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. Author manuscript; available in PMC: 2016 Aug 1.
Published in final edited form as: Cancer Epidemiol Biomarkers Prev. 2015 May 20;24(8):1199–1206. doi: 10.1158/1055-9965.EPI-15-0187

Table 2.

Pre-diagnostic Plasma CRP Levels and Risk of Breast Cancer Overall and Risk of Fatal Breast Cancer in the NHS and the WHS and the Combined Analysis.

Quintile 1 Quintile 2 Quintile 3 Quintile 4 Quintile 5 Trend-test P-value
Risk of incident breast cancer overall
All cases NHS Ca|Co 192|245 158|242 161|243 200|246 232|245
RR(95%CI)a 1.00Ref 0.86 (0.64, 1.16) 0.93 (0.69, 1.26) 1.12 (0.83, 1.52) 1.27 (0.93, 1.73) 0.02
WHS Ca|Person-years 401|89037 364|87230 384|86084 421|86008 349|85736
HR(95%CI)b 1.00Ref 0.92 (0.79, 1.06) 0.97 (0.84, 1.13) 1.05 (0.90, 1.23) 0.89 (0.76, 1.06) 0.38
Combined 1.00Ref 0.90 (0.79, 1.03) 0.97 (0.84, 1.10) 1.07 (0.93, 1.22) 1.04 (0.74, 1.46) 0.52
P-hetc 0.01
Risk of fatal breast cancer overall
All cases NHS Ca|Co 12|245 18|242 17|243 16|246 36|245
RR(95%CI)d 1.00Ref 1.35 (0.62, 2.94) 1.25 (0.56, 2.79) 1.10 (0.48, 2.53) 2.50 (1.17, 5.33) 0.004
WHS Ca|Person-years 16|87377 16|85191 27|84066 28|84049 18|83587
HR(95%CI)b 1.00Ref 0.97 (0.47, 2.00) 1.61 (0.83, 3.12) 1.35 (0.67, 2.70) 1.12 (0.52, 2.42) 0.97
Combined 1.00Ref 1.13 (0.67, 1.92) 1.45 (0.87, 2.42) 1.24 (0.73, 2.11) 1.68 (0.77, 3.67) 0.33
P-hetc 0.03
a

Conditional logistic regression adjusted for family history of breast cancer, history of benign breast disease, BMI at blood collection (<21, 21-<23, 23-<25, 25-<30, ≥30kg/m2), age at menarche (<12, 12, 13, >13 years), parity and age at first birth (nulliparous, 1-2 children and <25, 1-2 children and 25-<30, 1-2 children and ≥30, >2 children and <25, >2 children and ≥25 years), alcohol (none, >0-<5, 5-<10, ≥10 g/day, missing), smoking (never/former/current), and physical activity (quartiles of weekly recreational activities mets-h/week). Matching variables were age, month of blood collection, time of day of blood draw, fasting status, menopausal status at blood collection and diagnosis and PMH use at blood collection.

b

Adjusted for the same variables in a and age (continuous), randomized treatment assignment (aspirin vs. placebo, vitamin E vs. placebo, and beta-carotene vs. placebo), menopausal status and postmenopausal hormone use (premenopausal, postmenopausal without hormone use, postmenopausal with hormone use, unknown or missing).

c

P-value for test between study heterogeneity of the trend.

d

Adjusted for family history of breast cancer, history of benign breast disease, BMI at blood collection, age at menarche, parity and age at first birth, alcohol, smoking, physical activity, age, month of blood collection, time of day of blood draw, fasting status, menopausal status at blood draw and diagnosis and PMH use at blood collection.

Study-specific quintile cut-offs (mg/L): NHS: 0.49, 1.02, 1.82, 3.56; WHS: 0.65, 1.46, 2.74, 5.17.