Factors associated with overweight and childhood obesity in Spain according to the latest national health survey ( 2011 )

Objective: To describe the factors associated with overweight/obesity in Spain according to the latest National Health Survey (2011). Method: Descriptive cross-sectional study with 3,752 children aged 2 to 15 years (boys=2,007; girls=1,745). Main variables: overweight; obesity; gender; level of education of the head of the family; monthly income; hours of sleep; physical exercise; hours of TV and/or computer use; daily breakfast; parents' weight perception. Diagnostic criterion was based on WHO growth patterns, defined overweight with +1SD and obesity, +2SD. Results: Boys more obese than girls. Children whose parents had a lower level of education, those who did not practice physical activity and whose parents had an income of less than 900€ per month showed a higher percentage of overweight/obesity. Conclusions: Children whose parents had a lower education and monthly income presented a higher percentage of obesity. Sleeping the recommended hours and doing some type of physical activity reduces obesity.


INTRODUCTION
In order to promote healthy environments in different age groups, from birth to adolescence, the International Network of Nursing in Child Health (ENSI Network/Red ENSI) promotes the need to know the epidemiological scenario of diseases prevalent in these age groups.One of the most important, due to its prevalence, is childhood obesity.Today, it is considered a public health problem and has increased especially in Europe. 1 According to the World Health Organization (WHO), 2 it is a chronic disease that has become an epidemic in some areas, with an overall estimate of 17.6% in children under five years of age.Recent studies in different countries show that 10.0% of all school-age children have excess body fat, which leads to an increased risk of developing chronic diseases. 3,4mong the reasons that led obesity to become a social problem, we have an increasing prevalence in the general population, reaching epidemic proportions, pathology of all age groups, its role as a predictor of adult obesity, and its links with associated morbidity and mortality. 5,6here is evidence on the relationship between overweight and risk factors that favor its emergence as the development of health problems. 7Therefore, the study in children is important to know the likelihood that the disorders occurred in childhood persisted into adulthood. 8ccording to the different studies, the most important factors that determine the occurrence of overweight and obesity are gender, level of education of the parents/guardian, income level and factors related to lifestyle, such as daily breakfast, recommended sleep hours, the daily level of intense physical activity and the guardian's perception of the children's weight.The collection of these data is essential to prevent the onset of this disorder. 8,9The nurses, among their activities, is the promotion of health.In Spain, those who occupy primary care centers in health centers are those directly related to promotion in the field of overweight (overweight and obesity).Knowing what are the factors that are directly related to weight gain in the child population is the key to promotion and prevention.
The data were obtained through the use of a very useful tool that is the National Health Survey (Encuesta Nacional de Salud-ENS).The ENS is a series of surveys that periodically provide information about citizens' health and some of the key factors that determine it.Currently, few studies have been done in Spain for this purpose.It should be noted what has been done by the Spanish Agency of Food and Nutritional Security (AECOSAN).It developed a study on the prevalence of childhood obesity, called the ALADINO (Food, Physical Activity, Child Development and Obesity) study during 2010-2015.These studies are included in the Childhood Obesity Surveillance Initiative (COSI) of the Office for the European Region of WHO. 15 The objective of this study is to describe and analyze the main associated factors that influence overweight and obesity in children according to the latest National Health Survey (2011) and to assess whether this influence is different in boys and girls.

METHOD
A retrospective descriptive study was conducted using data from the latest ENS (2011). 10The survey reflects the health status of the Spanish population.It also provides information on aspects such as perceived morbidity, life habits, behaviors related to risk factors, use of health services and preventive measures.
The sample consisted of 3752 individuals (boys = 2007, girls = 1745), the age group ranged from 2 to 15 years, and stratified sampling was used in multiple stages.
The studied variables were overweight and obesity calculated with the data of weight and height provided by the parents in the Survey.Body mass index (BMI) was calculated.The diagnosis was made comparing the BMI with the growth patterns of the World Health Organization.They defined overweight with + 1SD and obesity with + 2SD. 11,12The other variables were gender, the recommended hours of sleep (3-4 years of age: 12 hours, 4-5 years of age: 11 hours, 5-11 years of age: 10 hours, more than 11 years of age: 9 hours), 9,13,14 physical exercise (yes/no), hours of use of related technologies (< 2 hours and ≥ 2 hours), 9,13,14 breakfast habits (yes/no), level of education of tutors (illiterate -compulsory education, FP, no Bachelor, higher education), monthly income (< 900 €, 901-1800 €, 1801-3600 €, > 3600 €), parents' weight perception (much higher than normal, slightly above normal, normal, below normal). 9,13,14

STATISTICAL ANALYSIS
The variables to be analyzed were defined and labeled.The descriptive study was carried out through the distribution of frequencies for the different variables.In order to evaluate whether there was a statistically significant association (p < 0.05) of the dependent variables with each of the independent variables, a bivariate analysis was performed using the Chi square test.Statistical processing of data was performed in SPSS (Statistical Package for the Social Sciences) software, version 21.0, for Windows.

ETHICAL CONSIDERATIONS
Data were obtained from secondary sources (public and anonymous data, www.ine.es).According to Spanish legislation, it was not necessary to obtain the approval of the Research Ethics Committee.
Regarding the hours of sleep, obesity was higher in children who did not sleep the recommended number of hours (13.6%
In relation to physical activity, children presented similar prevalences of overweight if they performed some type of physical activity (boys 20.9%, girls 17.5%) or not (boys 20.4%, girls 17.5%), and higher in boys rather than girls (p < 0.05).On the other hand, obesity was higher among children who did not exercise (20.1% boys, 14.8% girls) compared to those who performed some physical activity (9.6% boys, 10.8% girls), with a statistically significant association only in boys (Table 1).
Children who spent more than two hours a day using devices related to new technologies were more overweight (24.5% boys, 20.0% girls) than those who spent less than two hours (20.7% boys, 15.0% girls), with no statistically significant association (Table 1).
Out of the total children who were obese, 16.4% (boys) and 14.0% (girls) were perceived by parents as children of normal weight (p < 0.05) (Table 1).

DISCUSSION
Regarding the parents' level of education, children whose guardians had lower levels of education had higher percentages of obesity than the others.In the enKid study, were obtained data similar to ours, with a prevalence of obesity of 15.6% in children whose parents had lower levels of education and 10.9% in those with higher levels of education. 7,14Similar data obtained in the Aladino 2011 study, of the total overweight children 47.6% their parents only had elementary education and 41.2% had university studies. 15Therefore, when the level of education is lower, the prevalence of obesity increases, perhaps due to the limited number of resources and limited knowledge of what constitutes a healthy diet or by the different appreciation of the concept of the desirable aesthetic standard.This is also consistent with the known fact that the educational level is one of the main predictors of health. 16,17egarding the monthly income of each family, in the enKid 7 study data similar to ours was found, with a prevalence of obesity of 15.1% when the level of income was low and 12.0% when the level of income was high.Similar data were obtained by the Aladino 2011 study, of the total number of children with income below 1500 €, 50.1% were overweight and those receiving more than 2500 €, 39.5% were overweight. 15Similarly, in the SEEDO study, 18 people from socioeconomically disadvantaged backgrounds had significantly higher prevalences of obesity than people from medium or high socioeconomic groups.A low socioeconomic level of tutors does not favor the adoption of healthy lifestyles in their families. 19On the other hand, it should be borne in mind that the occasions that favor the achievement of adequate physical activity and the practice of healthy eating are largely determined by social, economic and cultural factors that influence their access and availability.Another factor to be considered is the level of education of the head of the household that is directly related to the level of income and purchasing power of the family.
Therefore, in health promotion programs in primary care centers carried out by nurses, it is important to direct interventions related to a healthy diet for the parents.
Regarding the hours of sleep, children who did not sleep the recommended number of hours had a higher percentage of obesity.The most likely cause for children to sleep less is that they go to sleep later because they spend more time in front of the television or computer.Correcting this sleep deficit involves correcting this other widespread habit of staying up late to watch television. 16,17s for physical activity, children who performed some type of activity presented a lower percentage of obesity.It coincides with the enKid study (2000), with a national sample (n = 1723, 6-18 years), showing that more than half of the children and young people (53%) were below the recommended level of moderatevigorous physical activity (< 60 minutes/day), worsening in girls (61%). 19There is a close relationship between sedentary leisure and lack of sleep.The most likely cause for children to sleep less is that they take longer to lie down because they spend more time in front of the television or computer.In educational terms, this means that children should not be watching television until the end of the program, but should go to bed at a predetermined time, regardless of what television programming currently offers.In the same way and by extension, having a television in the children's room only increases the likelihood of the child going to sleep much later.
That is why sleep control should also be taken into account in child health promotion campaigns.
No association was found between using more than two hours of devices and obesity.This contrasts with what has been found in other studies.For example, in Sweden, children who had a television in their bedrooms or who watched television more than 2 hours a day were more likely to be overweight/obese (OR 1.26 and 1.55, respectively). 20This discrepancy could be due to the small number of children in this study who actually spent < 2 hours per day on this activity.Likewise, the increase in the number of hours that children spend alone at home or with tutors, without the supervision of parents or educators of the time they spend on this activity, should be taken into account.
In relation to breakfast, children who did not eat breakfast had greater obesity than those who did.Similar results were found in the Aladino Study, in which out of the total number of children who did not eat breakfast, 2.7% were obese, compared to 1.4% who had normal weight. 15Among the factors that may cause that sometimes they do not have breakfast, could be the lack of time, the time of the beginning of classes, the time they get up, the time

Table 1 .
Distribution of the weight according to variables and gender (2011).
Source: own elaboration based on the data of the National Health Survey (2011), * p < 0.05.