Table 1.
Descriptive characteristics of breast cancer cases and controls, Washington County, MD
| Cases N =321 % |
Controls N =321 % |
OR1(95% CI2) | |
|---|---|---|---|
| Age (yrs3) at baseline | |||
| Mean (SD4) | 56.8 (12.4) | 56.6 (12.3) | 1.16 (0.98,1.37) |
| Race | |||
| White | 99 | 99 | N/A |
| Black | 1 | 1 | |
| Other | <1 | ||
| BMI5 at baseline (kg/m2) | |||
| < 25 | 42 | 50 | 1.0 |
| 25 – 29.9 | 34 | 31 | 1.39 (0.96,1.99) |
| ≥ 30 | 24 | 19 | 1.60 (1.04,2.45) |
| P trend = 0.02 | |||
| Smoking | |||
| Never | 62 | 65 | 1.0 |
| Former | 25 | 20 | 1.27 (0.87,1.85) |
| Current | 13 | 15 | 0.84 (0.52,1.36) |
| P trend = 0.91 | |||
| Education (grade) | |||
| <12 | 24 | 29 | 1.0 |
| =12 | 42 | 41 | 1.23 (0.82,1.84) |
| >12 | 34 | 30 | 1.39 (0.91,2.11) |
| >12 | 34 | 30 | P trend = 0.13 |
| Marital Status | |||
| Never Married | 5 | 5 | 1.0 |
| Married now | 73 | 68 | 1.09 (0.53,2.27) |
| Other | 22 | 27 | 0.84 (0.39,1.79) |
| Missing | <1 | P trend = 0.27 | |
| Ever pregnant | |||
| No | 12 | 8 | 1.0 |
| Yes | 68 | 68 | 0.61 (0.33,1.11) |
| Missing | 20 | 24 | |
| Age at first birth (yrs3) | |||
| Nulliparous | 12 | 8 | 1.0 |
| <20 | 18 | 17 | 0.61 (0.30,1.24) |
| 20–24 | 32 | 31 | 0.62 (0.32,1.20) |
| 25–29 | 15 | 14 | 0.71 (0.34,1.49) |
| ≥ 30 | 3 | 5 | 0.41 (0.13,1.29) |
| Missing | 20 | 25 | P trend = 0.26 |
| Months breast feeding | |||
| None | 43 | 40 | 1.0 |
| 1–6 | 9 | 10 | 0.87 (0.42,1.77) |
| >6 | 15 | 18 | 0.79 (0.45,1.41) |
| Missing | 33 | 32 | P trend = 0.43 |
| Age at menarche (yrs3) | |||
| <12 | 13 | 15 | 1.0 |
| 12–13 | 48 | 39 | 1.80 (1.02,3.16) |
| >13 | 19 | 22 | 1.17 (0.63,2.16) |
| Missing | 20 | 24 | P trend = 1 |
| Oral contraceptive use | |||
| Never | 74 | 75 | 1.0 |
| Former | 25 | 21 | 1.26 (0.80,2.00) |
| Current | 1 | 3 | 0.57 (0.17,1.95) |
| Missing | 1 | P trend = 0.3 | |
| Other hormone use | |||
| Never | 79 | 78 | 1.0 |
| Former | 9 | 12 | 0.79 (0.46,1.35) |
| Current estrogen and/or | 11 | 8 | 1.30 (0.71,2.37) |
| progesterone use | |||
| Missing | 1 | 2 | P trend = 0.4 |
|
Maternal Family history (1st & 2nd degree relatives) | |||
| No | 63 | 71 | 1.0 |
| Yes | 20 | 9 | 2.32 (1.35,3.97) |
| Missing | 17 | 20 | |
|
Menopausal status at baseline |
26 | 29 | 1.0 |
| Pre-menopausal | 71 | 70 | 2.00 (0.37,10.9) |
| Post-menopausal | 3 | 1 | |
| Missing | |||
1
OR = odds ratios that were calculated using conditional logistic regression.
2
CI = confidence interval.
3
yrs = years,
4
SD= standard deviation.
5
BMI = body mass index (kg/m2) calculated from self reported height and weight measurements.