Work in progress
Work in progress
Spatio-temporal heterogeneity in health impacts and life burden attributable to non-optimal temperatures in southern Europe (with X. Chen, D. G. Barroso, I. León Gómez, F. De' Donato, R. Slama, P. Vineis, M. Blangiardo, G. Konstantinoudis).
Abstract: Non-optimal temperatures increase all-cause mortality. Most previous studies have focused on the spatial heterogeneity in heat-related risks, with far less attention to cold and the temporal changes, and only a handful have examined the combined burden. In this study, we assessed the impacts of non-optimal temperatures on all-cause mortality in five European countries though health and life burden perspectives and described the varying effects across small areas and over years.
We obtained daily all-cause mortality counts for people aged 65+, 65-84 and 85+ years at subnational level in Greece, Italy, France, Spain and Portugal. Mean daily temperature was derived from ERA-5 at 9$\times$9km resolution. We fitted a single joint Bayesian hierarchical Poisson model with a distributed lag non-linear function for temperature, allowing the exposure-response association to vary in space (Besag-York-Mollié prior) and time (random walk of order 2). Models adjusted for national holidays, seasonality, long-term trends and spatial autocorrelation. We estimated heat- and cold-attributable fraction of deaths, excess mortality, years of life lost, and loss in life expectancy, while propagating the uncertainty of estimates by country, region, year and age groups..
We observed U-shaped temperature-mortality relationships in all countries, with substantial. spatio-temporal heterogeneity. Excluding 2020, the nationwide fraction of deaths attributable to heat was highest in Greece 2.13\% (95\% CrI: 1.81-2.51\%) and lowest in France 0.42\% (95\% CrI: 0.38-0.45\%). Cold-attributable fractions were highest in France (9.82\%, 9.29-10.36\%) and lowest in Spain (6.16\%, 5.75-6.63\%). While cold remained the dominant temperature-related burden, heat-related attributable fraction increased over time in all countries. In Spain in 2022, heat-related mortality exceeded cold-related mortality, with corresponding more than 2 years reduction in life expectancy in its central-west part. Meanwhile, we report an average of one year loss in life expectancy due to cold exposure across the study period.
Non-optimal temperatures impose a substantial, spatially unequal mortality burden in these five European countries. Although cold remains the main contributor, rising heat-related mortality in recent years and pronounced regional disparities highlight the urgent need for targeted, locally tailored adaptation action plans in the context of warming climate and population ageing.
A Unified Innovation–Diffusion Theory of Fertility Transitions: New Insights from French Regional Fertility, 1853-2023 (with S. Florian).
Abstract: We propose a theoretical framework that unifies the narratives of fertility trends into a single model with two successive innovation–diffusion processes: the spread of lower fertility (quantum) and delayed fertility (tempo), both proceeding through four phases and originating in wealthier regions before diffusing to lower-income ones. We test this framework using a new French dataset, analyzing trends in income per capita and Total Fertility Rates (TFR) by region from 1855 to 2023, decomposing TFRs into age-specific fertility rates (ASFR). During 1855–1945, TFRs were higher in poorer regions, as richer regions experienced earlier fertility decline. From 1970s, delayed fertility emerged first in high-income regions, increasing ASFRs at older ages, producing a rapid rise in mean age at birth (MAB), while poorer regions lagged behind. By 2023, results suggest that France has not yet entered the third phase of the tempo innovation, in which MAB converges across regions.
Spatial Disparities in Disability Prevalence at the District Level in Sub-Saharan African Countries. (with A Simo-Fotso and J. Martin).
Abstract: The World Health Organization reports the highest prevalence of disability under age 60 in sub-Saharan Africa, yet evidence remains scarce due to limited and non-comparable measurements. To address this gap, we estimate subnational disability prevalence using harmonized data from 26 countries, collected between 2016 and 2022 through Demographic and Health Surveys and Multiple Indicator Cluster Surveys. Both surveys assess functional limitations in vision, hearing, mobility, cognition, communication, and self-care. We focus on adults aged 18–49 and generate estimates at the second subnational administrative level. Because direct survey estimates are often unstable at this scale, we apply small area estimation methods that borrow strength across age groups and geographic units. From these results, we derive age-standardized prevalence rates to facilitate cross-regional and cross-country comparison. Our findings reveal that 682 subnational units show prevalence above 2.5%, 233 above 5%, and 31 above 10%. The highest-burden areas cluster along the Ghana–Togo and Central African Republic–Democratic Republic of the Congo borders, in southern Democratic Republic of the Congo, and in parts of Madagascar. These patterns call for greater attention from national and international policymakers to the most affected areas.
Vanguards and laggards in a healthy ageing society: Occupational disparities in life and disability-free life expectancy in France, 2011–2019 (with E. Cambois, C.-G. Camarda).
Abstract: During the 2010s, progress in life expectancy (LE) in low-mortality countries slowed, fuelling debate over the possible limits of human longevity. Within the framework of health transition models, this slowdown raises questions about changes in health patterns and about how progress is distributed across social groups. If a common model of transition toward high longevity exists, can the currently longest-living groups be considered “vanguards”? And can further gains in LE occur through the diffusion of these groups’ advantages to others? To address these questions, we analysed trends in disability and disability-free life expectancy (DLE and DFLE) by occupational class (OC) for overlapping three-year periods from 2011–13 to 2017–19, using the Sullivan method applied to census-linked mortality data and the French EU-SILC survey. The female highly skilled OC—our “vanguard” group—continued to gain LE at older ages but also experienced an expansion of DLE. Female skilled workers caught up with the vanguards’ situation observed in the early 2010s through a compression of DLE. However, other OCs displayed divergent trajectories once they reached similar levels of LE. These preliminary findings suggest that there is no shared model of transition to longer life, with vanguards being progressively followed by lagging groups. While they do not contradict the possibility of future longevity gains, they underline the importance of recognising the diversity of health trajectories and needs across social groups in an ageing society.