Table 2.
Multivariatea comparisons of personal and family health history, socioeconomic, and other characteristics of women with breast cancer and controls in Marin County, California, 1997–99
| All women | Women aged 50 years and over | Women under 50 years of age | |||||||||
| Variable | (Total N)a | Cases N (%)(285) | Controls N (%)(286) | Multivariate OR (95% CI) | Cases N (%)(201) | Controls N (%)(201) | Multivariate OR (95% CI) | Cases N (%)(84) | Controls N (%)(85) | Multivariate OR (95% CI) | |
| Personal and family health history | |||||||||||
| First-degree relative with breast cancer | |||||||||||
| No | 231 (81.1) | 230 (80.4) | 1.0 | 162 (80.6) | 157 (78.1) | 1.0 | 69 (82.1) | 73 (85.9) | 1.0 | ||
| Yes | 54 (18.9) | 56 (19.6) | 0.95 (0.58–1.5) | 39 (19.4) | 44 (21.9) | 0.84 (0.47–1.5) | 15 (17.9) | 12 (14.1) | 1.3 (0.40–4.0) | ||
| Benign biopsy history | |||||||||||
| None | 196 (68.8) | 213 (74.5) | 1.0 | 128 (63.7) | 145 (72.1) | 1.0 | 68 (81.0) | 68 (80.0) | 1.0 | ||
| Fine-needle aspiration only | 16 (5.6) | 19 (6.6) | 0.74 (0.34–1.6) | 14 (7.0) | 10 (5.0) | 1.4 (0.48–3.8) | 2 (2.4) | 9 (10.6) | 0.13 (0.02–0.98) | ||
| Surgical biopsyb | 73 (25.6) | 54 (18.9) | 1.1 (0.66–1.7) | 59 (29.4) | 46 (22.9) | 0.97 (0.56–1.7) | 14 (16.7) | 8 (9.4) | 0.78 (0.22–2.9) | ||
| Previous radiation treatment | |||||||||||
| No | 252 (88.4) | 266 (93.0) | 1.0 | 174 (86.6) | 185 (92.0) | 1.0 | 78 (92.9) | 81 (95.3) | 1.0 | ||
| Yes | 33 (11.6) | 20 (7.0) | 1.7 (0.89–3.3) | 27 (13.4) | 16 (8.0) | 1.6 (0.76–3.5) | 6 (7.1) | 4 (4.7) | 6.1 (1.1–34.9) | ||
| Age at menarche | |||||||||||
| 15 or more years old | 18 (6.3) | 26 (9.1) | 1.0 | 14 (7.0) | 18 (9.0) | 1.0 | 4 (4.8) | 8 (9.4) | 1.0 | ||
| 12–14 years old | 220 (77.2) | 197 (68.9) | 1.5 (0.74–3.1) | 152 (75.6) | 132 (65.7) | 1.3 (0.52–3.1) | 68 (81.0) | 65 (76.5) | 2.6 (0.53–12.5) | ||
| 11 or less years old | 47 (16.5) | 63 (22.0) | 1.2 (0.51–2.6) | 35 (17.4) | 51 (25.4) | 0.74 (0.27–2.0) | 12 (14.3) | 12 (14.1) | 2.5 (0.37–16.5) | ||
| Menopause status | |||||||||||
| Premenopausal | 81 (28.4) | 66 (23.1) | 1.0 | 13 (6.5) | 7 (3.5) | 1.0 | 68 (81.0) | 59 (69.4) | 1.0 | ||
| Perimenopausal | 29 (10.2) | 31 (10.8) | 0.52 (0.26–1.0) | 19 (9.5) | 13 (6.5) | 0.76 (0.19–3.0) | 10 (11.9) | 18 (21.2) | 0.17 (0.05–0.59) | ||
| Postmenopausal | 175 (61.4) | 189 (66.1) | 0.40 (0.19–0.84) | 169 (84.1) | 181 (90.0) | 0.45 (0.14–1.5) | 6 (7.1) | 8 (9.4) | 0.38 (0.06–2.3) | ||
| Reproductive history | |||||||||||
| Never pregnant | 45 (15.8) | 51 (17.8) | 1.0 | 23 (11.4) | 38 (18.9) | 1.0 | 22 (26.2) | 13 (15.3) | 1.0 | ||
| Pregnant, no birth | 27 (9.5) | 23 (8.0) | 1.4 (0.65–3.0) | 15 (7.5) | 11 (5.5) | 2.2 (0.75–6.3) | 12 (14.3) | 12 (14.1) | 0.52 (0.12–2.4) | ||
| Birth, did not breastfeed | 57 (20.0) | 33 (11.5) | 1.9 (0.97–3.9) | 53 (26.4) | 30 (14.9) | 2.6 (1.1–5.8) | 4 (4.8) | 3 (3.5) | 1.9 (0.22–16.0) | ||
| Breastfed | 156 (54.7) | 179 (62.6) | 0.98 (0.58–1.7) | 110 (54.7) | 122 (60.7) | 1.4 (0.68–2.7) | 46 (54.8) | 57 (67.1) | 0.35 (0.11–1.1) | ||
| Reproductive history, recategorization of those who had given birth versus never pregnanta | |||||||||||
| One birth | 53 (18.6) | 55 (19.2) | 1.0 (0.54–2.0) | 36 (17.9) | 33 (16.4) | 1.4 (0.62–3.4) | 17 (20.2) | 22 (25.9) | 0.36 (0.09–1.4) | ||
| Two births | 86 (30.2) | 88 (30.8) | 1.1 (0.59–1.9) | 61 (30.3) | 60 (29.9) | 1.4 (0.66–3.0) | 25 (29.8) | 28 (32.9) | 0.51 (0.15–1.8) | ||
| Three or more births | 74 (26.0) | 69 (24.1) | 1.3 (0.68–2.4) | 66 (32.8) | 59 (29.4) | 1.9 (0.89–4.1) | 8 (9.5) | 10 (11.8) | 0.18 (0.04–0.90) | ||
| Reproductive history, recategorization of those who had breastfed versus never pregnanta | |||||||||||
| Breastfed 6 months or less | 62 (21.8) | 71 (24.8) | 0.87 (0.47–1.6) | 50 (24.9) | 54 (26.9) | 1.2 (0.57–2.7) | 12 (14.3) | 17 (20.0) | 0.40 (0.1–1.7) | ||
| Breastfed 7–12 months | 41 (14.4) | 42 (14.7) | 1.3 (0.65–2.6) | 26 (12.9) | 29 (14.4) | 1.6 (0.65–3.8) | 15 (17.9) | 13 (15.3) | 0.54 (0.14–2.1) | ||
| Breastfed more than 12 months | 53 (18.6) | 66 (23.1) | 0.92 (0.49–1.7) | 34 (16.9) | 39 (19.4) | 1.4 (0.61–3.3) | 19 (22.6) | 27 (31.8) | 0.22 (0.06–0.83) | ||
| Oral contraceptive use | |||||||||||
| Never | 68 (23.9) | 42 (14.7) | 1.0 | 55 (27.4) | 37 (18.4) | 1.0 | 13 (15.5) | 5 (5.9) | 1.0 | ||
| Ever | 217 (76.1) | 244 (85.3) | 0.43 (0.26–0.72) | 146 (72.6) | 164 (81.6) | 0.41 (0.22–0.75) | 71 (84.5) | 80 (94.1) | 0.15 (0.03–0.65) | ||
| Hormone replacement therapy (HRT) | |||||||||||
| None | 129 (45.3) | 126 (44.1) | 1.0 | 58 (28.9) | 60 (29.9) | 1.0 | 71 (84.5) | 66 (77.6) | 1.0 | ||
| Combination therapy | 101 (35.4) | 103 (36.0) | 0.93 (0.55–1.6) | 96 (47.8) | 94 (46.8) | 0.99 (0.54–1.8) | 5 (6.0) | 9 (10.6) | 0.47 (0.08–2.7) | ||
| Other HRTc | 55 (19.3) | 57 (19.9) | 0.96 (0.55–1.7) | 47 (23.4) | 47 (23.4) | 1.1 (0.54–2.1) | 8 (9.5) | 10 (11.8) | 0.75 (0.17–3.4) | ||
| Highest body mass index (BMI) after age 21 daysd | |||||||||||
| BMI < 25 | 184 (64.6) | 141 (49.3) | 1.0 | 124 (61.7) | 89 (44.3) | 1.0 | 60 (71.4) | 52 (61.2) | 1.0 | ||
| 25 ≤ BMI < 30 | 66 (23.2) | 84 (29.4) | 0.53 (0.34–0.84) | 49 (24.4) | 62 (30.8) | 0.47 (0.27–0.83) | 17 (20.2) | 22 (25.9) | 0.52 (0.19–1.4) | ||
| BMI ≥ 30 | 35 (12.3) | 61 (21.3) | 0.38 (0.22–0.66) | 28 (13.9) | 50 (24.9) | 0.29 (0.15–0.57) | 7 (8.3) | 11 (12.9) | 0.30 (0.08–1.2) | ||
| P for trende | 0.0003 | 0.0008 | 0.05 | ||||||||
| Number of mammograms, 1990–94 | |||||||||||
| Less than four | 98 (34.4) | 145 (50.7) | 1.0 | 36 (17.9) | 73 (36.3) | 1.0 | 62 (73.8) | 72 (84.7) | 1.0 | ||
| Four or more | 187 (65.6) | 141 (49.3) | 2.5 (1.6–4.0) | 165 (82.1) | 128 (63.7) | 2.6 (1.5–4.6) | 22 (26.2) | 13 (15.3) | 2.1 (0.67–6.4) | ||
| Socioeconomic status | |||||||||||
| Socioeconomic status before age 21 | |||||||||||
| Poor/working class | 49 (17.2) | 58 (20.3) | 1.0 | 34 (16.9) | 51 (25.4) | 1.0 | 15 (17.9) | 7 (8.2) | 1.0 | ||
| Lower middle class | 44 (15.4) | 31 (10.8) | 1.7 (0.86–3.5) | 31 (15.4) | 26 (12.9) | 1.9 (0.84–4.5) | 13 (15.5) | 5 (5.9) | 1.2 (0.16–8.6) | ||
| Middle class | 113 (39.6) | 132 (46.2) | 1.0 (0.58–1.7) | 81 (40.3) | 85 (42.3) | 1.5 (0.80–2.9) | 32 (38.1) | 47 (55.3) | 0.30 (0.07–1.3) | ||
| Upper middle/upper class | 79 (27.7) | 65 (22.7) | 1.3 (0.73–2.4) | 55 (27.4) | 39 (19.4) | 2.2 (1.0–4.6) | 24 (28.6) | 26 (30.6) | 0.23 (0.05–1.1) | ||
| Separating upper middle and upper versus poor/working classa | |||||||||||
| Upper middle class | 68 (23.9) | 63 (22.0) | 1.1 (0.57–2.0) | 46 (22.9) | 38 (18.9) | 1.6 (0.73–3.4) | 22 (26.2) | 25 (29.4) | 0.22 (0.05–1.1) | ||
| Upper class | 11 (3.9) | 2 (0.7) | 9.7 (1.9–49.0) | 9 (4.5) | 1 (0.5) | 31.5 (3.3–298.6) | 2 (2.4) | 1 (1.2) | 1.6 (0.03–82.1) | ||
| Highest degree obtained | |||||||||||
| High school (HS) | 69 (24.2) | 66 (23.1) | 1.0 | 55 (27.4) | 55 (27.4) | 1.0 | 14 (16.7) | 11 (12.9) | 1.0 | ||
| Some college or other post-HS | 59 (20.7) | 66 (23.1) | 0.83 (0.47–1.4) | 37 (18.4) | 47 (23.4) | 0.63 (0.32–1.3) | 22 (26.2) | 19 (22.4) | 1.2 (0.32–4.9) | ||
| Bachelor's | 105 (36.8) | 103 (36.0) | 0.99 (0.59–1.7) | 71 (35.3) | 64 (31.8) | 1.1 (0.59–2.1) | 34 (40.5) | 39 (45.9) | 0.73 (0.19–2.8) | ||
| Graduate | 52 (18.2) | 51 (17.8) | 0.93 (0.50–1.7) | 38 (18.9) | 35 (17.4) | 0.89 (0.42–1.9) | 14 (16.7) | 16 (18.8) | 0.80 (0.17–3.8) | ||
| Religion in which raised | |||||||||||
| Protestant | 128 (44.9) | 111 (38.8) | 1.0 | 100 (49.8) | 84 (41.8) | 1.0 | 28 (33.3) | 27 (31.8) | 1.0 | ||
| Catholic | 104 (36.5) | 114 (39.9) | 0.72 (0.47–1.1) | 70 (34.8) | 78 (38.8) | 0.68 (0.40–1.1) | 34 (40.5) | 36 (42.4) | 0.53 (0.20–1.4) | ||
| Jewish | 23 (8.1) | 18 (6.3) | 1.2 (0.56–2.6) | 16 (8.0) | 11 (5.5) | 1.6 (0.57–4.3) | 7 (8.3) | 7 (8.2) | 0.95 (0.18–4.9) | ||
| Other | 18 (6.3) | 18 (6.3) | 0.94 (0.42–2.1) | 7 (3.5) | 14 (7.0) | 0.33 (0.11–1.0) | 11 (13.1) | 4 (4.7) | 3.2 (0.60–16.7) | ||
| None | 12 (4.2) | 25 (8.7) | 0.39 (0.17–0.91) | 8 (4.0) | 14 (7.0) | 0.53 (0.18–1.6) | 4 (4.8) | 11 (12.9) | 0.20 (0.03–1.1) | ||
| Alcohol and tobacco use | |||||||||||
| Age began drinking alcohol | |||||||||||
| Before age 21 years | 228 (80.0) | 255 (89.2) | 1.0 | 156 (77.6) | 176 (87.6) | 1.0 | 72 (85.7) | 79 (92.9) | 1.0 | ||
| After age 21 years | 57 (20.0) | 31 (10.8) | 2.8 (1.6–5.0) | 45 (22.4) | 25 (12.4) | 3.0 (1.5–5.9) | 12 (14.3) | 6 (7.1) | 2.9 (0.60–14.2) | ||
| Average drinks after age 21f | |||||||||||
| <1 drink per week | 81 (28.4) | 104 (36.4) | 1.0 | 56 (27.9) | 68 (33.8) | 1.0 | 25 (29.8) | 36 (42.4) | 1.0 | ||
| ≥ 1 drinks per week, <2 per day | 137 (48.1) | 149 (52.1) | 1.1 (0.72–1.8) | 90 (44.8) | 106 (52.7) | 0.63 (0.36–1.1) | 47 (56.0) | 43 (50.6) | 3.5 (1.2–10.1) | ||
| ~2 drinks per day | 52 (18.2) | 27 (9.4) | 2.3 (1.2–4.4) | 42 (20.9) | 22 (10.9) | 1.5 (0.70–3.3) | 10 (11.9) | 5 (5.9) | 3.6 (0.79–16.5)f | ||
| ≥ 3 drinks per day | 15 (5.3) | 6 (2.1) | 3.6 (1.2–11.5) | 13 (6.5) | 5 (2.5) | 2.9 (0.80–10.9) | 2 (2.4) | 1 (1.2) | |||
| P for trende | 0.004 | 0.090 | 0.030 | ||||||||
| Lifetime pack-years of cigarette smoking | |||||||||||
| None | 117 (41.1) | 130 (45.5) | 1.0 | 74 (36.8) | 87 (43.3) | 1.0 | 43 (51.2) | 43 (50.6) | 1.0 | ||
| Duration ≤ 8.25 years | 39 (13.7) | 38 (13.3) | 1.3 (0.70–2.2) | 24 (11.9) | 24 (11.9) | 1.3 (0.61–2.9) | 15 (17.9) | 14 (16.5) | 2.3 (0.72–7.4) | ||
| > 8.25 years to ≤ 15 years duration | 29 (10.2) | 42 (14.7) | 0.81 (0.44–1.5) | 21 (10.4) | 28 (13.9) | 0.99 (0.45–2.2) | 8 (9.5) | 14 (16.5) | 0.38 (0.11–1.3) | ||
| >15 years to ≤ 28.5 years duration | 36 (12.6) | 37 (12.9) | 1.1 (0.61–2.0) | 22 (10.9) | 26 (12.9) | 1.0 (0.47–2.3) | 14 (16.7) | 11 (12.9) | 1.1 (0.34–3.8) | ||
| Duration > 28.5 years | 64 (22.5) | 39 (13.6) | 2.4 (1.3–4.2) | 60 (29.9) | 36 (17.9) | 3.1 (1.6–5.9) | 4 (4.8) | 3 (3.5) | 2.0 (0.18–21.2) | ||
| P for trende | 0.02 | 0.004 | 0.78 | ||||||||
CI, confidence interval; OR, odds ratio. Statistically significant results are shown in bold. aWomen with complete full interviews were included in the multivariate analyses. ORs adjusted for age and other variables in this table are presented in normal font. Variables in italics are alternative categorizations of selected variables and are adjusted for age and the other variables in the table. bIncludes surgical biopsy alone and surgical biopsy in addition to fine-needle aspiration. cTook either only estrogen (N = 92) or only progesterone (N = 12) compounds, or took them during different times (N = 6), or name of hormone unknown (N = 2). dExcludes weight during pregnancy, nursing, or first 6 months after pregnancy. eP for linear trend in categories given are adjusted for age and other variables in the table. fFor women under age 50, those drinking about two drinks per day and those drinking three or more drinks per day were combined.