Table 3 The associations between multimorbidity and depression: the mediating effect of the number of body pain and sleep duration, among people aged 45 years and older in China, 2011–2018

Multimorbidity

1.97 (1.85, 2.10)

< 0.001

1.58 (1.48, 1.68)

< 0.001

1.54 (1.44, 1.64)

< 0.001

Age (years)

0.98 (0.97, 0.98)

< 0.001

0.98 (0.97, 0.98)

< 0.001

0.98 (0.97, 0.98)

< 0.001

Female

1.71 (1.59, 1.84)

< 0.001

1.49 (1.39, 1.61)

< 0.001

1.40 (1.31, 1.51)

< 0.001

Married/partnered

0.61 (0.55, 0.67)

< 0.001

0.61 (0.55, 0.67)

< 0.001

0.63 (0.58, 0.70)

< 0.001

Primary school

0.85 (0.77, 0.93)

< 0.001

0.86 (0.79, 0.94)

0.001

0.88 (0.80, 0.96)

0.004

Secondary school and above

0.58 (0.53, 0.64)

< 0.001

0.60 (0.55, 0.66)

< 0.001

0.62 (0.57, 0.68)

< 0.001

Urban residence

0.66 (0.61, 0.71)

< 0.001

0.71 (0.66, 0.77)

< 0.001

0.70 (0.65, 0.76)

< 0.001

Public health insurance

0.91 (0.80, 1.02)

0.111

0.89 (0.79, 1.00)

0.049

0.87 (0.77, 0.98)

0.019

Middle locations

1.57 (1.44, 1.71)

< 0.001

1.49 (1.37, 1.62)

< 0.001

1.47 (1.36, 1.60)

< 0.001

West locations

1.95 (1.79, 2.12)

< 0.001

1.73 (1.60, 1.88)

< 0.001

1.66 (1.53, 1.80)

< 0.001

Socioeconomic Status Class 2

0.97 (0.90, 1.04)

0.397

0.95 (0.88, 1.03)

0.209

0.95 (0.88, 1.03)

0.183

Socioeconomic Status Class 3

0.90 (0.83, 0.98)

0.012

0.88 (0.81, 0.95)

0.002

0.87 (0.80, 0.94)

0.001

Socioeconomic Status Class 4 (the most affluent)

0.84 (0.77, 0.92)

< 0.001

0.83 (0.76, 0.90)

< 0.001

0.82 (0.75, 0.89)

< 0.001

Impaired ADLs

2.71 (2.50, 2.94)

< 0.001

2.16 (1.99, 2.34)

< 0.001

2.07 (1.91, 2.25)

< 0.001

Impaired IADLs

2.21 (2.05, 2.38)

< 0.001

1.97 (1.83, 2.12)

< 0.001

1.97 (1.83, 2.13)

< 0.001

The number of body pain

1.19 (1.18, 1.20)

< 0.001

1.18 (1.16, 1.19)

< 0.001

Sleep duration

0.83 (0.82, 0.84)

< 0.001