Search

Background: Visceral adiposity is generally considered to play a key role in the metabolic syndrome., Objective: To examine the relationship between directly measured visceral adiposity and the risk for incident hypertension, independent of other adipose depots and fasting plasma insulin levels., Design: Community-based prospective cohort study with 10- to 11-year follow-up., Setting: King County, Washington., Participants: 300 Japanese Americans with a systolic blood pressure less than 140 mm Hg and a diastolic blood pressure less than 90 mm Hg who were not taking antihypertensive medications, oral hypoglycemic medications, or insulin at study entry., Measurements: Abdominal, thoracic, and thigh fat areas were measured by using computed tomography. Total subcutaneous fat area was calculated as the sum of these fat areas excluding the intra-abdominal fat area. Hypertension during follow-up was defined as having a systolic blood pressure of 140 mm Hg or greater, having a diastolic blood pressure of 90 mm Hg or greater, or taking antihypertensive medications., Results: There were 92 incident cases of hypertension during the follow-up period. The intra-abdominal fat area was associated with an increased risk for hypertension. Multiple-adjusted odds ratios of hypertension for quartiles of intra-abdominal fat area (1 = lowest; 4 = highest) were 5.07 (95% CI, 1.75 to 14.73) for quartile 3 and 3.48 (CI, 1.01 to 11.99) for quartile 4 compared with quartile 1 after adjustment for age, sex, fasting plasma insulin level, 2-hour plasma glucose level, body mass index, systolic blood pressure, alcohol consumption, smoking status, and energy expenditure through exercise (P = 0.003 for quadratic trend). The intra-abdominal fat area remained a significant risk factor for hypertension, even after adjustment for total subcutaneous fat area, abdominal subcutaneous fat area, or waist circumference; however, no measure of these fat areas was associated with risk for hypertension in models that contained the intra-abdominal fat area., Limitations: It is not known whether these results pertain to other ethnic groups., Conclusions: Greater visceral adiposity increases the risk for hypertension in Japanese Americans.

Background: Visceral adiposity is generally considered to play a key role in the metabolic syndrome, including hypertension. The purpose of this study was to evaluate cross-sectionally whether visceral adiposity is associated with prevalence of hypertension independent of other adipose depots and fasting plasma insulin., Methods and Results: Study subjects included 563 Japanese Americans with normal or impaired glucose tolerance or diabetes but not taking oral hypoglycemic medication or insulin at entry. Variables included plasma glucose and insulin measured after an overnight fast and during an oral glucose tolerance test, and abdominal, thoracic, and thigh fat areas by CT. Total fat area (TFA) was calculated as the sum of these fat areas. Hypertension was defined as having a systolic blood pressure > or =140 mm Hg, having a diastolic blood pressure > or =90 mm Hg, or taking antihypertensive medications. Intra-abdominal fat area (IAFA) was associated with a higher prevalence of hypertension. Adjusted odds ratio of hypertension by IAFA was 1.68 for a 1-SD increase (95% CI, 1.20 to 2.37) after adjusting for age, sex, fasting plasma insulin, a nonlinear transformation of 2-hour plasma glucose, and TFA. IAFA remained a significant predictor of prevalence of hypertension even after adjustment for total subcutaneous fat area, abdominal subcutaneous fat area, body mass index, or waist circumference, but no measure of regional or total adiposity was associated with the odds of prevalence of hypertension in models that contained IAFA., Conclusions: Greater visceral adiposity increases the odds of hypertension in Japanese Americans independent of other adipose depots and fasting plasma insulin.

Objective: Greater visceral adiposity, higher insulin resistance, and impaired insulin secretion increase the risk of type 2 diabetes. Whether visceral adiposity increases risk of impaired glucose tolerance (IGT) independent of other adipose depots, insulin resistance, and insulin secretion is not known.Research Design and Methods: Study subjects included 128 Japanese Americans with normal glucose tolerance at entry. Baseline variables included plasma glucose and insulin measured after an overnight fast and during a 75-g oral glucose tolerance test, fat areas by computed tomography, insulin secretion (incremental insulin response [IIR] [30 min insulin - fasting insulin]/30 min glucose), and insulin resistance index (homeostasis model assessment for insulin resistance [HOMA-IR]).Results: During the 10- to 11-year follow-up period, we confirmed 57 cases of IGT. Significant predictors of IGT included intra-abdominal fat area (IAFA) (odds ratio [OR] for a 1 SD increase 3.82, 95% CI 1.63-8.94 at a fasting plasma glucose [FPG] level of 4.5 mmol/l), HOMA-IR (2.41, 1.15-5.04), IIR (0.30, 0.13-0.69 at an FPG level of 4.5 mmol/l), the interactions of IAFA by FPG (P = 0.003), and IIR by FPG (P = 0.030) after adjusting for age, sex, FPG, and BMI. The multiple-adjusted OR of IAFA increased and that of IIR decreased as FPG level decreased because of these interactions. Even after adjustment for total fat area, total subcutaneous fat area, or abdominal subcutaneous fat area, all of these associations remained a significant predictor of IGT incidence.Conclusions: Greater visceral adiposity increases the risk of IGT independent of insulin resistance, insulin secretion, and other adipose depots in Japanese Americans. [ABSTRACT FROM AUTHOR]

Background: Despite having lower average body mass indexes (BMIs) than do whites, Asians are at high risk of type 2 diabetes, possibly because of their greater central adiposity. The criteria for identifying individuals at risk of obesity-related conditions are usually not population specific. Objective: Our goal was to determine whether the National Heart, Lung, and Blood Institute (NHLBI) overweight and obesity guidelines are useful for identifying diabetes risk in Japanese Americans. Design: This was a prospective, cohort study of 466 nondia-betic Japanese Americans [age: 52.2 ± 0.6 y; BMI (in kg/m²): 24.1 ± 0.2; ... ± SEM]. Diabetes status at a 5-y follow-up visit was assessed with an oral-glucose-tolerance test. Results: Among 240 subjects aged ≤55 y, incident diabetes was strongly associated with overweight (BMI ≥ 25) at baseline [relative risk (RR): 22.4; 95% CI: 2.7, 183; adjusted for age, sex, smoking, and family history] and weight gain of > 10 kg since the age of 20 y (adjusted RR: 4.5; 95% CI: 1.4, 14.5). NHLBI definitions of central obesity (waist circumference ≥ 88 cm for women and ≥ 102 cm for men) were unsuitable for this population because only 15 of 240 subjects met these criteria. A waist circumference greater than or equal to the third tertile was associated with diabetes (adjusted RR: 5.4; 95% CI: 1.7, 17.0). Among 226 subjects aged >55 y, incident diabetes was not associated with BMI, weight gain, or waist circumference. Conclusions: NHLBI definitions are useful for identifying overweight Japanese Americans aged < 55 y who are at high risk of diabetes. Although central adiposity is an important risk factor, the guidelines for waist circumference are insensitive predictors of diabetes risk in this population. [ABSTRACT FROM AUTHOR]

Objective: We conducted a prospective study among Japanese Americans of diabetes incidence in relation to visceral and regional adiposity, fasting insulin and C-peptide, and a measure of insulin secretion, because little prospective data exist on these associations.Research Design and Methods: Baseline variables included plasma glucose, C-peptide, and insulin measured after an overnight fast and 30 and 120 min after a 75-g oral glucose tolerance test; abdominal, thoracic, and thigh fat areas by computed tomography (CT); BMI (kg/m2); and insulin secretion (incremental insulin response [IIR]).Results: Study subjects included 290 second-generation (nisei) and 230 third-generation (sansei) Japanese Americans without diabetes, of whom 65 and 13, respectively, developed diabetes. Among nisei, significant predictors of diabetes risk for a 1 SD increase in continuous variables included intra-abdominal fat area (IAFA) (odds ratio, 95% CI) (1.6, 1.1-2.3), fasting plasma C-peptide (1.4, 1.1-1.8), and the IIR (0.5, 0.3-0.9) after adjusting for age, sex, impaired glucose tolerance, family diabetes history, and CT-measured fat areas other than intra-abdominal. Intra-abdominal fat area remained a significant predictor of diabetes incidence even after adjustment for BMI, total body fat area, and subcutaneous fat area, although no measure of regional or total adiposity was related to development of diabetes. Among sansei, all adiposity measures were related to diabetes incidence, but, in adjusted models, only IAFA remained significantly associated with higher risk (2.7, 1.4-5.4, BMI-adjusted).Conclusions: Greater visceral adiposity precedes the development of type 2 diabetes in Japanese Americans and demonstrates an effect independent of fasting insulin, insulin secretion, glycemia, total and regional adiposity, and family history of diabetes. [ABSTRACT FROM AUTHOR]