Obesity, dynapenia, and their combination: Implications for bone mineral density in Brazilian adults-the Pró-Saúde study.

Abstract

This study aimed to evaluate bone mineral density (BMD) in the presence or absence of dynapenia or obesity in Brazilian adults. This is a cross-sectional study conducted in 502 adults (age: 33-81 y; 51% women) participating in the Pró-Saúde study, a cohort of civil servants at the university campuses in Rio de Janeiro, Brazil. Body composition and BMD were determined by dual energy x-ray absorptiometry. Handgrip strength was measured using a dynamometer. According to measures of handgrip strength (≤19 kg for women; ≤32 kg for men) and fat mass (>30% for men; >40% for women), participants were classified into four groups: non-obese non-dynapenic, obese non-dynapenic, non-obese dynapenic, and obese dynapenic. The association between BMD at each specific bone site and obesity, dynapenia, and their interaction was evaluated using a general linear model. The prevalence of dynapenic obesity was 14% in men and 15.2% in women. Dynapenia alone was not associated with BMD at any site in either men nor women. Obesity and dynapenia interacted to influence BMD in women (P < 0.05). Total body, lumbar spine, and femoral neck BMD were higher by 6.3%, 9.3%, and 10.4%, respectively, in dynapenic obese women compared with their non-obese counterparts (P < 0.05). In men, obesity, dynapenia, and their combination were not associated with BMD at any site. Our results suggest that dynapenia, obesity, and their combination may affect BMD in a sex-dependent manner. In the presence of dynapenia, fat mass appears to exert a protective effect on BMD in women, but not in men.