Table 5

Patella cartilage volume r2 values and p values for Δ r2 for different linear regression models

Model for total patella cartilage volume

r2

p Value for delta r2 compared with the specified model

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


Bone volume only (+)

0.27

< 0.001

N/A

Bone volume (+) age (-)

0.30

0.003 compared with bone volume only

8.93

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

0.31

p = 0.65 compared with bone volume and age

0.43

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

0.32

p = 0.06 compared with bone volume, age, smoking and alcohol

3.54

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

0.32

p = 0.19 compared with bone volume, age, smoking, alcohol

1.78

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

0.33

p = 0.15 compared with bone volume age smoking alcohol

1.92 (both variables added together); if BMI added first, ΔF = 3.54, (p for ΔF = 0.06) followed by lnCRP ΔF = 0.31, (p for ΔF = 0.58); if ln CRP added first, ΔF = 1.78, (p for Δ= F 0.19) followed by BMI ΔF = 2.05, (p for ΔF = 0.15).


Parenthesis indicate the sign of regression co-efficients 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

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