Table 2

Subgroup analysis of the effects of isoflavones on serum total cholesterol. Isoflavones were shown to have significant benefits when given in the form of ISP or soy protein capsule. Regardless the forms of prescription, isoflavones decreased serum total cholesterol among normolipidemic but not hyperlipidemic subjects.
Subgroup outcome
 No. of comparisons
 No. of subjects ||
 Treatment effect on TC (mmol/L) ¶
 Heterogeneity p-value §
Form of intervention †:



     a.) isoflavones tablets
 12 [8-10,12,13,16-18,20,21]
 482
 0.01 (-0.17, 0.18)
 1.00
     b.) ISP(+)
 8 [14,15,22,23]
 229
 -0.11 (-0.21, -0.01)*
 0.34
     c.) soy protein capsule
 1 [11]
 78
 -0.69 (-1.19, -0.19)*
 NA
     d.) soy biscuit
 1 [7]
 20
 -0.05 (-0.47, 0.37)
 NA
     e.) soy burger
 1 [19]
 44
 0.09 (-0.38, 0.56)
 NA
     f.) Overall
 21 [7-23]
 853
 -0.09 (-0.18, -0.01)*
 0.77
Isoflavones mixture ‡:



     G&D&B&F
 5 [12,13,17,18]
 214
 -0.06 (-0.34, 0.21)
 0.96
     G&D
 6 [9-11,16,19,22]
 285
 -0.22 (-0.41, -0.03)*
 0.06
     G
 1 [21]
 60
 0.10 (-0.35, 0.55)
 NA
Isoflavones intake (mg per day):



     < 50
 3 [8,13,17]
 132
 -0.12 (-0.54, 0.29)
 0.99
     51–100
 12 [8,10,12,14,15,17-23]
 484
 -0.10 (-0.21,0.01)
 0.74
     101 – 150
 4 [9,11,15,23]
 176
 -0.10 (-0.24, 0.05)
 0.09
Design :



     parallel crossover
 9 [8-14,21]
 447
 -0.08 (-0.27, 0.10)
 0.48
          a.) no washout
 1 [22]
 56
 -0.43 (-0.73, -0.13)*
 NA
          b.) washout mentioned
 6 [15,19,20,23]
 208
 -0.07 (-0.17, 0.03)
 0.91
Gender:



     male
 2 [7,22]
 76
 -0.30 (-0.54, -0.05)*
 0.15
     female
 17 [8-11,13-18,20,21,23]
 674
 -0.07 (-0.17, 0.02)
 0.89
Treatment length:



     2–10 weeks
 14[7,10,12,13,15-17,19,20,22,23]
 541
 -0.09 (-0.18, 0.00)
 0.84
     11–20 weeks
 3 [11,14,18]
 155
 -0.22 (-0.52, 0.07)
 0.07
     21–30 weeks
 4 [8,9,21]
 157
 0.02 (-0.28, 0.31)
 0.96
Menopausal status:



     pre-menopausal
 3 [15,18]
 80
 -0.06 (-0.17, 0.06)
 0.58
     peri-menopausal
 1 [11]
 78
 -0.69 (-1.19, -0.19)*
 NA
     post-menopausal
 13 [8-10,13,14,16,17,20,21,23]
 516
 -0.05 (-0.20, 0.10)
 1.00
Subjects with:



     normolipidemia
 8 [11,12,15,18,19,21,22]
 377
 -0.11 (-0.21, -0.01)*
 0.08
     hyperlipidemia
 3 [7,9,14]
 105
 -0.05 (-0.36, 0.26)
 1.00

* statistically significant † 'ISP (+)' = isoflavone containing isolated soy protein; 'ISP (-)' = isoflavone depleting isolated soy protein ‡ 'G' = Genistein; 'D' = Daidzein; 'B' = Biochanin A; 'F' = Formononectin § NA = not applicable || Since subjects acted as their own controls in a crossover trial, the 'calculated' total number was thus doubled in a single pair comparison. ¶ 95% confidence interval in parenthesis

Yeung and Yu Nutrition Journal 2003 2:15   doi:10.1186/1475-2891-2-15