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Table 1 Baseline characteristics of breast cancer cases and matched controls, Nurses’ Health Study II

From: Erythrocyte membrane fatty acids and breast cancer risk by tumor tissue expression of immuno-inflammatory markers and fatty acid synthase: a nested case-control study

Characteristic1 Cases (n = 235) Controls (n = 235)
Age at blood collection (years), median (IQR)2 45.8 (42.5–49.0) 45.9 (42.6–49.2)
Age at menarche (years), median (IQR) 12.0 (12.0–13.0) 13.0 (12.0–13.0)
White race, %2 98.7 98.3
BMI at age 18 (kg/m2), median (IQR) 20.2 (18.8–22.3) 20.6 (19.1–22.3)
BMI at blood collection (kg/m2), median (IQR) 24.3 (21.7–27.9) 24.3 (21.7–28.1)
Weight change from age 18 to blood collection (kg), median (IQR) 10.5 (4.5–18.2) 9.5 (4.1–17.7)
Fasting at blood collection (≥ 8 h since last meal), %2 71.9 74.0
Menopausal status at blood collection, %2
 Premenopausal 75.7 74.5
 Postmenopausal 12.3 14.5
 Unknown 11.9 11.1
Parous women, % 79.6 82.6
Parity, median (IQR)3 2.0 (2.0–3.0) 2.0 (2.0–3.0)
Age at first birth (years), median (IQR)3 26.0 (23.0–29.0) 25.0 (22.0–28.0)
History of breastfeeding, %3 74.3 77.8
History of biopsy-confirmed benign breast disease, % 20.9 16.2
Family history of breast cancer, % 15.7 9.8
NSAIDs current regular use (≥ 2 times/week), % 14.9 13.6
Physical activity (MET-hours/week), median (IQR) 12.1 (7.1–22.2) 14.0 (7.3–27.9)
Alcohol consumption (grams/day), median (IQR) 1.4 (0.0–6.2) 1.0 (0.0–3.8)
Total fat consumption (% energy intake), median (IQR) 29.8 (25.5–34.3) 30.6 (25.5–35.0)
Total saturated fat consumption (% energy intake), median (IQR) 10.4 (8.4–12.3) 10.5 (8.6–12.6)
Total monounsaturated fat consumption (% energy intake), median (IQR) 11.6 (9.6–13.5) 11.9 (10.1–13.6)
Total polyunsaturated fat consumption (% energy intake), median (IQR) 4.8 (4.2–5.5) 4.6 (4.0–5.4)
  1. Abbreviations: IQR interquartile range, BMI body mass index, NSAIDs non-steroidal anti-inflammatory medications, MET metabolic equivalent of task
  2. 1Values are missing for age at menarche (0.9%), age at first birth among parous women (0.8%), NSAIDs current regular use (3.0%), physical activity (0.2%), alcohol consumption (0.6%), total fat consumption (4.9%), total saturated fat consumption (4.9%), total monounsaturated fat consumption (4.9%), and total polyunsaturated fat consumption (4.9%)
  3. 2Case-control matching factor
  4. 3Parity, age at first birth, and history of breast feeding among parous women