Regarding alcohol consumption, participants were asked whether or not they had consumed six or more drinks of beer, wine, or liquor in any given year of their life before an assigned reference date (date of diagnosis for cases and a comparable date for controls) in order to identify women who have rarely consumed alcohol throughout their lives.
'Former smokers' were individuals who quit smoking 1 year or more before the diagnosis date for case patients or selection date for control subjects, whereas 'current smokers' were regularly smoking at the time of their interview or had quit < 1 year before the reference date.
Women were considered postmenopausal if they had self-reported their last menstrual bleeding being at least 12 months before the reference date or had undergone a bilateral oophorectomy.
Women who reported their last natural menstrual bleeding at least 12 months before the reference date (age at diagnosis and recruitment for cases and controls, respectively), a bilateral oophorectomy, or cessation of menses because of radiation or chemotherapy were defined as postmenopausal.
We computed odds ratios (ORs) and their 95% confidence intervals (CIs) for bladder cancer associated with the use of glucocorticoids before the reference date using unconditional logistic regression, taking into account multiple confounding factors (Breslow and Day, 1980).
In their studies, Hardell and colleagues disregarded mobile and cordless phone use within the last year before the reference date.
Veterans who had experienced head injuries during the last 15years before the reference date had an adjusted odds ratio of 2.33 (95% confidence interval 1.18-4.61), relatoveteransterans without any head injuries.
We excluded exposures occurring 2, 10, or 20 years before the reference date.
Therefore each analysis was repeated for exposures beginning at least 10 years before the reference date.
