Table 2.

Univariable linear regressions between variables and femoral neck bone mineral density (g/cm²) for entire cohort and stratified by sex. Beta coefficients (β) and associated p-values are presented.

Variables	Whole cohort (N = 138)		Female (N = 117)		Male (N = 21)
	β	p-Value	β	p-Value	β	p-Value
Basic demographics
Age	−0.004	<0.0001	−0.004	<0.0001	−0.006	0.198
White race	0.000	0.991	−0.013	0.625	0.036	0.791
Female sex	−0.080	0.013	–	–	–	–
Disease characteristics
RF positive	−0.060	0.018	−0.062	0.014	−0.058	0.508
High positive anti-CCPa	−0.069	0.003	−0.063	0.007	−0.108	0.169
Disease duration (years)	−0.003	0.006	−0.002	0.043	−0.007	0.114
Current smoker	0.038	0.447	0.076	0.152	−0.114	0.393
RADAI score	0.006	0.375	0.010	0.106	−0.016	0.578
ESR	0.000	0.749	0.000	0.645	0.001	0.578
CRP	−0.001	0.452	0.000	0.787	−0.004	0.162
Body composition variables
BMI (kg/m2)	0.006	0.002	0.006	<0.0001	−0.008	0.446
FMI (kg/m2)	0.004	0.083	0.007	0.002	−0.026	0.061
DXA obeseb	0.035	0.143	0.063	0.007	−0.098	0.208
Appendicular LMI (kg/m2)	0.052	<0.0001	0.045	<0.0001	0.093	0.016
Medications
Mean prednisone dose (mg/day)	−0.003	0.261	0.000	0.913	−0.016	0.020
TNF inhibitor	−0.004	0.854	−0.003	0.909	−0.051	0.521
Osteoporosis medicationc, d	−0.100	<0.0001	−0.087	0.001	−0.150	0.162
Frailty categorye
Robust	Ref	–	Ref	–	Ref	–
Pre-frail	−0.101	0.001	−0.041	0.202	−0.246	0.001
Frail	−0.099	0.025	−0.035	0.443	−0.295	0.045

Bolded values = significant at p < 0.05 level. Italicized values = significant at p < 0.1 level.

RF: rheumatoid factor; CCP: cyclic citrullinated peptide antibody; RADAI: rheumatoid arthritis disease activity index; ESR: erythrocyte sedimentation rate; CRP: high-sensitivity c-reactive protein; BMI: body mass index; FMI: fat mass index; DXA: dual x-ray absorptiometry; LMI: lean mass index; BMD: bone mineral density; TNF: tumor necrosis factor.

^aHigh positive anti-CCP defined as level three times the upper limit of normal (>60 units) based on the 2010 EULAR/ACR RA classification criteria (Aletaha et al., 2010). This threshold was used to minimize heterogeneity of this group.

^bDXA obese was defined using % body fat from DXA based on age, sex, and race-specific criteria.

^cOsteoporosis medications represent bisphosphonate use. One patient self-reported estrogen use, but was also taking bisphosphonates. No subjects recorded use of parathyroid hormone, raloxifene or calcitonin.

^dn = 117. Due to differences in interview protocols, this question was not asked of all participants.

^eFrailty category as defined by Fried Frailty Index (Fried et al., 2001) (score of 0 = robust; 1–2 = pre-frail; 3+ = frail).