Bone mineral density and prevalent osteoarthritis of the hip in older men for the Osteoporotic Fractures in Men (MrOS) Study Group

Abstract

Summary: We evaluated the association of bone mineral density (BMD) and osteoarthritis (OA) of the hip in elderly men. We found that elderly men with moderate to severe radiographic hip OA (RHOA) had significantly higher areal BMD (aBMD) and volumetric BMD (vBMD) at both the lumbar spine and hip compared to age similar controls without OA.

Introduction: We evaluated the association of BMD measured by dual energy X-ray absorptiometry (DXA) and quantitative computerized tomography (integral, cortical, and trabecular vBMD) and RHOA in a cohort of elderly men.

Methods: A cross-sectional analysis was conducted within the Study of Osteoporotic Fractures in Men, a prospective cohort study of 5,995 US men age > or = 65 years. Standing pelvic x-rays were done in 4,024 subjects and scored for prevalent RHOA severity. DXA was done in 3,886 subjects, and aBMD and vBMD associations were compared with RHOA score using linear regression, adjusting for covariates.

Results: Both moderate and severe RHOA groups had significantly higher aBMD at all BMD sites (range, 3.7-10.0% difference; p value 0.0012 and p value < 0.005) compared to the control group with no RHOA. The difference remained strong after adjusting for covariates. While the total hip and lumbar spine cortical vBMD measurements of subjects with moderate or severe RHOA was increased compared to controls, trabecular vBMD was not.

Conclusion: Older men, with both moderate and severe RHOA, had significantly higher aBMD and integral vBMD at the hip and lumbar spine compared to controls without RHOA.

Figure 1

Percent Increases in aBMD Measurements in Subjects by RHOA Summary Grade Compared to Mean aBMD in Subjects with Summary Grade 0–1. † †Adjusted for age, BMI, height, activity level (PASE), Nottingham maximum power, 6 meter walk speed, inability to do chair stands, clinic site and race. RHOA= 2 (n= 209); RHOA ≥ 3 (n= 185). *Significant at P-value < 0.005. (See Table 2A for exact P-values).

Figure 2

Percent Differences in aBMD in the Osteophytic and Atrophic Phenotypes compared to Mean aBMD in Subjects with IRF scores ≤ 1.† †Adjusted for age, BMI, height, activity level (PASE), Nottingham maximum power, 6 meter walk speed, inability to do chair stands, clinic site and race. Osteophytic (n= 134); Atrophic (n= 120). * P-value < 0.005 compared to referent group.

Figure 3

Percent Differences in vBMD Measurements in Subjects by RHOA Summary Grade compared to Mean vBMD in Subjects with Summary Grade 0–1.† †Adjusted for age, BMI, height, activity level (PASE), Nottingham maximum power, 6 meter walk speed, inability to do chair stands, clinic site and race. RHOA=2 (n= 149); RHOA ≥ 3 (n= 122). *Significant at P-value < 0.05. (See Table 2B for exact P-values).

Figure 4

Percent Differences in vBMD Measurements in Subjects by radiographic phenotype compared to Subjects with IRF< 1.† †Adjusted for age, BMI, height, activity level (PASE), Nottingham maximum power, 6 meter walk speed, inability to do chair stands and race. Osteophytic (n= 100); Atrophic (n= 67). P-value <0.005 compared to referent group.