Table 4

Results from multiple linear regression analyses with BMD at different measuring sites as the outcome.

AP lumbar aBMD

Lateral lumbar aBMD

Lumbar

vBMD

Total hip

aBMD

Femoral neck aBMD

Total radius aBMD


Constant

all variables

0.829

0.539

0.2390

0.783

0.654

0.625

R2 all variables

0.290

0.245

0.266

0.402

0.343

0.591

R2 for demographic variables

0.254

0.163

0.171

0.338

0.279

0.569

R2 for disease related variables

0.079

0.181

0.276

0.174

0.198

0.253


Demographic variables

B

P-value

B

P-value

B

P-value

B

P-value

B

P-value

B

P-value


Sex

NA

NA

NA

-0.056

0.009

NA

-0.082

< 0.001

Age, years

NA

NA

NA

NA

NA

-0.001

0.002

Menopause

-0.156

< 0.001

-0.104

< 0.001

NA

-0.053

0.048

-0.076

< 0.001

-0.035

0.009

BMI, kg/m2

0.014

< 0.001

NA

NA

0.014

< 0.001

0.011

< 0.001

0.004

< 0.001


Disease-related variables

B

P -value

B

P -value

B

P -value

B

P -value

B

P -value

B

P -value


Years since diagnosis

NA

-0.003

< 0.001

NA

NA

NA

NA

Years since symptom debut

NA

NA

-0.001

< 0.001

-0.002

0.019

-0.002

0.028

NA

BASMI

NA

NA

-0.006

< 0.001

-0.023

< 0.001

-0.029

< 0.001

-0.008

0.016

Hemoglobin

NA

0.002

0.008

NA

NA

NA

NA

WBC

NA

NA

NA

-0.007

0.05

NA

NA

PLT

0.000

0.003

NA

NA

NA

NA

NA


All demographic and disease-related variables that were significantly correlated with BMD in the first analyses were entered as covariates. The table shows only covariates that remained significantly associated with BMD in the stepwise multiple linear regression models. Coding for categorical variables, 1 = yes, 0 = no; for sex, 1 = woman, 2 = man. Beta values are unstandardized regression coefficients.

AP, anteroposterior; BASMI, Bath Ankylosing Spondylitis Metrology Index; aBMD, areal bone mineral density; vBMD, volumetric BMD; BMI, body mass index; mSASSS, modified Stoke Ankylosing Spondylitis Spine Score; PLT, platelet count; WBC, white blood cell count.

Klingberg et al. Arthritis Research & Therapy 2012 14:R108   doi:10.1186/ar3833

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