Table 6 Binary logistics regression analysis of overall depression in the elderly (OR, 95% CI)

Years (2011)

Ref

Ref

Ref

Ref

 2013

1.080(0.996–1.172)

1.165^**(1.065–1.273)

1.213^***(1.114–1.321)

1.287^***(1.172–1.413)

 2015

1.278^***(1.181–1.383)

1.329^***(1.225–1.442)

1.449^***(1.333–1.575)

1.496^***(1.374–1.630)

 2018

1.374^***(1.274–1.482)

1.568^***(1.447–1.700)

1.968^***(1.810–2.140)

2.213^***(2.025–2.419)

Area (east)

Ref

Ref

 Middle

–

1.537^***(1.433–1.649)

–

1.416^***(1.315–1.524)

 Western

–

1.943^***(1.812–2.084)

–

1.777^***(1.652–1.912)

Gender (male)

Ref

Ref

 Formale

–

1.534^***(1.447–1.627)

–

1.521^***(1.431–1.618)

Age (60 ~ 69)

Ref

Ref

 70 ~ 79

–

0.871^***(0.817–0.928)

–

0.832^***(0.779–0.890)

 ≥ 80

–

0.833**(0.743–0.935)

–

0.798^***(0.707–0.901)

Marriage (married)

Ref

Ref

 Unmarried

–

1.262^***(1.174–1.356)

–

1.294^***(1.199–1.396)

Education (Illiterate or Primary school)

Ref

Ref

 Middle school

–

0.788^***(0.722–0.860)

–

0.775^***(0.708–0.849)

 High school or above

–

0.743^***(0.637–0.868)

–

0.771^**(0.656–0.907)

Residence (rural)

Ref

Ref

 City/town

–

0.643^***(0.593–0.696)

–

0.635^***(0.584–0.691)

Individual income (< 10,000)

Ref

Ref

 10,000 ~ 20,000

–

0.915^*(0.841–0.995)

–

0.923(0.845–1.007)

 ≥ 20,000

–

0.695^***(0.624–0.774)

–

0.741^***(0.662–0.829)

Social activity (no)

Ref

Ref

 Yes

–

–

0.770^***(0.727–0.816)

0.825^***(0.777–0.875)

Nighttime sleep (< 7 h)

Ref

Ref

 ≥ 7 h

–

–

0.543^***(0.511–0.576)

0.549^***(0.517–0.584)

ADL disability (no)

Ref

Ref

 Yes

–

–

1.991^***(1.806–2.194)

2.010^***(1.817–2.222)

Self-reported heath (good)

Ref

Ref

 General

–

–

1.735^***(1.561–1.929)

1.711^***(1.537–1.906)

 Poor

–

–

3.677^***(3.315–4.079)

3.553^***(3.197–3.950)

Chronic disease (0)

Ref

Ref

 ≥ 1

–

–

1.262^***(1.179–1.351)

1.287^***(1.200–1.380)