Total estradiol, rather than testosterone levels, predicts osteoporosis in aging men / Estradiol prediz melhor osteoporose que testosterona total em homens idosos

OBJECTIVE: To study and establish sex hormone cutoff levels for osteoporosis risk in men over 50 years old. METHODS: Case-control study of 216 men > 50 years, 110 with osteoporosis (O) and 106 with normal bone density (C). We measured estradiol (E2), sex hormone binding globulin (SHBG), total testosterone (TT) and albumin. Free testosterone (FT) and bioavailable testosterone (BT) were calculated through Vermeulen's formula. RESULTS: There was no difference in TT between groups. Relative risks of osteoporosis were 1.89 for E2 < 37 pg/mL (p = 0.02); 1.91 for SHBG > 55 nmol/L (p = 0.019); 2.5 for FT < 7 ng/dL (p = 0.015); 2.7 for BT < 180 ng/dL (p = 0.0003). CONCLUSIONS: In men over 50 years old, TT was not indicative of osteoporosis risk while E2 < 37 ng/mL was. SHBG > 55 nmol/L, FT < 7 ng/dL and BT < 180 ng/dL can represent additional indications for osteoporosis screening in men over 50 years old.

OBJETIVO: Estudar e estabelecer pontos de corte dos hormônios sexuais para risco de osteoporose em homens após os 50 anos de idade. MÉTODOS: Estudo caso-controle de 216 homens > 50 anos, 110 com osteoporose e 106 com densidade óssea normal. Foram dosados: estradiol (E2), globulina ligadora de hormônios sexuais (SHBG), testosterona total (TT) e albumina. Foram calculadas: testosterona livre (TLC) e testosterona biodisponível (TB) pela fórmula de Vermeulen. RESULTADOS: Não houve diferença na TT entre os grupos. Os riscos relativos de osteoporose foram de 1,89 para E2 < 37 pg/mL (p = 0,02); 1,91 para SHBG > 55 nmol/L (p = 0,019); 2,5 para TLC < 7 ng/dL (p = 0,015) e 2,7 para TB < 180 ng/dL (p = 0,0003). CONCLUSÕES: Em homens acima de 50 anos, TT não indicou risco de osteoporose, mas E2 < 37 pg/mL sim. SHBG > 55 nmol/L, TLC < 7 ng/dL e TB < 180 ng/dL podem representar indicações adicionais para pesquisa de osteoporose em homens acima de 50 anos.

Bone mineral density and sex steroids in middle aged men

BACKGROUND: Osteoporosis is a skeletal condition that is characterized by reduction in bone volume and an increased vulnerability to fracture, practically of the proximal femur and vertebrae. But the etiology of osteoporosis in most men without history of alcohol abuse, or glucocorticoid excess is unknown. Several studies revealed that bone density in aged men was associated with serum sex steroids or sex hormone binding globulin (SHBG). METHODS: We have analyzed bone density and sex steroids, and SHBG of healthy 100 middle aged men who visited one university hospital located in Taejon city from Jan. 1997 to Nov. 1997. Aim of this study was to determine whether bone density in middle aged men was associated with serum sex steroids or SHBG. RESULTS AND CONCLUSION: Body mass index was significantly associated with serum FEI. BMI also associated negatively with SHBG. Bone density at lumbar spine was significantly positively associated with FEI (Free Estradiol Index) (r=0.359, P<0.001). SHBG was negatively associated (r=-0.273, P<0.01) with lumbar bone mineral density. After controlling for age, FEI and SHBG were still associated with BMD of lumbar spine. Because of these associations, multiple stepwise regression models were constructed, and accounted for 12-17% of the variability in bone density. Also, these results showed consistent, significant positive associations between bone density and FEI, BMI in middle aged men. Therefore, our data suggest that FEI and BMI may play an important role in the maintenance of the male skeleton.