Table 1 Causal estimates for Education Years on T2D and 10 risk factors for T2D.

From: Can increasing years of schooling reduce type 2 diabetes (T2D)?: Evidence from a Mendelian randomization of T2D and 10 of its risk factors

Test (No. SNPs)

R2

F

IVW

MR-Egger

MR-Egger intercept

Weighted median

Weighted mode

OR

95% CI

P

OR (I2)

95% CI

P

OR

95% CI

P

OR

95% CI

P

OR

95% CI

P

T2D (17)

0.003

13

0.39

0.26, 0.58

< 0.001*

0.38 (35%)

0.05, 3.09

0.381

1.00

0.96, 1.04

0.979

0.41

0.24, 0.69

< 0.001*

0.37

0.17, 0.80

0.022

Sibling with T2D (64)

0.008

38

0.97

0.96, 0.98

< 0.001*

0.95 (32%)

0.90, 1.00

0.044

1.00

0.99, 1.00

0.424

0.97

0.95, 0.98

< 0.001*

0.94

0.90, 0.98

0.005

Mother with T2D (62)

0.009

36

0.97

0.96, 0.98

< 0.001*

0.98 (27%)

0.93, 1.04

0.563

1.00

1.00, 1.00

0.734

0.98

0.97, 1.00

0.016

0.99

0.96, 1.02

0.567

Father with T2D (60)

0.008

37

0.98

0.97, 0.99

< 0.001*

1.00 (11%)

0.94, 1.06

0.984

1.00

1.00, 1.00

0.547

0.98

0.96, 0.99

0.006

0.98

0.94, 1.01

0.192

Over-weight (54)

0.007

20

0.60

0.51, 0.72

< 0.001*

0.61 (6%)

0.22, 1.74

0.364

1.00

0.98, 1.02

0.972

0.58

0.46, 0.73

< 0.001*

0.47

0.25, 0.91

0.029

Phys-ical activity (49)

0.006

37

0.77

0.71, 0.84

< 0.001*

0.87 (21%)

0.54, 1.40

0.568

1.00

0.99, 1.01

0.623

0.79

0.70, 0.91

< 0.001*

0.97

0.69, 1.36

0.852

High blood pressure (45)

0.006

36

0.94

0.92, 0.96

< 0.001*

0.94 (0%)

0.83, 1.07

0.369

1.00

1.00, 1.00

0.928

0.93

0.91, 0.96

< 0.001*

0.91

0.85, 0.97

0.005

Gest. diabetes (69)

0.009

38

1.00

1.00, 1.00

0.171

1.00 (35%)

1.00, 1.00

0.748

1.00

1.00, 1.00

0.547

1.00

1.00, 1.00

0.257

1.00

1.00, 1.00

0.332

POS (68)

0.009

38

1.00

1.00, 1.00

0.284

1.00 (36%)

1.00, 1.01

0.606

1.00

1.00, 1.00

0.460

1.00

1.00, 1.00

0.469

1.00

1.00, 1.00

0.831

Test (No. SNPs)

R2

F

IVW

MR-Egger

MR-Egger intercept

Weighted median

Weighted mode

β

95% CI

P

β

95% CI

P

β

95% CI

P

β

95% CI

P

β

95% CI

P

HDL levels (52)

0.007

12

0.14

0.06, 0.22

< 0.001*

0.35 (7%)

− 0.14, 0.84

0.171

− 0.004

− 0.012, 0.005

0.403

0.09

− 0.04, 0.21

0.163

0.004

− 0.27, 0.28

0.977

Trigly-ceridelevels (52)

0.007

23

− 0.19

− 0.27, − 0.11

< 0.001*

− 0.19 (6%)

− 0.67, 0.29

0.440

− 4.06E−06

− 0.008, 0.008

0.999

− 0.19

− 0.30, − 0.08

0.001

− 0.23

− 0.48, 0.03

0.087

  1. T2D = type 2 diabetes; HDL = high-density lipoprotein cholesterol; Gest. diabetes = gestational diabetes; POS = polycystic ovarian syndrome; P = P-value; F = F-statistic; OR = odds ratio; CI = confidence interval. IVW = inverse-variance weighted test; IVW is the primary MR method. The MR-Egger, weighted median estimator, and weighted mode estimators are sensitivity tests for horizontal pleiotropy. If the magnitude and direction of their effects comport with those of the IVW estimate, this provides a screen against pleiotropy. The MR-Egger intercept is shaded grey because it is interpreted differently than the IVW estimate and the sensitivity estimators; the MR-Egger intercept provides a formal test for directional pleiotropy9. If the MR-Egger intercept is not different than 1 on the exponentiated scale or 0 when non-exponentiated (P > 0.05), this indicates a lack of evidence for bias due to pleiotropy in the IVW estimate.
  2. *Indicates P < 0.005 (the Bonferroni threshold).
Back to article page