Table 2 Results of multiple linear regression models comparing between comorbidities and TMD pain duration in the combined TMD group (n = 180)

TMD duration (years)

Number of comorbidities

1.73 (0.78 – 2.68)

1.64 (0.62 – 2.65)

1.56 (0.59 – 2.53)

p < 0.01, r² = 0.06

p < 0.01, r² = 0.13

p < 0.01, r² = 0.13

Migraine

1.56 (−0.83 – 3.95)

0.28 (−2.31 – 2.87)

0.01 (−2.47 – 2.49)

p = 0.20, r² = 0.01

p = 0.83, r² = 0.17

p = 0.99, r² = 0.16

Chronic Fatigue Syndrome

6.58 (3.32 – 9.84)

6.03 (2.52 – 9.54)

5.84 (2.38 – 9.30)

p < 0.01, r² = 0.08

p < 0.01, r² = 0.17

p < 0.01, r² = 0.16

Irritable Bowel Syndrome

3.03 (0.42 – 5.65)

2.24 (−0.41 – 4.90)

2.15 (−0.47 – 4.77)

p = 0.02, r² = 0.03

p = 0.10, r² = 0.17

p = 0.11, r² = 0.16

Interstitial Cystitis

4.04 (0.44 – 7.64)

0.71 (−3.17 – 4.59)

0.78 (−3.03 – 4.59)

p = 0.03, r² = 0.03

p = 0.72, r² = 0.17

p = 0.69, r² = 0.16

Restless Leg Syndrome

1.68 (−1.52 – 4.87)

−0.16 (−3.39 – 3.07)

−0.15 (−3.35 – 3.04)

p = 0.30, r² = 0.01

p = 0.92, r² = 0.17

p = 0.92, r² = 0.16