Introduction: Oxidized LDL (ox-LDL) is associated with lifestyle diseases such as cardiovascular diseases, metabolic syndrome, and type 2 diabetes. The present study investigated the association between ox-LDL and overweight/obesity and how cardiorespiratory or muscle fitness affects this association.
Methods: Healthy young (mean age = 25.1 yr, range = 18–48 yr) men (n = 831) were divided into normal-weight (n = 486), overweight (n = 269), and obese (n = 76) groups according to their body mass index (BMI). The participants underwent physical fitness tests (maximal oxygen uptake with bicycle ergometer and muscle fitness index using series of muscle endurance tests), a general health examination including determination of lipid profile, and a detailed questionnaire. Subjects were further divided into six subgroups according to BMI (normal vs overweight) and physical fitness (fitness tertiles: unfit, average, fit). Age and smoking were used in the statistical analysis as covariates.
Results: In overweight and obese participants, the concentrations of ox-LDL (14%/32%) and the ratio of ox-LDL/HDL cholesterol (32%/68%) were higher compared with subjects with normal weight (P < 0.005, in all). In BMI and cardiovascular fitness subgroups, ox-LDL (23%, P < 0.0001) and the ox-LDL/HDL cholesterol ratio (45%, P < 0.0001) were higher in the overweight/unfit subgroup when compared with the normal-weight/unfit subgroup, whereas no differences were observed between the overweight/fit and normal-weight/fit subjects. Among the BMI and muscle fitness subgroups, ox-LDL (24%, P < 0.0001) and the ox-LDL/HDL cholesterol ratio (51%, P < 0.0001) were higher in the overweight/unfit group compared with the normal-weight/unfit group.
Conclusions: Overweight and obesity are associated with ox-LDL lipids and serum conventional lipids. However, both good cardiorespiratory fitness and muscular fitness seem to protect overweight subjects from the atherogenic lipid profile.
1Department of Health and Exercise, Paavo Nurmi Center, University of Turku, Turku, FINLAND; 2MCA Research Laboratory, Department of Biochemistry and Food Chemistry, University of Turku, Turku, FINLAND; 3Department of Biology of Physical Activity, University of Jyväskylä, Jyväskylä, FINLAND; 4Defence Command, Personnel Division, Finnish Defence Forces, Helsinki, FINLAND; 5UKK Institute for Health Promotion Research, Tampere, FINLAND; and 6National Institute for Health and Welfare, Helsinki, FINLAND
Address for correspondence: Tommi Vasankari, M.D., Ph.D., UKK Institute for Health Promotion Research, Box 30, 33501 Tampere, Finland; E-mail: firstname.lastname@example.org.
Submitted for publication April 2011.
Accepted for publication September 2011.