Table 3.

Interaction of fish oil supplement use with factors associated with chronic inflammation in relation to breast cancer risk among female VITAL participants (n = 35,016)

Fish oil*
NonuserCurrent user
Cases/noncasesHR (95% CI)Cases/noncasesHR (95% CI)
    <25 kg/m2327/13,5941.00 (reference)21/1,2700.67 (0.41-1.07)
    ≥25 kg/m2475/16,7371.24 (1.06-1.44)26/1,3980.84 (0.56-1.27)
    P interaction0.94
    No767/28,7341.00 (reference)41/2,5390.62 (0.45-0.87)
    Yes35/1,5910.84 (0.58-1.20)6/1291.56 (0.64-3.78)
    P interaction0.03
NSAID use§
    Irregular616/23,1191.00 (reference)33/2,0250.64 (0.44-0.91)
    Regular177/6,8530.88 (0.74-1.05)12/6130.72 (0.41-1.28)
    P interaction0.52
Smoking status
    Nonsmoker/former smoker672/25,7431.00 (reference)43/2,3600.72 (0.53-1.00)
    Current/recent smoker119/4,3911.06 (0.86-1.31)4/2990.41 (0.13-1.27)
    P interaction0.30
Dietary arachidonic acid
    <0.09 g/d362/13,6331.00 (reference)21/1,1290.62 (0.38-1.00)
    ≥0.09 g/d358/13,3650.99 (0.85-1.15)22/1,2990.69 (0.44-1.06)
    P interaction0.71
  • *Former users dropped from analysis.

  • Adjusted for age, race, education, BMI, height, fruit consumption, vegetable consumption, alcohol consumption, physical activity, age at menarche, age at menopause, age at first birth, history of hysterectomy, years of combined hormone therapy, family history of breast cancer, history of benign breast biopsy, mammography, low-dose aspirin use, regular aspirin use, ibuprofen use, naproxen use, use of multivitamins, memory loss, and CAD.

  • Participants with a positive history of heart attack, angina, angioplasty, or bypass surgery.

  • §Ten-year average use: irregular, <4 d/week or <4 y; regular, ≥4 d/week and ≥4 y.

  • Former smokers, ≥10 y since quit; recent smokers, <10 y since quit.