Attrition in the COCON Cohort Between 2000 and 2002Razafindratsima Nicolas, Kishimba Ngoy and the COCON Group
The COCON (COhorte CONtraception) survey on contraception, unplanned pregnancy and induced abortion in France, was set up to interview by telephone a representative sample of women aged 18-44, and to follow them up annually over five years. Between 2000 and 2002, the survey sample fell in size by one third, from 2,863 to 1,912 women. This article describes this attrition process and evaluates the biases that it causes in the analyses.
The attrition is due, in roughly equal proportions, to two factors: first, an inability to re-contact the women; second, refusals to be re-interviewed. It is highly selective, concerning primarily foreign women, of low educational level, young and living alone, and was responsible for modifying the structure of the sample followed up and the means for several survey variables of interest. However, the attrition has little impact on the multivariate analyses. Finally, the implications of attrition in COCON are limited as regards the biases caused, and are seen mainly as the loss of precision in the estimates due to the reduction in sample size.
The Pill and the Condom, Substitution or Association? An Analysis of the Contraceptive Histories of Young Women in France, 1978-2000
Rossier Clémentine, Leridon Henri and the COCON Group
The contraceptive practices of young women (aged 15-29) underwent two important evolutions during recent decades in France. First of all, beginning in the late 1960s, the use of the pill became general in this age group. However, its diffusion was not yet complete when the AIDS epidemic appeared suddenly in the late 1980s. As a result of HIV prevention campaigns, the young adopted the condom massively as their principal contraceptive method. This had two consequences: an expansion of contraceptive coverage (by the late 1990s, nearly all first relations were protected), and a postponement of the age at first use of the pill. Within this context, it may be suggested that the introduction of the condom turned some young people away from the pill. By simultaneously using period data from the last four national surveys on contraception (INED-INSEE-INSERM), and complete contraceptive histories collected during the most recent of these surveys (COCON), we show that the proportion of users of the pill decreased - in the mid-1980s - only at the very onset of sexual life, and that the much more frequent use of the condom at these first relations finally led young women to turn rapidly to the pill.
Social Inequalities in Access to Contraception in France
Bajos Nathalie, Oustry Pascale, Leridon Henri, Bouyer Jean, Job-Spira Nadine, Hassoun Danielle and the COCON Group
Since contraception was legalized in France in 1967, there has been a sustained increase in use of medical contraception, notably third generation contraceptive pills that are not reimbursed by the social security. This change in contraceptive behaviour may well have generated new forms of inequality. This article shows that social inequalities in contraceptive use in France have changed in recent decades. At the beginning of the 1980s, access to the pill and the intrauterine device (IUD) was characterized by large inequalities. These inequalities subsequently declined sharply, for the pill in the 1990s and for the IUD at the end of the 1990s. COCON data show for the first time that such inequalities now affect access to third generation oral contraceptives. In addition to the financial obstacle of high price, the inequalities in access to these non-refundable products seem to result from women’s expectations, which are related to their social class, and from the behaviour of the prescribing doctors, which also varies with the woman’s social class. However, women seem not to prefer these new products.
Question Comprehension and Recall: The Reporting of Induced Abortions in Quantitative Surveys on the General Population
Moreau Caroline, Bajos Nathalie, Bouyer Jean and the COCON Group
The aims of this study on abortion underestimation are twofold. First, to compare the underreporting of induced abortion using different questions on this event from the same study, and the results from other recent French studies. Second, to estimate the classification errors due to misunderstanding of the terms used to describe induced abortion.
The data came from the COCON study on contraceptive use and induced abortion in France. A representative sample of 2,863 women aged 18-44 was used for the analysis.
Despite particular care over question wording, underestimation of induced abortion remained high (40%) in the COCON survey. Nevertheless, the study demonstrates the value of using a varied vocabulary to describe induced abortion, since this reduces classification errors and improves data quality. The study also raises questions about the significance of underreporting, which seems to be a constant regardless of the survey design and the form of questioning. One factor is the difficulty of talking about an event experienced as a failure, but other explanations are also possible, in particular the reluctance to disclose health-related events in general.
The Demography of Sub-Saharan Africa from the 1950s to the 2000s. A Survey of Changes and a Statistical Assessment
Tabutin Dominique, Schoumaker Bruno
This chronicle is focused on sub-Saharan Africa (48 nations, 730 million people) and includes both a summary of the major socio-demographic and health changes since the 1950s and a statistical report based on the most reliable recent data on each nation. Particular attention has been given to the size and structure of the population, fertility and its intermediate variables, nuptiality, mortality, child health, migration and population movements, urbanization and access to education. Even though Africa still has the most rapid growth and the youngest population in the world, many changes are in progress. They occur at different speed depending on the country, the region, and the type of residence. As a result, African demographic regimes are diversifying. One major trend is the decline of fertility that has been observed for Africa as a whole for the last fifteen years, with rapid declines in a few countries, but also stagnation in about fifteen others. The age at first marriage is increasing in most countries, but polygyny is resisting rather well. Adult and child mortality have decreased markedly over the last forty years, though at a different pace and with worrisome reversals of trends in recent times in the countries most affected by AIDS. Access to education, particularly for women, is still an issue. The overall situation in sub-Saharan Africa has improved since the 1950s or 1960s, but progress is slower than in other regions in the world and appears reversible or uncertain in the current context of economic crisis, poverty and the AIDS pandemic.
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