From: Risk factors for breast cancer in Iran: a case-control study
 | Number (%)* |  |  | |
---|---|---|---|---|
Parameter | Cases (n = 286) | Controls (n = 249) | OR (95% CI) | P |
Age groups (years) | Â | Â | Â | Â |
   = 39 | 87 (30.4) | 101 (40.6) | 1.00 (ref.) |  |
   40-49 | 84 (29.4) | 68 (27.3) | 1.43 (0.93-2.20) | 0.10 |
   50-59 | 57 (19.9) | 44 (17.7) | 1.50 (0.92-2.45) | 0.10 |
   = 60 | 58 (20.3) | 36 (14.5) | 1.87 (1.13-3.10) | 0.02 |
   Mean ± SD | 47.5 (12.8) | 44.2 (13.2) |  |  |
   Median (range) | 46.0 (24-81) | 43.0 (23-80) |  |  |
Educational level | Â | Â | Â | Â |
   Illiterate | 87 (30.4) | 91 (36.5) | 1.00 (ref.) |  |
   Primary | 113 (39.5) | 100 (40.2) | 1.18 (0.79-1.76) | 0.41 |
   Secondary | 60 (21.0) | 42 (16.9) | 1.49 (0.91-2.44) | 0.11 |
   University | 26 (9.1) | 16 (6.4) | 1.70 (0.85-3.38) | 0.13 |
Marital status | Â | Â | Â | Â |
   Married | 205 (71.7) | 209 (83.9) | 1.00 (ref.) |  |
   Widowed/divorced | 56 (19.6) | 34 (13.7) | 1.68 (1.05-2.68) | 0.03 |
   Never married | 25 (8.7) | 6 (2.4) | 4.25 (1.71-10.57) | 0.002 |
Family history of breast cancer | Â | Â | Â | Â |
   No | 267 (93.4) | 243 (97.6) | 1.00 (ref.) |  |
   Yes | 19 (6.6) | 6 (2.4) | 2.87 (1.13-7.30) | 0.03 |
Age at menarche (years) | Â | Â | Â | Â |
   = 12 | 72 (25.2) | 62 (24.9) | 1.20 (0.74-1.95) | 0.47 |
   13 | 78 (27.3) | 63 (25.3) | 1.28 (0.79-2.1) | 0.32 |
   14 | 74 (25.9) | 60 (24.1) | 1.27 (0.78-2.1) | 0.33 |
   = 15 | 62 (21.7) | 64 (25.7) | 1.00 (ref.) |  |
   Mean ± SD | 13.4 (1.5) | 13.5 (1.7) |  |  |
   Median (range) | 13.0 (9-18) | 13.0 (9-19) |  |  |
Parity | Â | Â | Â | Â |
   Parous | 249 (87.1) | 235 (94.4) | 1.00 (ref.) |  |
   Nulliparous | 37 (12.9) | 14 (5.6) | 2.78 (1.45-5.35) | 0.002 |
Age at first full term pregnancy (years) | Â | Â | Â | Â |
   <20 | 127 (51.0) | 131 (55.7) | 1.00 (ref.) |  |
   20-24 | 71 (28.5) | 72 (30.6) | 1.02 (0.68-1.53) | 0.93 |
   25-29 | 39 (15.7) | 27 (11.5) | 1.49 (0.86-2.58) | 0.15 |
   = 30 | 12 (4.8) | 5 (2.1) | 2.47 (0.84-7.22) | 0.10 |
   Mean ± SD | 20.5 (5.2) | 19.4 (4.3) |  |  |
   Median (range) | 19.0 (11-45) | 19.0 (10-35) |  |  |
Age at last full term pregnancy (years) | Â | Â | Â | Â |
   = 29 | 82 (32.9) | 85 (36.2) | 1.00 (ref.) |  |
   30-34 | 69 (27.7) | 70 (29.8) | 1.02 (0.65-1.60) | 0.92 |
   35-39 | 62 (24.9) | 49 (20.9) | 1.31 (0.81-2.12) | 0.27 |
   = 40 | 36 (14.5) | 31 (13.2) | 1.20 (0.68-2.12) | 0.52 |
   Mean ± SD | 32.5 (6.4) | 31.6 (6.9) |  |  |
   Median (range) | 32.0 (17-49) | 32.0 (15-51) |  |  |
Menopausal status | Â | Â | Â | Â |
   Premenopausal | 186 (65.0) | 180 (72.3) | 1.00 (ref.) |  |
   Postmenopasual | 100 (35.0) | 69 (27.7) | 1.40 (0.97-2.03) | 0.07 |
Age at menopause (years) | Â | Â | Â | Â |
   <50 | 42 (42) | 37 (53.6) | 1.00 (ref.) |  |
   = 50 | 58 (58) | 32 (46.4) | 1.60 (0.86-2.96) | 0.14 |
   Mean ± SD | 49.9 (4.9) | 48.0 (5.2) |  |  |
   Median (range) | 50.0 (36-70) | 48.0 (36-60) |  |  |
Oral contraceptive use | Â | Â | Â | Â |
   No | 279 (97.6) | 240 (96.4) | 1.00 (ref.) |  |
   Yes | 7 (2.4) | 9 (3.6) | 0.67 (0.25-1.82) | 0.43 |