American journal of epidemiology
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Tests for overall trend, such as the Mantel extension test, are not tests for monotonic dose response. A survey of epidemiologic articles shows widespread misinterpretation of the Mantel extension test and overstatement of evidence for monotonic dose response when there are few exposed subjects. To properly evaluate the hypothesis that risk continues to increase with further increases in exposure, one must examine several statistics and estimates. Given sufficient data, nonparametric or polynomial regression analyses can provide more detailed dose-response information.
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Comparative Study
Homicide and the prevalence of handguns: Canada and the United States, 1976 to 1980.
As compared with Americans, Canadians in the 1970s possessed one tenth as many handguns per capita. To assess whether this affected the total criminal homicide rate, the mean annual criminal homicide rates of Canadian provinces were compared with those of adjoining US states for the period of 1976 to 1980. ⋯ Major differences in the prevalence of handguns have not resulted in differing total criminal homicide rates in Canadian provinces and adjoining US states. The similar rates of criminal homicide are primarily attributable to underlying similar rates of aggravated assault.
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Emergency medical services with advanced life support systems were implemented in the Minneapolis-St. Paul, Minnesota, area in the mid-1970s. To assess the impact of emergency medical services on coronary heart disease mortality, the authors reviewed ambulance records and hospital emergency room logs for possible out-of-hospital cardiac arrest cases in the period 1972-1982. ⋯ Coronary heart disease mortality rates declined in that period by 34.9% for men (from 527.5 per 100,000 to 343.3 per 100,000) and by 41.7% for women (from 168.6 per 100,000 to 98.3 per 100,000). The authors estimate that improved survival from out-of-hospital cardiac arrest contributed 5.4% (9.9 of 184.2) of the mortality decline for men and 4.3% (3.0 of 70.3) of the decline for women. This was a significant contribution to the decline in coronary heart disease mortality, but it explains only a small part of it.
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This paper describes how and why John Snow's investigation of the transmission of cholera grew into an epidemiologic classic. The evolution of the interpretation of the work of John Snow was first studied in depth in the Dutch medical literature, and thereafter traced more superficially in the bacteriologic, hygienic, and epidemiologic literature of Germany, the United Kingdom, and the United States. ⋯ Frost was responsible for the revival of the work of John Snow in the 1930s. Besides the obvious and enjoyable clarity of thinking and reasoning, epidemiologically and medically, of the writings of John Snow, his example well suited epidemiology of the 1930s since his convictions came very close to the bacteriologic paradigm of the day.
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In August 1988, an estimated 3,175 women who attended a 5-day outdoor music festival in Michigan became ill with gastroenteritis caused by Shigella sonnei. Onset of illness peaked 2 days after the festival ended, and patients were spread throughout the United States by the time the outbreak was recognized. An uncooked tofu salad served on the last day was implicated as the outbreak vehicle (odds ratio = 3.4, p less than 0.0001). ⋯ S. sonnei isolated from women who became ill before, during, and after the festival had identical antimicrobial susceptibility patterns and plasmid profiles. Limited access to soap and running water for handwashing was one of the few sanitary deficits noted at this gathering. This investigation demonstrates the need for surveillance and prompt public health intervention when Shigella infections are recognized in persons attending mass outdoor gatherings, the singular importance of handwashing in reducing secondary transmission of shigellosis, and the potential for explosive outbreaks when communal meals are prepared by large numbers of food handlers.