the complex relationship between obesity and osteoporosis
research reveals a complex, often overlooked link between obesity and bone health
4 minute read
while obesity doesn't necessarily cause osteoporosis, different hormonal disruptions found often in people living with obesity can drive bone loss.
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people living with obesity often have to contend with a higher risk of developing a myriad of comorbidities, including heart disease, type 2 diabetes, some cancers, mental health conditions and sleep apnea.
osteoporosis, which is a disease that weakens the bones, isn’t often included in that list because it is typically associated with lower body weight. that said, research is continuing to form a new opinion on the matter, finding that while not as commonly accepted, obesity and osteoporosis do sometimes go hand-in-hand, albeit in a complex way.
the ‘obesity paradox’
osteoporosis is often considered an older-age disease, with the highest prevalence occurring in people over the age of 65. it is also correlated with lower body mass index (lower body weight) among people of all sizes with osteoporosis.
this led researchers to believe that carrying more weight would, in turn, strengthen bones over time, enabling the skeletal frame to support the body. essentially, some research suggests that having obesity is ‘good’ for bone health—the obesity paradox.
having more adipose tissue, or body fat, can also lead to higher estrogen levels, as this tissue is a direct source of the hormone. since estrogen is a key player in bone metabolism, higher levels are associated with greater protection of bone density rather than weakening it. other hormones found in high levels in adipose tissue, such as insulin and leptin, also play a role in stimulating bone growth, which provides further protection against osteoporosis in people living with obesity.
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that said, this protection does not apply to all bones. for example, research has found that only some bones in the body are more protected against weakening and fractures in people living with larger bodies, such as the hip or spine. ankle and leg bones still carry a high fracture risk for people living with obesity.
while both of these protective effects are true for people living with obesity, they don’t tell the whole story.
factors that affect bone quality in people with obesity
people living with obesity are at risk of various other physiological malfunctions that can affect bone health, such as insulin resistance and chronic inflammation. newer research continues to examine these connections to determine whether the older data still holds up regarding obesity’s protective effect against osteoporosis.
when looking at specific substances, there are a few that can be found in people with obesity that play a role in poorer bone health. leptin, which is primarily produced in fat cells, is found in higher amounts in people living with obesity, and because of that, it can affect bone health and quality.
however, whether that effect is positive or negative remains somewhat of a mystery.
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depending on where leptin is being used, it can cause bone loss by inhibiting the body’s ability to remodel or rebuild bones after cells have been broken down. there’s one catch, though—the studies that looked into it did so on mouse models, and human studies are a lot less clear on whether leptin is able to harm or help bone density in people living in larger bodies.
pro-inflammatory cytokines, which are molecules secreted by immune cells designed to regulate inflammation. these cells have lower levels of a specific hormone, known as adiponectin, which drives the regulation of pro-inflammatory cytokine production. when that happens, these molecules can reach levels far above typical levels, triggering several physiological reactions that make it more difficult for bone tissue to be reabsorbed, leading to reduced bone density.
other players in the osteoporosis-obesity connection
research has found several other factors that may drive the development of osteoporosis in people living with obesity. for example, fat accumulation in the bone marrow can increase the risk of osteoporosis, although researchers are still unclear as to why. it’s thought that it has something to do with the production of new cells.
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both fat cells and bone cells originate from the same types of stem cells, and in people living with obesity, more of them may turn into fat cells rather than bone-forming cells, leading to a loss of bone density over time.
vitamin d deficiency, which is prevalent in people living with obesity, could also drive bone density loss over time because of the way it inhibits the body’s ability to absorb calcium, which is crucial for bone health.
an accumulation of visceral fat, which surrounds organs, may also impair an enzyme that converts cortisone into active cortisol. this dysregulation could encourage bone damage in people living with obesity.
when all these factors work together, the protective effects found in the obesity paradox may not be enough to stop osteoporosis from developing in those living in larger bodies.
while there is a little positive and a little negative to the connection between osteoporosis and obesity, research continues to examine the correlation to see which way the scales really tip when it comes to obesity driving or protecting against the development of osteoporosis.
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