Table 3 Logistic regression models assessing the association of demographic variables, CTQ, FSIQ, urban birth and risk of schizophrenia.

From: Associations between urban birth or childhood trauma and first-episode schizophrenia mediated by low IQ

 

Step 1

Step 2

Step 3

Step 4

 

OR (95% CI)

OR (95% CI)

OR (95% CI)

OR (95% CI)

Age

1.41 (1.05, 1.88)*

1.44 (1.08, 1.93)*

1.39 (1.02, 1.89)*

0.95 (0.67, 1.33)

Sex

1.46 (0.85, 2.53)

1.52 (0.88, 2.64)

1.30 (0.72, 2.35)

1.38 (0.69, 2.79)

Education (year)

0.18 (0.13, 0.27)***

0.17 (0.12, 0.26)***

0.21 (0.14, 0.32)***

0.45 (0.30, 0.69)***

BMI

0.90 (0.68, 1.18)

0.87 (0.66, 1.45)

0.91 (0.67, 1.22)

1.05 (0.73, 1.51)

Birthplace

–

1.51 (0.89, 2.56)

1.51 (0.85, 2.67)

3.15 (1.54, 6.44)**

CTQ

–

–

2.76 (1.98, 3.86)***

2.79 (1.92, 4.06)***

FSIQ

–

–

–

0.18 (0.11, 0.28)***

Model R2

0.310

0.314

0.388

0.490

Model R2 change

–

∆R2 = 0.004

∆R2 = 0.074

∆R2 = 0.112

χ2 = 2.39

χ2 = 44.998

χ2 = 72.481

P = 0.122

P < 0.001

P < 0.001

  1. Step 1 effects of age, sex, and educational attainment, Step 2 variables retained from step 1 and birthplace, Step 3 variables retained from step 2 and CTQ, Step 4 variables retained from step 3 and FSIQ. CTQ childhood trauma questionnaire, IQ intelligence quotient, FSIQ the full scale of IQ, CI confidence interval, OR odds ratio, BMI body mass index.
  2. *P < 0.05, **P < 0.01, ***P < 0.001.
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