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The Effects Of Weight Loss And Exercise On Relative Bmd In Premenopausal Women, Kara Cook Hamilton

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Heavier individuals have higher bone mineral density (BMD) than individuals of lower body weight, but it is unclear whether BMD changes in proportion to body weight during weight loss. This study compared BMD relative to body weight following a six month weight loss program and a one-year weight maintenance phase in premenopausal women and determined whether African American (AA) and European-American (EA) women's BMD respond similarly during weight loss. Premenopausal women (n=115, 34±5 yrs.) were evaluated in an overweight state (BMI between 27 and 30 kg/m2), following an 800 kcal/day diet/exercise program designed to reduce BMI <25 kg/m2, and one-year following weight loss. Results indicated that BMD relative to body weight increased after weight loss, but decreased during the one-year weight maintenance phase. However, all one-year follow up BMD measurements were increased (all significant except Ward's triangle and L1) when compared to baseline measurements. These sites included the hip neck (mean Z-score difference of 0 .088, P=0.014), the greater trochanter (mean difference of 0.089, P=0.003), total hip (mean Z-score difference of 0.099, P=0.001), L2 (mean Z-score difference of 0 .126, P<0.013), L3 (mean Z-score difference of 0.136, P=0.014), and L4 (mean Z-score difference of 0.186, P=0.005). AAs had significantly higher BMD at all sites compared to EAs, but no time by race interactions were evident during weight loss (except in L3). These results indicate that it is safe and beneficial for overweight premenopausal women to lose weight since it improves BMD relative to body weight, while also combating obesity, heart disease, high blood pressure, and type II diabetes.