Incident Vertebral Fracture Risk in Former, Current Smokers With or Without COPD

The following article is part of conference coverage from the 2018 American Society for Bone and Mineral Research in Montreal, Canada. Endocrinology Advisor’s staff will be reporting breaking news associated with research conducted by leading experts on bone health. Check back for the latest news from ASBMR 2018 .

Bone attenuation was found to be an independent determinant for vertebral fractures in former smokers with and without chronic obstructive pulmonary disease (COPD), according to a study presented at the American Society for Bone and Mineral Research 2018 Annual Meeting, held September 28 to October 1, 2018, in Montreal, Canada.

There is an increased risk for osteoporosis and vertebral fractures in patients with COPD. Bone mineral density on dual-energy X-ray absorptiometry and prevalent vertebral fractures are associated with bone attenuation on computed tomography (CT) scans. However, because the association with incident vertebral fractures is unknown, this study aimed to evaluate the association of bone attenuation on chest CT scans with prevalent and incident vertebral fractures in former and current smokers with and without COPD.

The study included participants of the ECLIPSE study who were followed up at 3 times (baseline, 1 year, and 3 years), and CT scans were conducted at each timepoint. Measurement of bone attenuation used 3D cubic areas of around 275 mm³ in each vertebrae, T4-T12. Superposed sagittal reconstructions of CT scans were used to evaluate incident and prevalent vertebral fractures within 1 and 3 years. The grading system proposed by Genant was used to score vertebral fractures. Relationships between clinical parameters and prevalent or incident vertebral fractures were assessed with logistic regression and Cox proportional hazard models. Participants were split into 3 groups on the basis of bone attenuation tertiles.

A total of 1239 participants were included (mean age, 61.3 ± 8.0; 61.1% men); of this cohort, 999 participants had a diagnosis of COPD with a mean baseline bone attenuation of 155.6 ± 47.5 Hounsfield Units (HU). Prevalent vertebral fractures were associated with lower bone attenuation (per −10 HU; odds ratio [OR], 1.21; 95% CI, 1.16-1.27) and male sex (OR, 1.89; 95% CI, 1.35-2.64). Baseline bone attenuation and prevalent vertebral fractures were associated with incident vertebral fractures within 1 year (bone attenuation per −10 HU: hazard ratio [HR], 1.08 [95% CI, 1.02-1.13]; vertebral fracture: HR, 3.99 [95% CI, 2.67-5.93]) and 3 years (bone attenuation per −10 HU: HR, 1.05 [95% CI, 1.02-1.08]; vertebral fracture: HR, 3.12 [95% CI, 2.43-4.01]). Baseline bone attenuation was associated with incident vertebral fractures in participants without prevalent vertebral fractures (1 year: per −10 HU: HR, 1.09 [95% CI, 1.01-1.18]; and 3 years: per −10 HU: HR 1.07; 95% CI, 1.02-1.12). The lowest bone attenuation tertile was associated with 3-year vertebral fracture incidence in the absence of prevalent vertebral fractures (low vs high group: HR, 2.0; 95% CI, 1.3-3.0), but not with 1-year incidence (low vs high group: HR, 1.7; 95% CI, 0.8-3.3).

In conclusion, a prevalent vertebral fracture was a stronger determinant than baseline bone attenuation for prevalent and incident vertebral fractures in former smokers with and without COPD: “[bone attenuation] measurements combined with [vertebral fracture] assessment on CT are useful for [vertebral fracture] risk assessment.”

Reference

van Dort M, Driessen J, Geusens P, et al. The risk of incident vertebral fractures in current or former heavy smokers with and without COPD is associated with baseline vertebral bone attenuation and prevalent vertebral fractures: a 3-year chest-CT follow-up study. Presented at: 2018 American Society for Bone and Mineral Research Annual Meeting; September 28-October 1, 2018; Montreal, Canada. Abstract 0735.

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