Table 4

Total tibial cartilage volume r² values and p values for Δr² for different linear regression models

Model for total tibial cartilage volume

r²

p Value for Δ r² compared with the specified model

ΔF with addition to the model (p value for ΔF is the same as for Δr²)

Bone area only (+)

0.14

< 0.001

N/A

Bone area (+) age (-)

0.21

< 0.001 compared with bone area only

14.84

Bone area (+) age (-) smoking, alcohol

0.22

0.43 compared with bone area and age

0.86

Bone area (+) age (-) smoking, alcohol, BMI

0.22

0.53 compared with bone area, age, smoking and alcohol

0.39

Bone area (+) age (-) smoking, alcohol, ln hsCRP (-)

0.28

< 0.001 compared with bone area, age, smoking, alcohol

13.15

Bone area (+) age (-) smoking, alcohol, BMI ln hsCRP(-)

0.28

< 0.001 compared with bone area age smoking alcohol

7.23 (both variables added together); if BMI added first, ΔF = 0.43 (p for ΔF = 0.51) followed by lnCRP ΔF = 13.99, (p for ΔF < 0.001); if ln CRP added first, ΔF = 13.15, (p for ΔF < 0.001) followed by BMI ΔF = 1.28, (p for ΔF = 0.26)

Parenthesis indicate the sign of regression coefficients statistically significant at the 5% level. BMI, body mass index (kg/m²); ln hsCRP, natural log high sensitivity C-reactive protein.

Hanna et al. Arthritis Research & Therapy 2008 10:R27   doi:10.1186/ar2380