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

Table 1

Characteristics of women with and without breast cancer.

Variables	Women without breast cancer		Women with breast cancer
Continuous	N	M±SD	N	M±SD
Percentage mammographic density (%)	987	32.69±11.66	84	30.84±13.64
Dense area (pixels)	987	67957.49±52047.44	84	73672.17±63341.33
Breast area (pixels)	987	210179.29±134555.93	84	248991.78±169934.14
Age at mammography (years)	987	48.94±9.49	84	52.99±11.19
Height (cm)	987	160.63±4.74	84	159.73±3.80
Weight (kg)	987	57.84±7.90	84	61.75±9.01
BMI (kg/m^2)	987	22.40±2.81	84	24.19±3.34
Age at menarche (years)	987	14.22±1.88	84	15.20±1.62
Age at menopause (years)	370	50.39±3.80	48	50.23±3.81
Age at first delivery	926	27.84±3.48	84	25.54±3.46
Duration of breastfeeding	762	7.21±4.14	77	15.92±14.03
Categorical	N	%	N	%
Menopause status
Pre-menopausal	617	62.50	36	42.86
Post-menopausal	370	37.50	48	57.14
Parity status
Nulliparous	61	6.18	0	0.00
Parous	926	93.82	84	100.00
Number of children
=1	853	92.10	50	59.52
>1	73	7.90	34	40.48
Breastfeeding history
No	225	22.80	7	8.33
Yes	762	77.20	77	91.67
Personal history of breast cancer
No	977	98.99	83	98.81
Yes	10	1.01	1	1.19
Family history of breast cancer
No	915	92.71	76	90.48
Yes	72	7.29	8	9.52
Degree of consanguinity
1st degree	47	65.28	7	87.50
2nd degree	25	34.72	1	12.50
Ethnicity
Non-Han origin	11	1.11	N/A	N/A
Han origin	976	98.89	N/A	N/A
Smoking history
No	967	97.97	N/A	N/A
Yes	20	2.03	N/A	N/A
Alcohol consumption
No	864	87.54	N/A	N/A
Yes	123	12.46	N/A	N/A
Level of education
Secondary and below	176	17.83	N/A	N/A
Tertiary	811	82.17	N/A	N/A
Geographic location
Shanghai	800	81.05	N/A	N/A
Others	187	18.95	N/A	N/A

Number of cases.
Mean ± standard deviation for continuous variables.
Height range for women without breast cancer: 146.00-180.00; height range for women with cancer: 15.00-171.00.
^dWeight range for women without breast cancer: 38.00-90.00; weight range for women with cancer: 42.00-89.00.
Calculated by weight (kg)/[height (m)]², weight range (cancer-free).
Restricted to postmenopausal women.
Restricted to parous women.
Restricted to women with breastfeeding history.
Percentage of cases for categorical variables.
Restricted to women with family history.
Not available.