Margaret A.WinkerMD, Senior EditorIndividualAuthorPhil B.FontanarosaMD, Senior EditorIndividualAuthor
In Reply: Ever since the pioneering work of the English sanitarians, such as William Farr, looking at patterns of health and disease in large populations for clues to causes has been a touchstone of epidemiology. Analyses of these patterns can provide the basis for devising hypotheses but can neither prove nor refute such speculation. Thus, increases in lung cancer and heart disease in the general population were hypothesized to reflect changes in cigarette smoking, but this link was only confirmed by more detailed studies. Mr James and Dr Lancaster and Mr Day correctly note that shifts in health patterns in entire populations can seldom be attributed to specific agents. Viewed in this context, the examination of population trends, such as the decline in sex ratio and increases in testicular cancer and male birth defects, can serve as sentinel indicators of potentially avoidable underlying causes. As a modern pioneer in the analysis of sex ratio, James notes that alterations in the offspring sex ratio of selected groups with occupational or medical exposures can be a useful technique for identifying reproductive hazards.
Davis DL, Gottlieb M, Stampnitzky J. Declines in Population Sex Ratios at Birth—Reply. JAMA. 1998;280(13):1139-1141. doi:10-1001/pubs.JAMA-ISSN-0098-7484-280-13-jbk1007