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Table 2 Difference in adult mammographic density across categories of weight compared with peers at ages 7 and 11 years

From: Childhood body size and pubertal timing in relation to adult mammographic density phenotype

   Mammographic density parameters
    Absolute area
   Percent density difference, Dense area Non-dense
Weight and age Category percentage points (95% CI)a difference, cm2 (95% CI)a difference, cm2 (95% CI)a
Weight relative to peers, age 7 years
 A: Thinner 5.6 (3.0, 8.4) 6.1 (3.0, 9.3) -10.8 (-17.7, -3.6)
About the same 0.0 (baseline) 0.0 (baseline) 0.0 (baseline)
Heavier -4.1 (-7.0, -0.9) -2.1 (-5.7, 1.8) 17.7 (6.9, 28.9)
P trendb <0.001 <0.001 <0.001
 B: +BMI-adjusted Thinner 4.2 (1.8, 6.7) 5.7 (2.7, 8.9) -4.6 (-10.3, 1.3)
About the same 0.0 (baseline) 0.0 (baseline) 0.0 (baseline)
Heavier -1.6 (-4.5, 1.5) -1.1 (-4.8, 2.8) 3.5 (-4.7, 12.0)
P trendb <0.001 <0.001 0.050
Weight relative to peers, age 11 years
 A: Thinner 5.0 (2.4, 7.8) 4.3 (1.3, 7.5) -12.8 (-19.7, -5.7)
About the same 0.0 (baseline) 0.0 (baseline) 0.0 (baseline)
Heavier -7.0 (-9.3, -4.5) -6.4 (-9.3, -3.4) 23.3 (14.0, 32.9)
P trendb <0.001 <0.001 <0.001
 B: +BMI-adjusted Thinner 3.0 (0.7, 5.5) 3.8 (0.8, 7.0) -4.1 (-9.9, 1.9)
About the same 0.0 (baseline) 0.0 (baseline) 0.0 (baseline)
Heavier -4.1 (-6.5, -1.6) -5.4 (-8.3, -2.2) 5.8 (-1.3, 13.1)
P trendb <0.001 <0.001 0.017
Change in relative weight age 7 to 11 years c
 A: Decrease 0.2 (-4.6, 5.6) -0.7 (-6.3, 5.5) 2.8 (-12.3, 19.0)
About the same 0.0 (baseline) 0.0 (baseline) 0.0 (baseline)
Increase -6.3 (-9.0, -3.3) -6.1 (-9.4, -2.6) 24.1 (13.3, 35.3)
P trendb <0.001 0.007 <0.001
 B: +BMI-adjusted Decrease 0.2 (-4.3, 5.1) -0.3 (-5.9, 5.8) 3.2 (-8.8, 15.9)
About the same 0.0 (baseline) 0.0 (baseline) 0.0 (baseline)
Increase -2.8 (-5.6, 0.2) -4.4 (-7.9, -0.7) 5.9 (-2.2, 14.2)
P trendb 0.11 0.054 0.36
  1. aDifferences derived with respect to reference levels: 25% for percentage density, 30 cm2 for dense area and 110 cm2 for non-dense area. Models defined as A: analyses adjusted for age at mammogram (47–50, 50–54, 55–59 (baseline), 60–64, 65–69, 70–73 years), duration of oral contraception use (never (baseline), <5, 10–14, ≥15 years, not known), postmenopausal hormone treatment (never (baseline), former, current/<5, current/5–9, current/≥10 years duration), menopausal status and time since menopause (<5 (baseline), 10–14, 15–19, ≥20, unknown years postmenopausal, not postmenopausal), age at first birth and parity (nulliparous, 10–24 years/1–2, 10–24 years/≥3, 25–29 years/1–2 (baseline), 25–29 years/≥3, 30 years/≥1), alcohol units (none (baseline), 1–4 to ≥25, in 5-unit increments), physical activity (<31 (baseline), 32–55, 56–88, ≥88 metabolic energy equivalents/h/week); B: adjusted for covariates in model A plus body mass index (BMI) (<20.0 (baseline) to >35.0, in 2.5 kg/m2 increments). bP trend for linear regression fitted through categories of exposure. cIncrease or decrease in category of weight compared with peers between ages 7 and 11 years
  2. The p-values in bold are those with p<0.05