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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.