Opportunistic Screening Using Low-Dose CT and the Prevalence of Osteoporosis in China: A Nationwide, Multicenter Study

Abstract

Opportunistic screening for osteoporosis can be performed using low‐dose computed tomography (LDCT) imaging obtained for other clinical indications. In this study we explored the CT‐derived bone mineral density (BMD) and prevalence of osteoporosis from thoracic LDCT in a large population cohort of Chinese men and women. A total of 69,095 adults (40,733 men and 28,362 women) received a thoracic LDCT scan for the purpose of lung cancer screening between 2018 and 2019, and data were obtained for analysis from the China Biobank Project, a prospective nationwide multicenter population study. Lumbar spine (L1–L2) trabecular volumetric bone mineral density (vBMD) was derived from these scans using quantitative computed tomography (QCT) software and the American College of Radiology QCT diagnostic criteria for osteoporosis were applied. Geographic regional differences in the prevalence of osteoporosis were assessed and the age‐standardized, population prevalence of osteoporosis in Chinese men and women was estimated from the 2010 China census. The prevalence of osteoporosis by QCT for the Chinese population aged >50 years was 29.0% for women and 13.5% for men, equating to 49.0 million and 22.8 million, respectively. In women, this rate is comparable to estimates from dual‐energy X‐ray absorptiometry (DXA), but in men, the prevalence is double. Prevalence varied geographically across China, with higher rates in the southwest and lower rates in the northeast. Trabecular vBMD decreased with age in both men and women. Women had higher peak trabecular vBMD (185.4 mg/cm3) than men (176.6 mg/cm3) at age 30 to 34 years, but older women had lower trabecular vBMD (62.4 mg/cm3) than men (92.1 mg/cm3) at age 80 years. We show that LDCT‐based opportunistic screening could identify large numbers of patients with low lumbar vBMD, and that future cohort studies are now required to evaluate the clinical utility of such screening in terms of fracture prevention and supporting national health economic analyses. © 2020 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR)..

A phantom study comparing low-dose CT physical image quality from five different CT scanners

“…Therefore, it is acceptable to perform the LDCT and lumbar QCT scans together to simultaneously screen for lung cancer, osteoporosis, and osteoporosis-associated fragility fractures (11). The "China Biobank" project and some other related studies are in agreement with our study (3,9,10).…”

“…Due to the aging population in China, the prevalence of osteoporosis and the risk of fragility fractures have increased significantly (1). The diagnosis and prevention of osteoporosis is mainly dependent on opportunistic screening by quantitative computed tomography (QCT) and the accuracy of the bone mineral density (BMD) measurements obtained (2,3). However, patients with a high risk of osteoporosis are often exposed to a significant amount of radiation dose due to repeated lumbar CT scans.…”

“…According to the principle of "as low as reasonably achievable (ALARA)" (4), it is essential to optimize the radiation dose patients are exposed to while still maintaining the quality of the clinical diagnostic image. Lowdose computed tomography (LDCT) has been applied as a promising approach for lung cancer screening, especially for early-stage lung cancer (3,5,6), as it can reduce the radiation dose patients receive (7), thereby reducing mortality (8) in high-risk populations. Hence, the combination of LDCT and lumbar QCT was proposed by the China Health Big Data (China Biobank) project to screen for osteoporosis and lung cancer simultaneously with high precision.…”

“…Hence, the combination of LDCT and lumbar QCT was proposed by the China Health Big Data (China Biobank) project to screen for osteoporosis and lung cancer simultaneously with high precision. This method allows for improved quality of clinical diagnostic images without the need for extra equipment, repeated examination, extra patient time, excessive radiation exposure, or substantial additional costs (3,9,10). BMD is a primary tool used to evaluate the fracture risk of osteoporosis in patients.…”

“…While many studies have examined the use of LDCT screening for lung cancer and osteoporosis, few have compared the physical image quality obtained from the Catphan 500 using CT scanners from different manufacturers (3,9,13). Therefore, this study performed phantom experiment to systematically investigate the physical image quality of CT scanners from 5 different manufacturers using an LDCT scan protocol.…”