The combined influence of multiple sex and growth hormones on risk of postmenopausal breast cancer: a nested case-control study

Table 2 Risk of breast cancer among postmenopausal women not using hormones in the Nurses' Health Study on the basis of several hormone scores^a

	Sample size			RR (95% CI)^b
Hormone scores	Total cases	ER+ cases	Controls	All cases	ER+ cases^c
Number of hormones > geometric mean^d
0	11	5	43	1.0	1.0
1 to 2	35	18	113	1.1 (0.5 to 2.4)	1.2 (0.4 to 3.4
3 to 4	63	35	146	1.6 (0.8 to 3.3)	1.8 (0.7 to 5.0)
5 to 6	82	43	137	2.1 (1.0 to 4.5)	2.4 (0.9 to 6.5)
7 to 8	74	46	102	2.7 (1.3 to 5.7)	3.4 (1.3 to 9.4)
Per 1-unit increase	265	147	541	1.16 (1.08 to 1.24)	1.19 (1.09 to 1.29)
Per 1 SD increase^d	265	147	541	1.42 (1.21 to 1.66)	1.51 (1.24 to 1.85)
P trend	265	147	541	< 0.001	< 0.001
Score weighted by individual hormone associations^e
Quintile 1	30	14	109	1.0	1.0
Quintile 2	42	24	107	1.4 (0.8 to 2.4)	1.7 (0.8 to 3.5)
Quintile 3	48	25	109	1.6 (0.9 to 2.7)	1.8 (0.9 to 3.7)
Quintile 4	58	32	108	2.0 (1.2 to 3.3)	2.3 (1.1 to 4.5)
Quintile 5	87	52	108	3.0 (1.8 to 5.0)	3.9 (2.0 to 7.5)
Per 1 SD increase^e	265	147	541	1.45 (1.23 to 1.70)	1.54 (1.26 to 1.88)
P trend	265	147	541	< 0.001	< 0.001
Score weighted by MCF-7 proliferation^f
Quintile 1	35	16	108	1.0	1.0
Quintile 2	37	27	109	1.0 (0.6 to 1.7)	1.6 (0.8 to 3.2)
Quintile 3	55	23	108	1.6 (0.9 to 2.6)	1.5 (0.7 to 2.9)
Quintile 4	53	29	109	1.5 (0.9 to 2.5)	1.8 (0.9 to 3.5)
Quintile 5	85	52	107	2.5 (1.5 to 4.1)	3.5 (1.8 to 6.6)
Per 1 SD increase^f	265	147	541	1.44 (1.22 to 1.69)	1.55 (1.26 to 1.89)
P trend	265	147	541	< 0.001	< 0.001

ER = estrogen receptor. ^aHormones included in the score are estrone, estradiol, estrone sulfate, testosterone, androstenedione, dehydroepiandrosterone, dehydroepiandrosterone sulfate and prolactin. ^bRR and 95% CI were adjusted for age at blood draw and menopause, parity, history of benign breast disease, family history of breast cancer, fasting status and time of day of blood draw. ^cn = 147 ER-positive cases. ^dScore is the number of hormones for which the participant had higher than the age- and assay batch-adjusted geometric mean hormone level. Mean = 4.0 (SD = 2.4). ^eScore is the sum of the log₂-transformed hormone level multiplied by the β coefficient for that hormone with breast cancer risk. Mean = 10.8 (SD = 1.1) among controls. ^fScore is the sum (across all hormones) of the natural log-transformed hormone level multiplied by a standardized proliferation rate (compared to estradiol) for MCF-7 breast cancer cells. Mean = 20.2 (SD = 2.1) among controls.

ISSN: 1465-542X