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Table 4 Adjusted mean mammographic density measures according to anthropometric and lifestyle factors among premenopausal women

From: Predictors of mammographic density among women with a strong family history of breast cancer

   Premenopausal women (n = 97)
  Percent Density (%)   Dense Area (cm2)   Non-Dense Area (cm2)
n Mean1 PD 95% CI1 P 1 n Mean1 DA 95% CI1 P 1 n Mean1 NDA 95% CI1 P 1
Weight
 <77.0 kg 71 33.2 23.7-44.2   64 35.3 22.4-51.1   64 73.2 47.6-104.4  
 ≥77.0 kg 26 17.6 9.4-28.4 0.0006 24 31.9 17.1-51.4 0.59 24 165.2 115.9-223.2 <0.0001
Height
 <170 cm 69 27.0 18.3-37.5   63 32.4 19.2-48.9   63 97.7 66.5-135.0  
 ≥170 cm 28 33.2 23.1-45.1 0.18 25 37.0 23.1-54.3 0.47 25 78.6 51.3-111.8 0.16
TWA
 <43.0 MET-hrs/week 69 26.4 17.1-37.8   62 30.6 17.4-47.5   63 94.6 63.0-132.6  
 ≥43.0 MET-hrs/week 28 24.1 14.6-36.0 0.58 26 29.8 15.7-48.2 0.88 25 93.9 59.8-135.6 0.96
MVPA
 <27.0 METs/week 72 26.1 17.1-37.0   64 30.2 17.3-46.6   64 93.9 63.0-131.0  
 ≥27.0 METs/week 25 23.6 13.6-36.3 0.55 24 30.7 16.0-50.1 0.93 24 95.6 60.2-139.3 0.90
Smoking status
 Never 64 28.9 20.3-39.1 ref 58 33.5 20.8-49.3 ref 58 89.5 61.4-122.9 ref
 Former 26 29.3 19.3-41.5 0.93 23 36.2 21.5-54.8 0.68 23 102.4 68.7-142.9 0.36
 Current smoker 7 18.1 6.8-34.9 0.14 7 19.7 5.2-43.5 0.15 7 87.7 42.3-149.3 0.94
Age at first use
 <16 years 10 19.8 7.3-38.3   10 30.0 12.3-55.4   10 130.4 78.6-195.3  
 ≥16 years 23 28.8 14.0-49.0 0.15 20 46.7 25.0-75.1 0.07 20 127.9 79.8-187.4 0.90
Packs smoked
 <3 packs/week 20 29.2 14.4-49.3   18 48.1 27.5-74.5   18 125.5 78.4-183.6  
 ≥3 packs/week 13 19.5 7.3-37.6 0.12 12 25.5 10.0-48.2 0.01 12 135.9 81.7-203.8 0.64
Duration of use
 <14 years 16 32.2 17.4-51.3   14 53.1 32.0-79.5   14 126.0 77.5-186.3  
 ≥14 years 17 15.8 5.6-31.2 0.01 16 25.3 11.0-45.5 0.002 16 132.7 80.6-197.8 0.76
Alcohol use
 Never 10 29.7 17.4-45.1 ref 9 38.1 18.9-63.8 ref 9 103.3 61.0-156.6 ref
 Former 15 30.5 18.1-46.2 0.91 15 32.8 16.4-54.7 0.64 15 79.7 45.8-122.9 0.31
 Current user 72 27.9 19.1-38.3 0.78 64 33.8 21.0-49.7 0.66 64 96.0 67.3-129.7 0.73
Age at first use
 <18 years 29 21.5 11.8-34.2   27 28.9 15.2-47.0   27 118.8 78.4-167.6  
 ≥18 years 58 27.5 17.7-39.3 0.14 52 34.3 21.0-51.0 0.34 52 90.6 60.1-127.4 0.05
Drinks consumed
 <2 drinks/week 60 25.2 15.4-37.4   57 33.0 19.1-50.7   57 92.5 59.0-133.4  
 ≥2 drinks/week 27 27.7 17.0-41.1 0.58 22 33.2 19.0-51.3 0.98 22 101.1 65.3-144.6 0.58
  1. 1Adjusted least-square means, 95% confidence intervals, and P-values are from analyses using square root-transformed mammographic density measures. The adjusted least-square means and 95% confidence intervals were back-transformed
  2. All models were adjusted for age (continuous) and BMI (continuous) at the time of mammogram, parity (continuous), and mammogram modality (digital image, film scanned by study team, film scanned by imaging centre). The height and weight models were mutually adjusted for each other (continuous) instead of BMI. The physical activity models were additionally adjusted for smoking status (never, former, current). The smoking models were additionally adjusted for the number of alcoholic drinks consumed per week (continuous). The alcohol models were additionally adjusted for smoking status (never/ever). TWA, total weekly activity. MVPA, moderate-to-vigorous physical activity. METs, Metabolic Equivalent of Task