Estrogen in men: effects on bone accrual, maintenance and prevention of bone loss

Compromised Volumetric Bone Density and Microarchitecture in Men With Congenital Hypogonadotropic Hypogonadism

CONTEXT

Men with congenital hypogonadotropic hypogonadism (CHH) and Kallmann syndrome (KS) have both low circulating testosterone and estradiol levels. Whether bone structure is affected remains unknown.

OBJECTIVE

To characterize bone geometry, volumetric density and microarchitecture in CHH/KS.

METHODS

This cross-sectional study, conducted at a single French tertiary academic medical center, included 51 genotyped CHH/KS patients and 40 healthy volunteers. Among CHH/KS men, 98% had received testosterone and/or combined gonadotropins. High-resolution peripheral quantitative computed tomography (HR-pQCT), dual-energy x-ray absorptiometry (DXA), and measurement of serum bone markers were used to determine volumetric bone mineral density (vBMD) and cortical and trabecular microarchitecture.

RESULTS

CHH and controls did not differ for age, body mass index, and levels of vitamin D and PTH. Despite long-term hormonal treatment (10.8 ± 6.8 years), DXA showed lower areal bone mineral density (aBMD) in CHH/KS at lumbar spine, total hip, femoral neck, and distal radius. Consistent with persistently higher serum bone markers, HR-pQCT revealed lower cortical and trabecular vBMD as well as cortical thickness at the tibia and the radius. CHH/KS men had altered trabecular microarchitecture with a predominant decrease of trabecular thickness. Moreover, CHH/KS men exhibited lower cortical bone area, whereas total and trabecular areas were higher only at the tibia. Earlier treatment onset (before age 19 years) conferred a significant advantage for trabecular bone volume/tissue volume and trabecular vBMD at the tibia.

CONCLUSION

Both vBMD and bone microarchitecture remain impaired in CHH/KS men despite long-term hormonal treatment. Treatment initiation during adolescence is associated with enhanced trabecular outcomes, highlighting the importance of early diagnosis.

Prostate cancer and osteoporosis

Adenocarcinoma of the prostate is one of the commonest cancers in the world. Due to a combination of earlier detection and better treatments, survival has increased dramatically. Prostate cancer itself is associated with lower bone density and increased fractures. This is compounded by the use of androgen deprivation therapy, which causes dramatic falls in circulating testosterone and estrogen, resulting in rapid falls in bone density, decreased muscle mass, and increased fracture rates. Bisphosphonates have been demonstrated to prevent and reverse this bone loss, but there are no anti-fracture data. Denosumab, a monoclonal antibody to RANKL, has recently been shown to increase bone density and reduce fracture rates. Prostate cancer also commonly metastasizes to bone where it can cause complications such as fracture and pain. Both zoledronic acid and denosumab have been demonstrated to reduce skeletal related events. Comparative studies would suggest that densosumab may have an advantage over zoledronic acid.

Osteoporosis in men: Pathophysiology and treatment

Osteoporosis has long been long considered a disease of the aging female skeleton. However, it is now clear that men are also at risk for this disorder. Epidemiologic studies have confirmed that osteoporotic fractures in men are an increasing public health problem, in part due to increased longevity and increased public awareness. Recent large-scale population studies in men have led to advances in our understanding of bone fragility and its treatment in men. This article reviews what is known about the factors in men that lead to acquisition, maintenance, and loss of bone, as well as new insights into causes, pathogenesis, and treatment of osteoporosis in men.

Osteoporosis in men: pathophysiology and treatment

Osteoporosis has long been long considered a disease of the aging female skeleton. However, it is now clear that men are also at risk for this disorder. Epidemiologic studies have confirmed that osteoporotic fractures in men are an increasing public health problem, in part due to increased longevity and increased public awareness. Recent large-scale population studies in men have led to advances in our understanding of bone fragility and its treatment in men. This article reviews what is known about the factors in men that lead to acquisition, maintenance, and loss of bone, as well as new insights into causes, pathogenesis, and treatment of osteoporosis in men.