Mortality inequalities in France since the 1920s: Evidence of a reversal of the income gradient in mortality

Abstract

Many recent studies show that Europe has had a lower mortality inequality for most ages than the United States over the last thirty years. However, the evolution of the income gradient in mortality all along the twentieth century remains poorly understood. This article uses a unique dataset that gives the annual lifetables and fiscal income for the 90 administrative regions of mainland France from 1922 to 2020. The income gradients in mortality are computed across regions using a traditional method with calendar ages and, alternatively, with mortality milestones to control for the increase in life expectancy over time. The study reveals a systematic reversal of the gradient that occurred around the 1970s for both sexes and all ages or mortality groups when calculated at an aggregated level. Inequality in mortality amongst the oldest age groups has however returned to a level observed at least ten years earlier because of Covid-19, even after controlling for mortality improvements over the period.

Fig 1. Death rates by inverted income per capita percentile.

Lines represent the linear trend that fits the annual death rates per 1,000 for selected ages and sex across 20 income groups. A positive slope indicates that mortality decreases with income. In the S1 Appendix, figures for all age groups are provided for both men (S1 Fig in S1 Appendix) and women (S2 Fig in S1 Appendix).

Fig 2. Income gradient in mortality for 6 age groups, 1922–2020.

Plain curves plot the estimates of the linear trends across income groups; dotted lines are the 95% confidence intervals. Gradients are not represented for the period 1939–1945.

Fig 3. Ages at which 4 mortality milestones are reached, 1922–2020.

Plain curves plot the ages that correspond to the mortality threshold considered. Men are in red and women are in blue. Ages are not represented for the period 1939–1945.

Fig 4. Income gradient in mortality for 4 mortality milestones, 1922–2020.

Plain curves plot the estimates of the linear trends across income groups; dotted lines are the 95% confidence intervals. Red dots indicate dates at which the slope is significantly positive, while blue dots indicate those with significantly negative slopes. Gradients are not represented for the period 1939–1945.

Fig 5. 20 ventiles of départements in 1925, 1950, 1975 and 2020.

Départements are classified according to their place in the 20 ventiles. The richest départements are in dark red while the poorest ones are in dark blue.

Fig 6. Income gradient in mortality for 4 mortality milestones, 1922–2020 (1922 classification).

Plain curves plot the estimates of the linear trends across income groups; dotted lines are the 95% confidence intervals. Red dots indicate dates at which the slope is significantly positive, while blue dots indicate those with significantly negative slopes. Gradients are not represented for the period 1939–1945.

Fig 7. Income gradient in mortality for 4 mortality milestones, 1922–2020 (1922 classification).

Plain curves plot the estimates of the linear trends across income groups; dotted lines are the 95% confidence intervals. Red dots indicate dates at which the slope is significantly positive, while blue dots indicate those with significantly negative slopes. Gradients are not represented for the period 1939–1945.