Impact of progressive resistance training on lipids and lipoproteins in adults: Another look at a meta-analysis using prediction intervals

Objective. Given recently developed prediction intervals (Pis) in which a random mean effect for a new study is estimated from meta-analytic data, we used the results from our previously published meta-analysis to calculate Pis for changes in lipids and lipoproteins as a result of progressive resistance training (PRT) in adults. Methods. Twenty-nine studies representing 1329 men and women (676 exercise, 653 control) were included. The primary outcomes included total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), ratio of total cholesterol to high-density lipoprotein cholesterol (TC/HDL-C), non-high-density lipoprotein cholesterol (non-HDL-C,) low-density lipoprotein cholesterol (LDL-C), and triglycerides (TC). Separate Pis (95%) were calculated for all lipids and lipoproteins. Results. The expected outcomes of a new study on this topic were as follows: TC, -5.5 (-24.0, 13.0) mg/dl; HDL-C, 0.7 (-8.9, 10.4) mg/dl; TC/HDL-C, -0.5 (-1.8, 0.8); non-HIDL-C, -8.7 (-35.7, 18.3) mg/dl; LDL-C, -6.1 (-28.9, 16.4) mg/dI; TG, -8.1 (-34.5, 18.3) mg/dl. Conclusions. Caution may be warranted in recommending that PRT improves TC, HDL-C, TC/HDL-C, non-HDL-C, LDL-C. and TG in adults. Future research should continue to examine the effects of PRT on lipids and lipoproteins in adults so as to determine optimal programs and populations in which PRT may have a positive effect. (C) 2009 Elsevier Inc. All rights reserved.