Obesity and Osteoporosis

Dispelling the myth that overweight and obese people have a bone mass density advantage

It is becoming less frequent that one can see articles about how osteopenia and osteoporosis are diseases that are more likely in individuals who are slight in frame. Well-established research for over 100 years has shown that additional axial mechanical loading on the musculoskeletal system can produce a higher level of bone mass density. Researchers had previously assumed that, as more loading is induced on a heavier individual, through their activities of daily living, the opportunity to build additional bone of mass density exists. Critics of this theory have cited poor nutrition in overweight and obese individuals, and axial mechanical loading never being multiples of body weight, concluding that the chances of these individuals having greater bone mass density are in actuality lower.

Overweight People and DXA Scans

Simplified graph of body mass index Underweigh...

Simplified graph of body mass index Underweight Normal weight Overweight Obese (Photo credit: Wikipedia)

A study published in 1997 in the Journal of Clinical Endocrinology and Metabolism analyzed relationships of bodyweight, fat mass, and bone density. The results showed that greater fat free mass was indicative of healthy levels of bone mass density, whereas fat mass had little to no relationship. This means individuals with more muscular tissue had a greater advantage, but excess body fat did not indicate bone health.

A similar study looked at 79 obese females. The women had an average body mass index (BMI) of 35. As stated above, conventional thinking would assume these women would not be at risk of developing osteoporosis. The researchers found the opposite to be true. DXA scans showed that low bone mass density was common with 32% of the test group showing significant losses in bone mass density. Until thinking changes with regard to body weight, and not lean body mass, individuals should request regular DXA scans from their physicians. Some researchers have suggested links between decreased levels of human growth hormone (HGH) in overweight and obese individuals to lower bone mass density. Further research is needed.

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