Summary Data from a population-based case-control study conducted (Stanford et al., 1986). Complete absence of overlap between risk factors for the two types of breast cancer would provide evidence against a progression from one to the other, while overlap would suggest either that there is a progression or that they are independent outcomes with overlapping aetiologies. The few case-control studies conducted to date (Hildreth et al., 1983;McTiernan et al., 1986;Hislop et al., 1986Hislop et al., , 1988Stanford et al., 1987) suggest that there is some overlap in risk factors for ER+ and ER-breast cancer. This possibility, and the others outlined above, are investigated further in the population-based case-control study reported here, in which risk of ER+ and ER -breast cancer is examined in association with menstrual and reproductive history, dietary intake and other factors. Materials and methods Study subjectsA detailed description of the study methods has been presented elsewhere (Rohan et al., 1988 of breast cancer, who were also resident in the Adelaide metropolitan area and who were registered on the electoral roll. (In South Australia, 97.2% of persons eligible to vote are registered (Australian Electoral Office, 1983).) For each case, one control, matched as closely as possible to the age of the case at diagnosis, was selected at random from the electoral roll. A total of 648 individuals were approached in order to enrol 451 controls. The total study population therefore comprised 451 case-control pairs. Reasons for nonparticipation were recorded during the recruitment of the first 100 controls, which required attempting to recruit 151 persons. Of the 51 who did not participate, 39 refused, 11 were untraceable and one had died.Data collection procedure Subjects were interviewed in their own homes by trained interviewers whose performance was monitored regularly. Interviewers were assigned randomly to case-control pairs. For cases, the average interval between diagnosis and interview was 4.8 months. Each control was interviewed as soon as possible after her case had been enrolled and in a few instances interview of the control preceded that of her case. Approximately 90% of controls were interviewed within two months of the corresponding case. Matching on date of interview was introduced in an attempt to minimise dietary differences between cases and controls due to seasonal influences.Socio-demographic and medical information was collected by use of an interviewer-administered questionnaire which sought basic biographic information, personal medical history, family history of cancer, gynaecological and reproductive history and history of hormone use.Information on usual dietary intake was collected from the study participants by means of a self-administered quantitative food frequency questionnaire. The questionnaire, which was designed to ascertain total daily intake of energy, several nutrients, alcohol and methylxanthines, has been described in detail elsewhere (Baghurst & Baghurst, 1981;Baghurst an...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.