Inequalities in health issues can arise during childhood and determine health in the future, especially if no corrective measures are applied. In addition to classical indicators, other indicators of a social nature exist that are not as well studied, such as quantity and quality of social support networks, type of family structure, unemployment and the geographical origin of parents, which affect children’s health independently of their parents’ education, occupation and income.

Children belonging to vulnerable groups in these less studied aspects usually show poorer lifestyles, register higher levels of sedentary behaviour and lower levels of physical activity, follow a less healthy diet and, for these reasons, display higher levels of obesity. In summary, they present worse levels of physical and mental health.

Without understanding how these factors interact, we cannot understand what lies behind what we call the socioeconomic gradient of health; in other words, the phenomenon according to which a higher or lower socioeconomic level determines better or worse health. This is a correlation that we observe as much in Spain as in all countries in Europe. Ascertaining the causes of this gradient would be a first step towards resolving health inequalities.

People’s social and economic conditions influence their risk of falling ill. Our health is determined by the interaction of personal characteristics such as our physical, family, social and cultural environment as well as by political factors, for example the health services that we can access.

In turn, health inequalities are caused by unequal distribution of these health determinants. The data indicate that, in general, the poorer a person’s socioeconomic situation, the poorer their health. Seen from the contrary perspective, a higher socioeconomic status acts as a protective factor for an individual’s health. This social gradient of health, according to the WHO, runs from the apex to the base of the socioeconomic spectrum. It is a worldwide phenomenon, observable in high-, medium- and low-income countries alike. Children do not escape this phenomenon.

In recent years, as a consequence of the economic crisis of 2008, health inequalities in Europe have increased and the social gradient has been accentuated. If we consider health as a universal right that should not be subject to economic or social conditioning factors, then health inequalities, whether occurring among groups of people within the same country or between different countries, can be considered unjust if, with adequate policies, it would be possible to put an end to them. Furthermore, the existence of a social gradient in health implies that inequalities in health affect everyone.

We reflect in this work the results of the study IDEFICS (Identification and prevention of Dietary- and lifestyle-induced health EFfects In Children and infantS), whose objective was to analyse the association between social vulnerabilities and the lifestyles and physical and mental health of European children. The study included over 16,000 children aged from 2 to 9 years in eight European countries (Belgium, Cyprus, Estonia, Germany, Hungary, Italy, Spain and Sweden). To count on prospective data, the children were evaluated two years after the study started. In the specific case of Spain, another study, the CALINA study, was conducted, which included over 1,600 children from Aragón.

The children who were the subject of the study were classified into four vulnerable groups according to:

1) Family structure. For the purposes of the study, families in which children lived with both parents were considered to be traditional families. All other family models were considered non-traditional families.

2) Social network. Children whose parents lacked a social support network, in other words, who in case of need had nobody to count on or only one support person.

3) Ethnic origin. Children whose parents were immigrants, considering whether both parents, or only one of them, were born in a different country to the place where the study was carried out. Equally, in the specific case of obesity, and with data referring to young people born in Spain, it was also taken into account whether children were of gypsy ethnicity.

4) Employment situation of the parents. Children with one or both parents unemployed or the recipients of some kind of social benefit.

Obesity has become one of the main public health problems in the developed world and, alarmingly, among the child population. In fact, the WHO considers childhood obesity as one of the most serious public health challenges of the 21st century.

Although it is not the only health disorder that presents a social gradient, obesity is very highly conditioned by habits and lifestyles that, in turn, are influenced by social vulnerabilities. Specifically, diet and levels of physical activity and sedentary lifestyles are clearly different in the socially vulnerable groups and those of the lowest socioeconomic level, with respect to the rest of the population. The groups with the lowest socioeconomic level have approximately twice the possibilities of becoming obese and therefore a higher risk of diabetes type 2, musculoskeletal problems, ischemic heart disease, heart attack or psycho-social problems in comparison with groups of a higher socioeconomic level. In fact, many of the premature mortalities that are seen in groups of a lower socio-economic level can be explained by diseases related with obesity (Robertson A., 2007).

Among the reasons suggested to explain these differences, appears the fact that people of a lower socioeconomic level generally live in neighbourhoods with a higher density of fast-food establishments but lower availability of fresh fruit and vegetables and of safe places for undertaking physical activity (Cummins & Macintyre, 2006). However, more in-depth analysis is needed to reveal the underlying causes.

The majority of studies that have aimed to describe the socioeconomic factors implied in differences in childhood obesity have been carried out in the United States. The results have shown a higher prevalence of overweight and obesity among Afro-American and Hispanic children in comparison with white, non-Hispanic children. In Europe, studies have also examined ethnic variations in childhood overweight/obesity. Children belonging to ethnic minorities (especially Moroccans, Turks, Latin Americans, Sub-Saharans and Caribbean) have a greater tendency to be overweight and heading towards obesity than children not belonging to minorities in some European countries. Other minorities, such as the gypsy ethnic minority, also present higher rates of obesity in comparison with non-gypsy children.

The prevalence of overweight and obesity in Spanish children is one of the highest in Europe and varies between minorities and socio-economic groups. Our research, conducted among children born in Spain, showed that children of gypsy ethnicity and those with Latin American parents were, respectively, between 4 and 3 times more likely to be overweight or obese at the age of 6 years than the children of non-gypsy Spanish parents. As we can see in graph 1, at the age of 6 years, children whose parents were of Spanish non-gypsy origin had a percentage of obesity of 28.6% against 72.4% of Spanish gypsy children and 52.7% of children whose parents were of Latin American origin.

Children belonging to these minority groups are more exposed to a large number of vulnerabilities, which possibly leads to environments that favour obesity, characterised by low levels of physical activity, diets with a high energy density and a sedentary lifestyle in comparison with non-vulnerable groups.

We also observed in our research that the rate of overweight and obesity in children aged 6 years was over two times greater in those that presented an accumulation of three vulnerabilities (belonging to a minority group, with parents with low employment and a low education level) than in children without vulnerabilities. An accumulation of social vulnerabilities increases the risk of lifestyles that are not very healthy.

The study gives evidence that, despite stabilisation of the prevalence rates of overweight and obesity in children in Spain and other developed countries, the child population of vulnerable groups (those that belong to minority groups and of a low socioeconomic status) have not benefited from this tendency.

There are factors that directly influence obesity: diet, physical activity and a sedentary lifestyle. The first aspect that we must analyse is eating patterns and in what way socio-economic inequalities in childhood can determine them and, therefore, condition people’s future health.

To study eating patterns, three dietary patterns are considered: a processed group, characterised by high-frequency consumption of snacks, fast food and processed meat (for example cured meats, hamburgers, sausages, etc.); a sweet group, which show a higher-than-average consumption of sweet foods and sugary drinks; and a healthy group, characterised by higher-than-average frequency of consumption of fruits, vegetables and wholemeal products.

It has been shown that people with a lower socio-economic status are more prone to following diets of worse nutritional quality. In a recent study, based on the diets of the IDEFICS study, it was confirmed that children of people belonging to groups showing lower incomes, occupation and education tended to follow the unhealthy patterns (processed and sweet), while children of parents with a better education and average income were more likely to follow the healthy pattern.

Thus, as can be seen in graph 2, some 56.4% of the children of parents with low education levels followed a processed pattern, a percentage that fell to 40.1% if they had high levels of education. As for income, and also for this type of diet, the percentage was of 58.9% in the case of children with families with low incomes.

Independently of these classic indicators, our work observed differences associated with other social vulnerabilities. As can be confirmed in graph 3, some 65.1% of children whose parents manifested that they had a poor social support network followed a processed pattern, against the 38.7% of children whose parents had broad support networks, in other words, they could count at least two people in them. Some 57.4% of children with unemployed parents also followed this pattern, against 46% of those whose parents were in work.

As for the healthy pattern, the data also highlight social vulnerabilities: this pattern appears in 36.9% of children with both parents working, against 22.1% of children with families with at least one member that is unemployed, and also appears in 32.5% of children in traditional families, against 27.8% of children from single-parent families.

With respect to dietary patterns in the different countries (see graph 4), the processed group was observed mainly in Spain, Italy and Cyprus, while nearly all Swedish children were in the healthy group. The sweet group was represented mainly by Belgian and German children.

The reasons that are usually used to explain these differences in dietary patterns are price, accessibility and availability of products. In a recent study conducted in the United States, also pointed out as a possible reason was the different exposure to television advertisements for junk food and soft drinks. Specifically, Afro-American children are 50% more exposed to these types of advertisements than Caucasian children (Fleming-Milici & Harris, 2016).

Practising regular physical activity during childhood is associated with better musculoskeletal and cardiovascular health and lower adiposity. In contrast, insufficient physical activity and excessive exposure to screens (whether televisions, computers, tablets, mobiles or consoles) are associated with worse health results. Therefore, increasing physical activity and reducing sedentary time are public health priorities.

The World Health Organisation establishes patterns for children aged 5 to 18 years of at least one hour of moderate to vigorous physical activity per day (World Health Organisation, 2010). Also, the American Academy of Pediatrics recommended, when the IDEFICS study was conducted, limiting screen time to no more than two hours per day (American Academy of Pediatrics, 2001). However, last year the same institution reduced the recommendation for screen time for children aged 2 to 5 years to one hour. For children aged above 6 years, it recommends the establishment of coherent limits regarding time devoted to screens and to contents, in such a way that their use can be guaranteed not to take up the time required for adequate sleep and physical activity, as well as other behaviours essential for good health. 

Despite the benefits that come from these recommendations, many children do not follow them. And as observed in graph 5, children from vulnerable groups presented worse indicators for physical activity. The results showed that children whose parents manifested a poor social support network had greater probabilities of not following recommendations for physical activity. Equally, the results evidenced a greater risk of excessive screen time in children with unemployed parents of immigrant origin, as well as a lower probability of participating regularly in organised sporting activities. This tendency could be appreciated in all the vulnerable groups, independently of family income, parental employment and educational level of the parents (I. Iguacel, J. M. Fernandez-Alvira et al., 2017).

Children’s physical activity and amount of time spent sedentary were monitored through the use of accelerometers (devices that enable objective recording of the quantity and level of children’s physical activity time) and of questionnaires answered by their parents. They were asked about the total hours and minutes that children devoted to playing outside, as well as the time that the youngsters spent watching TV, DVDs and videos or playing with the console or computer, during the week and at weekends. The parents also reported on sports practice at an organised entity (“belonging to a sports club”), as the children that belong to a sports association have more possibilities of doing physical exercise and probably of interacting more with other children. In this sense, the highest percentages of children that do not belong to a sports club appeared among the children of parents who are unemployed (67%), those with a poor social support network (62.4%) and immigrants (61,5%).

Socio-economic level and social vulnerabilities not only affect children’s physical health but also their mental health. Diverse studies have evidenced the relationship between low socio-economic levels and worse psychological health (attention deficit and hyperactivity disorders), emotional difficulties (depression, anxiety) and social and behavioural problems (drugs consumption, delinquency) (Reiss, 2013). Among the reasons for these differences, it has been pointed out that social and economic disadvantages affect family stability, with negative repercussions on childrearing styles or parental styles.

In graph 6, the relationships are shown between the different social vulnerabilities and psychosocial problems (internalised problems, such as depression and anxiety, and low levels of mental wellbeing). It is observed that children belonging to vulnerable groups present a greater percentage of internalised problems and lower levels of mental wellbeing in comparison with children from non-vulnerable groups (I. Iguacel, N. Michels et al., 2017).

Of the vulnerabilities studied, having a poor social support network was most associated with greater psychosocial problems, specifically when the social isolation of the parents persisted over time. This could be explained because parents that have a solid social network can act as models for their children in friendship patterns, both due to having access to a greater circle of relations and due to benefiting from the difference experiences that these friendships bring to them. 

With respect to the family structure, the children of non-traditional families had a greater risk of suffering psychosocial problems than the children of traditional families. In contrast, although 20.6% of children whose parents were unemployed presented internalised problems, no statistically significant association between the unemployment situation and the children’s problems was detected.

Parents’ education, employment and income act as predictive factors for the health of their children. However, in addition to these classical indicators, it is important to also take into account socioeconomic factors, such as the support network, geographical origin, family structure and work situation of the parents, which may negatively affect their children through behavioural, mental health and biological factors. Children belonging to vulnerable groups in these aspects present worse levels of physical and mental health. Specifically, studies have shown that children from the more disadvantaged social groups have more psychosocial problems and in addition they show greater levels of childhood obesity, less healthy lifestyles, greater levels of sedentary behaviour, lower levels of physical activity and they follow a worse diet.

Therefore, interventions on a health level should do more to take into account ethnic, social and economic diversities in order to create effective policies that achieve a reduction in manifest inequalities in children’s health. Thus, a future challenge involves working on the diets and surroundings of children with accumulated vulnerabilities, to ensure that those who grow up in disadvantaged environments have healthier lifestyles, helping them to reduce obesity levels and the negative consequences resulting from these. Equally, and to counteract the negative effects that social vulnerabilities bring to bear on children’s health, social health policies should implement measures to strengthen social support for parents who lack an adequate social network.

Prevention of childhood obesity is a key strategy for the future prevention of obesity and its associated problems and diseases, such as diabetes type 2, musculoskeletal problems, sleep disorders, hypertension, metabolic syndrome and psychosocial problems, among others. These diseases are associated with the majority of deaths in developed countries and their prevention means avoiding in the future greater costs, both direct and indirect, from medical treatment.

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