Osteoporosis has traditionally been associated with postmenopausal women and elderly men. It becomes more challenging to diagnose and treat in premenopausal women and men younger than 50 years old. Fractures and osteoporosis in younger adults are less common but do occur in the setting of chronic disease, medications that affect bone metabolism, and other risk factors. Although rare, idiopathic osteoporosis with no identifiable secondary cause can also be associated with fractures. There is a range of obstacles to optimal management of osteoporosis in younger adults, made more difficult by a paucity of research in this population.
Dr. Adi Cohen
To address this, Adi Cohen, MD, MHS, Director of the Early-Onset Osteoporosis Center in the Division of Endocrinology at NewYork-Presbyterian/
In a comprehensive narrative review, published in the January 2022 issue of JBMR Plus, Dr. Cohen and her colleagues proposed a framework, based on available evidence and clinical experience, for the diagnosis, assessment, and management of osteoporosis in the young adult population. They also provided a systematic overview of the physiology of bone accrual and factors affecting peak bone mass, the potential secondary causes of osteoporosis that may disturb the achievement of optimal peak bone mass and hasten bone loss, bone mass changes associated with pregnancy and lactation, and idiopathic osteoporosis.
Dr. Cohen and her colleagues proposed a framework, based on available evidence and clinical experience, for the diagnosis, assessment, and management of osteoporosis in the young adult population.
The investigators conducted a literature search for the most relevant research findings published between January 2000 and August 2021. Among the dilemmas they outlined are:
The pathophysiology of osteoporosis is poorly understood. Chronic disease during childhood and young adulthood can hinder accrual of peak bone mass. Exposure to inflammatory cytokines, poor nutrition, weight loss, hypogonadism, and other disease‐specific mechanisms promote bone loss. The most common etiologies identified for bone loss in young adults include:
- Inflammatory/autoimmune disease
- Endocrine dysfunction, including hypogonadism, Cushing’s syndrome, hyperthyroidism, type 1 diabetes, and growth hormone deficiency
- Malabsorptive disease, including celiac disease
- Anorexia nervosa
The bone mineral density criteria for the diagnosis of osteoporosis are debatable. Osteoporosis in young adults can be diagnosed based on low-trauma fracture. In contrast, bone mineral density (BMD) criteria for diagnosis are debated. The 2019 International Society for Clinical Densitometry Position recommends against the use of dual-energy X-ray absorptiometry (DXA) alone in diagnosing osteoporosis in men and women under 50 years of age and note that the use of a Z-score ≤ 2 on DXA can be used as a marker of “low BMD” in young adults.
Meanwhile, the International Osteoporosis Foundation (IOF) recommends the use of T-score ≤ -2.5 on DXA at the lumbar spine or hip to diagnose osteoporosis in young adults with a known secondary cause of osteoporosis. The lack of cohesive and consistent guidance on the DXA-based diagnosis of osteoporosis in young adults adds an obstacle to optimal osteoporosis management. The International Society for Clinical Densitometry and IOF recommend a diagnosis of low BMD or osteoporosis based on Z‐scores or T‐scores, respectively, in young adults with underlying secondary causes.
Optimal investigations for the diagnosis and monitoring of osteoporosis in young adults are unclear. Although some of the challenges with use of DXA are also seen in older adults, it is worth noting that the underlying etiologies for osteoporosis in young adults are heterogeneous, resulting in the competing effects on reduced peak bone mass, ongoing bone accrual, and increased bone resorption. As a result, DXA may be a poorer predictor of fracture risk. There is also a scarcity of prospective data defining the relationship between BMD and fracture risk in young adults. Investigation of the helpfulness of supplementary DXA analyses, such as hip structural analysis and trabecular bone score, as well as innovative imaging modalities, including high resolution peripheral quantitative computed tomography, will help to determine whether this dilemma can be addressed through newer imaging methods.
Best practice management of osteoporosis or low bone density in young adults is poorly understood due to scarcity of focused research. This is also reflected in the lack of guidelines that address risk stratification for fracture and osteoporosis in young adults. With the lack of a substantial body of research, Dr. Cohen and her colleagues offer the following recommendations based on currently available evidence and clinical experience:
- All young adults with fragility fracture undergo a clinical and biochemical assessment for causes of secondary osteoporosis and assessment with DXA.
- As the importance of idiopathic low BMD is yet to be defined, they recommend against screening young adults with DXA in the absence of fragility fracture or established risk factors for fracture.
The researchers also suggest a diagnosis of osteoporosis if either of the following criteria is met:
- Fragility fracture
- BMD Z-score <2 or T-score < -2.5 at the lumbar spine or hip in the setting of chronic disease/medication exposure associated with osteoporosis, regardless of fracture status
The authors concluded that “Although the implications of idiopathic low BMD on long-term fragility fracture risk are less well-established, fractures in those with idiopathic osteoporosis and in those with or without chronic disease warrant expert management. A stronger research focus into optimizing the diagnosis, monitoring, and management of osteoporosis in young adults is now needed.”