Minoru Okada

Kameda Medical Center, Kameda, Niigata, Japan

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Publications (4)7.5 Total impact

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    ABSTRACT: Aim: Visceral fat accumulation is associated with obesity-related cardiovascular risk factor accumulation and atherosclerosis. The present study investigated whether one-year reduction of the visceral fat area (VFA) correlates with a decrease in the number of such factors in Japanese with or without visceral fat accumulation.Methods: The study subjects comprised 5,347 Japanese, who underwent health check-ups in 2007 and 2008, including measurements of VFA and subcutaneous fat area (SFA) by computed tomography at 9 centers in Japan. Subjects with one or more such factor(s) were categorized into tertiles based on the one-year change in VFA. We investigated the multivariate age, sex, and one-year change in SFA-adjusted odds ratios (ORs) and 95% confidence intervals (CI) for reductions in the number of risk factors in each of the three categories based on the one-year change in VFA, in subjects with one or more such factors (n= 3,648).Results: In the entire group (n=3,648), the OR and 95%CI for reductions in the number of risk factors in the first tertile were 0.804 (0.673-0.962, p=0.0172), compared with the second tertile set at 1.0. Subjects with VFA <100cm(2) showed no reduction in the number of risk factors. In subjects with VFA .100 cm(2), OR in the first tertile was 0.788 (0.639-0.972, p=0.0257) relative to the second tertile set at 1.0.Conclusions: In subjects with multiple cardiovascular risk factors, visceral fat reduction correlated with a decrease in the number of such factors in subjects with VFA≥100cm(2), but not in those with VFA<100cm(2).
    Journal of atherosclerosis and thrombosis 07/2012; DOI:10.5551/jat.12963 · 2.77 Impact Factor
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    ABSTRACT: Metabolic complications associated with obesity are becoming more common among Japanese subjects. However, visceral fat accumulation is not always apparent by measuring body mass index (BMI) or waist circumference in Asian populations because of the physiological characteristics particular to those ethnicities. Excess visceral fat accumulation raises the odds ratio for developing cardiovascular disease. Thus, high-throughput determination of the amount of abdominal adipose tissue is necessary. We hypothesized that accumulating visceral fat alters the peripheral amino acid profile and that a multivariate logistic regression model of plasma free amino acids can distinguish visceral obesity. A total of 1449 Japanese subjects (985 males and 464 females) who had undergone a comprehensive health screening were enrolled in this study. The visceral fat area was determined using computed tomography imaging, and a plasma free amino acid index to identify high visceral fat areas (≥100 cm2) was developed. The sensitivity and specificity values of the generated amino acid index were 80% and 65%, respectively. In particular, the sensitivity of the generated index to identify subjects with non-apparent visceral obesity (BMI < 25 kg m−2; visceral fat area ≥ 100 cm2) was much greater than that of the waist circumference (73% vs. 46%, respectively). This index's high sensitivity and specificity may be the result of specific alterations in the patients' amino acid profiles, which were specifically correlated with the visceral fat areas and not with subcutaneous fat areas. This profile can be used as a predictor of elevated visceral obesity and a risk assessment tool for metabolic complications in Asian populations.
    05/2012; 2(1-2):29-40. DOI:10.1111/j.1758-8111.2012.00039.x
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    ABSTRACT: The management of cardiovascular risk factors is important for prevention of atherosclerotic cardiovascular diseases (ACVD). Visceral fat accumulation plays an important role in the clustering of cardiovascular risk factors, leading to ACVD. The present study investigated the gender- and age-specific relationship between obesity-related cardiovascular risk factor accumulation and computed tomography (CT)-measured fat distribution in a large-scale Japanese general population. Fat distribution was measured on CT scans in 12,443 subjects (males/females = 10,080/2,363), who underwent medical health check-up at 9 centers in Japan. The investigated obesity-related cardiovascular risk factors were hyperglycemia, dyslipidemia, and elevated blood pressure. Visceral fat area (VFA) for all males and old females showed almost symmetric distribution, while that of young females showed skewed distribution with a marked left shift. Only a small proportion of young females had large visceral fat and cardiovascular risk accumulation. The mean number of risk factors exceeded 1.0 at around 100 cm(2) for VFA in all groups, irrespective of gender, age (cut-off age 55), and BMI (cut-off BMI 25 kg/m(2)). In this large-scale Japan-wide general population study, an absolute VFA value of about 100 cm(2) equated with obesity-related cardiovascular risk factor accumulation, irrespective of gender, age, and BMI.
    Annals of Medicine 10/2010; 44(1):82-92. DOI:10.3109/07853890.2010.526138 · 4.73 Impact Factor
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    ABSTRACT: Background: The plasma amino acid profile can be a useful indicator in clinical settings because it changes in response to various metabolic alternations. However, the association between the plasma amino acid profile and body fat accumulation has not been evaluated in humans.Objective: This study aimed to relate plasma amino acids to visceral fat accumulation in humans because excess visceral fat raises the odds ratio of developing metabolic syndrome.Design: A total of 1,449 subjects (985 males and 464 females) who had undergone a comprehensive health screening were enrolled in this study. The visceral fat area (VFA) was determined in each subject using CT imaging. Subjects were then divided into two groups according to VFA: high-VFA (≥100 cm2, n=867) and low-VFA (<100 cm2, n=582). The plasma amino acid profile was analyzed together with other metabolic valuables and then compared between the two groups using uni- and multivariate analyses. Results: As the degree of visceral fat accumulation increased, plasma concentrations of several amino acids changed significantly. Glu, Val, Leu, Ile, Tyr, Ala, Phe, Pro, Lys, Orn, Trp, Met, His and alpha-aminobutyric acid (ABA) levels were significantly higher in the high-VFA group compared to the low-VFA group, whereas the levels of Gly, Ser, Gln and Asn were significantly lower. To evaluate the potential of using amino acids as an indicator of VFA, a discriminant analysis was conducted with the multivariate logistic regression analysis "AminoIndex", and the ROC curve was calculated. The resulting "AminoIndex" exhibited an area under the ROC curve of 0.81 (95% confidence interval; 0.78 to 0.83), with higher sensitivity and specificity by 80% and 65%, respectively.Conclusions: The plasma amino acid profile changes depending on visceral fat content and can be used as a marker for diagnosing elevated visceral obesity in humans.