Everything you do on the social network contributes, in one way or the other, to your being categorized ever more specifically.
We categorized ever smokers according to current and former smoking status at enrollment.
A recording of insulin use during the study year was categorized "ever" or "never" on the basis of prescription orders for any insulin product.
We categorized ever smokers according to current and former smoking status, age at smoking initiation, smoking duration, average number of cigarettes smoked daily, pack-years of smoking (i.e., number of cigarettes smoked per day, divided by 20, multiplied by the number of years smoked), and latency (i.e., age at enrolment in the study minus age at smoking initiation) all at enrolment.
When we categorized ever smokers by whether they were current or past smokers, the OR for the association between breast cancer risk and three or more GST variants was 0.62 (95% CI, 0.27 1.43) among current smokers, and 1.66 (95% CI, 0.93 2.97) among past smokers, compared with never smokers with all four common alleles.
We further categorized ever smokers according to the following factors: age at smoking initiation (≤16, 17 19, 20 24, ≥25 years), numbers of cigarettes smoked per day (1 9, 10 19, ≥20), smoking duration in years (1 19, 20 29, 30 39, ≥40) and number of pack-years (i.e., number of cigarettes smoked per day, divided by 20, multiplied by the duration of smoking in years; 0 9, 10 19, ≥20).
Smoking status was categorized as "ever" or "never".
Treatment with TNF-alpha inhibitors was categorized as ever exposed versus never exposed.
Breastfeeding was categorized as ever versus never, and ≤1 month, 2-3, 4–6, 7 12, 13 17 and ≥18 months for total cumulative duration of breastfeeding.
Eligible cohort members were categorized as "ever users" of glargine or NPH if they filled at least two prescriptions for the specific drug within a 6-month period.
Smoking was categorized as ever smoked versus never smoked, and BMI was computed as weight in kilograms divided by height in meters squared.
