Table 4.

Subgroup analysis of fish oil supplementation and placebo by intervention duration

Outcome	No. of studies	Overall effect		Heterogeneity(%)
		Effect size(95%CI)	p	I2
FPG	13	0.13(− 0.03,0.28)	0.11	22.5
≤1 month	3	0.35(−0.18,0.88)	0.19	21.9
1-3 months	6	0.17(−0.04,0.38)	0.11	23.0
> 3 months	4	0.00(−0.26,0.27)	0.99	27.6
FINS	8	−0.00(− 0.22,0.21)	0.98	38.3
≤1 month	2	−0.53(−1.08,0.01)	0.06	0
1-3 months	2	−0.04(− 0.30,0.23)	0.79	0
> 3 months	4	0.14(−0.19,0.47)	0.41	51.7
HbAc1	10	0.01(−0.14,0.17)	0.88	0
≤1 month	1	0.89(− 0.03,1.82)	0.06	–
1-3 months	5	− 0.00(− 0.22,0.22)	1.00	0
> 3 months	4	−0.03(− 0.26,0.20)	0.81	0
HOMA-IR	8	−0.02(− 0.18,0.14)	0.82	0
≤1 month	2	−0.28(− 0.82,0.26)	0.31	0
1-3 months	2	− 0.06(− 0.37,0.25)	0.71	22
> 3 months	4	0.06(− 0.16,0.28)	0.59	0
TG	15	−0.40(− 0.53,-0.28)	0	0
≤1 month	2	−0.53(−1.07,0.02)	0.06	0
1-3 months	8	−0.40(− 0.56,-0.23)	0.00	0
> 3 months	5	−0.43(− 0.68,-0.17)	0.00	36.8
TC	15	−0.07(− 0.19,0.05)	0.28	0
≤1 month	2	0.05(− 0.50,0.60)	0.86	4.7
1-3 months	8	−0.05(− 0.23,0.14)	0.61	16.7
> 3 months	5	−0.12(− 0.32,0.07)	0.20	0
HDL cholesterol	15	0.21 (0.05,0.37)	0.01	37.1
≤1 month	2	0.29(−0.25,0.83)	0.29	0
1-3 months	8	0.14(−0.07,0.35)	0.20	33.3
> 3 months	5	0.29(−0.04,0.61)	0.09	60.6
LDL cholesterol	15	0.02(−0.10,0.14)	0.72	0
≤1 month	2	0.23(−0.40,0.86)	0.47	26.2
1-3 months	8	0.09(−0.08,0.25)	0.29	0
> 3 months	5	−0.10(− 0.29,0.10)	0.33	0

Abbreviations: FPG fast plasma glucose; FINS fast insulin; HbA1c glycosylated hemoglobin; HOMA-IR HOMA of insulin resistance; TG triglyceride; TC total cholesterol; HDLcholesterol high density lipoprotein cholesterol; LDL cholesterol low density lipoprotein cholesterol; −, not available