Table IV.
Association between global DNA methylation level classified by the tertiles of the distribution of controls and breast cancer (cases = 176 and controls = 173)
| 5-mdC | Cases, n (%) | Controls, n (%) | OR (95% CI)a | |
| Allb | Mean ± SD | 4.18 ± 0.34 | 4.38 ± 0.36 | <0.001 |
| T3 | 33 (18.8) | 58 (33.5) | 1.0 (reference) | |
| T2 | 49 (27.8) | 58 (33.5) | 1.49 (0.84–2.65) | |
| T1 | 94 (53.4) | 57 (33.0) | 2.86 (1.65–4.94) | |
| P for trend | <0.001 | |||
| Menopausal status | ||||
| Premenopausal | T3 | 11 (19.0) | 21 (30.0) | 1.0 (reference) |
| T2 | 18 (31.0) | 26 (36.6) | 1.27 (0.48–3.35) | |
| T1 | 29 (50.0) | 24 (33.8) | 2.21 (0.88–5.57) | |
| P for trend | 0.074 | |||
| Postmenopausal | T3 | 14 (15.9) | 34 (35.1) | 1.0 (reference) |
| T2 | 24 (27.3) | 31 (32.0) | 1.88 (0.82–4.31) | |
| T1 | 50 (56.8) | 32 (33.0) | 3.76 (1.73–8.19) | |
| P for trend | 0.001 | |||
| P for interaction | 0.410 | |||
| Age at diagnosis | ||||
| <55 | T3 | 16 (22.2) | 31 (33.7) | 1.0 (reference) |
| T2 | 18 (25.0) | 33 (35.9) | 0.96 (0.40–2.26) | |
| T1 | 38 (52.8) | 28 (30.4) | 2.50 (1.13–5.50) | |
| P for trend | 0.013 | |||
| 55+ | T3 | 17 (16.4) | 27 (33.3) | 1.0 (reference) |
| T2 | 31 (29.8) | 25 (30.9) | 1.89 (0.84–4.26) | |
| T1 | 56 (53.9) | 29 (35.8) | 2.81 (1.29–6.11) | |
| P for trend | 0.010 | |||
| P for interaction | 0.947 | |||
| Family history of breast cancer | ||||
| No | T3 | 21 (17.7) | 42 (30.9) | 1.0 (reference) |
| T2 | 35 (29.4) | 47 (34.6) | 1.50 (0.75–2.99) | |
| T1 | 63 (52.9) | 47 (34.6) | 2.60 (1.35–4.98) | |
| P for trend | 0.003 | |||
| Yes | T3 | 5 (17.2) | 15 (41.7) | 1.0 (reference) |
| T2 | 7 (24.1) | 11 (30.6) | 2.08 (0.50–8.66) | |
| T1 | 17 (58.6) | 10 (27.8) | 5.73 (1.49–21.97) | |
| P for trend | 0.009 | |||
| P for interaction | 0.345 | |||
| BMI (by median) | ||||
| Below 26.5 | T3 | 9 (15.3) | 18 (25.4) | 1.0 (reference) |
| T2 | 14 (23.7) | 26 (36.6) | 1.08 (0.36–3.29) | |
| T1 | 36 (61.0) | 27 (38.0) | 2.36 (0.88–6.28) | |
| P for trend | 0.044 | |||
| At or higher 26.5 | T3 | 15 (17.9) | 32 (37.2) | 1.0 (reference) |
| T2 | 25 (29.8) | 28 (32.6) | 2.05 (0.88–4.77) | |
| T1 | 44 (52.4) | 26 (30.2) | 3.98 (1.77–8.95) | |
| P for trend | 0.001 | |||
| P for interaction | 0.820 | |||
| Smoking habit | ||||
| Never smoker | T3 | 7 (9.5) | 27 (32.9) | 1.0 (reference) |
| T2 | 22 (29.7) | 27 (32.9) | 3.02 (1.09–8.37) | |
| T1 | 45 (60.8) | 28 (34.2) | 6.02 (2.29–15.78) | |
| P for trend | <0.001 | |||
| Ever smoker | T3 | 18 (25.0) | 29 (34.9) | 1.0 (reference) |
| T2 | 20 (27.8) | 27 (32.5) | 1.17 (0.50–2.72) | |
| T1 | 34 (47.2) | 27 (32.5) | 1.97 (0.89–4.39) | |
| P for trend | 0.086 | |||
| P for interaction | 0.084 | |||
| Alcohol consumption habit | ||||
| Never drinking alcohol | T3 | 9 (25.0) | 13 (40.6) | 1.0 (reference) |
| T2 | 10 (27.8) | 12 (37.5) | 1.35 (0.39–4.63) | |
| T1 | 17 (47.2) | 7 (21.9) | 3.98 (1.11–14.23) | |
| P for trend | 0.033 | |||
| Ever drinking alcohol | T3 | 17 (15.2) | 44 (31.4) | 1.0 (reference) |
| T2 | 32 (28.6) | 46 (32.9) | 1.80 (0.87–3.74) | |
| T1 | 63 (56.3) | 50 (35.7) | 3.06 (1.55–6.05) | |
| P for trend | 0.001 | |||
| P for interaction | 0.826 | |||
| Multivitamin use | ||||
| Never or occasional use | T3 | 12 (17.9) | 26 (43.3) | 1.0 (reference) |
| T2 | 26 (38.8) | 14 (23.3) | 4.68 (1.75–12.58) | |
| T1 | 29 (43.3) | 20 (33.3) | 4.04 (1.54–10.57) | |
| P for trend | 0.007 | |||
| Regular use | T3 | 14 (17.3) | 31 (27.9) | 1.0 (reference) |
| T2 | 16 (19.8) | 43 (38.7) | 0.76 (0.31–1.83) | |
| T1 | 51 (63.0) | 37 (33.3) | 2.94 (1.34–6.42) | |
| P for trend | 0.001 | |||
| P for interaction | 0.684 |
T1, first tertile; T2, second tertile; T3, third tertile.
a
Logistic regression model adjusting for age (continuous variable), race (Caucasian, African-American) and batches.
b
T1 methylation level < 4.25; T2 4.25 ≤ methylation level < 4.50; T3 ≥ 4.50.