Skip to main content

Table 2 The association of each socioeconomic status with low back pain after multiple data imputations (n = 26,037. Multilevel Poisson regression analysis)

From: Socioeconomic inequalities in low back pain among older people: the JAGES cross-sectional study

Socioeconomic status

Model 1

Model 2

Model 3

Model 4

PR

95% CI

PR

95% CI

PR

95% CI

PR

95% CI

Fixed parameter

 Education, years (ref, ≥13)

  10–12

1.05

1.01, 1.10

1.04

0.99, 1.09

1.03

0.99, 1.09

1.03

0.98, 1.08

   < 10

1.12

1.07, 1.17

1.09

1.04, 1.14

1.07

1.02, 1.12

1.05

1.002, 1.10

  P for trend

< 0.01

< 0.01

< 0.01

0.01

 Random part

  Municipality level variance (standard error)

0.001 (< 0.001)

0.001 (< 0.001)

0.001 (< 0.001)

0.001 (< 0.001)

Past occupation (ref, professionals)

 Fixed parameter

  White-collared workers

1.02

0.97, 1.07

1.00

0.95, 1.06

1.01

0.95, 1.06

1.01

0.95, 1.06

  Blue-collared workers

1.08

1.03, 1.14

1.06

1.02, 1.11

1.06

1.01, 1.11

1.04

1.001, 1.10

  Never worked before

1.11

1.04, 1.19

1.04

0.97, 1.12

1.03

0.95, 1.12

1.01

0.93, 1.09

  P for trend

< 0.01

< 0.01

< 0.01

0.02

 Random part

  Municipality level variance (standard error)

0.001 (< 0.001)

0.001 (< 0.001)

0.001 (< 0.001)

0.001 (< 0.001)

 Income, yen (ref, ≥3 million)

  2 million–2.99 million

1.03

0.98, 1.09

1.03

0.98, 1.08

1.03

0.97, 1.09

1.02

0.97, 1.08

  1 million–1.99 million

1.09

1.04, 1.14

1.09

1.04, 1.14

1.08

1.02, 1.13

1.05

1.002, 1.11

  < 1 million

1.20

1.14, 1.26

1.17

1.11, 1.23

1.16

1.10, 1.23

1.12

1.06, 1.19

  P for trend

< 0.01

< 0.01

< 0.01

< 0.01

 Random part

  Municipality level variance (standard error)

0.001 (< 0.001)

0.001 (< 0.001)

0.001 (< 0.001)

0.001 (< 0.001)

Subjective economic situation (ref, very comfortable)

 Fixed parameter

  Comfortable

1.06

1.00, 1.12

1.07

1.004, 1.13

1.05

0.99, 1.12

1.04

0.98, 1.11

  Difficult

1.19

1.12, 1.26

1.21

1.14, 1.29

1.18

1.10, 1.26

1.14

1.07, 1.22

  Very difficult

1.34

1.25, 1.44

1.36

1.26, 1.47

1.32

1.22, 1.44

1.22

1.11, 1.33

  P for trend

< 0.01

< 0.01

< 0.01

< 0.01

 Random part

  Municipality level variance (standard error)

0.001 (< 0.001)

0.001 (< 0.001)

0.001 (< 0.001)

0.001 (< 0.001)

Wealth, yen (ref, ≥50 million)

 Fixed parameter

  10 million–49.99 million

1.07

1.01, 1.12

1.07

1.01, 1.12

1.05

0.99, 1.11

1.04

0.98, 1.10

  5 million–9.99 million

1.09

1.03, 1.16

1.09

1.02, 1.15

1.07

1.004, 1.14

1.05

0.98, 1.12

  1 million–4.99 million

1.15

1.09, 1.23

1.14

1.08, 1.22

1.11

1.04, 1.19

1.08

1.01, 1.16

  < 1 million

1.22

1.15, 1.30

1.21

1.14, 1.29

1.18

1.11, 1.27

1.13

1.06, 1.21

  P for trend

< 0.01

< 0.01

< 0.01

< 0.01

 Random part

  Municipality level variance (standard error)

0.001 (< 0.001)

0.001 (< 0.001)

0.001 (< 0.001)

0.001 (< 0.001)

  1. Abbreviations: PR prevalence ratio, 95% CI 95% credible interval
  2. Socioeconomic status was separately added to each model. Model 1, a crude model; Model 2, with age and sex adjusted to Model 1; Model 3, with number of persons living together, marital status, musculoskeletal disease, BMI, drinking habit, smoking and physical activity added to Model 2; Model 4, with depression added to Model 3