Table 4

Pooled differences (95% CI) in body mass index (kg/m2) between individuals homozygous and heterozygous carriers of the 363S allele of the GRL gene and homozygotes for the N363 allele. Fixed effects model

Studies
Difference in BMI (kg/m2) Pooled estimates
95% CI
Q statistic
k
p#

Overall studies
+0.18
+0.004 to +0.35*
84.47
21
<0.0001
     BMI < 27 kg/m2
+0.14
-0.052 to +0.32
29.15
10
0.0006
     BMI > 27 kg/m2
+0.37
-0.047 to +0.79
54.31
11
<0.0001
     Adults (>25 years)
+0.51
+0.31 to +0.72*
27.47
16
0.0252
     Children and adolescents (<25 years)
-0.67
-0.99 to -0.35*
19.94
5
0.0005
- Ethnicity





     European Countries
+0.16
-0.01 to +0.34
74.84
15
<0.0001
     Australia
+0.45
-0.34 to +1.24
9.03
5
0.06
- Gender





     Men
-0.37
-1.25 to +0.51
1.20
3
0.5487
     Men and women
+0.20
+0.02 to +0.37
81.76
18
<0.0001
- Mutation prevalence





     (<5%)
-0.54
-0.96 to -0.12
20.69
6
0.0009
     (5–10%)
+0.34
+0.15 to +0.54
37.74
9
<0.0001
     (>10%)
+0.10
-0.57 to +0.77
11.84
6
0.037
One population





     BMI < 27 kg/m2
+0.41
+0.17 to +0.66*
5.88
4
0.1177
     BMI ≥ 27 kg/m2
+1.19
+0.64 to +1.74*
13.34
5
0.0097
Normal weight subjects





     already published data
+0.56
-0.07 to +1.19
1.04
3
0.5941
     novel data
-0.50
-0.84 to -0.17*
1.72
3
0.4227
Obese subjects





     already published data
+0.32
-0.82 to +1.46
0.07
3
0.9633
     novel data
-1.26
-2.10 to -0.49*
15.77
3
<0.001

k: number of studies;

# test for heterogeneity;

* p < 0.05 for the pooled difference in BMI.

Marti et al. BMC Medical Genetics 2006 7:50   doi:10.1186/1471-2350-7-50