [11]. Several serious consequences of excess weight occur in adults with the most common being chronic non-communicable diseases [13]. Anthropometric measurements as BMI are important for epidemiological investigations of obesity prevalence. Anthropometric indexes can best predict childhood obesity [8], [9].
In spite of a wide range of investigations and reviews that consider the early onset of on excess weight problem fro m various perspectives, we didn't find works on detailed analyses of the relationship between obesity and age in children and adolescent populations.
It is also evident that there is a lack of data the prevalence of obesity in specific age groups in the Russian Federation in general. The last statistical data that was presented in the works of Peterkova  [15].
Our observations of the last years demonstrated high level of obesity and overweight prevalence in schoolchildren, mainly during and after puberties [16]. Boys are more obese than girls. Early we demonstrated prevalence of a central type of adipose tissue allocation related to weight increase is observed in investigated samples of peripuberty children [17]. Considering obvious economic g rowth in Russia during the last several years and a strong tendency for a western lifestyle the adopter of among the Russian population, especially those dwelling in cities, an increase in obesity rates might be expected.
The number of schoolchildren with overweight in RF is comparable with those in USA [18], [19]. The level of obesity in Moscow in children 's' and adolescent'spopulatio n is much higher then those in European countries [20], [21], [22], and some developing countries [23], [24].
According to data indicated above, the prevalence of obesity is the highest in male adolescents. Among them, the most pro minent figures are reg istered during prepuberty and early puberty ages. In the girls prepuberty age groups have the maximu m levels of obesity. The subsequently pronounced lowering of obesity levels could be exp lained with its relationship to a puberty growth spurt.
Also we demonstrated low level of usual physical activity among schoolchildren. Nu mber of schoolchildren with adynamia is twice h igher in group with obesity in comparison with those with normal BMI. Low level of physical activity may be an additional risk factor of cardiovascular diseases development in future [25], [26].

Conclusions
We demonstrated corresponding between prevalence of overweight and obesity and age. It might be assumed that the highest levels of overweight and obesity are reg istered in pre-puberties and puberties ages. So, some hormonal mechanis ms are play ing role in our finding.
Our results established high level prevalence of overweight and obesity in Moscow schoolchildren. We can speak about prevalence of overweight in girls' population and prevalence of obesity in boys' population.
In co mparison with the same monitoring of overweight and obesity prevalence in Moscow schoolchildren population we done 3 years ago [17], nu mber of boys with overweight and obesity seems to be the identical. In the same time, nu mber o f girls with overweight and obesity increase.
In any case we have to speak about critical levels of overweight and obesity in population of Moscow schoolchildren. Such high levels of obesity and overweight in schoolchildren population might influence on serious public health problems in future.
We have studied the relation o f physical health of schoolchildren with the peculiarities of their develop ment. Shown that the maturation of schoolchildren acco mpanied by an increase of IPH. At the same t ime increases the mean value of BM I, wh ich may indicate an increase in the intensity of risk factors for cardiovascular disease.