The interpretation of epidemiologic studies

Article Abstract:

Epidemiologic studies present the clinician with special interpretive problems, and public interest in their findings has escalated in recent years. Single causes for many chronic, degenerative diseases (such as coronary artery disease) are almost impossible to identify, and epidemiologic studies are the only way such multifaceted problems can be studied. They are also essential to answer many questions that could not, or should not, be investigated experimentally. There are two types: case-control and cohort. Case-control studies identify patients with the disease of interest (the cases), then compare the frequency with which they are associated with a particular risk factor, and the frequency with which controls (a group similar to cases in many ways, but without the disease) are associated with the same risk factor. Cohort studies follow a group of people with the risk factor from a time prior to the development of the disease, and compare disease frequency in this group with that in another group not exposed to the risk factor. Both types are open to bias, which is briefly discussed. Finding groups of people ''alike'' in all ways but one (the disease) is virtually impossible. In deciding which epidemiologic articles to publish, the editors of The New England Journal of Medicine evaluate several aspects. An exposure that affects the outcome in a major way is more convincing, since it is less likely to have been produced by unknown variables. This is a different matter from statistical significance, which can easily be attained if the sample size is large enough. The effect should be biologically plausible. When clinicians read a new epidemiologic study, they should not rush to advise their patients accordingly, but should wait for confirmation by other investigators. Advice to patients must be tempered by appreciation of individuals' preferences: will a man want to change his eating habits to reduce his risk of cardiovascular disease by 3 percent? On the larger scale of public health, on the other hand, small changes have broad implications. Caution and a good critical sense should guide interpretation of epidemiologic research. (Consumer Summary produced by Reliance Medical Information, Inc.)

Methods, Evaluation, Statistics, Epidemiology

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New ways to get pregnant

Article Abstract:

Recent cases brought before courts of law illustrate the changing context of reproduction. In one case, a divorced couple fought over the disposition of embryos they had created for the purpose of implantation. In another, the genetic parents of a child carried by another woman won custody to the child after a court threatened to send the child to a foster home if the three parents could not resolve the issue: a modern version of King Solomon's dilemma. These cases illustrate the complexity brought about by modern developments in reproductive technology: there are now more ways to get pregnant than there used to be and social strategies have not yet evolved to regulate the consequences. A brief history of these developments is presented, from artificial insemination to in vitro fertilization using sex cells from married couples to the use of cryopreservation (freezing) of embryos - which has raised ethical and legal questions regarding the disposition of cryopreserved embryos. Not only can the genetic ''parents'' change their minds (as in one legal case), but another woman can become the ''mother'' to someone else's offspring (as in the other). Two articles in the October 25, 1990 issue of The New England Journal of Medicine report on techniques that potentially expand reproductive possibilities. One reports on the greater success rate when fresh, rather than previously frozen, embryos are implanted. The other reports successful pregnancies in older women with ovarian failure after implantation of embryos made from younger women's ova. Such developments raise profound questions about what is ''natural.'' In addition, the cost of these technologies will make them inaccessible to all but the affluent. Selling organs is illegal; selling sperm or eggs, however, is not. While the problems raised by the new reproductive technologies are substantial, the fact that they benefit people who desperately desire children cannot be denied. Ultimately, their price may not be too high. (Consumer Summary produced by Reliance Medical Information, Inc.)

Social aspects, Laws, regulations and rules, Ethical aspects, Fertility, Human, Human fertility, Human reproductive technology

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The pharmaceutical industry -- to whom is it accountable?

Article Abstract:

It may be time to regulate the pharmaceutical industry. The pharmaceutical industry is one of the most profitable in the US, earning an 18.6% average return on revenues. Much of the research on new drugs is done at universities and therefore publicly funded. The industry also gets substantial subsidies from the federal government, including the exclusive right to market the drug and charge whatever the market will bear. Many drugs are similar to existing drugs and do not represent breakthrough treatments. New drugs should be compared to existing ones and price controls may be inevitable.

Editorial, Pharmaceutical industry, Prices and rates

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