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Table 1 Demographics of Study 1 (cancers detected at first screen on entry to the PROCAS study) and Study 2 (cancers detected at a subsequent screen or between screening rounds)

From: Exploring the prediction performance for breast cancer risk based on volumetric mammographic density at different thresholds

  Study 1 Study 2
Controls Cases p value Controls Cases p value
Number (%) Number (%)   Number (%) Number (%)  
Age at consent (years)    0.9997    0.9997
 < 50 53 (6) 19 (6)   46 (5) 16 (5)  
 50–54 242 (26) 79 (25)   194 (21) 64 (20)  
 55–59 153 (16) 52 (16)   164 (18) 58 (18)  
 60–64 229 (24) 77 (24)   286 (31) 96 (30)  
 65–69 196 (21) 66 (21)   198 (21) 68 (21)  
 70+ 74 (8) 24 (8)   47 (5) 16 (5)  
HRT use    0.0778    0.9320
 Unknown 14 (1) 9 (3)   23 (2) 6 (2)  
 Never 568 (60) 208 (66)   475 (51) 166 (52)  
 Previous 315 (33) 83 (26)   332 (36) 110 (35)  
 Current 50 (5) 17 (5)   105 (11) 36 (11)  
BMI (kg/m2)    0.9954    0.9389
 Unknown 1 (0)     1 (0)  
 < 25 332 (35) 112 (35)   335 (36) 117 (37)  
 25–29 331 (35) 111 (35)   341 (36) 113 (36)  
 ≥ 30 283 (30) 94 (30)   259 (28) 87 (27)  
Menopausal status    0.4272    0.9889
 Unknown 31 (3) 10 (3)   32 (3) 12 (4)  
 Premenopausal 92 (10) 32 (10)   67 (7) 22 (7)  
 Perimenopausal 112 (12) 38 (12)   134 (14) 46 (14)  
 Postmenopausal 712 (75) 237 (75)   702 (75) 238 (75)  
Ethnic origin    0.1880    0.2208
 Other/unknown 52 (5) 24 (8)   81 (9) 35 (11)  
 White 895 (95) 293 (92)   854 (91) 283 (89)  
Parity    0.7134    0.0399
 Unknown 1 (0)    1 (0) 4 (1)  
 Nulliparous 112 (12) 40 (13)   91 (10) 44 (14)  
 Parous 834 (88) 277 (87)   843 (90) 270 (85)  
Tyrer-Cuzick (10 year risk, % (median, Q1–Q3)) 2.74 (2.18–3.58) 2.94 (2.29–3.88) 0.0006 2.67 (2.09–3.55) 2.91 (2.24–4.05) <.0001
Volumetric PD (median, Q1–Q3) 4.90 (3.63–7.19) 5.43 (4.06–8.13) 0.0034 4.79 (3.58–7.01) 5.51 (3.81–7.98) 0.0044
  1. The p values, from likelihood-ratio chi-square tests, indicate whether there are significant difference between cases and controls
  2. HRT hormone replacement therapy, BMI body mass index, Q1 25th percentile, Q3 75th percentile, PD percent density