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Table 4 Decomposition of effects of social class on physical function in older age

From: Working conditions mediate the association between social class and physical function in older age in Sweden: a prospective cohort study

 

Mediation analysis of working conditions

Mobility limitations

Physical impairment

 

Total effects

Direct effects

Indirect effects

Mediation %a

Total effects

Direct effects

Indirect effects

Mediation %a

Model 2 Physical working conditions (ref: upper white-collar)

 Lower white-collar

0.30

0.37†

−0.07

−23.92

0.51*

0.44†

0.08

14.63

 Skilled blue-collar

0.55*

0.70**

−0.15†

− 26.40

0.50†

0.36

0.14

28.80

 Unskilled blue-collar

0.42†

0.55*

− 0.14†

−31.89

0.42†

0.28

0.14

32.50

Model 3 Psychosocial working conditions

 3a Passive (ref: upper white-collar)

  Lower white-collar

0.30

0.30

0.00

−3.05

0.51*

0.42†

0.09

17.59

  Skilled blue-collar

0.55*

0.56*

−0.01

−2.50

0.49†

0.36

0.14†

27.61

  Unskilled blue-collar

0.41†

0.43†

−0.02

−4.32

0.42†

0.23

0.19†

45.71

 3b High-strain (ref: upper white-collar)

  Lower white-collar

0.30

0.26

0.04

14.41

0.51*

0.52*

−0.01

−1.64

  Skilled blue-collar

0.56*

0.56*

−0.00

−0.11

0.50†

0.50†

0.00

0.01

  Unskilled blue-collar

0.41†

0.39†

0.02

5.98

0.42†

0.42†

−0.00

−0.91

 3c Low-strain (ref: upper white-collar)

  Lower white-collar

0.29

0.25

0.04

15.20

0.51*

0.47†

0.04

8.50

  Skilled blue-collar

0.55*

0.51*

0.04

6.54

0.50†

0.46†

0.04

7.19

  Unskilled blue-collar

0.41†

0.37

0.10†

23.38

0.42†

0.32

0.10

23.92

 3d Active (ref: upper white-collar)

  Lower white-collar

0.30

0.32

−0.02

−8.13

0.51*

0.52*

−0.01

−1.61

  Skilled blue-collar

0.54*

0.57*

−0.03

−5.15

0.50†

0.51†

−0.01

−1.97

  Unskilled blue-collar

0.41†

0.53†

−0.03

−7.33

0.42†

0.43†

−0.01

−2.57

Model 4 Physical and psychosocial working conditions (ref: upper white-collar)

 Lower white-collar

0.31

0.28

0.02

7.92

0.52*

0.33

0.18†

35.35

 Skilled blue-collar

0.56*

0.60*

−0.04

−8.00

0.50†

0.25

0.26*

50.91

 Unskilled blue-collar

0.43†

0.42†

0.01

3.00

0.42†

0.11

0.31*

73.69

  1. aMediation % corresponds to conf_pct in khb decomposition output in STATA 14 which stands for confounding percentage net of rescaling p < 0.10†, p < 0.05*, p < 0.01**. Effect size expressed as beta coefficients unless otherwise specified. All models were adjusted for age, sex, level of education, mobility, and health problems at baseline (Model 1). Model 2 was additionally adjusted for physical working conditions. Model 3 was adjusted like Model 1 and additionally for psychosocial working conditions. Model 4 was adjusted like Model 1 and additionally for physical and psychosocial working conditions