Iran’s 100-Year Projection of Population Aging and Momentum

Researchers projected Iran’s population over 100 years and analyzed how long-term demographic forces affect the number of older people. Using historical fertility and mortality estimates, the study decomposed population momentum and followed age distribution changes to forecast trends. The results show a substantial rise in the elderly population through mid-century, with the aging index climbing sharply by 2061. After that point, the momentum effect wanes and then turns negative, causing the growth of the older population to level off and decline later in the century. The authors highlight that this transition presents policy challenges for retirement, health, and elder care systems in Iran.

What the study examined

This research produced a 100-year projection of Iran’s population with a focus on the growth of older age groups. The analysis used fertility and mortality estimates from 1996 to 2016 and applied a cohort-component projection method implemented in statistical software.

The study also decomposed a core demographic driver called population momentum to see how residual effects of past fertility and age structure contribute to future aging trends. Age distribution patterns were examined to track how the share and number of older people change over the projection period.

Key findings

Across the historical years analyzed, the population momentum remained positive but its strength declined over time. Age-specific analysis showed the largest momentum values were linked to older age groups, indicating that past demographic patterns continued to push up numbers of elderly people.

• The projected elderly population is expected to increase about fourfold over the century examined, with a pronounced rise up to 2061.
• The study reports the aging index rising from around 25 in 2016 to about 110 in 2061, reflecting a substantial shift in age structure by mid-century.
• Beyond 2061, the influence of momentum is projected to fall to zero and then become negative, driven by sustained low fertility, which leads to a later leveling and decline in the growth of the older population.

Why it matters

The projected changes signal a major demographic shift with implications for public systems and social planning. A rapid increase in the number and share of older people through mid-century will affect demands on retirement arrangements, health services, and long-term care provision.

As the driving momentum declines and reverses later in the century, the pattern of change will also alter long-term needs and policy priorities. The authors emphasize that these trends pose significant challenges for social policy and call for reforms related to retirement, health, elderly care, and family-oriented measures to adapt to the changing age profile.