This means their figures include some deaths that occurred in years prior to the reference year (approximately 4%).
We evaluated potential confounding by PSA screening during the 5 years prior to the reference year among the cases and controls from the SFBA study site, for whom we had data on PSA screening.
For example, the estimated effect of −2.232 for the low track on the whole sample indicates that low track students are more likely to get a positive count of VET years, compared to the reference case of high track students.
All subjects were required to have at least one non-diabetes diagnosis or electronic code documenting a well-visit from a Marshfield Clinic provider in at least one of the three calendar years prior to the reference date.
As exposure to ionising radiation is a known risk factor for acoustic neuroma, we repeated the analysis after excluding subjects who reported having had radiotherapy more than 10 years prior to the reference date.
The relative risk for more than 82 h (82=median) of analogue use in the period 10 or more years prior to the reference date was 1.5 (95% CI: 0.9 2.5) (data not shown).
The finding that meningioma risk is increased among women who were postmenopausal on the reference date, but decreased among women who were postmenopausal 10 years prior to the reference date is curious and could be due to chance given the number of comparisons made.
Orchitis diagnosed more than 1 year prior to the reference age was not associated with risk (OR: 1.17; 95% CI: 0.71 1.94).
Diet in the year prior to the reference date was assessed with the National Cancer Institute's self-administered Diet History Questionnaire, previously adapted for use in Canada [ 36].
