Circulating insulin-like growth factor-I, insulin-like growth factor binding protein-3 and terminal duct lobular unit involution of the breast: a cross-sectional study of women with benign breast disease

Table 1 Selected characteristics of women in the BREAST Stamp Project with benign breast disease, stratified by menopausal status

Characteristic	Premenopausal: n = 155		Postmenopausal: n = 73
Characteristic	age = 40–55 (median 47) years		age = 44–64 (median 57) years
	Number	Percent	Number	Percent	P ^t
Age at biopsy (years)
40–44	53	34.2	1^*	1.4	<0.001
45–49	64	41.3	2	2.7
50–54	37	23.9	21	28.8
55–59	1	0.6	24	32.9
60–65	0	0	25	34.2
Race/Ethnicity
White, non-Hispanic	147	94.8	67	91.8	0.37
Other	8	5.2	6	8.2
Body mass index (kg/m²)
<25	84	54.2	32	43.8	0.34
25.0–29.9	35	22.6	21	28.8
≥30	36	23.2	20	27.4
Age at menarche (years)
≤12	56	36.1	30	41.1	0.36
13	60	38.7	21	28.8
≥14	38	24.5	21	28.8
Missing	1	0.6	1	1.4
Parity
Nulliparous	41	26.4	17	23.3	0.12
1	13	8.4	14	19.2
2	65	41.9	29	39.7
≥3	36	23.2	13	17.8
Age at first birth (years)
<25	37	23.9	33	45.2	0.01
25–29	44	28.4	14	19.2
≥30	33	21.3	9	12.3
Oral contraceptive use
Never	23	14.8	10	13.7	0.82
Ever	132	85.2	63	86.3
Type of menopause
Natural	~	~	53	72.6	~
Surgical	~	~	3	4.1
Type unknown	~	~	17	23.3
Age at menopause (years)
≤45	~	~	21	28.8	~
46–49	~	~	13	17.8
50–52	~	~	19	26
≥53	~	~	13	17.8
Unknown	~	~	7	9.6
Any menopausal hormone therapy use^a
Never	135	87.1	49	67.1	<0.001
Ever	19	12.3	24	32.9
Missing	1	0.6	0	0
Cigarette smoking (100+ cigarettes/lifetime)
Never	83	53.5	28	38.4	0.07
Former	55	35.5	31	42.5
Current	10	6.5	10	13.7
Missing/Unknown	7	4.5	4	5.5
Family history of breast cancer^b
0	114	73.5	52	71.2	0.96
≥1	41	26.5	19	26
Missing	0	0	2	2.7

^aData on any use of menopausal hormone therapy (MHT) missing for one premenopausal woman, and current MHT use missing for one postmenopausal woman who reported ever use. ^bWomen with at least one first degree relative with a diagnosis of breast cancer. P ^t is the value for testing for differences in distribution by menopausal status using the chi square (Χ ²) test or Fisher's exact test when the number for a category was <5. *This woman experienced natural menopause

ISSN: 1465-542X