Table 1

Basic characteristics

VariablesCases
n (%)
Controls
n (%)
Total
n (%)
P value
Total495 (100)478 (100)973 (100)
BMI (kg/m2)<0.001
 ≤18.424 (4.85)37 (7.74)61 (6.27)
 18.5–23.9185 (37.37)290 (60.67)475 (48.82)
 24–27.9202 (40.81)128 (26.78)330 (33.92)
 ≥28.084 (16.97)23 (4.81)107 (10.10)
Education<0.001
 <Middle school179 (36.16)48 (10.04)227 (23.33)
 High school181 (36.57)82 (17.15)263 (27.03)
 >University135 (27.27)348 (72.80)483 (49.64)
Marital status<0.001
 Single10 (2.02)66 (13.81)76 (7.81)
 Married435 (87.88)387 (80.96)822 (84.48)
 Divorced50 (10.10)25 (5.23)75 (7.71)
Smoking0.311
 Yes13 (2.63)8 (1.67)21 (2.16)
 No482 (97.37)470 (98.33)952 (97.84)
Alcohol consumption0.438
 Yes13 (2.63)9 (1.88)22 (2.26)
 No482 (97.37)469 (98.12)951 (97.74)
Nighttime eating0.012
 Yes48 (9.70)72 (15.06)120 (12.33)
 No447 (90.30)406 (84.94)853 (87.67)
Sleeping time per day (hours)<0.001
 <22:00189 (38.18)104 (21.76)293 (30.11)
 22:00–24:00292 (58.99)353 (73.85)645 (66.29)
 0:00–4:0014 (2.83)21 (4.39)35 (3.60)
Oestrogen receptor status
 Negative381 (76.97)
 Positive114 (23.03)
Progesterone receptor status
 Negative358 (72.32)
 Positive137 (27.68)
Breast cancer type
 Non-invasive71 (14.34)
 Invasive424 (85.66)
Metastasis
 Yes121 (24.44)
 No374 (75.56)