Participation in a Social-Support Physical Activity Intervention Modestly Improves Lipoprotein Cholesterol Distribution Among Postpartum Sedentary Hispanic Women

Background: The effects of moderate intensity walking on lipoprotein remodeling in postpartum Hispanic women are unknown. Methods: Sedentary postpartum Hispanic women (28.2 +/- 5.6 y; BMI = 29.3 +/- 3.3 kg/m(2)) participating in a social support physical activity (PA) intervention, were randomly assigned to a 12-month walking program (walkers; n = 22; target 150 min/wk, moderate intensity) or a control group (nonwalkers; n = 22). Fasting lipids and cholesterol distribution within low-density lipoprotein (LDL) and high-density lipoprotein (HDL) particles were measured at baseline (BL), 6 months, and 12 months. Results: Walkers had an 11% increase and nonwalkers a 7% decrease in HDL cholesterol from 6 to 12 months (P = .0367) without an effect on LDL cholesterol. Whereas nonwalkers had virtually no change in mean LDL particle size, walkers had a borderline reduction in LDL size from BL (268.7 +/- 4.1 angstrom) to 6 months (266.9 +/- 4.9 angstrom), followed by a significant increase in size by 12 months (269.7 +/- 4.1 angstrom; P =.011). The proportion of cholesterol in large LDL particles decreased by 15% from BL to 6 months, but subsequently increased 25% by 12 months among walkers; changes among nonwalkers were smaller and in opposite direction (4% and -3%, respectively; P =.0004). Conclusions: Participation in the social-support PA intervention resulted in slightly increased HDL cholesterol concentrations and a modest and beneficial shift toward larger, less atherogenic LDL particles.