Expert article with contributions from Prof. Dr. Michael Zitzmann. Learn how testosterone deficiency in men affects bone health and increases the risk of osteoporosis and fractures.
Men's bone health is often overlooked in health discussions, yet it deserves special attention, particularly in men with hypogonadism. Hypogonadism, better known as low testosterone, is widespread and can have significant effects on bone health. Studies indicate that between 10% and 40% of men are affected ( Mulligan et al., 2008 ). In this article, we explore the important link between hypogonadism and bone health in men, and how a lack of testosterone can lead to reduced bone density, increasing the risk of fractures and osteoporosis ( Fink et al., 2006 ).
Hypogonadism and bone health
Hypogonadism, or testosterone deficiency, is a condition characterized by low testosterone levels in the body ( Traish et al., 2011 ). Testosterone, an important hormone from the androgen group, plays a crucial role in many physiological processes, including maintaining and strengthening bone structure. Men with hypogonadism often struggle not only with obvious symptoms such as decreased libido, fatigue, and muscle weakness ( Sizar et al., 2024 ), but also with less visible but equally serious problems such as reduced bone density and consequently increased bone fragility, also known as osteoporosis ( Shigehara et al., 2021 ).
Furthermore, a testosterone deficiency can lead to a reduction in muscle mass ( Bhasin et al., 1997 ) and an increase in body fat ( Wittert et al., 2003 ), which also affects bone stress and the risk of fractures. Lower muscle mass weakens the mechanical support of the bones, while increased body fat and thus increased body weight lead to greater stress on the bones.
You can learn more about testosterone deficiency in our article " Testosterone deficiency in men: causes, symptoms and solutions ".
Osteoporosis and fracture risk
Osteoporosis, a disease characterized by weak and brittle bones, is often considered a women's disease ( General, 2004 ). However, men, especially those with hypogonadism, are also at risk. Studies have shown that men with low testosterone levels have an increased risk of fractures, particularly of the hip, spine, and wrist. These fractures can have serious health consequences and significantly impair quality of life ( Golds et al., 2017 ).
Men with hypogonadism are particularly susceptible to decreased bone density because testosterone plays a crucial role in maintaining bone mass ( Narla & Ott, 2018 ). Without sufficient levels of this hormone, bone strength decreases, leading to increased fragility. This increased fragility means that even minor bumps or falls can result in serious injuries. Hip fractures are especially concerning because they often lead to prolonged hospital stays, reduced mobility, and an increased risk of further health complications ( Fox et al., 1993 ).
The spine is also at risk, as fractures in this area can lead to chronic pain, limited mobility, and impaired posture. Wrist fractures, often considered less serious, can nevertheless cause significant impairment in daily life, especially if they recur or do not heal properly. Therefore, prevention and early treatment of bone weakness in men with hypogonadism are crucial to maintaining their quality of life and avoiding serious health consequences.
Testosterone and bone metabolism
Testosterone plays a crucial role in maintaining bone density by stimulating the activity of osteoblasts, the cells that form bone, and inhibiting the breakdown of bone tissue by osteoclasts, the cells that resorb bone ( Mohamad et al., 2016 ). These two cell types are central to bone metabolism. Osteoblasts are responsible for forming new bone matrix and incorporating minerals, thereby strengthening and densifying bones. Osteoclasts, on the other hand, are involved in the resorption of bone tissue by breaking down old or damaged bone material.
A deficiency in testosterone can therefore lead to an imbalance in this delicate system ( Narla & Ott, 2018 ). When testosterone levels drop, osteoblast activity decreases and osteoclast activity increases, resulting in bone resorption exceeding bone formation. This imbalance leads to a decrease in bone density. Reduced bone density means that the bones are less mineralized and therefore less stable and resilient ( Shigehara et al., 2021 ).
The important role testosterone plays in regulating bone metabolism makes it clear why adequate testosterone levels are crucial for maintaining healthy bone structure. Men with hypogonadism, whose testosterone levels are chronically low, should therefore have their bone health monitored regularly and, if necessary, take steps to stabilize testosterone levels and maintain bone density.
Diagnosis of osteoporosis in hypogonadal men
The diagnosis of osteoporosis in men with hypogonadism should be comprehensive and thorough. An essential component of the diagnosis is measuring testosterone levels in the blood to determine the extent of hypogonadism. Ideally, this measurement should be taken in the morning when testosterone levels are highest ( Brambilla et al., 2009 ). The German guideline of the German Osteology Society (DVO) points out that measuring testosterone levels is mandatory in cases of osteoporosis or osteopenia. Furthermore, testosterone replacement therapy is necessary in cases of hypogonadism and osteoporosis, also according to the osteologists ( DVO Guideline Osteoporosis 2023 , nd ).
Another essential tool for assessing bone health is bone density measurement, also known as DXA scan (dual-energy X-ray absorptiometry). This non-invasive test measures bone density and helps detect early signs of osteoporosis or reduced bone density before fractures occur. The DXA scan provides precise information about bone density in different parts of the skeleton, particularly the hip, spine, and wrist, which are most prone to fractures ( Blake & Fogelman, 2007 ).
A comprehensive diagnosis should also include an assessment of vitamin D and blood calcium levels. Vitamin D is crucial for calcium absorption and bone health. A deficiency can lead to reduced bone density and an increased risk of fractures ( Branch, 2023 ). Therefore, it is important to check vitamin D levels and correct them with supplements if necessary. Additionally, other relevant blood parameters important for bone health should be examined. These include parathyroid hormone (PTH), which regulates calcium metabolism ( Kroll, 2000 ), and markers of bone turnover such as osteocalcin and C-terminal telopeptide (CTX). These markers provide information about the activity of osteoblasts and osteoclasts and help assess the balance between bone formation and bone resorption ( Szulc et al., 2017 ).
Prevention and treatment strategies
There are several strategies to improve bone health and reduce the risk of fractures in hypogonadal men:
- Testosterone replacement therapy (TRT): Testosterone replacement therapy (TRT) can help normalize testosterone levels and improve bone density. Large, placebo-controlled, double-blind studies have shown that men receiving TRT have increased bone density and reduced fracture susceptibility. By restoring normal testosterone levels, osteoblast activity is stimulated and osteoclast bone resorption is inhibited, resulting in an overall stronger and more resilient bone structure ( Snyder et al., 2017 ; Fui et al., 2021 ). However, a study published this year in The New England Journal of Medicine showed an increased fracture rate in the TRT group compared to the placebo group, and this increased rate occurred from the start of the study. Bone density was not measured in this study. It is thought that increased physical activity in untrained, older, hypogonadal men with likely osteopenia or osteoporosis at the start of TRT may have caused this. For this reason, it is particularly important for older men at the beginning of TRT to start exercising carefully and under guidance, and to be aware of the risk of falling ( Snyder et al., 2024 ).
- Nutrition: A balanced diet rich in calcium and vitamin D is crucial for bone health. Calcium is the most important mineral for bone formation and strengthening, while vitamin D promotes calcium absorption in the intestines, thus supporting bone mineralization. Foods such as dairy products, leafy green vegetables, fish, and fortified foods can help provide these important nutrients. In cases where dietary intake is insufficient, supplements may be beneficial ( Laird et al., 2010 ).
- Physical activity: Regular physical activity, especially weight-bearing exercises such as walking, running, and strength training, can promote bone strength and slow bone loss. These activities stress the bones and stimulate bone formation by promoting osteoblast activity. Furthermore, physical activity improves muscle strength, coordination, and balance, thereby reducing the risk of falls and fractures ( Pinheiro et al., 2020 ).
- Drug treatment: In some cases, medications such as bisphosphonates or denosumab may be necessary to inhibit bone resorption and increase bone density. Bisphosphonates work by reducing osteoclast activity, thus slowing bone loss. Denosumab is a monoclonal antibody that inhibits the formation and function of osteoclasts, also reducing bone resorption. These medications are particularly useful for men with advanced osteoporosis or a high risk of fracture ( Watts & Diab, 2010 ) .
- Lifestyle changes, such as avoiding smoking ( Trevisan et al., 2020 ) and excessive alcohol consumption, as well as managing chronic conditions like diabetes or thyroid disorders, are also important factors in maintaining bone health. Smoking and excessive alcohol consumption can reduce bone density and increase the risk of fractures ( Sampson, 1998 ). Managing chronic conditions is crucial because certain diseases and their associated medications can negatively impact bone health.
Our conclusion, your knowledge
Testosterone deficiency is a significant risk factor for reduced bone density and an increased risk of fractures in men. It is important for men to be aware of the potential impact of low testosterone levels on their bone health and to take appropriate measures. Regular monitoring of hormone levels and bone density, combined with preventive and therapeutic measures, can help maintain bone health and reduce the risk of fractures.
At Adon Health, we place great importance on educating men about the importance of bone health and helping them proactively manage their health. With the right diagnosis and treatment, men with hypogonadism can improve their bone health and lead an active, healthy life.
