According to quantitative computed tomography (QCT), diagnosis of osteoporosis is more common among patients with diabetes and impaired glucose tolerance (IGT) compared with patients with normal glucose tolerance, according to study results published in The Journal of Clinical Endocrinology & Metabolism.
Previous studies have reported that patients with type 2 diabetes have increased risk for fracture despite normal or increased bone mineral density (BMD), supporting the theory that factors other than BMD may contribute to bone strength and fracture risk. The noninvasive imaging modality QCT can measure volumetric BMD (vBMD) and provide additional important data on fracture risk.
The goal of the current study was to assess bone characteristics evaluated by QCT and other metabolic factors that may affect bone health in Chinese patients with normal glucose tolerance, impaired glucose tolerance, or diabetes.
The cross-sectional population-based study was based on the Pinggu Metabolic Disease Study conducted in the Pinggu district of Beijing, China, between September 2013 and July 2014. All patients completed an oral glucose tolerance test, and measurements were taken for hemoglobin A1c (HbA1c), fasting glucose levels, and additional blood and urine tests. QCT analysis of the total vBMD of the lumbar vertebra 2 to 4 (L2-L4) was performed with Mindways QCT pro 5.0 v software (Mindways software, Inc, Austin, Texas) calibrated with an Image Analysis QCT phantom.
The study enrolled 4001 individuals (mean age, 47.41±11.86 years; 47% men), including 2211 patients in the normal glucose tolerance group, 1161 patients in the impaired glucose tolerance group, and 629 patients with diabetes.
In the normal glucose tolerance group, 10.6% presented with osteoporosis (mean total vBMD by QCT, 134.72±41.63 mg/cm3). In the impaired glucose tolerance group, 14.8% presented with osteoporosis (mean total vBMD by QCT, 121.45±39.06 mg/cm3). The prevalence of osteoporosis in the diabetes group was 16.9% (mean total vBMD by QCT, 117.13±36.97 mg/cm3).
In men and women, multivariable linear regression analysis found that age was negatively associated with vBMD, whereas body mass index and the waist-to-hip ratio were positively associated with vBMD.
Among all patients, levels of HbA1c and fasting and postprandial glucose were not associated with vBMD after adjusting for metabolic factors as covariates. However, after adjustment for the study variables, fasting plasma glucose was positively associated with vBMD in men but not women.
The researchers acknowledged that the study had several limitations, including the cross-sectional design, no data on dietary and lifestyle factors or the prevalence of osteoporosis from the study questionnaire, and missing data on other risk factors for osteoporosis.
“This is the first time, among Chinese population-based subjects, that the prevalence of osteoporosis evaluated by QCT was reported in participants with different levels of glucose tolerance,” concluded the researchers.
Zhao Z, Wang L, Fu Z, Ji L, Li Y, Wu X. The prevalence of osteoporosis tested by quantitative computed tomography in patients with different glucose tolerances [published online September 23, 2019]. J Clin Endocrinol Metab. doi:10.1210/clinem/dgz036