High sensitivity C-reactive protein is associated with lower tibial cartilage volume but not lower patella cartilage volume in healthy women at mid-life

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.