Hirotsugu Mitsuhashi

Adiponectin Level and Left Ventricular Hypertrophy in Japanese Men

A recent study has demonstrated that adiponectin inhibited hypertrophic signaling in the myocardium of mice, implying that a decrease in the blood adiponectin level could cause cardiac muscle hypertrophy. We hypothesized that a relationship might exist between the serum adiponectin level and electrocardiographically diagnosed left ventricular hypertrophy (ECG-LVH), and we examined this hypothesis by epidemiological study of 2839 Japanese male workers who were not taking medications for hypertension. ECG-LVH was defined as meeting Sokolow–Lyon voltage criteria and/or Cornell voltage-duration product. The subjects were categorized by tertiles of serum adiponectin level, and a multivariate logistic regression analysis was conducted relating left ventricular hypertrophy to adiponectin tertiles adjusting for potential confounding factors. Prevalence of ECG-LVH in the studied sample was 16.7%. Adiponectin ranged from 1.0 to 5.0 &mgr;g/mL in the lowest category and from 7.4 to 30.6 &mgr;g/mL in the highest. Compared with subjects in the highest adiponectin category, those in the lowest one had a significantly higher prevalence of ECG-LVH independent of age, body mass index, and systolic blood pressure with an odds ratio of 1.50 and a 95% CI of 1.16 to 1.94. Further adjustment for high-density lipoprotein cholesterol, triglyceride, and insulin resistance did not change the association (odds ratio: 1.68; 95% CI: 1.28 to 2.21; P<0.001). Similar results were obtained when different criteria for ECG-LVH were used or when subjects were stratified by blood pressure or body mass index. Adiponectin concentration was inversely and independently associated with ECG-LVH in Japanese men.

Self-reported medical history was generally accurate among Japanese workplace population

OBJECTIVE To assess the validity of self-reported medical history of several diseases among the Japanese population, and to clarify to what extent the self-reported year of diagnosis for chronic diseases is different from the physicians reports. STUDY DESIGN AND SETTING Subjects were 8,947 persons who responded to questions about medical history in a self-administered questionnaire. Of them, 854 subjects reported one or more medical histories and gave permission to contact their physician. The physicians were then requested to provide information on 809 subjects. Valid responses of 714 subjects were collected. We compared the self-reported medical histories with those reported by the physician. RESULTS Of 15 persons who reported myocardial infarction, 13 (87%) were confirmed. Angina pectoris was verified in eight out of the 11 (73%). The confirmation proportions of hypertension, diabetes, hyperlipidemia, and hyperuricemia were 97%, 96%, 95%, and 95%, respectively. The self-reported year of diagnosis was 1.70-2.49 years earlier than the physician-reported year for chronic diseases. Agreement between the self-reported and the physician-reported years was higher, the more recent the self-reported year was. CONCLUSION Self-reported medical histories were generally accurate, especially for diseases with clear diagnostic criteria. However, investigators should be aware of the errors in reporting the year of diagnosis.

The transition to menopause reinforces adiponectin production and its contribution to improvement of insulin‐resistant state

Objective  To evaluate the influence of menopausal status on the serum adiponectin concentration and investigate whether the contribution of adiponectin to insulin resistance is modified by menopausal status.

Higher dietary intake of alpha-linolenic acid is associated with lower insulin resistance in middle-aged Japanese

OBJECTIVE To investigate the associations between dietary intake of n-3 polyunsaturated fatty acids (plant-derived alpha-linolenic acid: ALA, and marine-derived eicosapentaenoic and docosahexaenoic acid: EPA+DHA) and insulin resistance (IR) in a lean population with high n-3 PUFA intake. METHOD We cross-sectionally studied 3383 Japanese local government workers aged 35-66 in 2002. IR was defined as the highest quartile of homeostasis model assessment, and nutrient intake was estimated from a diet history questionnaire. The odds ratios (ORs) of IR taking the lowest quartile of ALA or EPA+DHA intake as the reference were calculated by logistic regression analysis. RESULTS Mean age, body mass index (BMI), and dietary ALA, and median of dietary EPA+DHA were 47.9 years, 22.9 kg/m(2), and 1.90 g/day (0.88%E) and 0.77 g/day (0.36%E), respectively. The ORs of IR decreased across the quartiles of ALA intake (multivariate-adjusted OR for Q4 versus Q1=0.74, P for trend=0.01) and the association was observed only in subjects with a BMI of <25 kg/m(2) (P for interaction=0.033). However EPA+DHA showed no such associations consistently. CONCLUSION Higher ALA intake was significantly associated with a lower prevalence of IR in normal weight individuals of middle-aged Japanese men and women.

Contribution of adipocytokines to low-grade inflammatory state as expressed by circulating C-reactive protein in Japanese men: Comparison of leptin and adiponectin

BACKGROUND Circulating C-reactive protein (CRP) is a marker of inflammation and is associated with the incidence of cardiovascular events. Although it has been known that adiponectin protects, whereas leptin accelerates, the development of atherosclerotic diseases, the comparative strength of their reciprocal effects on circulating CRP remains unclear. METHODS We studied a population of 2049 Japanese men aged 35 to 66. For all subjects, multiple regression analysis performed with log-transformed CRP concentration as the dependent variable, and with log-transformed leptin, log-transformed adiponectin, age, BMI, smoking status, and components of metabolic syndrome as independent variables. RESULTS Both leptin (positively) and adiponectin (negatively) were significantly and independently associated with CRP concentration. The absolute value of the standardized regression coefficient (st-beta) of leptin (st-beta=0.201) was higher than that of adiponectin (st-beta=-0.082). After subjects were stratified by current BMI level, both of the adipocytokines were significantly associated with CRP concentration among subjects with BMI <25 kg/m(2), whereas only leptin was significantly associated with CRP concentration among subjects with BMI >=25 kg/m(2). CONCLUSIONS Both leptin and adiponectin were independently associated with CRP concentration. Leptin was more strongly related to CRP levels than adiponectin was, especially among obese subjects.

Low leptin but high insulin resistance of smokers in Japanese men.

AIMS To investigate the association between smoking and leptin, and to discuss their influence on diabetes in a large-scale study of Japanese men. METHODS A cross-sectional study was carried out in 2002. The subjects were 2836 men aged 35-66. Smoking history was investigated in a self-administered questionnaire. Blood leptin, glucose and insulin were measured. RESULTS Significant differences in leptin levels and homeostasis model assessment of insulin resistance (HOMA-IR) related to smoking status were observed (P=0.001 and P=0.008, respectively). The multivariate-adjusted geometric means of leptin in current, past and never smokers were 3.88, 4.08 and 4.12 ng/ml, respectively, while the means of HOMA-IR were 1.64, 1.61 and 1.49, respectively. The age-, body mass index-, and other lifestyle-adjusted prevalences of diabetes in current and never smokers were 9.2 and 4.7%, respectively. That of current smokers was significantly higher than in never smokers (P<0.001). The dose-dependent association found between the intensity of smoking and leptin levels in current smokers was statistically significant (P=0.030). CONCLUSIONS The present finding may explain in part an association among smoking, leptin levels and diabetes. Smoking is one of the important modifiable risk factors for the prevention of diabetes.