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Table 1 Characteristics of cases and age-matched controls

From: A population-based case-control study of Selective Serotonin Reuptake Inhibitors (SSRIs) and breast cancer: The impact of duration of use, cumulative dose and latency

Characteristic Cases (N = 1701) Controls (N = 17017) Unadjusted OR a
(95% CI)
  n (%) n (%)  
Age (yrs)      
Mean (SD) 60.4 (11.5) 60.3 (11.6) 1.00 (1.00, 1.01)
Age categories      
<40 (%) 50 (2.9) 500 (2.9) 1.00
40-55 (%) 540 (31.8) 5500 (32.3) 1.01 (0.75, 1.36)
>55 (%) 1111 (65.3) 11017 (64.7) 0.98 (0.73, 1.33)
Follow-up (yrs) b      
Mean (SD) 28.4 (3.3) 28.4 (3.5) 1.03 (1.00, 1.06)
Median (range) 29 (10,31) 29 (10,31)  
Marital Status c      
Other (widowed, separated, divorced) 309 (18.2) 3565 (21.0) 1.00
Single 108 (6.4) 1111 (6.5) 1.12 (0.89, 1.41)
Married 1284 (75.4) 12341 (72.5) 1.20 (1.05, 1.37)
Income support status d      
No income support 1232 (72.4) 12088 (71.0) 1.00
Low income support 412 (24.2) 4235 (24.9) 0.96 (0.85, 1.07)
High income support 57 (3.4) 694 (4.1) 0.81 (0.61, 1.06)
Residence status e      
Urban 731 (43.0) 6984 (41.0) 1.00
Rural 970 (57.0) 10033 (59.0) 0.92 (0.84, 1.02)
OC use f      
None or light use (<12 prescriptions) 1318 (77.5) 13557 (79.7) 1.00
Heavy use (≥ 12) 383 (22.5) 3460 (20.3) 1.14 (1.01, 1.28)
HT use f      
None or light use (<12 prescriptions) 1200 (70.6) 12441 (73.1) 1.00
Heavy use (≥12) 501 (29.4) 4576 (26.9) 1.14 (1.02, 1.27)
  1. OR = odds ratio; CI = confidence interval; OCs = oral contraceptive(s); HT = hormone therapy.
  2. a Frequency-matched on age in five-year groups but not adjusted for the influence of other risk factors.
  3. b Follow-up: Number of years eligible to receive outpatient prescription drug benefits in Saskatchewan.
  4. c Marital status: attributed to the marital state six years prior to index date.
  5. d Income support status: based on yearly demographic data and assigned to one of three categories based on the greatest proportion of time having received income support: that is, no income support, ≤50% of time receiving income support = low income support, and >50% of time receiving income support = high income support.
  6. e Residence status: based on yearly demographic data and assigned based on the greatest proportion of time spent in a given residence state: that is, ≤50% of time in urban location (population >100,000) = rural residence status and >50% of time as urban = urban residence status.
  7. f OC and HT use: defined as total number of prescriptions two or more years prior to index date. These drugs are typically dispensed as a two-month supply; therefore, in most cases, 12 prescriptions would correspond to a two-year supply. All oral and injectable contraceptives were included as were all hormone therapy formulations except vaginal creams and rings.
  8. Note: Percentages may not add up to 100% due to rounding.