One hundred years of population change in three Colombian cities: Bogotá, Cali, and Medellín (1918-2018)

Introduction: The use of Colombian census microdata between 1918 and 2018 enables the consolidation of indicators summarizing the evolution of population volume and structure. This article analyzes the transition of the population structure in the three main cities of Colombia. Objective: To conduct a demographic analysis of the census results in Bogotá, Cali, and Medellín between 1918 and 2018 to understand the progress of the demographic transition in these cities. Methodology: A historical reconstruction of census sources was carried out, with calculation and analysis of demographic indicators applied to the information collected and standardized. Results: Relevant transformations were identified in the three cities over the last century: changes in population structure by age, urbanization, shifts in ethnic composition and birthplace, as well as the formation of conjugal unions. Discussion: The analysis reveals not only quantitative changes in population size, but also significant reconfigurations in the social, territorial, and cultural structure of the country. Bogotá Cali, and Medellín, concentrate population, attract migrants and reflect dynamics that affect urban and rural inequalities. Conclusions: Demographic, social, cultural, and political transitions have occurred earlier in these cities. Furthermore, the feminization of aging poses additional risks of vulnerability, loneliness, and isolation for older women, emphasizing the need for public policies with a gender perspective and territorial equality.