Table 4 Adjusted effect of study variables on depressive symptoms

  ≤ −3 (≥ +3)

0.309

0.084

0.000

0.645

0.109

<.0001

  −2 ~ −1 (+1 ~ +2)

0.004

0.063

0.955

0.194

0.082

0.018

  0

ref

ref

  +1 ~ +2 (−2 ~ −1)

−0.045

0.045

0.321

0.015

0.059

0.796

  +3 ~ +4 (−4 ~ −3)

0.024

0.044

0.586

−0.024

0.057

0.668

  +5 ~ +6 (−6 ~ −5)

−0.054

0.047

0.251

0.075

0.060

0.212

  ≥ +7 (≤ −7)

0.000

0.048

0.996

0.074

0.061

0.222

Age

  ≤55

ref

ref

  56-65

−0.038

0.028

0.184

−0.026

0.035

0.464

  66-75

−0.087

0.035

0.014

0.220

0.048

<.0001

  ≥75

0.108

0.054

0.045

0.524

0.087

<.0001

Education

  ≤ Middle school

0.079

0.030

0.009

0.063

0.062

0.316

  High school

0.032

0.032

0.318

−0.077

0.065

0.240

  ≥ College

ref

ref

Income

  Yes

0.026

0.025

0.296

0.002

0.045

0.967

  No

ref

ref

Frequency of social activities

  Everyday

ref

ref

  Sometimes

0.063

0.023

0.005

0.062

0.053

0.247

  Never

0.160

0.039

<.0001

−0.062

0.056

0.268

Smoking status

  Never

0.002

0.026

0.947

−0.312

0.113

0.006

  Former smoker

0.080

0.028

0.005

0.305

0.221

0.168

  Smoker

ref

ref

Alcohol use

  No

ref

ref

  Former user

0.167

0.038

<.0001

0.437

0.086

<.0001

  Yes

−0.002

0.029

0.952

−0.008

0.037

0.824

Economically active

  Yes

−0.071

0.026

0.006

−0.059

0.035

0.093

  No

ref

ref

Self-rated health

  Good

−0.266

0.031

<.0001

−0.536

0.040

<.0001

  Normal

−0.205

0.030

<.0001

−0.421

0.037

<.0001

  Bad

ref

ref

Depression in partner

  Yes

0.469

0.024

<.0001

0.811

0.036

<.0001

  No

ref

ref

Marital satisfaction

  Low

0.144

0.059

0.015

0.325

0.063

<.0001

  Medium

0.069

0.020

0.001

0.189

0.029

<.0001

  High

ref

ref

Year

  2006

ref

ref

  2008

1.386

0.038

<.0001

1.688

0.048

<.0001

  2010

2.586

0.049

<.0001

2.510

0.055

<.0001

  2012

4.105

0.057

<.0001

3.338

0.061

<.0001