Table 3 Hazard ratios of variables and mortality by multivariate Cox frailty model

 healthy periodontium

reference

reference

 periodontitis

1.092*

1.038–1.149

1.114*

1.032–1.203

Age

1.106*

1.103–1.110

1.002

0.992–1.013

 married living together

0.782*

0.744–0.822

0.809*

0.683–0.959

 other

reference

reference

 illiterate

reference

reference

 education 1–6 years

0.766*

0.704–0.833

0.740

0.538–1.017

 education 7–14 years

0.592*

0.545–0.644

0.698*

0.510–0.954

 education above 14 years

0.507*

0.462–0.557

0.573*

0.407–0.806

 female

reference

reference

 male

1.799*

1.704–1.899

2.712*

2.326–3.161

 no

reference

reference

 occasionally

1.412*

1.307–1.525

1.126

0.956–1.326

 daily

1.753*

1.469–2.092

1.840*

1.455–2.326