Aldersstruktur

Aldersstruktur refers to how a population is distributed across different age groups. It is a fundamental dimension of demographic structure and is commonly presented as a breakdown by cohorts such as 0–14, 15–24, 25–64, and 65 years and over, or as a population pyramid showing the relative sizes of age groups. The age structure influences and reflects fertility, mortality, and migration patterns, and it affects social and economic dynamics.

Data are usually collected by censuses and vital statistics and can be summarized by indicators such as median age, the proportion in each age group, and age-dependency ratios (youth dependency or old-age dependency). The demographic transition model describes typical shifts: high birth and death rates give way to lower death rates, followed by lower birth rates, resulting in an aging population. Some regions experience a youth bulge with a large share of young people.

Implications arise from different age structures. A younger age structure can support future growth but requires investments in education and job creation; an older age structure increases demand for healthcare, pensions, and elder care, and may necessitate policies on labor force participation and retirement.

Regional patterns vary. Many high-income countries have rising median ages and a shrinking working-age population, while parts of sub-Saharan Africa maintain relatively young age structures. Migration can also reshape the age composition, introducing younger workers or older dependents depending on who migrates.