Association of the Differences in Average Glandular Dose with Breast Cancer Risk

Table 1

Breast cancer risk factors analyzed in the training and test sets.

Risk factor	Training set ()		Test set ()
	Healthy subjects	Cancer patients	Healthy subjects	Cancer patients
Age (y)
<45	556	210	137	56
45-55	568	239	220	80
>55	167	159	64	67
Total number	1261	608	421	203
^# value	<0.001^†	0.100^‡	<0.001^§	0.051^¶
Age at menarche
<13	143	64	54	20
13	254	133	82	32
14	239	94	99	42
15	229	102	69	24
>15	396	215	117	85
^# value	0.236^†	0.074^‡	<0.001^§	0.077^¶
Menopausal status
Premenopausal	942	347	280	109
Postmenopausal	319	261	141	94
^$ value	<0.001^†	0.001^‡	0.002^§	0.402^¶
Parity
Nulliparous	45	27	12	9
Multiparous	1216	581	409	194
^$ value	0.359^†	0.481^‡	0.305^§	0. 997^¶
Age at first birth
^# value	0.685^†	0.444^‡	0.365^§	0.418^¶
Family history of breast cancer
0	1220	595	410	201
≥1	41	13	11	2
^$ value	0.177^†	0.509^‡	0.072^§	0.121^¶
BI-RADS density
Fatty	53	16	5	7
Scattered	149	112	49	45
Heterogeneous	958	422	318	133
Dense	101	58	49	18
^$ value	0.512^†	0.529^‡	<0.001^§	0.224^¶

Note: SD = standard deviation. ^#Student’s unpaired -test, two sides. ^$Mann–Whitney test. ^†Values are for healthy subjects versus cancer patients in the training set. ^‡Values are for healthy subjects in the training set versus healthy subjects in the test set. ^§Values are for healthy subjects versus cancer patients in the test set. ^¶Values are for cancer patients in the training set versus cancer patients in the test set.