Sex steroids, growth factors and mammographic density: a cross-sectional study of UK postmenopausal Caucasian and Afro-Caribbean women

Table 2 Comparison of plasma biomarkers and mammographic measures in Afro-Caribbean women compared with Caucasian women

	Adjustment^a
	Age and batch	Age, batch and BMI	Age, batch, BMI and breast cancer risk factors^b
Plasma biomarker^c
Leptin (ng/ml)^d	6.8 (4.8, 8.9)****	3.2 (1.7, 4.7)****	3.6 (1.9, 5.2)****
Oestradiol (pmol/l)	1.31 (1.12, 1.52)****	1.11 (0.96, 1.29)	1.11 (0.94, 1.31)
Free oestradiol (pmol/l)	1.39 (1.17, 1.65)****	1.11 (0.95, 1.30)	1.11 (0.94, 1.32)
Oestrone (pmol/l)	1.13 (1.01, 1.27)**	1.05 (0.93, 1.18)	1.05 (0.93, 1.19)
SHBG (nmol/l)	0.86 (0.78, 0.96)***	0.98 (0.89, 1.08)	0.96 (0.86, 1.07)
Testosterone (nmol/l)	0.94 (0.80, 1.11)	0.88 (0.74, 1.03)	0.86 (0.72, 1.03)
Prolactin (mIU/l)	1.02 (0.90, 1.16)	1.04 (0.91, 1.19)	1.00 (0.87, 1.16)
IGF-I (ng/ml)	1.09 (1.00, 1.19)**	1.13 (1.03, 1.24)***	1.12 (1.01, 1.24)**
IGF-I:IGFBP-3 molar ratio	1.13 (1.04, 1.23)***	1.20 (1.10, 1.30)***	1.20 (1.10, 1.32)***
IGF-II (ng/ml)	0.83 (0.77, 0.89)****	0.82 (0.76, 0.89)****	0.82 (0.76, 0.90)****
IGF-II:IGFBP-3 molar ratio	0.86 (0.80, 0.92)****	0.87 (0.81, 0.94)**	0.89 (0.82, 0.96)**
IGFBP-3 (ng/ml)	0.96 (0.91, 1.02)*	0.94 (0.89, 1.00)**	0.93 (0.87, 0.99)**
Mammographic measures^e
Mammographic density (%)	-5.4 (-7.8, -3.0)****	-2.5 (-5.1, 0.2)*	-0.8 (-3.7, 2.2)
Dense area (cm²)	-2.7 (-6.9, 1.4)	-1.9 (-6.4, 2.7)	0.7 (-4.4, 5.8)
Nondense area (cm²)	50.5 (33.2, 67.8)***	19.6 (7.7, 31.5)***	15.7 (3.1, 28.3)**
Total breast area (cm²)	48.7 (31.3, 66.0)****	18.7 (6.3, 31.1)***	17.0 (3.6, 30.5)**

IGF, insulin-like growth factor; IGFBP, IGF binding protein; SHBG, sex hormone binding globulin. ^aAdjustment made for age at blood collection and processing batch (or age at mammography) in all models, in addition to listed factors. ^bAge at menarche, parity, age at first birth, smoking, age at menopause. ^cData presented as ratio (95% confidence interval) of mean levels (Afro-Caribbean:Caucasian). ^dArithmetic scale (absolute differences reported as leptin did not need to be log-transformed). ^eData presented as difference (95% confidence interval) in means (Afro-Caribbean-Caucasian). *P < 0.1, **P < 0.05, ***P < 0.01, ****P < 0.001.

ISSN: 1465-542X