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. 2019 Apr 30;11:66. doi: 10.1186/s13148-019-0664-7

Table 2.

Table of characteristics for case-control pairs in EPIC-Italy and the Generations Study

EPIC-Italy The Generations Study
Cases (n = 162) Controls (n = 162) Cases (n = 339) Controls (n = 339) P b
Age Mean (st.dev.), years 52.9 (7.2) 53.0 (7.1) 53.9 (10.3) 54.1 (10.4) 0.054
Time to diagnosis Mean (st.dev.), years 5.3 (4.4) NA 4.0 (2.4) NA 0.022
Menopausal status n (%) 0.690
 Premenopausal 52 (32.1%) 49 (30.2%) 135 (39.8%) 127 (37.5%)
 Postmenopausal 85 (52.5%) 87 (53.7%) 204 (60.2%) 212 (62.5%)
Age at menarche Mean (st.dev.), years 12.7 (1.4) 12.7 (1.7) 12.7 (1.4) 12.7 (1.5) 0.914
Age at menopause Mean (st.dev.), years 50.2 (3.7) 49.1 (3.8) 50.3 (4.3) 50.1 (4.5) 0.126
Number of pregnancies Mean (st.dev.) 1.6 (1.1) 1.7 (1.0) 1.9 (1.1) 1.9 (1.2) 4 × 10 −4
Ever breastfed n (%) 103 (63.6%) 112 (69.1%) 265 (78.2%) 274 (80.8%) 0.179
Breastfeeding duration Mean (st.dev.), years 0.7 (0.6) 0.8 (0.7) 0.9 (1.0) 0.8 (0.9) 2 × 10 −5
BMI Mean (st.dev.), kg/m2 25.8 (4.1) 25.3 (4.3) 25.7 (4.3) 25.2 (4.3) 0.626
Alcohol consumptiona Mean (st.dev.) 5.5 (7.0) 7.4 (9.9) 15.8 (16.7) 14.6 (15.5) 2 × 10 −26
Smoking status n (%) 8 × 10 −10
 Smoker 31 (19.1%) 36 (22.2%) 25 (7.4%) 23 (6.8%)
 Former 23 (14.2%) 41 (25.3%) 98 (28.9%) 86 (25.4%)
 Never 106 (65.4%) 85 (52.5%) 216 (63.7%) 230 (67.9%)
Smoking duration Mean (st.dev.), years 8.1 (12.6) 10.6 (13.4) 4.4 (9.0) 3.9 (9.0) 4 × 10 −10
OC ever n (%) 59 (36.4 %) 67 (41.4 %) 253 (74.6%) 256 (75.5%) < 2 × 10 −16
OC duration Mean (st.dev.), years 4.1 (5.1) 5.6 (5.8) 8.1 (6.4) 8.8 (6.8) 4 × 10 −9
HRT ever n (%) 23 (14.2 %) 28 (17.3 %) 239 (70.5%) 241 (71.1%) 2 × 10 −7
HRT duration Mean (st.dev.), years 2.8 (2.7) 2.6 (3.4) 6.7 (5.7) 5.4 (4.3) 5 × 10 −8

aAlcohol consumption in the Generations Study reported in average units per week, converted to average gram per day by multiplying with 8 (1 unit = 8 g alcohol) and dividing by 7

bP values indicate differences between all subjects from EPIC-Italy and all subjects from the Generations Study: t test for continuous variables, chi-squared test for categorical variables