Skip to main content

Advertisement

Table 2 Association between mammographic density and other selected risk factors, and risk of total, invasive, and in situ breast cancer in the NBCSP case-control study

From: Mammographic density and risk of breast cancer according to tumor characteristics and mode of detection: a Spanish population-based case-control study

   Total breast cancer   Invasive breast cancer   Ductal carcinoma in situ
Baseline risk factor No. of controls (%) No. of cases (%) Odds ratioa (95% CI)   No. of cases (%) Odds ratioa (95% CI)   No. of cases (%) Odds ratioa (95% CI)
Age at first live birthb          
   5-year increase 4,048 (86.8) 940 (81.3) 1.12 (1.02-1.22)   795 (81.8) 1.10 (1.00-1.21)   145 (78.8) 1.19 (0.97-1.46)
   Nulliparous 618 (13.2) 216 (18.7) 1.34 (1.12-1.61)   177 (18.2) 1.30 (1.06-1.58)   39 (21.2) 1.58 (1.04-2.40)
Age at menopausec          
   5-year increase 3,040 (65.2) 728 (63.0) 1.18 (1.06-1.30)   619 (63.7) 1.17 (1.05-1.30)   109 (59.2) 1.20 (0.92-1.55)
   Premenopausal 1,626 (34.8) 428 (37.0) 1.14 (0.93-1.41)   353 (36.3) 1.20 (0.95-1.51)   75 (40.8) 0.96 (0.59-1.55)
Family history of breast cancer          
   None 4,055 (86.9) 932 (80.6) 1.00 (reference)   790 (81.3) 1.00 (reference)   142 (77.2) 1.00 (reference)
   Second-degree relative 325 (7.0) 107 (9.3) 1.39 (1.10-1.75)   89 (9.2) 1.39 (1.08-1.79)   18 (9.8) 1.42 (0.83-2.43)
   First-degree relative ≥50 years 172 (3.7) 64 (5.5) 1.46 (1.08-1.98)   49 (5.0) 1.33 (0.95-1.87)   15 (8.2) 2.11 (1.13-3.94)
   First-degree relative <50 years 114 (2.4) 53 (4.6) 1.90 (1.35-2.68)   44 (4.5) 2.00 (1.38-2.91)   9 (4.9) 1.63 (0.77-3.47)
Previous breast biopsy          
   No 4,263 (91.4) 986 (85.3) 1.00 (reference)   826 (85.0) 1.00 (reference)   160 (87.0) 1.00 (reference)
   Yes 403 (8.6) 170 (14.7) 1.57 (1.28-1.92)   146 (15.0) 1.68 (1.36-2.08)   24 (13.0) 1.11 (0.68-1.83)
Mammographic density (%)          
   0-10 1,710 (36.6) 263 (22.7) 1.00 (reference)   233 (24.0) 1.00 (reference)   30 (16.3) 1.00 (reference)
   11-25 1,136 (24.3) 244 (21.1) 1.43 (1.18-1.74)   206 (21.2) 1.39 (1.12-1.71)   38 (20.7) 1.65 (1.01-2.83)
   26-50 1,157 (24.8) 375 (32.4) 2.24 (1.85-2.71)   319 (32.8) 2.18 (1.78-2.68)   56 (30.4) 2.65 (1.60-4.40)
   51-75 528 (11.3) 215 (18.6) 2.76 (2.19-3.48)   164 (16.9) 2.38 (1.85-3.06)   51 (27.7) 5.60 (3.24-9.67)
   >75 135 (2.9) 59 (5.1) 3.06 (2.14-4.40)   50 (5.1) 2.95 (2.01-4.35)   9 (4.9) 3.47 (1.46-8.27)
   P value for trendd    <0.001    <0.001    < 0.001
  1. aOdds ratios and 95% confidence intervals (CIs) for total, invasive, and in situ breast cancer obtained from separate multivariate conditional logistic regression models adjusted for all risk factors shown in the table. bAdjusted odds ratios per 5-year increase in age at first live birth among parous women, as well as for nulliparous women compared with women having their first live birth at 25 years. cAdjusted odds ratios per 5-year increase in age at menopause among postmenopausal women, as well as for premenopausal women compared with women having their menopause at 45 years. dP values for linear trend by using an ordinal variable with values 1 through 6 across successive categories of mammographic density.