Impact of obesity on lipid profiles in middle-aged women

The goal of the study was to analyze the impact of overweight on lipid and apolipoprotein A-I and B (apoA-I, apoB) profiles in the women's blood serum.

Seventy-five women without any symptoms of coronary heart disease were examined. Women were divided into two groups: those with normal weight and the body mass index (BMI) less than 25 (n=34, BMI 22.3+/-1.5; mean age 62+/-8.7 years) and overweight women (n=41, BMI 29.7+/-3.7; mean age 59+/-9.4). Weight and height were measured and blood serum concentrations of total cholesterol, high-density lipoprotein cholesterol, and triglycerides were determined after an overnight fasting. In the same serum samples the levels of apoA-I and B were measured using monoclonal antibodies against apo (Spinreact AA, Sant Esteve De Bas, Spain) by the immunoturbidimetry method. The serum samples were kept frozen at -40 degrees C until used.

Total cholesterol and triglycerides levels were similar in the healthy and the overweight women groups (6.49+/-1.25 vs 6.52+/-1.18 mmol/l; p>0.05 and 1.21+/-0.71 vs 1.41+/-0.98 mmol/l; p>0.05, respectively). The concentrations of high-density lipoprotein cholesterol and apoA-I were significantly higher in the normal weight women compared to the overweight women (1.84+/-0.52 vs 1.40+/-0.29 mmol/l, p<0.001 and 1.40+/-0.26 vs 1.24+/-0.23 g/l, p<0.01, respectively). The level of apoB was significantly higher in the overweight female group compared to normal weight women (0.83+/-0.21 vs 0.74+/-0.18 g/l, p=0.049). The apoB/A-I ratio was significantly lower in the normal weight group than in the overweight group (0.055+/-0.15 vs 0.70+/-0.22; p<0.001). Moderate to strong correlations between apoA-I and high-density lipoprotein cholesterol concentrations were found in both groups (r=0.41, p<0.01 in the control female group and r=0.59, p<0.0001 in the overweight group, respectively). A similar level of correlation between apoB and total cholesterol was established in both groups (r=0.54, p<0.0005 and r=0.67, p<0.0001, respectively).

Obesity in middle-aged women is associated with a significant decrease in serum high-density lipoprotein cholesterol and apoA-I levels, a significant increase in apoB and apoB/A-I ratio, even if serum total cholesterol and triglycerides concentrations are unaltered. Changes of the lipid profile in obese women are indicative of a higher risk of coronary heart disease.