Epidemiologic Reviews Copyright © 1991 by The Johns Hopkins University School of Hygiene and Public Health All rights reserved
Vol. 13, 1991 Printed in U.S. A.
Toxic Shock Syndrome and Tampons
Anne Schuchat1 and Claire V. Broome2
In May 1980, state investigators reported in Morbidity and Mortality Weekly Report (1) 55 cases of toxic shock syndrome, a severe multisystem disease first described by Todd et al. (2) in 1978. The cases occurred predominantly among healthy young women, most of whom were menstruating during the onset of their illness. The subsequent need to determine risk factors for the pathogenesis of menstrual toxic shock syndrome challenged investigators to conduct epidemiologic studies rapidly in the midst of substantial attention from the media and the public. The first case-control studies, reported in June 1980, associated the risk of toxic shock syndrome with the use of tampons (3-5). Subsequently, the use of Rely brand tampons (Procter and Gamble, Cincinnati, Ohio) in particular (5-7) and the use of high-absorbency tampons of any brand (7-9) were identified as risk factors for toxic shock syndrome. However, the results of these studies have been the subject of substantial controversy (10-14). Ten years after the first studies of tamponassociated risk factors for toxic shock syn-
drome, the number of cases reported to the Centers for Disease Control (CDC) has decreased markedly (figure 1). Trends in the occurrence of a disease must be interpreted in the context of the reporting systems by which disease surveillance is accomplished. The decrease in cases of toxic shock syndrome might merely reflect changes in reporting; alternatively, a true decrease in incidence could have occurred. In this review, we will develop the position that the trends observed in toxic shock syndrome surveillance reflect a true decrease in the incidence of menstrual toxic shock syndrome; that temporal changes in tampon absorbency, composition, and usage patterns contributed to the decreased incidence of menstrual toxic shock syndrome; and that the observed trends in disease occurrence are consistent with the findings of the initial case-control studies that identified risk factors for toxic shock syndrome. We suggest that methodological biases that may have affected the early studies did not limit the generalizability of the results or the impact of the studies' conclusions on the public health. CASE-CONTROL STUDIES
Received for publication January 15, 1991, and in final form May 24, 1991. Abbreviations: CDC, Centers for Disease Control; Cl, confidence interval; FDA, Food and Drug Administration; OR, odds ratio; TSST-1, toxic shock syndrome toxin-1. 1 Meningitis and Special Pathogens Branch, Division of Bacterial and Mycotic Diseases, National Center for Infectious Diseases, Centers for Disease Control, Atlanta, GA. 2 Office of the Director, Centers for Disease Control, Atlanta, GA. Reprint requests to Dr. Anne Schuchat, Meningitis and Special Pathogens Branch, Division of Bacterial and Mycotic Diseases, National Center for Infectious Diseases, Mailstop C09, Centers for Disease Control, Atlanta, GA 30333. The authors are grateful to Allen Hightower and Ray Ransom for consultation and assistance.
Investigations were conducted individually or collaboratively by the State Health Departments of Wisconsin, Minnesota, Utah, and Iowa, in addition to national studies conducted by the CDC (3-7). Preliminary findings of the first three studies— Wisconsin, Utah, and CDC-I—reported in the June 29, 1980, issue of Morbidity and Mortality Weekly Report, described an association between the use of tampons and the risk of toxic shock syndrome (15). Although the results of the three studies were 99
100
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Vol. 13, 1991 Printed in U.S. A.
Toxic Shock Syndrome and Tampons
Anne Schuchat1 and Claire V. Broome2
In May 1980, state investigators reported in Morbidity and Mortality Weekly Report (1) 55 cases of toxic shock syndrome, a severe multisystem disease first described by Todd et al. (2) in 1978. The cases occurred predominantly among healthy young women, most of whom were menstruating during the onset of their illness. The subsequent need to determine risk factors for the pathogenesis of menstrual toxic shock syndrome challenged investigators to conduct epidemiologic studies rapidly in the midst of substantial attention from the media and the public. The first case-control studies, reported in June 1980, associated the risk of toxic shock syndrome with the use of tampons (3-5). Subsequently, the use of Rely brand tampons (Procter and Gamble, Cincinnati, Ohio) in particular (5-7) and the use of high-absorbency tampons of any brand (7-9) were identified as risk factors for toxic shock syndrome. However, the results of these studies have been the subject of substantial controversy (10-14). Ten years after the first studies of tamponassociated risk factors for toxic shock syn-
drome, the number of cases reported to the Centers for Disease Control (CDC) has decreased markedly (figure 1). Trends in the occurrence of a disease must be interpreted in the context of the reporting systems by which disease surveillance is accomplished. The decrease in cases of toxic shock syndrome might merely reflect changes in reporting; alternatively, a true decrease in incidence could have occurred. In this review, we will develop the position that the trends observed in toxic shock syndrome surveillance reflect a true decrease in the incidence of menstrual toxic shock syndrome; that temporal changes in tampon absorbency, composition, and usage patterns contributed to the decreased incidence of menstrual toxic shock syndrome; and that the observed trends in disease occurrence are consistent with the findings of the initial case-control studies that identified risk factors for toxic shock syndrome. We suggest that methodological biases that may have affected the early studies did not limit the generalizability of the results or the impact of the studies' conclusions on the public health. CASE-CONTROL STUDIES
Received for publication January 15, 1991, and in final form May 24, 1991. Abbreviations: CDC, Centers for Disease Control; Cl, confidence interval; FDA, Food and Drug Administration; OR, odds ratio; TSST-1, toxic shock syndrome toxin-1. 1 Meningitis and Special Pathogens Branch, Division of Bacterial and Mycotic Diseases, National Center for Infectious Diseases, Centers for Disease Control, Atlanta, GA. 2 Office of the Director, Centers for Disease Control, Atlanta, GA. Reprint requests to Dr. Anne Schuchat, Meningitis and Special Pathogens Branch, Division of Bacterial and Mycotic Diseases, National Center for Infectious Diseases, Mailstop C09, Centers for Disease Control, Atlanta, GA 30333. The authors are grateful to Allen Hightower and Ray Ransom for consultation and assistance.
Investigations were conducted individually or collaboratively by the State Health Departments of Wisconsin, Minnesota, Utah, and Iowa, in addition to national studies conducted by the CDC (3-7). Preliminary findings of the first three studies— Wisconsin, Utah, and CDC-I—reported in the June 29, 1980, issue of Morbidity and Mortality Weekly Report, described an association between the use of tampons and the risk of toxic shock syndrome (15). Although the results of the three studies were 99
100
Schuchat and Broome 350
300 Rely withdrawn 9/80
250
y) 200
