From the Guidelines
Low body weight is a significant risk factor for osteoporosis, as it is associated with lower bone mass and increased risk of fracture. According to a high-quality meta-analysis 1, the most important risk factors for osteoporosis in men are age (>70 years), low body weight (body mass index <20 to 25 kg/m2 or lower), weight loss (>10% [compared with the usual young or adult weight or weight loss in recent years]), physical inactivity, use of oral corticosteroids, and previous fragility fracture.
Some key points to consider:
- Low body weight, particularly a body mass index (BMI) below 20-25 kg/m², significantly increases the risk of developing osteoporosis 1.
- Individuals with lower body weight typically have less bone mass to begin with and may experience more rapid bone loss over time.
- Lower weight means less mechanical loading on bones, which reduces the stimulus for bone formation and maintenance.
- Fat tissue also produces estrogen, which helps protect bone density, so individuals with low body weight often have lower estrogen levels.
- Other risk factors, such as age, weight loss, physical inactivity, and use of oral corticosteroids, also play a significant role in the development of osteoporosis 1.
It is essential to note that while other factors, such as alcohol use and cigarette smoking, may also contribute to the risk of osteoporosis, the evidence is less clear, and they are considered moderate predictors of an increased risk for low bone mass 1.
In clinical practice, it is crucial to evaluate non-DXA osteoporosis tests that are sensitive, inexpensive, and easily implemented, as DXA is not universally available and may not be cost-effective in all groups 1.
Overall, low body weight is a critical risk factor for osteoporosis, and healthcare providers should consider this factor when assessing patients' risk of developing osteoporosis and fractures.
From the Research
Risk Factors for Osteoporosis
- Low body weight is a significant risk factor for osteoporosis, as it is associated with reduced bone mineral density (BMD) and increased risk of fractures 2, 3, 4.
- Studies have shown that low body mass index (BMI) is inversely associated with BMD status, and women with low BMI are at increased risk of osteoporosis 3.
- A low body weight, defined as a BMI < 22-24, increases the risk of osteoporosis, while a higher body weight, particularly with a BMI > 26-28, may confer limited protection 4.
- However, high fat mass, particularly visceral adiposity, has been associated with prevalent vertebral fracture in women, but not in men 5.
- The relationship between body weight and osteoporosis is complex, and other factors such as hormone replacement therapy, lifestyle changes, and specific treatments for osteoporosis should also be considered 6.