RACIAL DIFFERENCES IN BONE, BONE FREE LEAN MASS, AND FAT IN YOUNG WOMEN: PRELIMINARY RESULTS

Japneet Kaur1, Ryan M. Miller1, Eduardo D.S. Freitas1, Aaron Heishman1, Debra Bemben1, FACSM, Michael G. Bemben1, FACSM 1Department of Health and Exercise Science, University of Oklahoma, Norman, OK The burden of osteoporosis and fracture incidence varies significantly with race/ethnicity. Caucasians are reported to have a lower bone mineral density (BMD) than African Americans, and a higher, lower, or similar BMD than Asians. However, the majority of these studies are focused on East-Asians, with few well-defined studies focusing on South-Asians, who are culturally and geographically different from East-Asians. PURPOSE: The purpose of the current study is to evaluate bone mineral density/content, bone free lean mass (BFLM) and strength, and fat mass in young women belonging to Caucasian, East-Asian and South-Asian descent. METHODS: Twenty-nine young women aged 18-30 years self-identified themselves as Caucasian (Cau; n=13), South-Asian (SA; n=11), and East-Asian (EA; n=5). Quadriceps (Q) angle was measured using a hand-held goniometer. Body composition (fat, BFLM, and bone mineral content) and total and regional BMD were measured using Dual Energy X-Ray Absorptiometry, while handgrip, jump test, and 1Repetition-Maximum (1-RM) leg press were used to quantify lower limb muscle strength and power. Ethnic differences in each outcome variable were determined using one-way ANOVA, and Pearson correlation coefficients quantified relationships between variables. Statistical significance was set at p\u3c0.05. RESULTS: Q-angle was significantly higher in SA in comparison to Cau (p\u3c0.05). Muscle strength tests revealed that Cau had considerably higher values for 1-RM leg press than SA (p=0.027). Jump height (p=.002) and time in air (p=.003) were considerably higher for Cau and EA compared to SA. Additionally, SA had a significantly higher percent body fat and fat mass at the total body and in the lower limbs (p≤0.001). Though non-significant, BFLM was highest in Cau, followed by EA, and least in SA (p=0.068). CONCLUSION: Our preliminary data indicates an increased adiposity in SA, without a concurrent increase in muscle mass. Such a phenotype is deteriorative for bone, and suggestive of an early, sub-clinical form of osteosarcopenic obesity. We also see differences in percent body fat and muscle strength between EA and SA, emphasizing the need to consider these two groups separately while assessing the bone-muscle-fat unit