Subject Characteristics
As shown in Figure 1, of the 168 participants, three in the placebo group, three in the vitamin D group, one in the omega-3 group and one in the co-supplementation group were excluded from the study. Exclusion was due to pregnancy in three cases and personal reason in five cases. The analysis was performed by the intention-to-treat and per protocol methods; the results obtained were similar. The present report is based on the intention-to-treat analysis of 168 participants. The mean age of the participants was 40.14±7.06 years; 55.4% of the participants had diabetes in first-degree relatives and 53.6% had second-degree relatives with diabetes.
At the beginning of the intervention, there was no significant statistical difference between the four groups in terms of mean age, anthropometric indices, physical activity, food intake, glycemic indices, and serum lipids (Table 1). Physical activity, dietary intake (micronutrients and macronutrients) and time spent out door showed no significant statistical difference within the groups before and after the intervention.
No side effects were reported following the consumption of supplements or placebos.
Table 1 Baseline characteristics of the participants by group
characteristic
|
Placebo group
(n=42)
|
Omega3 group(n=42)
|
Vitamin D group(n=42)
|
Vitamin D + Omega3 group(n=42)
|
P value
|
Age(years)
|
41.85(7.48)
|
39.78(6.88)
|
39.92(6.04)
|
39.00(7.68)
|
0.29
|
Vitamin D
|
25.47(5.83)
|
23.56(6.42)
|
21.43(8)
|
22.03(6.92)
|
.44
|
FBS(mg/dL)
|
104.52(6.39)
|
103.87(5.88)
|
103.74(5.11)
|
103.71(4.73)
|
.98
|
Insulin(µIU/mL)
|
7.36(4.12)
|
9.14(3.14)
|
7.73(3.66)
|
10.35(3.13)
|
.30
|
Triglycerides
(mg/ dL )
|
123.69(48.17)
|
132.10(66.77)
|
126.68(77.7)
|
137.42(67.02)
|
.77
|
Total cholesterol (mg/dL)
|
188.59(32.82)
|
194.05(32.4)
|
197.73(37.8)
|
199.35(42.11)
|
.40
|
HDL- c (mg/dL)
|
48.43(8.76)
|
51.08(8.91)
|
51.73(11.47)
|
48.55(8.92)
|
.34
|
LDL- c (mg/dl)
|
111(30.74)
|
115.36(26.91)
|
119.15(32.71)
|
122.76(36.47)
|
.40
|
Weight(kg)
|
74.32(12.65)
|
69.65(9.09)
|
72.80(9.23)
|
72.54(10.62)
|
.24
|
BMI(kg/m2)
|
27.28(2.74)
|
27.17(2.74)
|
27.01(2.91)
|
27.04(2.86)
|
.82
|
waist circumference(cm)
|
85.05(10.42)
|
82.78(6.41)
|
84.6(8.49)
|
85.29(9.85)
|
.62
|
Dietary energy intake (kcal)
|
1639.0(601.9)
|
1645.5(451.8)
|
1523(499.6)
|
1570.60(509.8)
|
.26
|
Physical activity(MET-min/week)
|
698.19(618.83)
|
815.34(778.54)
|
706.78(656.76)
|
808.66(766.99)
|
.85
|
Time spent out door(h/day)
|
1.7(1.8)
|
1.8(1.2)
|
1.8(1.4)
|
1.8(1.8)
|
.88
|
BMI, Body Mass Index; FBS, Fasting blood sugar; HDL-C , High-density lipoprotein cholesterol; HOMA-IR, Homeostasis Model Assessment estimated Insulin Resistance; HOMA-B, homeostatic model assessment for B-cell function-B; LDL-C, Low-density lipoprotein cholesterol
All values are means (SDs)
*P value is significant
Obtain from One-way analysis of variance
Effects on glycemic indices
Tables 2 and 4 present the effects of supplements intake on glycemic status.
A significant group*time interaction was observed for fasting insulin and glucose, HOMA-IR and HOMA-B changes (P<0.001).
The fasting glucose levels decreased significantly in the groups 2, 3 and 4 at the end of the study. A significant statistical difference was observed in fasting glucose changes between the co-supplementation group and the other three groups (P<0.05).
At the end of the intervention the fasting insulin levels decreased significantly in the co-supplementation group and the omega-3 group (P<0.001), but increased in the placebo and vitamin D groups. A significant statistical difference was observed between the co-supplementation group and the other three groups in terms of fasting insulin changes (P<0.05).
The co-supplementation group and the omega-3 group showed a significant reduction in HOMA-IR at the end of the study (P<0.001). There was no other statistically significant differences between groups in HOMA-IR.
At the end of the intervention, the decrease in HOMA-B was observed in the co-supplementation and omega-3 groups. There was also a significant statistical difference (P<0.05) between the co-supplementation group and the other three groups in HOMA-B changes (P<0.05).
Effects on Lipid Profiles
Tables 3and4 show the effects of supplements intake on serum lipids.
A significant group*time interaction was observed for the changes in cholesterol, triglyceride, HDL-C and LDL-C (P<0.05).
Although, at the end of the study, there was a significant reduction in the groups 2, 3 and 4 in terms of total cholesterol (P<0.05), there were no significant differences in the changes in total cholesterol between the groups.
There was a significant reduction in triglyceride (P<0.001) after the intervention in the co-supplementation group and the omega-3 group, but no other statistically significant difference was observed in triglyceride changes between the groups.
At the end of the study, the HDL-C level had increased significantly in the groups 2, 3 and 4 (P<0.05). There was a statistically significant difference between the co-supplementation group and the other three groups in HDL-C changes (P<0.05).
Despite the fact that LDL-C levels decreased significantly in the groups 2, 3 and 4 after the intervention (P<0.001), there was no statistically significant difference between the groups in LDL-C changes.
Effects on Anthropometric Indices
The effects of supplements intake on anthropometric indices is shown in Tables 3and 4. A significant group*time interaction was observed for waist circumference and weight changes (P<0.001). After the intervention, statistical significant decrease in weight was observed in the co-supplementation group. Weight decreased in the omega-3 group and increased in the other two groups; however, the changes were not statistically significant. There was a significant difference in terms of weight changes between the co-supplementation group and other three groups (P<0.05). Although BMI had more decreased in the co-supplementation group and the omega-3 group, no statistically significant difference was observed in BMI changes between the groups.
At the end of the study, waist circumference had decreased significantly in the groups
2, 3 and 4 (P<0.001). There was a significant difference between the co-supplementation group and other three groups in waist circumference changes (P<0.05).
After adjusting for covariates (age, BMI, physical activity level and food intake), no change was observed in results of the repeated measures ANOVA for any of these outcomes.
Table2 Comparison of glycemic indices and Vitamin D in each group before and after the intervention
Variables
|
Time
|
Group1
placebo group
(n=42)
|
Group2
Omega3 group
(n=42)
|
Group3
vitaminD group
(n=42)
|
Group4
Vitamin+ Omega3 group
(n=42)
|
Vitamin D
|
Before
|
25.47(5.83)
|
23.56(6.42)
|
21.43(8)
|
22.03(6.92)
|
After
|
20.97(6.63)
|
21.17(7.40)
|
29.71(12.11)
|
31.71(11.51)
|
P
|
<.001*
|
<.001*
|
<.001*
|
<.001*
|
FBS
(mg/dL)
|
Before
|
104.52(6.39)
|
103.87(5.88)
|
103.74(5.11)
|
103.71(4.73)
|
After
|
107.12(9.94)
|
97.23(5.87)
|
100.18(8.94)
|
94.33(8.02)
|
P
|
<.001*
|
<.001*
|
<.001*
|
<.001*
|
Insulin
(µIU/mL)
|
Before
|
7.36(4.12)
|
9.14(3.14)
|
7.73(3.66)
|
10.35(3.13)
|
After
|
10.42(4.89)
|
7.34(3.53)
|
9.65(4.08)
|
7.73(2.4)
|
P
|
<.001*
|
<.001*
|
<.001*
|
<.001*
|
HOMA-IR
|
Before
|
1.91(1.13)
|
2.34(0.82)
|
1.98(0.94)
|
2.65(0.83)
|
After
|
2.75(1.34)
|
1.75(0.78)
|
2.38(1.07)
|
1.79(0.6)
|
P
|
<.001*
|
<.001*
|
<.001*
|
<.001*
|
HOMA-B
|
Before
|
0.64(0.34)
|
0.82(0.56)
|
0.69(0.33)
|
0.95(0.42)
|
After
|
0.92(0.64)
|
0.81(0.29)
|
0.96(0.4)
|
0.92(0.28)
|
P
|
<.001*
|
.92
|
<.001*
|
0.04*
|
FBS, Fasting blood sugar; HOMA-IR, Homeostasis Model Assessment estimated Insulin
Resistance; HOMA-B, homeostatic model assessment for B-cell function-B
All values are means (SDs)
*P values is significant
Obtain from paired samples t-test
Table3 Comparison of anthropometric indices and lipid profiles in each group before and after the intervention
Variables
|
Time
|
Group1
placebo group
(n=42)
|
Group2
Omega3 group
(n=42)
|
Group3
vitaminD group
(n=42)
|
Group4
Vitamin+ Omega3 group
(n=42)
|
Triglycerides
(mg/ dL )
|
Before
|
123.69(48.17)
|
132.10(66.77)
|
126.68(77.7)
|
137.42(67.02)
|
After
|
134.51(63.45)
|
116.62(60.02)
|
129.95(74.65)
|
115.09(53.36)
|
P
|
<.001*
|
<.001*
|
0.34
|
<.001*
|
Total cholesterol (mg/dL)
|
Before
|
188.59(32.82)
|
194.05(32.4)
|
197.73(37.8)
|
199.35(42.11)
|
After
|
184.37(34.09)
|
179.75(30.76)
|
187.49(32.61)
|
176.61(40.16)
|
P
|
.23
|
<.001*
|
<.001*
|
<.001*
|
HDL- c (mg/dL)
|
Before
|
48.43(8.76)
|
51.08(8.91)
|
51.73(11.47)
|
48.55(8.92)
|
After
|
48.10(9.32)
|
51.88(51.88)
|
52.23(10.55)
|
49.76(10.17)
|
P
|
.12
|
.01*
|
.11
|
<.001*
|
LDL- c (mg/dl)
|
Before
|
111(30.74)
|
115.36(26.91)
|
119.15(32.71)
|
122.76(36.47)
|
After
|
106.88(29.81)
|
103.82(28.98)
|
108.85(28.04)
|
103.71(35.52)
|
P
|
.26
|
<.001*
|
<.001*
|
<.001*
|
Weight(kg)
|
Before
|
74.32(12.65)
|
69.65(9.09)
|
72.80(9.23)
|
72.54(10.62)
|
After
|
74.64(12.81)
|
69.58(9.23)
|
72.86(9.4)
|
72.17(10.41)
|
P
|
<.001*
|
.45
|
.38
|
<.001*
|
BMI(kg/m2)
|
Before
|
27.28(2.74)
|
27.17(2.74)
|
27.01(2.91)
|
27.04(2.86)
|
After
|
27.27(2.96)
|
27.09(2.77)
|
26.98(2.91)
|
26.99(2.91)
|
P
|
.94
|
.13
|
.13
|
<.001*
|
waist circumference(cm)
|
Before
|
85.05(10.42)
|
82.78(6.41)
|
84.60(8.49)
|
85.29(9.85)
|
After
|
85.04(11.05)
|
81.94(6.73)
|
84.17(8.69)
|
84.13(9.16)
|
P
|
.88
|
<.001*
|
<.001*
|
<.001*
|
BMI, Body Mass Index; HDL-C, High-density lipoprotein cholesterol; LDL-C, Low-density lipoprotein cholesterol
All values are means (SDs)
*P value is significant
Obtain from paired samples t-test
Table4 Adjusted changes in glycemic indices, lipid profiles and anthropometric indices in each group
Variables
|
Group1
placebo group
(n=42)
|
Group2
Omega3 group
(n=42)
|
Group3
vitaminD group
(n=42)
|
Group4
Vitamin+ Omega3 group
(n=42)
|
P value¥
|
ηp2¥
|
time
|
Time*
Group
interaction
|
time
|
Time*
Group
interaction
|
Vitamin D
|
-4.49(5.03)
|
-2.38(5.28 )
|
8.27(7.77)
|
9.68(7.34)#
|
<.001*
|
<.001*
|
.15
|
.49
|
FBS(mg/dL)
|
2.60(6.59)
|
-6.64(5.14)
|
-3.56(7.11)
|
-9.37(6.4)ǁ
|
<.001*
|
<.001*
|
.3
|
.33
|
Insulin
(µIU/mL)
|
3.06(3.69)
|
-1.80(2.16)
|
1.92(3.91)
|
-2.61(1.68)ǁ
|
.13
|
<.001*
|
.002
|
.38
|
HOMA-IR
|
0.83(1.05)
|
-0.58(0.51)
|
0.40(1.05)
|
-0.85(0.48)
|
.04*
|
<.001*
|
.004
|
.42
|
HOMA-B
|
0.28(0.53)
|
-0.002(0.42)
|
0.27(0.4)
|
-0.04(0.31)ǁ
|
<.001*
|
<.001*
|
.08
|
.19
|
Triglycerides
(mg/ dL)
|
10.81(54.27)
|
-15.48(40.02)
|
3.27(56.55)
|
-22.32(34.58)
|
<.001*
|
<.001*
|
.01
|
.07
|
Total-cholesterol
(mg/dL)
|
-4.21(22.71)
|
-14.29(26.8)
|
-10.23(29.89)
|
-22.74(29.7)
|
<.001*
|
<.001*
|
.18
|
.006
|
HDL- - C (mg/dL)
|
-0.32(3.74)
|
0.82(5.35)
|
0.4(5.15)
|
1.29(5.68)ǁ
|
<.001*
|
.004*
|
.01
|
.01
|
LDL- C (mg/Dl)
|
-4.12(20.58)
|
-11.53(25.52)
|
-10.29(26.40)
|
-19.04(29.03)
|
<.001*
|
<.001*
|
.16
|
.04
|
weight
|
0.31(1.03)
|
-0.06(1.42)
|
0.06(1.27)
|
-0.36(1.65)ǁ
|
.77
|
<.001*
|
0
|
.03
|
BMI
|
-0.002(0.54)
|
-0.07(0.81)
|
-0.036(0.63)
|
-0.05(0.68)
|
.04
|
.63
|
.004
|
.002
|
waist circumference
|
-0.01(1.7)
|
-0.84(1.77)
|
-0.43 (1.8)
|
-1.15(2.23)ǁ
|
<.001*
|
<.001*
|
.09
|
.05
|
All values are means (SDs)
*P value is significant
¥ obtain from two way repeated measures ANOVA after adjusting for covariates
# Significant difference with group1 and 2
ǁ Significant difference with and other 3 groups
(¥, ǁ, #) Obtain from Two way repeated measures ANOVA with Bonferroni correction
ηp2 (partial eta squared) = 0.14 or more are large effects, 0.06 to 0.14 are medium effects and Less than 0.6 are small effects