Effect Of Weight Loss And Exercise On Serum Osteocalcin In Overweight Women

Abstract

Weight loss interventions typically incorporate a combination of reductions in energy intake and an increase in energy expenditure. However, due to the reduction in macro- and micro-nutrients with weight loss, this may negatively impact bone health. PURPOSE To characterize levels of serum osteocalcin and to examine changes in serum osteocalcin with weight loss and exercise in overweight women. METHODS Data from 50 women (BMI = 30.4 ± 2.5 kg/m2, age = 45.2 ± 6.6 years) who completed a 6-month behavioral weight loss program were analyzed. Participants were prescribed a reduced energy (1,200 to 1,500 kcal/d) and dietary fat (20 to 30%) diet. Subjects were randomly assigned to: 1) AERO: aerobic exercise (40 min/day, 5 day/wk) 2) RES: aero exercise + resistance exercise using a home exercise machine (40 min/day, 5 day/wk aero + 3 day/wk of resistance exercise) or 3) YOGA: aero exercise + yoga (40 min/day, 5 day/wk aero + 3 day/wk of yoga). Body weight and fasting serum osteocalcin were measured at baseline and 6-months. RESULTS Significant weight loss of −9.2 ± 4.8 kg, −10.5 ± 5.1 kg, and −12.7 ± 4.9 kg was observed in AERO, RES, and YOGA, respectively (p<0.05), with no significant difference between groups. Mean baseline serum osteocalcin was 12.9 ± 6.5 ng/mL, with no significant difference between groups. A non-significant decrease in serum osteocalcin of 1.3 ± 7.5 ng/mL was observed at 6-months, with no significant difference between groups. Spearman Rank Order correlation coefficients between change in body weight and change in serum osteocalcin were not statistically significant. CONCLUSION There has been some suggestion that weight loss may have a negative impact on bone health. Using serum osteocalin as a marker of bone health, this study showed no significant negative impact of 6-month weight loss on this outcome. Future research should use imaging techniques and other biomarkers to examine the potential change in bone health from weight loss. Supported by National Institutes of Health (HL64991) and Life Fitness