Foreign Residents Effect on Population Ageing Assessment Over Space and Time

Abstract Developed countries are experiencing an intense and widespread process of demographic ageing, driven by persistently low fertility and increasing life expectancy at birth. In this context, international migration is often considered a potential mitigating factor, capable of balancing the population structures to some extent. However, the actual impact of foreign residents on ageing trends is uncertain, particularly at local level. This study explores whether and to what extent foreign residents have affected the spatial patterns and temporal changes of population ageing, measured by the proportion of residents aged 65 and over. By considering that Italy is one of the most ageing demographic contexts worldwide, the relationship between the dynamics of the foreign population and demographic ageing is assessed for the Italian municipalities between 2002 and 2022, by using annual data from the Italian National Institute of Statistics (ISTAT). For this aim, an integrated global–local modeling framework is proposed, where Ordinary Least Squares (OLS) is used as global benchmark for national-level associations and Geographically Weighted Regression (GWR) is adopted to account for spatial non-stationarity and reveal local variations over time. A multi-step variable selection procedure is implemented to enhance model parsimony and reduce overfitting. Results show that foreign populations have mitigated demographic ageing, but this effect has weakened over time, reflecting convergence in demographic behaviour with native populations. The spatial distribution of effects is highly uneven, with more persistent influences observed in parts of southern Italy and urban peripheries. The study highlights the analytical value of spatially explicit models for analysing local demographic dynamics and provides evidence supporting place-based policies addressing territorial disparities and long-term structural change.