Prevalence and predictors of bone density loss in men with low testosterone.

backgroundLow testosterone (T) is associated with several sequelae, including a high prevalence of bone density loss (BDL).

aimWe aimed to identify predictors of BDL in men with low T.

methodsThe sample included (1) men ≥50 years old, (2) with low total T levels (<300 ng/dL using LCMS on 2 early morning blood draws), (3) who had dual-energy X-ray absorptiometry (DEXA) within 6 months of T measurement. Men with prior T therapy were excluded. On DEXA, osteopenia was defined as a T score between -1.0 and -2.5, and osteoporosis as a T score below -2.5. Additionally, demographics and comorbidity data were collected. We report BDL rates and identify predictors of any BDL using logistic regression. OUTCOMES: Bone density loss, which was defined as the presence of osteopenia or osteoporosis.

resultsNine hundred ninety-seven men were analyzed, with a median age of 64 (IQR 59, 70) years. Median total T was 202 (IQR: 107, 256) ng/dL, median free T 5.8 (IQR: 4.3, 7.5) ng/dL. 24% had a total T ≤ 100 ng/dL. Thirty-three percent had ≥3 comorbidities. Seventy-four percent of our cohort had an oncological history; most of them had a history of prostate cancer. Bone density loss was present in 36% of the patients (89% osteopenia, 11% osteoporosis). On multivariable analysis, significant predictors of BDL were lower total T levels (OR = 1.09), older age (OR = 1.59), and the presence of ≥3 comorbidities (OR = 1.60). CLINICAL IMPLICATIONS: It is critical to be aware of the significant prevalence of BDL in men with low T. Early identification may enable targeted counseling, the initiation of preventive or therapeutic strategies to improve bone density outcomes, and the reduction of the risk of fractures and other serious skeletal complications. STRENGTHS & LIMITATIONS: Limitations related to retrospective design, including selection bias and unmeasured confounding factors. Another limitation is that most cases had an oncological history. However, several strengths include the use of a large, systematically audited database; T labs were assessed using gold-standard methodology; and bone mineral density was assessed using a standardized scanning protocol.

conclusionIn our cohort of older men, most with oncological history and low T, around one-third had BDL, and around 10% of those with BDL had osteoporosis. Lower T levels, older age, and a greater number of comorbidities were significant predictors of BDL.