Elevated bone mineral density lowers risk for hip OA
Although higher bone mineral density can reduce a patient’s risk for hip radiographic osteoarthritis, intermediate density could increase the risk for knee radiographic OA and symptomatic radiographic OA, according to findings published in Arthritis Care and Research.
“Higher bone mineral density (BMD) has been shown to reduce the risk of fractures in both men and women,” Kamil E. Barbour, PhD, of the CDC, told Healio Rheumatology. “Some studies indicate that this lower fracture risk may occur at the expense of an increased risk of incident knee radiographic OA in middle-aged and older adults. In addition to looking at the risk of BMD on incident knee radiographic OA, this is the first study to examine the impact of BMD on incident symptomatic OA, which is an outcome of greater clinical and public health significance. To my knowledge, this is the first study that examines the association between BMD and incident radiographic OA of the hip.”
To evaluate BMD and its association with incident hip or knee OA, the researchers collected data on 1,474 patients aged 45 and older who were included in the Johnston County Osteoarthritis Project’s first and second follow-up. The first follow-up occurred from 1999 to 2004, and the second was from 2005 to 2010. The researchers measured total hip BMD with dual X-ray absorptiometry, and placed patients into one of four groups — low, intermediate-low, intermediate-high and high BMD.
The researchers defined radiographic OA as a Kellgren/Lawrence grade of 2 or more, and symptomatic radiographic OA as onset of both radiographic OA and symptoms.
According to the researchers, patients with intermediate-high (HR = 0.52; 95% CI, 0.31–0.86) and high (HR = 0.56; 95% CI, 0.31–0.86) BMD were less likely to develop hip symptomatic ROA (P = .024) compared with patients with low BMD. High BMD was not associated with an increased risk for hip radiographic OA. In addition, patients with intermediate-low (HR = 2.15; 95% CI, 1.4–3.3) and intermediate-high (HR = 0.65; 95% CI, 1.02–2.67) total hip BMD were more likely to develop knee symptomatic radiographic OA and (P = .325). Similar associations were seen with knee radiographic OA, the researchers found.
“Our ﬁndings suggest that having high hip BMD does not increase the risk of knee OA and may reduce the risk of hip OA,” Barbour said. “Patients are encouraged to continue to maintain a high BMD to reduce their risk of fracture and hip OA.” – by Jason Laday
Disclosure: The researchers report support from the CDC and the National Institute of Arthritis and Musculoskeletal and Skin Diseases.