MedWire News: Researchers have highlighted the importance of lean mass in predicting bone mineral density (BMD) in men.
In their study of various risk factors for osteoporosis, the team found that lean mass accounted for most of the variance in BMD at the hip, wrist, and spine.
“Although a causal relationship still needs to be determined, low lean mass is a modifiable risk factor that can be improved with resistance training and physical activity,” G Chiu and co-workers, from New England Research Institutes in Watertown, Massachusetts, USA, write in the journal Osteoporosis International.
“Therefore, our study may have clinical implications for care and future studies of skeletal health.”
The researchers also note, however, the limitation of focusing on individual risk factors. They assessed a wide range of risk factors, grouped into age, demographics, body composition, hormones, lifestyle, health, function, and serum, yet these risk factors explained only about half the variance in BMD at the hip, wrist, and spine.
For the study, data from the cross-sectional Boston Area Community Health/Bone (BACH/BONE) survey for 2544 men aged 30–79 years were used.
The risk factors studied explained just 41.0% of the variance in BMD at the hip, 30.0% at the wrist, and 24.0% at the spine.
Multivariate analysis showed that height-adjusted appendicular lean mass accounted for most explained variance at all three sites. It was positively associated with BMD and contributed to nearly 60.0% of the variance in BMD at the hip, 43.4% at the wrist, and 43.4% at the spine.
Black ethnicity was also positively associated with BMD at all three sites, and was the next biggest contributing factor, explaining 17.0%, 21.4%, and 17.3% of variance at the hip, wrist, and spine, respectively.
Asthma was also a consistent contributor at all three sites, showing an inverse correlation with BMD.
Among the remaining risk factors, health status was a strong contributor to BMD and lifestyle factors were important to BMD in the hip, while grip strength was strongly related to wrist BMD, and age and Type I collagen were important to BMD in the spine.
“Our findings identify the potential limitations of risk factor epidemiology as a general approach and highlight the need to better understand the relationships in context with other risk factors,” say Chiu et al.
“Our findings contribute to the current literature by suggesting that the most important risk factor for BMD, in the context of many others, is appendicular lean mass.”
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