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Table 2 Breast cancer-specific mortality according to smoking exposure at time of diagnosis among 5,892 women with invasive breast cancer (1987 to 2008)

From: Smoking at time of diagnosis and breast cancer-specific survival: new findings and systematic review with meta-analysis

Smoking status   Breast cancer-specific mortality
Number of Crude HR (95% CI) Agea-adjusted HR (95% CI) AdjustedbHR (95% CI)
Women Deaths
Neverc 3,510 583 1.00 1.00 1.00
Former 1,303 185 0.94 (0.79 to 1.11) 0.99 (0.84 to 1.17) 1.04 (0.88 to 1.24)
Currentd 1,079 185 0.99 (0.84 to 1.16) 0.99 (0.83 to 1.17) 1.15 (0.97 to 1.37)
≤15 pack years 232 40 0.82 (0.60 to 1.13) 0.73 (0.53 to 1.01) 0.92 (0.66 to 1.28)
>15 to ≤30 pack years 278 54 1.06 (0.80 to 1.40) 1.05 (0.79 to 1.39) 1.23 (0.92 to 1.64)
>30 pack years 273 58 1.20 (0.91 to 1.57) 1.35 (1.03 to 1.78) 1.52 (1.15 to 2.00)
P-value, test for trende    0.08 0.004 0.002
≤10 cigarettes/day 287 36 0.75 (0.54 to 1.05) 0.73 (0.52 to 1.02) 0.97 (0.69 to 1.37)
>10 to ≤20 cigarettes/day 395 75 1.05 (0.83 to 1.34) 1.06 (0.83 to 1.35) 1.13 (0.88 to 1.45)
>20 cigarettes/day 337 70 1.17 (0.91 to 1.50) 1.19 (0.92 to 1.53) 1.32 (1.02 to 1.70)
P-value, test for trende    0.06 0.04 0.03
≤20 years 191 44 1.06 (0.78 to 1.44) 0.87 (0.63 to 1.19) 1.05 (0.76 to 1.45)
21 to 30 years 258 49 0.93 (0.69 to 1.24) 0.92 (0.68 to 1.24) 1.06 (0.78 to 1.44)
>30 years 340 61 1.11 (0.85 to 1.45) 1.30 (1.00 to 1.70) 1.56 (1.19 to 2.05)
P-value, test for trende    0.67 0.07 0.004
  1. aHRs adjusted for age at diagnosis (≤39, 40 to 49, 50 to 59, 60 to 69, ≥70 years). bHRs adjusted for age at diagnosis (≤39, 40 to 49, 50 to 59, 60 to 69, ≥70 years), year of diagnosis (≤1994, 1995 to 1999, 2000 to 2004, ≥2005), age at menarche (≤11, 12, 13, ≥14 years), parity (0, 1, 2, ≥3), menopausal status (premenopausal, postmenopausal), current hormone replacement therapy use (yes, no), first degree family history of breast cancer (yes, no), estrogen and progesterone receptors positivity (positive, negative, not investigated), histological grade (well, moderately, poorly differentiated), size of the tumor (≤10, 11 to 20, 21 to 30, 31 to 40, >40 mm, no pathological investigation), regional or distant involvement (node-negative, 1 to 3 positive nodes, ≥4 positive nodes, unknown nodal involvement, distant metastases), locoregional treatment (mastectomy, breast-conserving surgery, no surgery), neoadjuvant therapy (yes, no), adjuvant endocrine therapy (yes, no), adjuvant chemotherapy (yes, no). cReference category. dAmong the 1,079 current smokers, number of pack years of smoking, number of cigarettes smoked and duration of smoking were unknown for 296, 60 and 290 women, respectively. eP for trend in hazard ratios comparing current smokers further categorized based on number of pack years of smoking, number of cigarettes smoked daily or duration of smoking, to never smokers. HR, hazard ratio; CI, confidence interval.