The overall aim of this thesis is to contribute to an understanding of the pathways through which structural and intermediary determinants influence child health in Colombia and how they operate through the context where children live in a more comprehensive way than has been determined to date. Colombia has made significant progress in child health in the last few decades and it is currently on track to meet the Millennium Development Goals (MDG). Nearly 90% of the goals on global malnutrition, infant mortality rate and under-five mortality rate have been achieved. However, despite the progress, national averages remain masking huge territorial disparities. While some regions present figures similar to those of a developed country, others report indicators similar to those of a very poor African country. Some municipalities, for example, record no stunted children, whereas in others, the prevalence of chronic malnutrition is greater than 50%. In this context, empirical research that enhances our understanding of socioeconomic determinants of child health and guide policy-making is crucial in order to reduce place-based health inequities in Colombia. This thesis is based on three research articles. The data used in these studies are drawn from the 2010 Colombian Demographic and Health Survey (DHS). The DHS is a large survey programme designed to collect high-quality nationally representative data on population, health and nutrition for developing countries. The DHS are widely recognised as the most important source of information for the analysis of health inequities in the developing world. Firstly, intermediary determinants of early childhood health have been analysed through the construction of a composite index (Chapter 3). The intermediary determinants are the most immediate mechanisms through which socioeconomic position influence child health inequities. Therefore, their identification should contribute to the drafting of intervention policies at this level, given the importance of these factors in programmes aimed at improving maternal and child care. The index allowed us to identify key immediate determinants of child health and their relative importance among Colombian departments (administrative subdivisions). The index was constructed using a more sophisticated methodological approach than that commonly used in the literature, termed polychoric principal component analysis (PCA). A hierarchical cluster analysis was also carried out in order to identify how departments cluster based on the health of their children rather than their geographic proximity. The results showed that the largest differences in intermediary determinants of child health are associated with health care before and during delivery. Furthermore, the departments that perform relatively better in the most immediate determinants of child health are located in the centre of the country. In contrast, those departments that perform worse are located in the peripheral region. This region has a per capita gross domestic product (GDP) well below the national average, little state presence, a hostile environment and a large proportion of the ethnic minorities. Our index provides very useful information in terms of public policy since it facilitates measuring, visualizing and monitoring of child health indicators, and may, therefore, help identify potential intervention strategies for improving the well-being of Colombian children. Secondly, this thesis examines the effect of individual, family and community socioeconomic conditions on different indices representing intermediary determinants of child health, using a coherent conceptual framework (Chapter 4). Using a weighted multilevel approach, the results indicate that whilst community socioeconomic context can exert a greater influence on factors linked directly to health, in the case of psychosocial factors and parent’s behaviours, the family context can be more important. In addition, the results indicate that a significant percentage of the variability in the overall index of intermediary determinants of child health is explained by the community context, even after controlling for individual, family and community characteristics. This study provides evidence that community socioeconomic context is a key component for improving child health in Colombia. However, the role played by context may vary according to the category of the intermediary determinants of child health analysed, highlighting the importance of distinguishing between community and family intervention programmes. Thirdly, the influence of education of other women in the community and family socioeconomic characteristics on child nutrition outcomes, as well as their interactions, was investigated (Chapter 5). The contextual effects of education on child health were studied using weighted multilevel models. This study takes into account important methodological issues such as sample weights and second level endogeneity in multilevel modelling, which have not been addressed in the empirical literature and can lead to biases in the estimates. Different ways through which community education can substitute for the effect of family characteristics on child nutrition were found, suggesting that child care programmes should focus not only on individuals but should also target the broader context of communities. In particular, those communities with less educated mothers and with low female autonomy are those that could benefit more from intervention policies that focus on encouraging female education. To conclude, previous studies on the social determinants of child health in Colombia are limited. Most of them have covered the issue from the perspective of the individual and little attention has been paid to the effect of context. In this vein, understanding the structural and intermediary determinants of child health inequities, as well as the role played by community socioeconomic context, is essential for the design, monitoring and tracking of public child care policies in Colombia. / El objetivo de esta tesis es contribuir a un entendimiento de los mecanismos a través de los cuales los determinantes estructurales e intermediarios de la salud influencian la salud de los niños en Colombia y como estos operan a través del contexto donde los niños viven, de una manera más completa que la que se ha hecho hasta ahora. Esta tesis se base en tres artículos de investigación. Los datos usados en estos estudios son de la “Demographic and Health Survey” (DHS) para Colombia en el año 2010. En primer lugar, los determinantes intermediarios de salud infantil se analizan a través de un indicador compuesto. El indicador permite identificar determinantes intermediarios claves de salud infantil y su importancia relativa entre departamentos colombianos. En segundo lugar, esta tesis examina el efecto de las condiciones socioeconómicas de la comunidad, la familia y los individuos sobre diferentes índices que representan determinantes intermediarios de salud infantil. Por último, se analiza la influencia de la educación de otras mujeres en la comunidad y de características socioeconómicas de las familias sobre la nutrición infantil, así como sus interacciones. Se utilizan diferentes enfoques metodológicos. Para la construcción de los indicadores compuestos se utiliza un análisis de componentes principales usando correlaciones policóricas, con el fin de analizar cómo se agrupan los departamentos de acuerdo a la salud de sus niños se hace un análisis de cluster jerarquico. Finalmente, con el fin de medir efectos contextuales se utilizan modelos multinivel de regresión lineal ponderados. Los resultados de esta tesis demuestran que el contexto de la comunidad es un componente clave en la determinación de determinantes intermediarios de salud infantil, así como de indicadores de nutrición de los niños, tanto en el mediano como en el largo plazo en Colombia. Por lo tanto, es necesario que los gobiernos municipales y departamentales involucren no sólo a los individuos, sino que también tengan en cuenta el contexto de las comunidades para el desarrollo, ejecución, monitoreo y evaluación de las políticas de cuidado infantil.