Table 1.
Characteristics of cases and controls. Values are mean (SD) unless stated otherwise
| Variable | Breast cancer group (n=106) | Control group (n=226) | P value |
|---|---|---|---|
| Age | 61.6 (10.9) | 51.0 (8.5) | 0.000* |
| Social class† (%): | |||
| I | 10 (10) | 20 (9) | 0.094‡ |
| II | 38 (36) | 82 (36) | |
| III non-manual | 28 (26) | 72 (32) | |
| III manual | 13 (12) | 24 (11) | |
| IV | 11 (10) | 21 (9) | |
| V | 3 (3) | 2 (1) | |
| VI | 3 (3) | 4 (2) | |
| No of children (%): | |||
| 0 | 15 (14) | 31 (14) | |
| 1 | 16 (15) | 31 (13.7) | 0.97 |
| 2 | 42 (40) | 84 (37) | |
| ⩾3 | 32 (31)† | 80 (35) | |
| Age at birth of first child | 21.3 (5.6) | 20.5 (4.3) | 0.500* |
| Age at menarche | 12.8 (1.4) | 13.0 (1.6) | 0.200* |
| Menopausal state (%): | |||
| Premenopausal | 14 (13) | 66 (29) | 0.000§ |
| Perimenopausal | 9 (9) | 43 (19) | |
| Postmenopausal | 83 (78) | 117 (52) | |
| Age at menopause | 47.7 (4.5) | 45.6 (5.2) | 0.001* |
| Lifetime use of oral contraceptives (%) | 38 | 61 | 0.000‡ |
| No of years taking oral contraceptives | 3.0 (5.4) | 4.2 (5.0) | 0.065§ |
| No of months breastfeeding | (n=90) | (n=195) | |
| 7.4 (9.9) | 7.4 (12.1) | 0.990* | |
| Lifetime use of hormone replacement therapy (%) | 29 (27) | 78 (35) | 0.193§ |
| Mean years of hormone replacement therapy | 1.6 (3.7) | 1.9 (4.0) | 0.460* |
| Family history of ovarian cancer (%) | 8 (8) | 10 (4) | 0.241§ |
| History of benign breast disease (%) | 15 (15) | 105 (47) | 0.000§ |
| Family history of breast cancer¶ (%) | 16 (15) | 35 (16) | 0.997§ |
| Units of alcohol/week (%): | |||
| 0 | 38 (36) | 59 (26) | 0.927‡ |
| 0-4 | 26 (25) | 71 (31) | |
| 5-9 | 20 (19) | 52 (23) | |
| ⩾10 | 22 (21) | 44 (20) | |
| No of cigarettes/day: | |||
| 0 | 83 (78.3) | 170 (75.2) | 0.383‡ |
| 1-9 | 8 (7.6) | 14 (6.2) | |
| ⩾10 | 15 (14.2) | 42 (18.6) | |
| Body mass index (kg/m2) | 26.8 (5.5) | 24.8 (4.2) | 0.001* |
*
Two sample t test.
†
Data for one case missing.
‡
χ2 test for trend.
§
χ2 test.
¶
No data for one control.