Table 2.

Mean hormone concentrations in adult US males, comparing NHANES 1988–1991 and 1999–2004.

	1988–1991		1999–2004
	Meana, b	95% CIc	Meana, b	95% CIc	Difference	P-value
Testosterone (ng/ml)	5.37	5.20, 5.53	5.34	5.16, 5.52	−0.03	0.75
Free testosterone (ng/ml)	0.099	0.094, 0.103	0.097	0.093, 0.103	−0.001	0.67
SHBG (nmol/L)	34.71	33.36, 36.12	33.54	32.10, 35.04	−1.17	0.19
3α-diol-G (ng/ml)	11.98	11.41, 12.58	10.15	9.72, 10.60	−1.83	<0.01
Estradiol (pg/ml)	35.74	34.25, 37.29	29.67	28.20, 31.20	−6.07	<0.01

^aadjusted for age (1 year intervals), race/ethnicity, BMI, waist circumference, smoking, and alcohol use

^bmeans for free testosterone, SHBG, 3α-diol-G, and estradiol are geometric means

^cCI – confidence interval