Table 3.
Multivariable polytomous logistic regression for the association of participant characteristics stratified by race among 37 839 women*
| Variable | No. participants† | Extremely dense |
Heterogeneously dense |
Scattered fibroglandular tissue |
Almost entirely fatty |
|||
|---|---|---|---|---|---|---|---|---|
| %‡ or mean (SD) | OR (95% CI) | %‡ or mean (SD) | OR (95% CI) | %‡ or mean (SD) | OR (95% CI) | %‡ or mean (SD) | ||
| Among African American women | ||||||||
| Total, No. (%) | 14 673 (100) | 430 (2.9) | 3231 (22.0) | 8475 (57.8) | 2537 (17.3) | |||
| Parity, age at first birth | ||||||||
| Nulliparous | 1406 | 5.2 | 1.00 (Referent) | 26.3 | 1.00 (Referent) | 51.6 | 1.00 (Referent) | 17.0 |
| 1–4 children, <25 y | 8939 | 2.6 | 0.48 (0.34 to 0.68) | 21.3 | 0.72 (0.58 to 0.89) | 58.8 | 0.99 (0.83 to 1.19) | 17.3 |
| 1–4 children, 25–29 y | 1657 | 3.8 | 0.70 (0.44 to 1.14) | 26.9 | 0.89 (0.67 to 1.19) | 52.9 | 0.91 (0.70 to 1.19) | 16.4 |
| 1–4 children, ≥30 y | 1004 | 3.8 | 0.69 (0.41 to 1.16) | 28.5 | 1.03 (0.75 to 1.40) | 53.3 | 1.06 (0.81 to 1.39) | 14.4 |
| ≥5 children, <25 y | 1625 | 1.6 | 0.28 (0.17 to 0.48) | 13.6 | 0.43 (0.32 to 0.58) | 64.7 | 0.92 (0.75 to 1.15) | 20.1 |
| ≥5 children, ≥25 y | 42 | 0.0 | Undefined | 12.7 | 0.35 (0.09 to 1.34) | 69.8 | 0.99 (0.41 to 2.40) | 17.5 |
| Age group, y | ||||||||
| <40 | 133 | 6.8 | 1.53 (0.59 to 3.97) | 33.8 | 1.20 (0.61 to 2.35) | 48.1 | 1.06 (0.58 to 1.95) | 11.3 |
| 40–49 | 3770 | 5.2 | 1.00 (Referent) | 29.7 | 1.00 (Referent) | 51.1 | 1.00 (Referent) | 14.0 |
| 50–59 | 5289 | 2.5 | 0.26 (0.19 to 0.36) | 21.5 | 0.44 (0.37 to 0.52) | 57.4 | 0.71 (0.61 to 0.82) | 18.7 |
| 60–69 | 3409 | 1.8 | 0.18 (0.12 to 0.27) | 17.5 | 0.33 (0.27 to 0.40) | 61.5 | 0.69 (0.58 to 0.81) | 19.2 |
| ≥70 | 2072 | 1.6 | 0.10 (0.06 to 0.16) | 16.2 | 0.23 (0.18 to 0.29) | 65.3 | 0.64 (0.53 to 0.78) | 16.9 |
| BMI§ | 14 673 | 24.2 (5.1) | 0.15 (0.13 to 0.17) | 28.6 (5.8) | 0.40 (0.38 to 0.42) | 32.6 (7.2) | 0.66 (0.64 to 0.69) | 38.2 (8.8) |
| BMI at age 18 y§ | 14 673 | 20.1 (4.9) | 0.80 (0.67 to 0.95) | 20.8 (3.7) | 0.70 (0.62 to 0.78) | 22.1 (4.4) | 0.84 (0.80 to 0.89) | 24.3 (5.7) |
| Age at menarche‖ | 14 673 | 13.1 (1.8) | 1.07 (1.01 to 1.14) | 12.8 (1.8) | 1.02 (0.98 to 1.05) | 12.6 (1.8) | 1.01 (0.98 to 1.04) | 12.5 (1.8) |
| FHOBC | 2228 | 2.9 | 1.34 (0.97 to 1.84) | 23.4 | 1.40 (1.19 to 1.65) | 58.0 | 1.22 (1.06 to 1.39) | 15.6 |
| Current alcohol use | 5356 | 3.5 | 1.01 (0.80 to 1.27) | 23.8 | 0.99 (0.88 to 1.12) | 57.2 | 1.04 (0.94 to 1.15) | 15.5 |
| Oral contraceptive use | ||||||||
| Current | 1022 | 4.3 | 1.07 (0.69 to 1.65) | 30.0 | 1.25 (0.97 to 1.62) | 52.3 | 1.07 (0.86 to 1.33) | 13.4 |
| Past | 8463 | 2.8 | 0.93 (0.73 to 1.20) | 22.1 | 1.01 (0.89 to 1.14) | 57.5 | 0.98 (0.88 to 1.08) | 17.6 |
| Never | 5188 | 2.9 | 1.00 (Referent) | 20.4 | 1.00 (Referent) | 59.2 | 1.00 (Referent) | 17.5 |
| Postmenopausal status | 10 311 | 2.2 | 0.57 (0.42 to 0.78) | 19.2 | 0.63 (0.54 to 0.74) | 60.2 | 0.83 (0.73 to 0.96) | 18.5 |
| Ever HRT¶ | 2033 | 2.2 | 1.18 (0.77 to 1.80) | 19.7 | 1.01 (0.83 to 1.23) | 62.1 | 1.08 (0.93 to 1.26) | 16.0 |
| Age at menopause, y,‖,¶ | — | 46.3 (6.4) | 0.99 (0.96 to 1.02) | 47.3 (6.6) | 1.00 (0.99 to 1.01) | 47.6 (6.4) | 1.00 (0.99 to 1.01) | 47.5 (6.4) |
| Among non-Hispanic white women | ||||||||
| Total, No. (%) | 23 166 (100) | 1167 (5.0) | 7399 (31.9) | 12 211 (52.7) | 2389 (10.3) | |||
| Parity, age at first birth | ||||||||
| Nulliparous | 3254 | 7.8 | 1.00 (Referent) | 36.1 | 1.00 (Referent) | 45.6 | 1.00 (Referent) | 10.5 |
| 1–4 children, <25 y | 9586 | 3.0 | 0.44 (0.33 to 0.58) | 27.3 | 0.68 (0.58 to 0.81) | 57.3 | 0.98 (0.84 to 1.16) | 12.4 |
| 1–4 children, 25–29 y | 5353 | 5.1 | 0.58 (0.45 to 0.76) | 34.0 | 0.85 (0.70 to 1.03) | 52.1 | 1.09 (0.92 to 1.29) | 8.9 |
| 1–4 children, ≥30 y | 4079 | 8.2 | 0.91 (0.68 to 1.21) | 39.0 | 1.09 (0.87 to 1.37) | 46.3 | 1.26 (1.02 to 1.57) | 6.5 |
| ≥5 children, <25 y | 734 | 1.9 | 0.27 (0.13 to 0.54) | 20.2 | 0.49 (0.36 to 0.68) | 63.4 | 0.98 (0.75 to 1.28) | 14.6 |
| ≥5 children, ≥25 years | 160 | 1.0 | 0.13 (0.02 to 1.01) | 32.8 | 0.91 (0.45 to 1.85) | 58.4 | 1.34 (0.71 to 2.55) | 7.8 |
| Age group, y | ||||||||
| <40 | 306 | 15.7 | 0.98 (0.52 to 1.83) | 43.1 | 0.75 (0.43 to 1.30) | 34.0 | 0.68 (0.41 to 1.14) | 7.2 |
| 40–49 | 4953 | 8.9 | 1.00 (Referent) | 42.1 | 1.00 (Referent) | 42.1 | 1.00 (Referent) | 7.0 |
| 50–59 | 7913 | 5.2 | 0.54 (0.43 to 0.69) | 33.1 | 0.59 (0.49 to 0.71) | 51.3 | 0.82 (0.69 to 0.97) | 10.5 |
| 60–69 | 6030 | 2.8 | 0.27 (0.20 to 0.37) | 26.4 | 0.39 (0.32 to 0.48) | 58.7 | 0.75 (0.63 to 0.91) | 12.0 |
| ≥70 | 3964 | 2.5 | 0.17 (0.12 to 0.23) | 24.6 | 0.26 (0.21 to 0.33) | 61.2 | 0.64 (0.53 to 0.78) | 11.8 |
| BMI§ | 23 166 | 22.2 (3.6) | 0.11 (0.10 to 0.13) | 25.3 (4.8) | 0.34 (0.32 to 0.35) | 29.3 (6.6) | 0.64 (0.62 to 0.66) | 35.0 (8.2) |
| BMI at age 18 y§ | 23 166 | 19.6 (2.3) | 0.60 (0.51 to 0.70) | 20.2 (2.8) | 0.58 (0.53 to 0.63) | 21.5 (3.7) | 0.79 (0.74 to 0.84) | 23.6 (5.1) |
| Age at menarche, y‖ | 23 166 | 13.1 (1.5) | 1.06 (1.00 to 1.12) | 12.9 (1.5) | 1.04 (1.01 to 1.08) | 12.7 (1.5) | 1.02 (0.99 to 1.05) | 12.4 (1.5) |
| FHOBC | 4271 | 6.4 | 1.93 (1.59 to 2.36) | 32.7 | 1.42 (1.23 to 1.63) | 52.3 | 1.29 (1.14 to 1.46) | 8.7 |
| Current alcohol use | 13 134 | 6.1 | 1.35 (1.12 to 1.61) | 35.4 | 1.24 (1.11 to 1.39) | 50.4 | 1.13 (1.02 to 1.25) | 8.0 |
| Oral contraceptive use | ||||||||
| Current | 3808 | 7.8 | 1.65 (1.29 to 2.10) | 39.5 | 1.40 (1.17 to 1.67) | 46.4 | 1.28 (1.09 to 1.51) | 6.3 |
| Past | 12 067 | 4.7 | 0.98 (0.81 to 1.18) | 30.5 | 0.95 (0.85 to 1.07) | 54.1 | 1.06 (0.95 to 1.17) | 10.8 |
| Never | 7291 | 4.2 | 1.00 (Referent) | 30.3 | 1.00 (Referent) | 53.8 | 1.00 (Referent) | 11.6 |
| Postmenopausal status | 16 669 | 3.3 | 0.30 (0.24 to 0.38) | 28.1 | 0.47 (0.40 to 0.56) | 56.8 | 0.70 (0.60 to 0.81) | 11.7 |
| Ever HRT¶ | 6560 | 4.0 | 1.39 (1.07 to 1.81) | 30.3 | 1.21 (1.05 to 1.40) | 55.9 | 1.11 (0.98 to 1.26) | 9.8 |
| Age at menopause, y,‖,¶ | 16 669 | 49.1 (5.3) | 1.03 (1.01 to 1.06) | 48.7 (5.8) | 1.01 (0.99 to 1.03) | 48.7 (6.0) | 1.01 (0.99 to 1.02) | 48.3 (6.3) |
Fully adjusted for all covariates, model includes age at first birth, age group, BMI, BMI at age 18 years, age at menarche, family history of breast cancer, alcohol use, history of oral contraceptive use, and menopausal status. The results from the polytomous logistic regression can be interpreted as the log odds of either extremely dense, heterogeneously dense, or scattered fibroglandular tissue compared with the log odds of almost entirely fatty (the referent mammographic breast density category). Results using fully conditional specification (FCS) multiple imputation. BMI = body mass index; CI = confidence interval; FHOBC = family history of breast cancer; HRT = hormone replacement therapy; OR = odds ratio.
Approximated strata population derived from multiple imputations.
Presented as proportion within variable strata with breast density category. No. (%) represents the total number of participants within strata and proportion of total population.
BMI and BMI at age 18 years are interpreted as per 5-unit increase.
Continuous variables odds ratios are interpreted as per 1-unit increase.
Among postmenopausal women only (African American women, n = 10 311; non-Hispanic white women, n = 16 669). Models among postmenopausal further adjusted ever HRT and age at menopause.