Background: Sarcopenia and obesity influence bone health however, there is limited data on these associations in ethnic populations where there are differences in body composition. This study investigated sex differences between BMD and bone mineral apparent density (BMAD) and obesity, sarcopenia and sarcopenic obesity among Indian older adults.
Methods: 1057 adults aged ≥50 years were included. Dual-energy X-ray absorptiometry measured BMD at the hip, spine and whole-body; and body composition (lean and fat mass) and hand grip strength was assessed. Obesity was defined by body fat percentage (>25% for men and >35% for women), and sarcopenia was defined using the revised Asian Working Group for Sarcopenia classification. BMAD was calculated as BMD/√bone area. Participants were classified into four groups: non-sarcopenic non-obesity (NSNO), obesity (O), sarcopenia (S) or sarcopenic obesity (SO). Linear regression (β-coefficients and 95%CI) was performed with adjustments for age, sex, smoking status, education and occupation type.
Results: Prevalence of S (37%) and SO (6%) were higher in men than women (17% and 4%, respectively). Older men with O had lower whole-body BMD (-0.055; -0.078, -0.032) and BMAD (-0.002; -0.002, -0.001) than NSNO, but men with SO had lower hip, spine and whole-body BMD and BMAD (all p<0.05) than NSNO. Older women with S had lower hip and spine BMD and BMAD than NSNO, but those with obesity had higher hip and spine BMD and BMAD (all p<0.05) than NSNO.
Conclusion: In Indian older adults, obesity is associated with higher bone density, while sarcopenia is associated with lower bone density in women. Sarcopenic obesity is associated with poorer bone density at all three sites in men. Future studies should focus on understanding the contributions of body composition in ethnic populations to poor bone health to develop targeted effective interventions for sarcopenia, obesity, and osteoporosis in Indian older adults.