| Abstract: |
The COVID-19 pandemic has significantly increased mortality rates, disrupting
historical trends and making it challenging to forecast future life expectancy
levels. São Paulo, the first city in Brazil to report a COVID-19 case and
death saw a decrease of over four years in life expectancy at birth for males
and over three years for females between 2019 and 2021. São Paulo has been at
the forefront of the demographic transition in the country and experienced a
nonlinear mortality decline over the 20th century. The city's historical
mortality trajectory and the disruptive effects of COVID-19 have introduced
challenges to mortality forecasting. In this study, we used a unique dataset
starting from 1920 to forecast life expectancy in São Paulo until 2050 using
the Lee-Carter (LC) and Lee-Miller (LM) methods. Mortality rates were obtained
from a combination of deaths gathered by the SEADE Foundation (SEADE) and
population collected by the Brazilian Institute of Geography and Statistics
(IBGE). To mitigate the dependency on the fitting period's choice and better
incorporate the effects of the recent mortality shock, we used different
baseline periods, using all years from 1920 to 1995 as the starting year of
the analysis and six scenarios for post-pandemic mortality levels.
Additionally, we used a simulation approach for the time-index parameter to
calculate prediction intervals. Based on 73, 200 simulations for each year
between 2023 and 2050, we synthesized the resulting life expectancy forecasts
into median values and 95% prediction intervals (PI). By 2050, we predict that
life expectancy at birth in São Paulo will reach approximately 81.5 years for
men and 88.3 years for women. Also, within the 95% PI, we estimated that by
2045, male life expectancy could reach the levels of best-performing
countries. Our approach is among the first attempts to forecast mortality in
the presence of shocks. Additionally, by evaluating different baseline
periods, we advocate for the adoption of more accurate forecasting strategies,
particularly in contexts of recent mortality decline. These findings provide
valuable resources for policymakers and researchers working to address public
health challenges arising from the pandemic and plan for the future well-being
of many populations. |