Smaller bone size, less bone turnover in men with hypogonadism type 2 diabetes
Men with hypogonadism and type 2 diabetes have a higher bone mineral density, but smaller bone area and lower bone turnover rate compared with men with hypogonadism but without diabetes, according to findings from a cross-sectional study.
“Men who have both hypogonadism and diabetes mellitus have inactive bone remodeling and smaller bone size compared with men who only have hypogonadism,” Reina Armamento-Villareal, MD, associate professor of medicine at Baylor College of Medicine in Houston, told Endocrine Today. “These bone characteristics could predispose to a greater risk for fractures.”
Armamento-Villareal and colleagues analyzed data from 105 men aged 40 to 74 years with an average morning testosterone level of less than 300 ng/dL (mean age, 60 years; average testosterone level, 210.4 ng/dL; 49 with type 2 diabetes; mean BMI, 32.3 kg/m²). Areal BMD was measured via DXA at the lumbar spine, total hip and femoral neck; volumetric BMD and bone geometry at the left tibia were measured via peripheral quantitative CT. Researchers also measured bone turnover markers, including serum C-telopeptide (CTX), osteocalcin, sclerostin and sex hormone-binding globulin; testosterone; and 25-hydroxyvitamin D.
There were no between-group differences for areal BMD at the lumbar spine or femoral neck. Researchers noted that areal BMD at the total hip was greater in men with hypogonadism and type 2 diabetes, but differences did not persist after adjustment for BMI, age and estradiol levels.
Adjusted volumetric BMD at 38% tibia was greater in men with hypogonadism and type 2 diabetes (mean, 857.3 g/cm²) vs. men with hypogonadism but no diabetes (mean, 828.7 g/cm2; P = .02).
Endosteal (43.9 ± 5.8 mm vs. 47.1 ± 7.8 mm; P = .04) and periosteal (78.4 ± 5 mm vs. 81.3 ± 6.5 mm; P = .02) circumferences at the 38% tibia were lower among men with hypogonadism and type 2 diabetes, as was total area at the 38% tibia (491 ± 61 mm2 vs. 527.7 ± 87.2 mm2; P = .02) with results persisting after adjustment for BMI, age and estradiol levels. However, additional adjustment for diabetes medications reduced the significance to borderline, according to the researchers.
In assessing bone turnover markers, researchers found that both CTX (mean, 0.25 ng/mL vs. 0.4 ng/mL; P < .001) and osteocalcin (mean, 4.8 ng/mL vs. 6.8 ng/mL; P = .006) were lower in men with hypogonadism and type 2 diabetes vs. men without diabetes; however, results did not persist after adjustment for medication use. Researchers did not observe between-group differences for levels of sclerostin, 25-(OH)D or circulating gonadal hormones.
“An inactive bone remodeling would mean accumulation of old bone with poor ability to heal microcracks, while a small bone size indicates a lower bone capacity to adapt to mechanical load and reduced resistance to compression forces, which are considered the main trigger for fractures,” Armamento-Villareal said. “Thus, these men could be at higher risk for fractures.”
Armamento-Villareal added that the bone health of men with both conditions should be evaluated, and general measures to prevent fractures should be implemented.
“Future studies should examine modalities to reverse the inactive bone remodeling and the role of testosterone replacement in these patients, as well as studies investigating if men with both conditions are indeed at greater risk for fractures than men with either condition alone,” Armamento-Villareal said. – by Regina Schaffer
For more information:
Reina Armamento-Villareal, MD, can be reached at the Michael E. DeBakey VA Medical Center, 2002 Holcombe Blvd., Houston, TX 77030; email: email@example.com.
Disclosure: Armamento-Villareal reports no relevant financial disclosures.