Table 2. Omega-3 versus placebo (subgroups DHA dosage).
| Overall effect | Heterogeneity | ||||||
|---|---|---|---|---|---|---|---|
| Outcome | No. of studies | No. of participants | Statistical method | Effect size[95%CI] | P | I2,% | P' |
| Glycemic control | |||||||
| FPG (mmol/L) | 17 | 990 | WMD (IV, Fixed) | 0.181[-0.022,0.385] | 0.081 | 0.0 | 0.964 |
| Low dose (≤1.0 g/d DHA) [13,14,16–18,22,23,29] | 8 | 752 | WMD (IV, Fixed) | 0.219[-0.003,0.440] | 0.053 | 0.0 | 0.801 |
| High dose (>1.0 g/d DHA) [19,20,24–28,30,32] | 9 | 238 | WMD (IV, Fixed) | -0.023[-0.538,0.493] | 0.932 | 0.0 | 0.939 |
| PPG (mmol/L) | 2 | 42 | WMD (IV, Fixed) | -1.036[-3.280,1.208] | 0.366 | 9.5 | 0.293 |
| High dose (>1.0 g/d DHA) [19,25] | 2 | 42 | WMD (IV, Fixed) | -1.036[-3.280,1.208] | 0.366 | 9.5 | 0.293 |
| HbAc1 (%) | 15 | 1179 | WMD (D+L, Random) | -0.050[-0.219,0.119] | 0.565 | 45.7 | 0.028 |
| Low dose (≤1.0 g/d DHA) [14–18,22,23,29] | 8 | 981 | WMD (D+L, Random) | -0.106[-0.313,0.101] | 0.318 | 68.9 | 0.002 |
| High dose (>1.0 g/d DHA) [19,20,24,25,28,30,32] | 7 | 198 | WMD (D+L, Random) | 0.210[-0.209,0.628] | 0.326 | 0.0 | 0.906 |
| INS (pmol/L) | 9 | 588 | WMD (D+L, Random) | -4.288[-10.911,2.335] | 0.204 | 2.8 | 0.411 |
| Low dose (≤1.0 g/d DHA) [16,18,22,23] | 4 | 506 | WMD (D+L, Random) | -2.353[-13.970,9.264] | 0.691 | 52.1 | 0.100 |
| High dose (>1.0 g/d DHA) [19,24,26–28] | 5 | 82 | WMD (D+L, Random) | -2.716[-17.148,11.715] | 0.712 | 0.0 | 0.755 |
| Lipid parameters | |||||||
| TG (mmol/L) | 12 | 703 | WMD (IV, Fixed) | -0.243[-0.339,-0.147] | <0.001 | 0.0 | 0.912 |
| Low dose (≤1.0 g/d DHA) [13,15,17,22,23,29] | 6 | 533 | WMD (IV, Fixed) | -0.248[-0.355,-0.141] | <0.001 | 0.0 | 0.628 |
| High dose (>1.0 g/d DHA) [24–27,30,32] | 6 | 170 | WMD (IV, Fixed) | -0.225[-0.438,-0.011] | 0.039 | 0.0 | 0.867 |
| TC (mmol/L) | 15 | 874 | WMD (IV, Fixed) | -0.023[-0.120,0.073] | 0.635 | 0.0 | 0.831 |
| Low dose (≤ 1.0 g/d DHA) [13–17,22,23,29] | 8 | 664 | WMD (IV, Fixed) | -0.033[-0.139,0.072] | 0.533 | 0.0 | 0.543 |
| High dose (>1.0 g/d DHA) [20,24–27,30,32] | 7 | 210 | WMD (IV, Fixed) | 0.028[-0.210,0.266] | 0.815 | 0.0 | 0.832 |
| BMI (kg/m2) | 3 | 392 | WMD (IV, Fixed) | 0.055[-0.800,0.909] | 0.900 | 0.0 | 0.947 |
| Low dose (≤ 1.0 g/d DHA) [15,23] | 2 | 348 | WMD (IV, Fixed) | 0.049[-0.861,0.959] | 0.916 | 0.0 | 0.744 |
| High dose (>1.0 g/d DHA) [30] | 1 | 44 | WMD (IV, Fixed) | 0.100[-2.394,2.594] | 0.937 | ― | ― |
| Weight(kg) | 9 | 248 | WMD (IV, Fixed) | 0.365[-2.788,3.518] | 0.820 | 0.0 | 1.000 |
| Low dose (≤1.0 g/d DHA) [17,22,29] | 3 | 88 | WMD (IV, Fixed) | -0.081[-4.929,4.767] | 0.974 | 0.0 | 0.988 |
| High dose (>1.0 g/d DHA) [20,24,25,27,28,30] | 6 | 160 | WMD (IV, Fixed) | 0.693[-3.459,4.844] | 0.744 | 0.0 | 1.000 |
Notes: BMI, body mass index; FPG, fast plasma glucose; PPG, postprandial glucose; HbA1c, glycosylated hemoglobin; INS, insulin; TG, Triglyceride; TC, total cholesterol; WMD, weighted mean difference; IV, inverse variance; D+L, DerSimonian & Laird;-, not available.