Breast asymmetry and predisposition to breast cancer

Breast Cancer Research

Table 2 Conditional logistic regression analyses with presence or absence of cancer as the dependent variable, for both absolute and relative breast fluctuating asymmetry (n = 504)

Risk factor	Crude relative odds	(95% CI)	p-value	Adjusted relative odds^a	(95% CI)	p-value	Adjusted relative odds^b	(95% CI)	p-value
Absolute breast FA (100 ml)	1.29	(1.01, 1.64)	0.039	1.50	(1.10, 2.04)	0.010	-	-	-
Relative breast FA (%)	1.07	(0.99, 1.14)	0.070	-	-	-	1.09	(1.01, 1.18)	0.032
BMI	1.00	(0.95, 1.06)	0.98	1.00	(0.91, 1.09)	0.97	1.00	(0.92, 1.09)	0.98
Height (cm)	1.06	(1.03, 1.09)	<0.001	1.06	(1.02, 1.09)	0.001	1.05	(1.02, 1.09)	0.002
Age at menarche (years)	0.81	(0.72, 0.90)	<0.001	0.78	(0.69, 0.89)	<0.001	0.78	(0.69, 0.89)	<0.001
Number of pregnancies	0.94	(0.84, 1.04)	0.23	1.04	(0.92, 1.18)	0.49	1.04	(0.92, 1.18)	0.52
Family history (no. of relatives)	2.00	(1.37, 2.94)	<0.001	2.08	(1.35, 3.20)	0.001	2.10	(1.36, 3.23)	0.001
Mean breast volume (ml)	1.00	(0.999, 1.001)	0.82	1.00	(0.999, 1.000)	0.33	1.00	(0.999, 1.001)	0.94
Parenchyma type: right breast
N1	1.0	-	-	1.0	-	-	1.0	-	-
P1	3.25	(1.62, 6.52)	0.001	3.23	(1.51, 6.91)	0.003	3.30	(1.54, 7.05)	0.002
P2	4.27	(2.23, 8.17)	<0.001	3.61	(1.73, 7.53)	0.001	3.75	(1.80, 7.82)	<0.001
DY	2.69	(1.51, 4.79)	0.001	2.94	(1.48, 5.84)	0.002	3.02	(1.52, 5.99)	0.002
Menopausal status
Pre	1.0	-	-	1.0	-	-	1.0	-	-
Peri	0.49	(0.26, 0.91)	0.023	0.45	(0.23, 0.87)	0.017	0.46	(0.24, 0.89)	0.022
Post	0.29	(0.14, 0.61)	0.001	0.37	(0.16, 0.83)	0.017	0.38	(0.17, 0.85)	0.018
Age at menopause^c (years)	1.16	(1.06, 1.27)	0.002	1.18	(1.06, 1.31)	0.002	1.17	(1.06, 1.30)	0.002

All variables are continuous unless otherwise indicated. ^aAbsolute breast FA = unsigned values (|L - R|) of breast volume. ^bRelative breast fluctuating asymmetry (FA) = 100 × |L - R| breast volume/[|L + R| breast volume] 0.5. ^cFor subgroup of post-menopausal women. When age at menopause is included in the model body mass index (BMI), height, number of pregnancies and parenchyma types P1 and P2 become insignificant, and mean breast volume and parenchyma type DY have borderline significance. Absolute breast FA and relative breast FA remain significant effects. CI, confidence interval.

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