# Table 3 Factors affecting annual percentage change in tibial plateau bone area

Tibial plateau area factorsa

Univariate analysis Regression coefficient (95% CI)

P

Multivariate analysisb Regression coefficient (95% CI)

P

Medial tibial plateau area

Age

-0.10 (-0.23, 0.03)

0.13

-0.07 (-0.18, 0.05)

0.26

Gender

0.94 (-1.78, 3.66)

0.49

-5.42 (-8.67, -2.18)

0.001

BMI

0.43 (0.17, 0.70)

0.002

0.42 (0.16, 0.67)

0.002

Physical activity

-0.85 (-1.58, -0.11)

0.02

-0.30 (-1.00, 0.40)

0.40

0.02 (-1.78, 1.83)

0.98

0.27 (-1.53, 2.07)

0.77

0.35 (-1.10, 1.80)

0.63

1.88 (0.43, 3.33)

0.01

Baseline medial tibial area

-0.006 (-0.010, -0.003)

<0.001

-0.012 (-0.017, -0.008)

<0.001

Lateral tibial plateau area

Age

-0.02 (-0.10, 0.07)

0.67

-0.01 (-0.11, 0.08)

0.80

Gender

0.25 (-1.62, 2.12)

0.79

-0.08 (-2.51, 2.36)

0.95

BMI

-0.02 (-0.19, 0.15)

0.82

-0.04 (-0.23, 0.16)

0.72

Physical activity

-0.05 (-0.57, 0.48)

0.85

-0.16 (-0.74, 0.41)

0.57

-0.63 (-1.68, 0.42)

0.24

-0.18 (-1.70, 1.35)

0.82

-0.87 (-2.35, 0.61)

0.25

-0.42 (-2.31, 1.48)

0.66

Baseline lateral tibial area

-0.003 (-0.007, 0.001)

0.11

-0.002 (-0.008, 0.003)

0.38

1. aFactors were defined as follows: age = percentage change per 1-year increase in age; gender = men compared with women; BMI = percentage change per unit increase in body mass index; physical activity = percentage change per unit increase in physical activity level; grade of osteophytes = percentage change per increase 1 in grade of osteophytes; grade of JSN=percentage change per increase 1 in grade of joint-space narrowing; baseline tibial area = percentage change per 1 mm2 increase in baseline tibial plateau bone area. bIncludes age, gender, BMI, physical activity, grade of osteophytes, grade of JSN, and baseline tibial plateau bone area in regression equation. BMI, body mass index; JSN, joint-space narrowing.