Impact of gastrectomy on high-density lipoprotein cholesterol elevation in nonobese patients during a 10-year follow-up.

AIM: The role of gastrectomy in glycemic control has been established in the current era of bariatric surgery for obesity. Gastrectomy in obese patients is associated with increased levels of high-density lipoprotein cholesterol (HDL-C). However, limited data on the effects of gastrectomy in nonobese patients are available. We herein investigated the long-term plasma lipid changes in nonobese patients who had undergone gastrectomy. METHODS: Patients were enrolled as part of routine healthcare examinations from 1984 to 2003. Preoperative and postoperative data from patients who had undergone curative gastrectomy were analyzed for up to 10 years postoperatively. Three age- and sex-matched controls were assigned to each case. RESULTS: Sixty-four nonobese patients without diabetes mellitus or a history of having taken lipid-lowering drugs who underwent curative gastrectomy during the study period were enrolled (60 subtotal gastrectomies, four total gastrectomies). The median follow-up period was 7.6 years. The mean body mass index was 9.6% lower one year after gastrectomy (p < 0.01), then plateaued with a slight recovery. Intriguingly, the preoperative HDL-C level was 21% higher one year after gastrectomy (p < 0.01), increased by another 30% six years after gastrectomy and remained at this level for the rest of the follow-up period. No significant changes in the HDL-C level were observed in the controls. The degree of HDL-C elevation was consistently significant, irrespective of the baseline triglyceride level, HDL-C level or body weight. CONCLUSIONS: Gastrectomy in nonobese patients was associated with consistent and distinct long-term HDL-C elevations and body mass index reductions.

Insulin secretion and insulin sensitivity on the oral glucose tolerance test (OGTT) in middle-aged Japanese.

The aim of this study was to assess the changes in insulin secretion and insulin sensitivity in relation to fasting and 2-hour plasma glucose (PG) levels and to assess the independent contributions of their impairments to non-diabetic hyperglycemia. A total of 2157 Japanese workers (mean age 52.6±7.3 years and mean BMI 23.9±3.2 kg/m(2)) underwent an oral glucose tolerance test (OGTT). Of these subjects, 1125 had normal glucose tolerance (NGT), 525 subjects had isolated impaired fasting glucose (IFG), 159 subjects had isolated impaired glucose tolerance (IGT), 263 subjects had combined IFG and IGT, and 85 subjects had newly diagnosed type 2 diabetes. Insulinogenic index and Matsuda insulin sensitivity index (ISI) were significantly attenuated in subjects with normal but slightly elevated fasting PG, or in subjects with normal but slightly elevated 2-hour PG. Whereas, InsAUC(120)/GluAUC(120) was not significantly decreased in those subjects, and significant decrease of it was observed exclusively in subjects with abnormal fasting PG (≥ 106 mg/dL) or abnormal 2-hour PG (≥ 221 mg/dL). Using multiple regression analyses, both Matsuda ISI and insulinogenic index were independently correlated with PG concentrations in subjects with IFG and/or IGT, while Matsuda ISI alone was independently correlated with fasting PG concentrations in normoglycemic subjects. In conclusion, both insulinogenic index and Matsuda ISI were significantly attenuated in subjects with normal but slightly elevated PG. Lowering of Matsuda ISI was likely to be a strong contributor to 'elevation of fasting PG within the normal range' in this population.

Age-related changes in abdominal fat distribution in Japanese adults in the general population.

OBJECTIVE: Early studies have indicated that body fat shifts from peripheral stores to central stores with aging. The objective of this study was to investigate age-related changes in abdominal fat distribution of Japanese men and women of the general population over a wide range of body mass indices (BMI). METHODS: A total of 2,220 non-diabetic, apparently healthy Japanese adults (1,240 men and 980 women; age range 40-69 years) were included in the study sample. All subjects underwent a CT scan at the level of the umbilicus, and the areas of visceral adipose tissue (AT) and subcutaneous AT were quantified. RESULTS: When the subjects were stratified by BMI into 18.5-23.0 kg/m(2), 23.0-27.5 kg/m(2), and 27.5 kg/m(2) or higher, visceral AT was positively correlated with age in all of the BMI strata in both genders (p<0.01). In contrast, subcutaneous AT was negatively correlated with age in men with BMIs in excess of 23.0 kg/m(2) (p<0.01) and not at all in women. The mean levels of subcutaneous AT were over 2-fold greater than visceral AT in women aged 60-69 years in any BMI stratum. CONCLUSION: In Japanese men and women, visceral AT was increased with age in all BMI strata in both genders, whereas subcutaneous AT was decreased with age in men with BMIs in excess of 23.0 kg/m(2) and not at all in women. Even with these age-related changes in abdominal fat distribution, women retained the subcutaneous-dominant type of fat distribution up to 70 years.

Diabetes progression from "high-normal" glucose in school teachers.

OBJECTIVE: High-normal, the intermediate category between normal fasting glucose (NFG) and impaired fasting glucose (IFG), was introduced in the criteria of the disordered glucose metabolism in 2008. The aim of this study was to investigate the risk for future incidence of type 2 diabetes of the subjects with high-normal and to examine how other metabolic variables could be useful for their risk stratification. METHODS: A historical cohort study was conducted from 2001 to 2008, inclusive, in 4,165 non-diabetic employees at public schools (2,229 men and 1,936 women; age 45.8+/-5.9 years, range 25-55 years). They were classified at baseline as NFG with fasting plasma glucose (FPG)<100 mg/dL, high-normal with FPG 100-109 mg/dL, and IFG with FPG 110-125 mg/dL. The incidence of type 2 diabetes (defined either by FPG > or = 126 mg/dL or by receiving treatments) was measured. RESULTS: The cumulative incidence during a mean follow-up of 5.1 years were 16/3,364 (0.5%), 40/613 (6.5%), and 53/188 (28.2%) in subjects with NFG, high-normal, and IFG, respectively. Multivariate-adjusted odds ratios for the incidence were still significant both in high-normal and IFG compared to NFG. Body mass index (BMI) and alanine aminotransaminase (ALT) were associated with the incidence of type 2 diabetes independently of FPG categories (p<0.05). CONCLUSION: The future incidence of type 2 diabetes in subjects with high-normal was significantly higher than in those with NFG in this population. BMI and ALT can improve risk stratification in high-normal subjects.

Impacts of visceral adipose tissue and subcutaneous adipose tissue on metabolic risk factors in middle-aged Japanese.

Regional fat distribution rather than overall fat volume has been considered to be important to understanding the link between obesity and metabolic disorders. We aimed to evaluate the independent associations of visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) with metabolic risk factors in apparently healthy middle-aged Japanese. Participants were 1,119 men and 854 women aged 38-60 years who were not taking medications for diabetes, hypertension, or dyslipidemia. VAT and SAT were measured by use of computed tomography (CT) scanning. VAT and SAT were significantly and positively correlated with each other in men (r = 0.531, P < 0.001) and women (r = 0.589, P < 0.001). In multiple regression analyses, either measure of abdominal adiposity (VAT or SAT) was positively associated with blood pressure, fasting plasma glucose, and log triglyceride (P < 0.001) and inversely with high-density lipoprotein (HDL)-cholesterol (P < 0.001). When VAT and SAT were simultaneously included in the model, the association of VAT with triglycerides was maintained (P < 0.001) but that of SAT was lost. The same was true for HDL-cholesterol in women. For fasting plasma glucose, the association with VAT was strong (P < 0.001) and the borderline association with SAT was maintained (P = 0.060 in men and P = 0.020 in women). Both VAT and SAT were independently associated with blood pressure (P < 0.001). Further adjustment for anthropometric indices resulted in the independent association only with VAT for all risk factors. In conclusion, impacts of VAT and SAT differed among risk factors. VAT showed dominant impacts on triglyceride concentrations in both genders and on HDL-cholesterol in women, while SAT also had an independent association with blood pressure.

Difference between fasting and nonfasting triglyceridemia; the influence of waist circumference.

AIM: Postprandial hypertriglyceridemia is recognized as an independent risk factor for cardiovascular disease. The aim of this study was to identify differences between fasting and postprandial TG levels, focusing on the influence of waist circumference. METHODS: Subjects included 1,505 men and 798 women aged 3865 years who were not taking medications for diabetes or dyslipidemia. Fasting TG levels were measured after an overnight fast, and postprandial TG levels were measured 2 hours after a standardized rice-based lunch (total 740 kcal, 20 g fat, 30 g protein, and 110 g carbohydrates) in the afternoon on the same day. RESULTS: Fasting and postprandial TG levels were highly correlated in both men (r=0.86, p<0.001) and women (r=0.84, p<0.001). Waist circumference was positively correlated with fasting TG (r=0.38 in men and r=0.36 in women) and postprandial TG (r=0.42 in men and r=0.45 in women), respectively. On multiple regression analyses, the association of waist circumference with postprandial TG was still significant (standardized beta=0.10 in men and standardized beta=0.15 in women, p<0.001) after the inclusion of HbA1c, age, high-density-lipoprotein (HDL)-cholesterol, alcohol consumption, and fasting TG in the regression model. CONCLUSION: Postprandial TG has a better relation with waist circumference than fasting TG.

Comparison of waist circumference with body mass index for predicting abdominal adipose tissue.

AIMS: To compare waist circumference (WC) with body mass index (BMI) for the prediction of abdominal adipose tissues in Japanese men and women. METHODS: 1432 men and 1038 women aged 38-60 years were recruited. WC, BMI, visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) using CT scans were measured. RESULTS: Women had a lower mean VAT than men (79.3 cm(2) vs. 132.3 cm(2); p<0.001) and a higher mean SAT (196.2 cm(2) vs. 139.7 cm(2); p<0.001). The correlation with WC or BMI was greatest for total adipose tissue (TAT), followed by SAT, and least for VAT. The correlation coefficients were not significantly different between WC and BMI for any adipose tissue except for VAT in men (p<0.05). Age was positively correlated with VAT in both genders (p<0.001). Using multiple regression analyses on VAT, R(2) values using WC and age were 0.45 in men and 0.48 in women. For SAT, the values were 0.57 in men and 0.59 in women. CONCLUSIONS: The relationship with WC or BMI was greatest for TAT and SAT, and least for VAT. WC and BMI provided essentially similar estimates of TAT, VAT, and SAT in both genders.

Reassessment of the cutoff values of waist circumference and visceral fat area for identifying Japanese subjects at risk for the metabolic syndrome.

In the new world-wide criteria for metabolic syndrome (MetS) by the International Diabetes Federation (IDF) in 2006, the Japanese is the only ethnicity in which the recommended waist circumference (WC) cutoff value is higher in women (>or=90cm) than in men (>or=85cm), and its validity appears to be controversial. We investigated the optimal cutoff points for the diagnosis of central obesity in Japanese men and women, using the receiver operating characteristic (ROC) curve analysis for both of WC and visceral fat area (VFA) in 1870 middle-aged Japanese. VFA was superior to WC and Body mass index (BMI) for discriminating the subjects with two or more nonadipose components of MetS. The optimal cutoff points of VFA and WC were 132.6cm(2) and 89.8cm for men and 91.5cm(2) and 82.3cm for women. The stratifications of MetS components more than 1.0 in average occurred more steeply by the accumulation of VFA in women than in men. In conclusion, setting the cutoff points of WC and VFA lower values in women than in men for the definition of central obesity is needed to identify the subjects with MetS in Japanese, as in other Asian populations.