American journal of epidemiology
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Some studies (but not all) have suggested that there may be an increase in the risk of breast cancer associated with a prior induced abortion. The risk, if present, may vary according to the duration of the pregnancy in which the abortion occurred, or to a woman's age or parity at that time. The authors conducted a case-control study of breast cancer in white women under age 45 years to address the question of breast cancer risk in relation to induced abortion, with the intention of identifying subgroups of women who might be at particularly increased risk. ⋯ There was no excess risk of breast cancer associated with induced abortion among parous women. These data support the hypothesis that there may be a small increase in the risk of breast cancer related to a history of induced abortion among young women of reproductive age. However, the data from this study and others do not permit a causal interpretation at this time; neither do the collective results of the studies suggest that there is a subgroup of women in whom the relative risk associated with induced abortion is unusually high.
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The authors have conducted an analysis to validate a computer model that uses age-specific human immunodeficiency virus (HIV) prevalence data to estimate age-specific HIV incidence rates. Data for the analysis are from a cohort study of volunteer male workers in Bujumbura, the capital city of Burundi. Testing for HIV prevalence was conducted at baseline, and HIV-negative subjects were retested annually from 1990 to 1993 to determine rates of seroconversion. ⋯ Expected numbers of cases within age intervals did not differ significantly from observed number of cases. The authors conclude that the model proved to be successful in approximating observed incidence rates and that it is a useful tool, particularly in countries where prevalence data are available and where HIV prevalence has stabilized, which is when the underlying assumptions in the model are best met. The model provides crucial information about incidence rates that might not be evident from prevalence data alone.