Effects Of Weight Loss And Maintenance On Apolipoprotein B In Overweight And Obese Adults

PURPOSE: Apolipoprotein B (ApoB) is a predictor of cardiovascular disease and may have greater prognostic value compared to traditional lipid risk factors. Data is limited on the effects of clinically significant weight loss (CWL) (≥ 7%) on ApoB and how weight loss maintenance alters ApoB. The purpose of this study was to examine the effect of weight loss and exercise level after CWL on ApoB concentrations in overweight and obese adults. METHODS: Thirty overweight and obese adults (age: 45.7 [10.7] yrs; BMI: 34.4 [3.4] kg/m2) completed a 10-week weight loss intervention followed by 18 weeks of weight maintenance. During the weight loss phase, participants completed a hypocaloric weight loss program and supervised aerobic exercise 2-3x/week. The participants that achieved CWL were randomized to either weight maintenance (WM-REC:970 MET min/wk [n = 6]) or physical activity (PA-REC:550 MET min/wk [n = 8]) groups. Nuclear magnetic resonance (NMR) of plasma was used to assess blood markers at baseline, after weight loss, and after weight maintenance. RESULTS: Following weight loss, participants decreased mass (-8.5 kg), BMI (-3.1 kg/m2), ApoB (-11.6 mg/dL), triglycerides (TG) (-27.2 mg/dL), apolipoprotein A1 (-8.3 mg/dL) (all p's = 0.001), low-density lipoprotein (LDL-C) (-8.0 mg/dL, p = 0.013), and HDL-C (-5.2 mg/dL, p = 0.028). After the weight maintenance, ApoB (20.9 mg/dL, p = 0.006) and HDL-C (11.4 mg/dL, p = 0.003) increased, while LDL-C and TG did not change (p > 0.05). There were no differences between groups in changes in ApoB (WM-REC: 17.0; PA-REC: 23.8 mg/dL), HDL-C (WM-REC: 9.0; PA-REC: 13.3 mg/dL), LDL-C (WM-REC: 11.4; PA-REC: 2.4 mg/dL), and TG (WM-REC: 13.4; PA-REC: 1.0 mg/dL) (all p > 0.05) following weight maintenance. Moreover, ApoB was not correlated with weight, body composition or fitness variables (eg., METs and exercise HR) in either phase of the study (p > 0.05). CONCLUSIONS: ApoB decreased following CWL and exercise in overweight and obese adults yet returned to baseline values during weight maintenance. These results indicate that high levels of aerobic exercise did not prevent regression in ApoB following weight loss. Future lifestyle interventions could investigate the effects of various exercise intensities on the maintenance of improvements in ApoB after clinically significant weight loss.