Contribution of visceral fat accumulation to the risk factors for atherosclerosis in non-obese Japanese.

OBJECTIVE: To clarify the contributions of visceral fat tissue (VAT) mass deposition to the accumulation of risk factors for atherosclerosis in normal weight subjects.

SUBJECTS AND METHODS: We investigated the relationship between VAT accumulation and both risk factors and waist circumference in non-obese subjects. In the 955 normal weight Japanese subjects (782 men and 173 women), visceral fat area (VFA), subcutaneous fat area (SFA) and waist circumference were measured through computed tomography. Total cholesterol, high-density lipoprotein (HDL) cholesterol, triglyceride, uric acid, fasting blood glucose, and 2-hour postprandial glucose in the oral glucose tolerance test (OGTT) were measured to assess the risk factors for atherosclerosis.

RESULTS: In both men and women with normal body weight, VFA was correlated with total cholesterol (r=0.78 and r=0.71, respectively), HDL cholesterol (r=-0.89 and r=-0.82, respectively), triglyceride (r=0.72 and r=0.91, respectively), uric acid (r=0.71 and r=0.69, respectively), fasting blood glucose (r=0.84 and r=0.82, respectively), OGTT 2-hour postprandial glucose (r=0.75 and r=0.50, respectively), and systolic (r=0.93 and r=0.73, respectively) and diastolic (r=0.91 and r=0.73, respectively) blood pressure. The average number of risk factors was also correlated with VFA both in men (r=0.88, p=0.005) and women (r=0.91, p=0.003) with normal body weight. Based on the results of the multiple regression analyses, among VFA, SFA, body mass index (BMI) and age, VFA was considered to be the most important predictor for explaining the average number of risk factors. We also demonstrated that VFA was correlated with the waist circumference in normal weight men (r=0.74) and women (r=0.59). In normal weight subjects, the waist circumference equivalent to more than 1.0 of the average number of risk factors was 81 cm in men and 89 cm in women.

CONCLUSION: VAT accumulation itself plays a role as a risk factor for atherosclerosis irrespective of BMI, and measurement of VFA may be more important than that of BMI for predicting the presence of risk factors in normal weight subjects. Measurement of waist circumference also might be important for assessing the possibility of VAT accumulation leading to atherosclerosis.