Characteristics of Mammographic Breast Density and Associated Factors for Chinese Women: Results from an Automated Measurement

Table 2

Output from univariate analysis of PD and DA for women with and without breast cancer.

Variables	Women without breast cancer				Women with breast cancer
	Percentage density		Dense area		Percentage density		Dense area
Continuous	r	P	r	P	r	P	r	P
Breast area (pixels)	-0.043	0.174	0.790	<0.001	-0.142	0.197	0.739	<0.001
Age at mammography (years)	-0.202	<0.001	-0.086	0.007	-0.451	<0.001	-0.011	0.920
Height (cm)	0.030	0.352	0.034	0.283	-0.028	0.803	0.041	0.708
Weight (kg)	-0.237	<0.001	0.110	<0.001	-0.495	<0.001	-0.075	0.498
BMI (kg/m^2)	-0.272	<0.001	0.099	0.002	-0.520	<0.001	-0.088	0.425
Age at menarche (years)	-0.078	0.014	-0.080	0.012	-0.084	0.447	0.104	0.344
Age at menopause (years)	0.007	0.887	-0.003	0.950	-0.290	0.046	-0.225	0.124
Age at first delivery	-0.026	0.437	-0.014	0.678	0.157	0.155	-0.021	0.852
Duration of breastfeeding	-0.068	0.059	0.058	0.110	-0.173	0.133	-0.081	0.486
Categorical	M±SD	P	M±SD	P	M±SD	P	M±SD	P
Menopause status
Pre-menopausal	34.85±10.89	<0.001	72178.87±53101.24	<0.001	37.06±11.36	<0.001	78641.39±60101.65	0.364
Post-menopausal	29.09±12.01		60918.05±49515.81		26.17±13.44		69945325±66046.94
Number of children
=1	32.74±11.58	0.250	69656.06±52925.99	0.101	33.02±13.06	0.075	72208.90±60232.08	0.954
>1	31.09±13.69		59848.41±47664.33		27.62±14.04		75824.03±68528.80
Breastfeeding history
No	31.76±11.15	0.173	58874.45±41826.50	0.002	39.18±14.20	0.091	95541.71±98622.02	0.380
Yes	32.97±11.80		70639.49±54436.41		30.08±13.43		71684.03±59713.81
Personal history of breast cancer
No	32.71±11.66	0.724	67935.83±52101.27	0.939	30.80±13.72	0.832	72544.88±62872.93	0.132
Yes	31.40±1.33		70073.65±48958.06
Family history of breast cancer
No	32.58±11.76	0.278	68018.35±52313.70	0.991	30.74±13.43	0.844	73065.19±63672.86	0.644
Yes	34.13±10.27		67184.01±48874.61		31.75±16.57		79438.44±63969.64
Degree of consanguinity
1st degree	33.31±9.55	0.354	67363.28±46429.23	0.857	29.14±16.02	0.269	83744.14±67831.43	0.659
2nd degree	35.68±11.56		66846.98±54173.46		N/A		N/A
Parity status
Nulliparous	34.00±9.96	0.367	53909.78±41139.40	0.014		N/A		N/A
Parous	32.61±11.76		68882.88±52573.07
Ethnicity
Non-Han origin	37.25±3.81	0.192	98537.64±65684.04	0.255		N/A		N/A
Han origin	32.64±11.65		67612.84±51812.92
Smoking history
No	32.72±11.63	0.625	67877.39±51861.52	0.902		N/A		N/A
Yes	31.43±13.30		71830.55±61786.61
Alcohol consumption
No	32.84±11.61	0.291	68481.84±52155.77	0.365		N/A		N/A
Yes	31.65±11.99		64274.29±51338.71
Level of education
Secondary and below	28.67±12.19	<0.001	61590.39±47918.12	0.040		N/A		N/A
Tertiary	33.56±11.36		69339.25±52827.48
Geographic location
Shanghai	32.50±11.50	0.276	67946.45±51558.11	0.861		N/A		N/A
Others	33.53±12.30		68004.75±54233.54

Pearson’s correlation coefficient for continuous variables.
P values from Pearson and t-tests for continuous and categorical variables, respectively.
Calculated by weight (kg)/[height (m)]².
Restricted to postmenopausal women.
Restricted to parous women.
Restricted to women with breastfeeding history.
Mean ± standard deviation.
Restricted to women with family history.
Not applicable due to insufficient number/unavailable data.