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.