Individual and contextual socioeconomic conditions affect the lifestyle and health status of individuals, leading to social inequalities in health. Evaluating social inequalities in health with respect to socioeconomic context is complicated by variations in the conceptual frameworks, methodological heterogeneity and differences in the interpretation guidelines of related indexes and indicators.Some studies have investigated the social differences between rural and urban populations by exclusively using the number of inhabitants as an indicator . Such a methodof classification may limit the findings generated by those studies as it does not consider other properties specific to the studied populations.Research on social inequalities in health has been mainly centred in large populations , while only a few studies have reported poorer access to social services, health care facilities or medically inappropriate behaviours in populations considered as rural in comparison with other larger populations .

Relying on population size exclusively in studying the social inequalities in health would lead to generalizing findings of numerous indicators that could differ between settings, even in regions with a similar number of inhabitants. The characteristics of the environment where people live, as one of the potential determinants in health, could affect the health behaviors of the population. For instance, studies carried out in Spain have suggested that behaviors such as eating habits differ between populations living in north and east Spain, pointing out, therefore, the need for surveillance of different risk factors for health in these populations . The prevalence of other risky behaviors such as substance consumption also differs between regions in Spain . These variations could be related to the different socioeconomic status between regions and might affect the physical and mental health status . Accordingly, we hypothesize that these populations, despite sharing certain socioeconomic characteristics and belonging to the same country and public health system, could present differences in factors that may influence health behaviors. Evaluating those factors could allow a better management of social and health services and resources. Extrapolating the findings of contextual socioeconomic conditions that are routinely used to explain the health status or health behaviour of another population that shares similar characteristics to the population under study, may introduce important biases.

This is particularly relevant in small municipalities . In addition to the contextual socioeconomic factors, other indicators such as family income, access to social and health services, public transport, leisure options , or demographic density may play an important role in explaining the health status or health behaviours of adolescents . Evaluating the association of population characteristics other than the number of inhabitants will help prevent misclassifying a population. The misclassification of populations can lead to erroneously associating a determinant or a characteristic with a specific outcome in the population. To study the health determinants and improve the health level of a population, it is crucial to adequately allocate it in the correct socioeconomic and sociodemographic categories, otherwise, health behaviors and health outcomes in different populations will be erroneously generalized, and fundamental determinants for the design and success of health interventions will be ignored. Accordingly, healthcare professionals must consider the contextual determinants of health that are specific to each population in order to design population-specific preventive strategies. In Europe, including Spain, most of the research on the association of socioeconomic context with health status and behaviour has focused on comparing mortality and comorbidity rates between large municipalities.

However, to-date, none have compared the health status and health behaviours between small municipalities while taking into account the factors related to inequalities in health, such as ethnicity, gender and social class. Health behaviours acquired in adolescence can have implications on health status in adulthood. Mental health problems during adolescence lead to increased morbidity and mortality. Suffering from bullying during adolescence affects physical and mental health . Moreover, risky behaviors such as the initiation of substance consumption, e.g., cannabis dependence in youth, are related to great psychological distress . In the Galician population, which forms a part of this study, an association was found between the following variables: negative mood, alcohol, tobacco and cannabis consumption, and having suffered bullying. Therefore, it is relevant to check if these associations are maintained across populations with similar socioeconomic characteristics.This study was carried out in Spain, Southern Europe.