Table 2

Sex hormone-binding globulin and endogenous sex hormones by treatment group at week 4 and week 8 in men
Week 4 Week 8
Value (95% confidence interval) Value (95% confidence interval)
Caffeinated Decaffeinated No Coffee Caffeinated Decaffeinated No Coffee
Coffee Coffee Coffee Coffee Coffee
(N = 4) (N = 4) (N = 6) (N = 4) (N = 4) (N = 6)
SHBG (nmol/L)
Geometric means 20.7 (15.2, 28.1) 23.9 (16.7, 34.2) 23.0 (16.3, 32.4) 23.1 (19.4, 27.5) 25.0 (20.4, 30.6) 23.1 (19.0, 28.0)
Difference in CFB (%) −10.2 (−44.7, 45.7) 3.8 (−39.3, 77.4) Reference 0.2 (−23.8, 31.8) 8.2 (−20.1, 46.5) Reference
Testosterone (ng/dL)
Geometric means 546.2 (412.8, 722.7) 493.6 (350.5, 695.1) 327.4 (227.7, 470.8) 403.8 (349.8, 466.0) 386.1 (324.0, 460.1) 373.1 (309.8, 449.5)
Difference in CFB (%) 66.8 (3.9, 167.9) a 50.8 (−13.1, 161.6) Reference 8.2 (−15.1, 37.9) 3.5 (−22.0, 37.2) Reference
Free testosterone (ng/dL)
Geometric means 11.7 (7.0, 19.6) 9.2 (5.1, 16.8) 6.6 (3.6, 12.2) 8.0 (6.6, 9.6) 7.6 (6.1, 9.5) 7.0 (5.6, 8.7)
Difference in CFB (%) 76.0 (−21.8, 295.9) 39.0 (−42.8, 238.0) Reference 14.5 (−14.9, 54.1) 9.7 (−20.8, 51.9) Reference
Estradiol (pg/mL)
Geometric means 22.5 (17.2, 29.5) 35.9 (26.3, 49.0) 42.6 (30.9, 58.7) 25.2 (19.3, 32.8) 27.1 (20.0, 36.9) 20.7 (15.1, 28.4)
Difference in CFB (%) −47.1 (−65.5, -19.1) b −15.8 (−47.3, 34.5) Reference 21.7 (−20.0, 85.3) 31.2 (−17.4, 108.2) Reference
Free estradiol (pg/mL)
Geometric means 0.4 (0.3, 0.6) 0.7 (0.5, 0.9) 0.8 (0.6, 1.1) 0.5 (0.4, 0.6) 0.5 (0.4, 0.71) 0.4 (0.3, 0.6)
Difference in CFB (%) −42.8 (−63.7, -9.9) a −12.7 (−46.5, 42.4) Reference 21.4 (−21.9, 88.8) 31.1 (−18.5, 110.9) Reference
Testosterone : Estradiol
Geometric means 24.2 (15.2, 38.4) 12.6 (7.5, 21.4) 8.4 (4.8, 14.5) 16.1 (12.2, 21.3) 14.6 (10.6, 20.1) 17.5 (12.5, 24.4)
Difference in CFB (%) 188.8 (38.5, 502.1) b 50.9 (−31.7, 233.6) Reference −8.0 (−41.1, 43.8) −16.6 (−48.5, 35.1) Reference
DHEAs (ng/mL)
Geometric means 178.0 (161.1, 196.8) 165.4 (147.7, 185.3) 159.8 (143.7, 177.6) 193.9 (168.1, 223.7) 164.1 (139.6, 193.0) 162.9 (140.1, 189.5)
Difference in CFB (%) 11.4 (−4.2, 29.5) 3.5 (−12.0, 21.7) Reference 19.0 (−4.0, 47.6) 0.7 (−20.1, 27.0) Reference

SHBG, sex hormone-binding globulin; CFB, change from baseline; DHEAs, dehydroepiandrosterone sulfate.

Geometric mean as the dependent variable with treatment as a main effect, and baseline log value (grand mean centered) and age (grand mean centered) as covariates.

Difference in change from baseline compared to No Coffee (i.e., ratio of ratios) adjusted for the above covariates.

a p < 0.05 compared to No Coffee.

b p < 0.01 compared to No Coffee.

Wedick et al.

Wedick et al. Nutrition Journal 2012 11:86   doi:10.1186/1475-2891-11-86

Open Data