Table 6 Multiple logistic regression analysis of factors associated with bone mineral density <70 % of young adult mean

Age (per 1 year increase)

1.015–1.101

0.003*

sex

1.367–18.43

0.015*

Disease duration (per 1 year increase)

1.028–1.128

0.002*

History of past vertebral fracture

2.505–23.72

<0.001*

BMI (per 1 point increase)

0.665–0.883

<0.001*

Steinbrocker classification

1.473–3.597

<0.001*