Changes of Central Obesity is the Major Determinant of Influences of Weight Reduction on Bone Mineral Density / 대한골다공증학회지

ABSTRACT

OBJECTIVES: Obesity and osteoporosis have been increasing for decades but their relationship to bone mineral density (BMD) and fat mass has not been defined. The aim of this study was to investigate how changes in body composition affect BMD after a weight reduction. MATERIALS AND METHODS: We reviewed 48 middle-aged obese women who had participated in our diet program and succeeded in reducing their weight. Body composition was measured by the dual-energy X-ray absorptiometry method, and metabolic syndrome was defined as described in the ATP-III guidelines. All differences between baseline and 12 weeks later were expressed as [{12th week data-baseline data}/baseline datax100]. RESULTS: The mean age of the participants was 38.29+/-10.89 years, and the mean follow-up time was 85 days. The mean body mass index was 31.50+/-5.19 kg/m2. Basal BMD decreased with age and increased with weight and appendicular lean mass. In a regression analysis, appendicular lean mass was positively correlated with leg BMD (R2=0.235, B=0.015, P<0.001) and age (B=-0.002, P=0.046), and appendicular lean mass (B=0.019, P=0.049) was the main determinant of total BMD (R2=0.272). After weight reduction, the total body BMD change ratio (R2=0.281) was negatively related to the change of fat mass, trunk fat mass (B=-0.042, P=0.087) and waist circumference (B=-0.108, P=0.014). CONCLUSIONS: Our findings suggest that BMD is determined by muscle mass, and that changes in central obesity may also affect BMD.