Yu Chiba

Relationship between visceral fat and cardiovascular disease risk factors: the Tanno and Sobetsu study.

We assessed the amount of visceral fat using ultrasonography (US) and studied its relationship to cardiovascular disease risk factors, particularly blood pressure. The subjects in the first study were 45 male and 61 female outpatients. We measured the visceral fat area (VFA) of each subject using abdominal CT and waist circumference (WC), and visceral fat distance (VFD) using US. The subjects in the second study were 353 male and 457 female inhabitants of a rural community, for whom VFD and WC were measured. We divided subjects into tertiles based on VFD and WC, and studied the relationship between each group and individual risk factors. In an analysis of outpatient subjects, the correlation coefficient between VFA and VFD was satisfactory: r=0.660 for men and r=0.643 for women. In the analysis of the rural subjects, the high VFD group had a significantly higher odds ratio than the low VFD group in high blood pressure (HBP) and hypertriglyceridemia (HTG) for men and in HBP, HTG and low high-density lipoprotein cholesterolemia (LHDL) for women. Moreover, adjusting VFD for body mass index revealed that, in comparison to WC, VFD was significantly related to risk factors. VFD was used as an independent variable in multiple regression analysis with blood pressure level as a dependent variable; no significant association between WC and blood pressure was obtained. Visceral fat assessment by US may be useful for epidemiological study and for clinics with no abdominal CT equipment for identifying high-risk individuals, such as those with metabolic syndrome.

Incidence of Type 2 Diabetes in Individuals With Central Obesity in a Rural Japanese Population: The Tanno and Sobetsu Study

According to the new International Diabetes Federation (IDF) definition of metabolic syndrome, for a person to be defined as having metabolic syndrome they must have central obesity defined by waist circumference (1). In the definition, there are some ethnic or country-specific differences in the cutoff points of waist circumference, and Japanese cutoff points have been separately established in the IDF definition (≥85 cm for men and ≥90 cm for women). The Japanese Society of Internal Medicine and eight related scientific societies have also jointly announced new Japanese criteria of metabolic syndrome using the same cutoff points of waist circumference (2). However, the impact of central obesity using the cutoff points as a risk of type 2 diabetes is not known. In this study, we investigated the incidence of type 2 diabetes in citizens of two rural communities in Japan to determine the relationship between type 2 diabetes and central obesity, and we also investigated the independent effects of central obesity compared with those of overall obesity. The subjects were 348 men and 523 women selected from 938 citizens who had undergone medical examinations in the towns of Tanno and Sobetsu, Hokkaido, both in 1994 and 2003 or 2004. The following participants in medical examinations in 1994 were excluded: those with missing data on blood …

Incidence of insulin resistance in obese subjects in a rural Japanese population: The Tanno and Sobetsu study

Objectives:  Although it is well known that obesity is closely related to insulin resistance, the incidence of the development of insulin resistance in people with obesity is not known. In this study, we investigated the incidence of insulin resistance in citizens of two rural communities in Japan.

Development and progression of atherosclerotic disease in relation to insulin resistance and hyperinsulinemia

It is unclear whether the role of insulin resistance in the development of atherosclerotic cardiovascular disease is similar in populations in which the incidence of atherosclerotic diseases significantly differs from that in Western countries. The aim of this study was to determine the relationship between insulin resistance and the development of cardiovascular disease in the Japanese population. We conducted 75 g-oral glucose tolerance tests (OGTTs) on 1,928 inhabitants of two towns in Hokkaido, Japan. Subjects using anti-hypertensive agents and known diabetic patients were excluded from the study. Data from the remaining 1,227 subjects (540 males and 687 females; mean age 56.0±10.8 years) were used for the analysis, and 1,051 subjects were seen in a follow-up care setting for a period of 8 years. The presence of insulin resistance was defined according to the guidelines reported our previous study: insulin levels of 64.0 mU/l or higher 2 h after the 75 g-OGTT. The insulin-resistant (IR) group had several risk factors such as hypertension, diabetes, treated or untreated hypercholesterolemia, hypertriglyceridemia, low high-density-lipoprotein (HDL) cholesterol levels, and obesity. During the follow-up period of 8 years, the incidence of coronary artery disease, which was adjusted for age, body mass index, sex, systolic blood pressure, fasting plasma glucose, total cholesterol, triglyceride, and HDL cholesterol was significantly (3.2 times) higher in the IR group than in the insulin non-resistant group. The results suggested that insulin resistance is an independent risk factor for coronary artery disease in Japanese subjects, as has also been demonstrated in the case of individuals in Europe and USA.

Relation of hypertension and glucose tolerance impairment in elderly people to the development of arteriosclerosis: Investigation using pulse wave velocity

Background:  The aim of the present study was to determine the correlation between the combination of hypertension and diabetes mellitus and arteriosclerosis using pulse wave velocity (PWV).