To identify the drivers of changes in modern contraceptive use (MCU) among women of reproductive age in three selected sub-Saharan African countries.

This is a secondary analysis of cross-sectional Demographic and Health Survey (DHS) data using a multivariable Blinder-Oaxaca decomposition approach.

The sample consisted of 73 777 women aged 15–49 years from the two most recent DHSs conducted in Gabon (2012, 2019–2021), Senegal (2018, 2023), and Tanzania (2015, 2022). Pregnant women were excluded from the sample.

We assessed the change in MCU over the two most recent DHS waves for the three countries.

MCU declined in Gabon from 26.5% to 18.4%, in Senegal from 20.5% to 18.5% and in Tanzania from 29.7% to 27.6%. Across the three countries, the contributions of compositional changes to trends in MCU varied significantly. In Senegal, characteristics explained 181% of the change, driven by reduced exposure to family planning information (157%), high parity (147%) and employment (9%), while education, urbanisation, union type and lower parity mitigated the decline. In Gabon, the overall characteristics included led to an increase in MCU (–44%), rather than a decline, reflecting the effect of favourable changes toward higher education (–19%) and urban residence (–10%). However, the behavioural effect was predominant (144%). This suggests that modifications in individual attitudes, practices and preferences regarding contraception outweighed structural changes, leading to the overall downward trend observed in Gabon. In Tanzania, neither characteristics nor coefficients significantly explained observed changes. Results for Tanzania indicate that none of the factors included in the model made a significant contribution to the change in MCU. Conversely, increases in educational attainment and urbanisation contributed to an increase in MCU in both Senegal and Gabon.

Interventions promoting MCU should consider the role of receiving family planning information at a health facility, parity, work status, educational attainment and urbanisation in informing changes in the use of modern contraceptive methods.

Preventing loss of autonomy has become a public health issue due to the increase in healthcare costs associated with ageing. It has become even more pressing with the arrival of the baby-boomer generation. This has given rise to several initiatives. This is the background to the VIVADOM project. The project provides a complete kit for older adults aged 60 years and over living at home. First, the kit includes a technological package (telecare, light path and digital tablet). Then, these older adults benefit from personalised human support provided by postal workers trained in gerontology. The aim of this study will be to carry out a health economic assessment (HEA) of the VIVADOM project as part of the prevention of frailty and/or dependency (by comparing beneficiaries of the complete kit with non-beneficiaries). The comparator will be the fact of not benefiting from the complete kit. In addition, the efficiency of the project in preventing falls and cognitive problems will be studied. We will calculate three incremental cost-effectiveness ratios (ICER) for these three issues.

The economic model used will be the Markov model. Transition probabilities, average costs and average quality-adjusted life year (QALY) will be calculated for the two groups being compared. The ICER will be obtained by dividing the difference in average costs by the difference in average QALYs. Finally, ICERs will be compared with willingness-to-pay (WTP) to assess the efficiency of the system. Thus, the VIVADOM project will be efficient when these ICERs are lower than the WTP. Univariate and probabilistic sensitivity analysis will be carried out to ensure the robustness of the analysis results.

The HEA of the VIVADOM project has been approved by the research unit of the University of Limoges in France. The results will be published in a peer-reviewed journal and presented at relevant national and international conferences.