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Table 1 Main characteristics of the study population

From: Prospective analysis of circulating metabolites and breast cancer in EPIC

VariablesNControlsCases
N = 1624N = 1624
Mean (SD) or N (%)Mean (SD) or N (%)
Age at blood collection (years)324852.5 (7.9)52.5 (8.0)
Length of follow-up from blood collection (years)32488.3 (2.8)
Age at diagnosis (years)162460.8 (8.3)
ER status1624  
 Negative 313 (19.3)
 Positive 1311 (80.7)
PR status1624  
 Negative 516 (31.8)
 Positive 1108 (68.2)
HER2 status1624  
 Negative 1270 (78.2)
 Positive 354 (21.8)
Age at first menstrual period (years)324813.1 (1.6)13.0 (1.5)
Number of full-term pregnancies3248  
 0 215 (13.2)244 (15.0)
 1 253 (15.6)310 (19.1)
 2 729 (44.9)686 (42.2)
 ≥ 3 427 (26.3)384 (23.6)
Age at first full-term pregnancy (years)278924.9 (4.3)25.3 (4.4)
Ever breastfed3248  
 No 194 (11.9)206 (12.7)
 Yes 1116 (68.7)1080 (66.5)
 Never pregnant 215 (13.2)244 (15.0)
 Missing 99 (6.1)94 (5.8)
Use of exogenous hormones at blood collection3248  
 No 1124 (69.2)1130 (69.6)
 Yes 492 (30.3)494 (30.4)
 Missing 8 (0.5)0 (0.0)
Menopausal status at blood collection3248  
 Premenopausal 434 (26.7)434 (26.7)
 Postmenopausal 869 (53.5)872 (53.7)
 Perimenopausal 321 (19.8)318 (19.6)
Fasting status at blood collection (time since last meal)3248  
 < 3 h 737 (45.4)731 (45.0)
 3–6 h 284 (17.5)285 (17.5)
 > 6 h 580 (35.7)580 (35.7)
 Unknown 23 (1.4)28 (1.7)
Alcohol consumption at recruitment (g/day)32488.9 (12.2)10.2 (13.5)
Education level3248  
 Primary/no schooling 610 (37.6)597 (36.8)
 Technical/professional/secondary 687 (42.3)688 (42.4)
 Longer education 327 (20.1)339 (20.9)
Height (cm)3248161.4 (6.6)162.0 (6.6)
Weight (kg)
 Age at diagnosis < 50 years old38263.8 (11.3)63.0 (10.9)
 Age at diagnosis ≥ 50 years old286666.7 (10.8)68.4 (12.2)
Body mass index (kg/m2)
 Age at diagnosis < 50 years old38224.2 (4.1)23.9 (4.2)
 Age at diagnosis ≥ 50 years old286625.7 (4.1)26.1 (4.6)
Waist circumference (cm)
 Age at diagnosis < 50 years old38276.8 (9.8)76.4 (10.3)
 Age at diagnosis ≥ 50 years old286681.0 (10.4)82.5 (11.3)
Hip circumference (cm)
 Age at diagnosis < 50 years old38299.0 (8.6)98.3 (8.4)
 Age at diagnosis ≥ 50 years old2866101.4 (8.0)102.7 (9.1)
  1. ER estrogen receptor, HER2 human epidermal growth factor receptor 2, PR progesterone receptor