Cardiovascular/non–insulin-dependent diabetes mellitus risk factors and intramyocellular lipid in healthy subjects: a sex comparison

Little is known about the relationship between intramyocellular lipid (IMCL) and coronary artery disease (CAD)/non–insulin-dependent diabetes mellitus risk factors. The aim of the study was to examine the relationship between IMCL and CAD/non–insulin-dependent diabetes mellitus risk factors in healthy male (n = 9) and female (n = 10) subjects with similar norm-based aerobic fitness and body composition. Nineteen volunteers (21-36 years) completed health and physical activity questionnaires, cardiovascular and body composition evaluation, and assessment of thigh IMCL using proton magnetic resonance spectroscopy. Outcome measures were blood pressure, total cholesterol, high-density lipoprotein cholesterol, C-reactive protein, interleukin 6, tumor necrosis factor α (TNF-α), homocysteine, insulin resistance (IR), percentage of body fat, waist-to-hip ratio, physical activity levels, and cardiovascular fitness. Analysis of variance was used for group comparisons. Correlation analyses were used to determine association between variables, and stepwise regression was used to determine predictive variables of IR. Women had 2-fold higher IMCL and greater IR than men (P < .05). Men had greater plasma homocysteine and interleukin 6 concentration (P < .05) as well as stronger correlations with CAD risk factors than female subjects. Correlation analyses using all subjects revealed a significant relationship between IMCL and waist-to-hip ratio, body weight, percentage of body fat, and IR. In the regression analysis, age, IMCL, and TNF-α were the strongest predictors of IR (R2 = 0.62, P < .01). Our results suggest that female subjects, matched for age and fitness, have higher IMCL compared with their male counterparts. IMCL was correlated with several CAD and prediabetes markers in both male and female subjects. In the final regression model, age, IMCL, and TNF-α were the strongest predictors of IR. Future studies with larger sample sizes are warranted.