HbA1c, fasting and 2 h plasma glucose in current, ex- and never-smokers: a meta-analysis.

AIMS/HYPOTHESIS: The relationships between smoking and glycaemic variables have not been well explored. We compared HbA1c, fasting plasma glucose (FPG) and 2 h plasma glucose (2H-PG) in current, ex- and never-smokers. METHODS: This meta-analysis used individual data from 16,886 men and 18,539 women without known diabetes in 12 DETECT-2 consortium studies and in the French Data from an Epidemiological Study on the Insulin Resistance Syndrome (DESIR) and Telecom studies. Means of three glycaemic variables in current, ex- and never-smokers were modelled by linear regression, with study as a random factor. The I (2) statistic was used to evaluate heterogeneity among studies. RESULTS: HbA1c was 0.10% (95% CI 0.08, 0.12) (1.1 mmol/mol [0.9, 1.3]) higher in current smokers and 0.03% (0.01, 0.05) (0.3 mmol/mol [0.1, 0.5]) higher in ex-smokers, compared with never-smokers. For FPG, there was no significant difference between current and never-smokers (-0.004 mmol/l [-0.03, 0.02]) but FPG was higher in ex-smokers (0.12 mmol/l [0.09, 0.14]). In comparison with never-smokers, 2H-PG was lower (-0.44 mmol/l [-0.52, -0.37]) in current smokers, with no difference for ex-smokers (0.02 mmol/l [-0.06, 0.09]). There was a large and unexplained heterogeneity among studies, with I (2) always above 50%; I (2) was little changed after stratification by sex and adjustment for age and BMI. In this study population, current smokers had a prevalence of diabetes that was 1.30% higher as screened by HbA1c and 0.52% lower as screened by 2H-PG, in comparison with never-smokers. CONCLUSION/INTERPRETATION: Across this heterogeneous group of studies, current smokers had a higher HbA1c and lower 2H-PG than never-smokers. This will affect the chances of smokers being diagnosed with diabetes.

Clinical assessment and management of obesity in individuals with spinal cord injury: a review.

BACKGROUND: Diagnosing and managing obesity in individuals with spinal cord injury (SCI) remain challenging. METHODS: Literature on the epidemiology, impact, and management of obesity in individuals with SCI was reviewed. FINDINGS: Although nearly 66% of individuals with SCI are either overweight or obese, little guidance is available to measure and monitor obesity in the clinical setting. The use of anthropometric indices and specific cut points available for able-bodied persons is limited by the body composition changes that follow SCI. Indices of upper body obesity warrant examination in SCI because they provide an index of central obesity, which is more closely linked to some obesity-related conditions than is overall obesity. Investigations into the sequelae of excess body fat and its distribution are also needed in SCI because past research in this area has been inconclusive. Although limited, evidence regarding obesity interventions in SCI may be promising. CONCLUSIONS: The best anthropometric tool to define obesity in the clinical setting remains unknown. SCI-specific assessment tools and a better understanding of the sequelae of excess body weight will lead to better targeting of prevention and treatment efforts. More research is needed on the individual components of a weight management program unique to SCI. Until then, providers are urged to use a team approach and draw on existing resources and applicable research in able-bodied individuals to facilitate weight management in individuals with SCI.

Minimum waist and visceral fat values for identifying Japanese Americans at risk for the metabolic syndrome.

OBJECTIVE: Japanese American is an ethnic group with a high risk for type 2 diabetes, which is linked to the metabolic syndrome. Central adiposity is considered to play a key role in the metabolic syndrome. Not known are the optimal cut point values for central and visceral adiposity to identify Japanese Americans at risk for the metabolic syndrome. RESEARCH DESIGN AND METHODS: Study subjects included 639 Japanese Americans. The nonadipose variables of the metabolic syndrome were defined using modified International Diabetes Federation criteria, and the accuracy of identifying at least two of these by intra-abdominal fat area (IAFA) as measured by computed tomography and waist circumference was cross-sectionally assessed using area under receiver operating characteristic (ROC) curves. The values for IAFA and waist circumference that resulted in maximizing the Youden index were defined as "optimal." RESULTS: The area under the ROC curve for IAFA exceeded that for waist circumference (men 0.787 vs. 0.686; women 0.792 vs. 0.721). For women, the optimal cut points for IAFA and waist circumference were 51.5 cm(2) and 80.8 cm (age < or = 56 years) and 86.3 cm(2) and 89.0 cm (age > 56 years). For men, the optimal cut points for IAFA and waist circumference were 88.6 cm(2) and 90.0 cm (age < or = 57 years) and 96.1 cm(2) and 87.1 cm (age > 57 years). CONCLUSIONS: These results argue that current Japanese waist circumference cut points for the metabolic syndrome need to be revised. Moreover, the waist circumference and IAFA cut points should be age specific, especially in women. Appropriate waist circumference cut points are from 80 to 90 cm in women and from 87 to 90 cm in men.

Superiority of the Modification of Diet in Renal Disease equation over the Cockcroft-Gault equation in screening for impaired kidney function in Japanese Americans.

The Cockcroft-Gault and the Modification of Diet in Renal Disease (MDRD) Study equations have not been validated in Asian Americans with varying degrees of glucose tolerance. We compared both equations to 24-h urinary creatinine clearance, the latter as a standard measurement of glomerular filtration rate (GFR), in 398 Japanese Americans (62.1+/-5.8 years, mean+/-S.D.) who had normal glucose tolerance (NGT) (n=138), impaired glucose tolerance (IGT) (n=136) and diabetes (n=124). Although both the Cockcroft-Gault (r=0.65, P<0.001) and the MDRD (r=0.74, P<0.001) equations correlated well with creatinine clearance, the latter was significantly superior (P=0.013 between r values). Receiver operating characteristic (ROC) curve analysis showed that the area under the curve (AUC) for the MDRD equation was significantly greater than for the Cockcroft-Gault equation (AUC 0.86 versus 0.80, P=0.015) in classifying subjects as having mildly reduced GFR (<90ml/min per 1.73m(2)). However, both equations overestimated the number of individuals with decreased GFR. We conclude therefore that while the MDRD equation more accurately identifies Asians who are in the early stages of kidney disease, as for other groups, a correction term appears necessary in order to reduce the number of Asian subjects being falsely diagnosed with CKD.

Insulin, C-peptide, and leptin concentrations predict increased visceral adiposity at 5- and 10-year follow-ups in nondiabetic Japanese Americans.

We prospectively examined the relationship between leptin and markers of insulin resistance and secretion and future visceral adipose tissue accumulation. In this study, 518 nondiabetic Japanese-American men and women underwent the following measurements at baseline and at 5- and 10-year follow-ups: plasma glucose and insulin measured after an overnight fast and during a 75-g oral glucose tolerance test, insulin secretion ratio (ISR) [(30-min insulin - fasting insulin)/30-min glucose], fasting C-peptide levels, plasma leptin (baseline only), and fat areas (intra-abdominal and subcutaneous) measured by computed tomography. Predictors of future intra-abdominal fat (IAF) were determined using multiple linear regression. Fasting insulin and C-peptide levels at baseline were significantly associated with IAF area at 5 years (coefficient = 0.041, P = 0.001 and coefficient = 1.283, P < 0.001, respectively) and 10 years (coefficient = 0.031, P = 0.020 and coefficient = 0.221, P = 0.035, respectively). ISR was not significantly associated with IAF at 5 or 10 years. Leptin level at baseline was positively associated with IAF at 5 years (coefficient = 0.055, P = 0.002) and 10 years (coefficient = 0.059, P = 0.003). In conclusion, higher levels of fasting insulin, C-peptide, and circulating leptin level predicted visceral fat accumulation independent from subcutaneous fat accumulation in nondiabetic Japanese-American men and women in both short-term (5 years) and long-term (10 years) follow-up.

Association of endothelial lipase gene (LIPG) haplotypes with high-density lipoprotein cholesterol subfractions and apolipoprotein AI plasma levels in Japanese Americans.

The LIPG gene on chromosome 18 encodes for endothelial lipase, a member of the triglyceride lipase family. Mouse models suggest that variation in LIPG influences high-density lipoprotein (HDL) metabolism, but only limited data are available in humans. This study examined associations of LIPG haplotypes, comprising a single nucleotide polymorphism (SNP) in the promoter region (-384A>C), and a nonsynonymous SNP in exon 3 (Thr111Ile or 584C>T), with lipoprotein risk factors in 541 adult Japanese Americans. A marginal association was found between LIPG diplotypes and HDL cholesterol (p=0.045). Stronger associations were seen for HDL3 cholesterol (p=0.005) and Apolipoprotein AI plasma levels (p=0.002). After adjustment for age, gender, smoking and medications, individuals homozygous for the minor allele at both SNPs (*4 haplotype) had a more favorable risk factor profile, compared to other haplotype combinations. No relationship was seen for plasma triglyceride levels or low-density lipoprotein (LDL) size, but the homozygous *4 diplotype was also associated with lower Apolipoprotein B and LDL cholesterol levels (p=0.001 and 0.015, respectively). In conclusion, this community-based family study of Japanese Americans demonstrates that LIPG variants are associated with HDL related risk factors, and may play a role in susceptibility to cardiovascular disease in this population.

Association of apolipoprotein A5 variants with LDL particle size and triglyceride in Japanese Americans.

A new apolipoprotein (apo) gene, APOA5, was recently identified on chromosome 11q23, and common variants in the gene have been associated with plasma triglyceride (TG) levels in several studies. The purpose of the present study was to examine the association of five single nucleotide polymorphisms (SNPs) and haplotypes in the APOA5 gene with low-density lipoprotein (LDL) particle size using a community-based sample of Japanese American families, including examining whether the associations with LDL size are independent of, or primarily reflecting, TG levels. Genetic association analyses were performed using 154 unrelated individuals, quantitative transmission disequilibrium tests (TDT) in 238 nuclear families, a sample of 24 hypertriglyceridemic subjects with matched, normotriglyceridemic controls, and using haplotype analyses. There was a high degree of allelic association between several of the SNPs, with complete linkage disequilibrium (LD) between -1131C>T and the -3A>G SNP which alters a potential Kozak sequence. All approaches demonstrated associations between the -3A>G APOA5 variant and both decreased LDL size and increased TG levels. The frequency of the rare allele was higher than reported for Caucasian, Hispanic, and African Americans, but similar to that in Japan and China. Therefore, the haplotype containing the -1131C and -3G variants, and possibly specifically the -3A>G SNP in APOA5, may be a major genetic determinant of LDL particle size and TG levels among ethnic Asians.

Visceral adiposity and the prevalence of 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.

Heritability of multivariate factors of the metabolic syndrome in nondiabetic Japanese americans.

A rapidly growing body of evidence demonstrates important associations between the metabolic syndrome, characterized by a cluster of risk factors or phenotypes that include dyslipidemia, central obesity, hypertension, and hyperinsulinemia, and both cardiovascular disease and type 2 diabetes. The purpose of the present study was to characterize the metabolic syndrome in a sample of 432 individuals from 68 Japanese-American families, using factor analysis of quantitative phenotypes, and to estimate the heritability of these independent factors. Using nine characteristic phenotypes that included LDL particle size and C-reactive protein (CRP), factor analysis identified three multivariate factors interpreted as lipids, body fat/insulin/glucose/CRP, and blood pressure, explaining 65% of the variance. Heritability analysis revealed significant genetic effects on all of the factors: lipids (h(2) = 0.52, P < 0.001), body fat/insulin/glucose/CRP (h(2) = 0.27, P = 0.016), and blood pressure (h(2) = 0.25, P = 0.026). This analysis shows that independent, multivariate factors of the metabolic syndrome are heritable, demonstrating genetic influences on the underlying pathophysiological mechanisms of the syndrome.

Small, dense LDL and elevated apolipoprotein B are the common characteristics for the three major lipid phenotypes of familial combined hyperlipidemia.

OBJECTIVE: Familial combined hyperlipidemia (FCHL) is associated with variable lipid and lipoprotein phenotypes arbitrarily defined as type IIa, IIb, and IV based on plasma total cholesterol and triglyceride levels. This study sought to characterize consistent lipoprotein and lipid abnormalities across the 3 lipoprotein phenotypes in 62 patients with documented FCHL (IIa [n=14], IIb [n=19], and IV [n=29]) and 44 healthy individuals. METHODS AND RESULTS: The lipoprotein cholesterol distribution was determined over 38 fractions obtained by density gradient ultracentrifugation. As expected, FCHL patients with hypertriglyceridemia (IIb and IV) had higher cholesterol levels in VLDL than IIa, whereas IIa showed higher cholesterol in the big, buoyant LDL and in HDL. LDL cholesterol was higher in IIb than IV; most of the increase in LDL cholesterol was associated with big, buoyant LDL rather than small, dense LDL (sdLDL). The differences in lipoproteins between phenotypes were attributable to changes in VLDL and big, buoyant LDL levels. Comparison of the FCHL patients with healthy individuals showed a significant elevation in plasma apolipoprotein B levels and sdLDL in all 3 FCHL phenotypes. CONCLUSIONS: Although triglyceride and cholesterol levels are variable by lipoprotein phenotype, sdLDL and elevated plasma apolipoprotein B levels are consistent characteristics of FCHL shared by the 3 different lipoprotein phenotypes.

Diabetes-related comorbidities in Asian Americans: results of a national health survey.

OBJECTIVE: The aim of this study was to compare the prevalence of diabetes-related comorbidities in Asian Americans to the prevalence in other racial and ethnic groups in the United States using data from the 2001 Behavioral Risk Factor Surveillance System (BRFSS). METHODS: The BRFSS is a population-based telephone survey of the health status and health behaviors of 212,510 Americans aged > or = 18 years in all 50 states, Guam, Puerto Rico, and the U.S. Virgin Islands. In 2001, participants included 196 Asian Americans, 1138 African Americans, 1276 Hispanics, 294 Native Americans, 71 Pacific Islanders, and 7799 non-Hispanic Whites with a self-reported physician diagnosis of diabetes. Comorbidity was determined by self-report. Odds ratios (OR) were adjusted for age, sex, body mass index (BMI) or height and weight, duration of diabetes, smoking, and health-insurance status. RESULTS: The adjusted prevalences of hypercholesterolemia and retinopathy were similar across groups. Relative to Asian Americans, only African Americans were more likely to report hypertension [adjusted OR=2.1, 95% confidence interval (CI)=1.0-4.2, P<.05]. Higher odds of current or past foot ulceration was observed for Hispanics (adjusted OR=2.8, 95% CI=1.2-6.9), Native Americans (adjusted OR=4.2, 95% CI=1.4-12.8), and Pacific Islanders (adjusted OR=7.4, 95% CI=1.3-41.2) compared with Asian Americans. CONCLUSIONS: Among Americans with diabetes, Asian Americans have a prevalence of hypertension, hypercholesterolemia, retinopathy, and foot ulceration that is similar to that in Whites. Asian Americans had a significantly lower prevalence of hypertension than African Americans did and a lower prevalence of foot ulceration than Hispanics, Native Americans, and Pacific Islanders did.

Visceral adiposity is an independent predictor of incident hypertension in Japanese Americans.

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.

Type 2 diabetes prevalence in Asian Americans: results of a national health survey.

OBJECTIVE: Asians are thought to be at high risk for diabetes, yet there is little population-based information about diabetes in Asian Americans. The purpose of this study was to directly compare the prevalence of type 2 diabetes in Asian Americans with other racial and ethnic groups in the U.S. using data from the 2001 Behavioral Risk Factor Surveillance System (BRFSS). RESEARCH DESIGN AND METHODS: The BRFSS is a population-based telephone survey of the health status and health behaviors of Americans in all 50 states, Guam, Puerto Rico, and the U.S. Virgin Islands. Subjects included 3,071 Asians, 12,561 blacks, 12,153 Hispanics, 2,299 Native Americans, 626 Pacific Islanders, and 129,116 non-Hispanic whites aged >/=30 years. Subjects who reported a physician-diagnosis of diabetes were considered to have type 2 diabetes unless they were diagnosed before age 30. RESULTS: Compared with whites, odds ratios (95% CIs) for diabetes, adjusted for age and sex, were 1.0 (0.7-1.4) for Asians, 2.3 (2.1-2.6) for blacks, 2.0 (1.8-2.3) for Hispanics, 2.2 (1.6-2.9) for Native Americans, and 3.1 (1.4-6.8) for Pacific Islanders. Results adjusted for BMI, age, and sex were 1.6 (1.2-2.3) for Asians, 1.9 (1.7-2.2) for blacks, 1.9 (1.6-2.1) for Hispanics, 1.8 (1.3-2.5) for Native Americans, and 3.0 (1.4-6.7) for Pacific Islanders. CONCLUSIONS: Similar proportions of Asian and non-Hispanic white Americans report having diabetes, but after accounting for the lower BMI of Asians, the adjusted prevalence of diabetes is 60% higher in Asian Americans.

Comparison of a clinical model, the oral glucose tolerance test, and fasting glucose for prediction of type 2 diabetes risk in Japanese Americans.

OBJECTIVE: To test the validity of a published clinical model for predicting incident diabetes in Japanese Americans. RESEARCH DESIGN AND METHODS: A total of 465 nondiabetic Japanese Americans (243 men, 222 women), aged 34-75 years, were studied at baseline and at 5-6 years. A total of 412 subjects were studied at 10 years. The clinical model included age, sex, ethnicity, BMI, systolic blood pressure, fasting plasma glucose (FPG), HDL cholesterol, and family history of diabetes at baseline. Diabetes status at 5-6 and 10 years was determined by 75-g oral glucose tolerance test. The clinical model, 2-h glucose, and FPG were compared using receiver-operating characteristic (ROC) curves. RESULTS-The diabetes risk associated with BMI, sex, and HDL cholesterol differed by age (P

Visceral adiposity and the risk of impaired glucose tolerance: a prospective study among Japanese Americans.

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.

Differential Association Between HDL Subclasses and the Development of Type 2 Diabetes in a Prospective Study of Japanese Americans.

OBJECTIVE: Recent studies have suggested that HDL cholesterol is inversely associated with the development of type 2 diabetes. However, little is known about the association between different HDL subclasses and the risk for future type 2 diabetes. RESEARCH DESIGN AND METHODS: The study enrolled 406 Japanese Americans (51% male) without diabetes, aged 34-75 years. Oral glucose tolerance tests were performed to determine type 2 diabetes status at baseline, 2.5 years, 5 years, and 10 years after enrollment. HDL2, HDL3, total HDL cholesterol, and visceral adipose tissue (VAT) area by computed tomography were measured at baseline. RESULTS: In univariate analysis, total HDL and HDL2 cholesterol were inversely associated with the incidence of type 2 diabetes, but HDL3 cholesterol was not. In multivariate analysis, total HDL cholesterol (odds ratio per 1-SD increment, 0.72 [95% CI 0.52-0.995], P = 0.047) and HDL2 cholesterol (odds ratio per 1-SD increment, 0.64 [95% CI 0.44-0.93], P = 0.018) were inversely associated with the risk for type 2 diabetes independent of age, sex, BMI, waist circumference, family history of diabetes, lifestyle factors, systolic blood pressure, lipid-lowering medication use, triglyceride level, HOMA-insulin resistance, and 2-h glucose; however, HDL3 cholesterol was not associated with diabetes risk. The association between diabetes risk and total HDL and HDL2 cholesterol became insignificant after adjustment for VAT area. CONCLUSIONS: Subjects with higher HDL2 cholesterol were at lower risk for incident type 2 diabetes, but this association was confounded by and not independent of VAT. Higher HDL3 cholesterol was not associated with diabetes risk.

Optimum BMI cut points to screen asian americans for type 2 diabetes.

OBJECTIVE: Asian Americans manifest type 2 diabetes at low BMI levels but may not undergo diagnostic testing for diabetes if the currently recommended BMI screening cut point of ≥25 kg/m(2) is followed. We aimed to ascertain an appropriate lower BMI cut point among Asian-American adults without a prior diabetes diagnosis. RESEARCH DESIGN AND METHODS: We consolidated data from 1,663 participants, ages ≥45 years, without a prior diabetes diagnosis, from population- and community-based studies, including the Mediators of Atherosclerosis in South Asians Living in America study, the North Kohala Study, the Seattle Japanese American Community Diabetes Study, and the University of California San Diego Filipino Health Study. Clinical measures included a 2-h 75-g oral glucose tolerance test, BMI, and glycosylated hemoglobin (HbA1c). RESULTS: Mean age was 59.7 years, mean BMI was 25.4 kg/m(2), 58% were women, and type 2 diabetes prevalence (American Diabetes Association 2010 criteria) was 16.9%. At BMI ≥25 kg/m(2), sensitivity (63.7%), specificity (52.8%), and Youden index (0.16) values were low; limiting screening to BMI ≥25 kg/m(2) would miss 36% of Asian Americans with type 2 diabetes. For screening purposes, higher sensitivity is desirable to minimize missing cases, especially if the diagnostic test is relatively simple and inexpensive. At BMI ≥23 kg/m(2), sensitivity (84.7%) was high in the total sample and by sex and Asian-American subgroup and would miss only ∼15% of Asian Americans with diabetes. CONCLUSIONS: The BMI cut point for identifying Asian Americans who should be screened for undiagnosed type 2 diabetes should be <25 kg/m(2), and ≥23 kg/m(2) may be the most practical.

Change in visceral adiposity independently predicts a greater risk of developing type 2 diabetes over 10 years in Japanese Americans.

OBJECTIVE: Visceral adiposity is an important risk factor for cardiovascular disease and type 2 diabetes. We sought to determine whether change in intraabdominal fat area (IAF) over time predicts subsequent development of diabetes. RESEARCH DESIGN AND METHODS: We followed up 436 nondiabetic Japanese-American subjects (mean age 51.9 years, mean BMI 24.2 kg/m(2), 54% male) for development of diabetes. We fit a logistic regression model to examine the association over a 10-year follow-up between change in IAF at 5-year follow-up and other fat areas (measured by computed tomography) and development of incident diabetes, adjusted for age, sex, family history of diabetes in a first-degree relative, second-generation versus third-generation Japanese American (Nisei vs. Sansei), baseline IAF, BMI, weight change over time, smoking status, physical activity level, and subcutaneous fat (SCF) depot areas. RESULTS: Cumulative incidence of diabetes was 20.4% at 10 years. Mean change in IAF was 10.9 cm(2). An increase of 1 SD in IAF was associated with a 1.65-fold increase in the odds of diabetes over 10 years (OR = 1.65, 95% CI 1.21-2.25) after adjusting for the above covariates. This association was also independent of changes in thoracic, thigh, and abdominal SCF, as well as change in weight. CONCLUSIONS: We conclude that baseline IAF and accumulation of fat in this area over time are independent predictors of the development of type 2 diabetes in Japanese Americans.

Patterns of insulin concentration during the OGTT predict the risk of type 2 diabetes in Japanese Americans.

OBJECTIVE: To examine whether the patterns of insulin concentration during the oral glucose tolerance test (OGTT) predict type 2 diabetes. RESEARCH DESIGN AND METHODS: We followed 400 nondiabetic Japanese Americans for 10-11 years. Insulin concentrations at 30, 60, and 120 min during a 2-h 75-g OGTT at baseline were used to derive the following possible patterns of insulin: pattern 1 (30-min peak, higher insulin level at 60 than at 120 min), pattern 2 (30-min peak, lower or equal level at 60 vs. 120 min), pattern 3 (60-min peak); pattern 4 (120-min peak, lower level at 30 than at 60 min), and pattern 5 (120-min peak, equal or higher level at 30 vs. 60 min). Insulin sensitivity was estimated by homeostasis model assessment of insulin resistance (HOMA-IR) and Matsuda index. Insulin secretion was estimated by the insulinogenic index (IGI) [Δinsulin/Δglucose (30-0 min)] and disposition index (IGI/HOMA-IR). RESULTS: There were 86 incident cases of type 2 diabetes. The cumulative incidence was 3.2, 9.8, 15.4, 47.8, and 37.5% for patterns 1, 2, 3, 4, and 5, respectively. Compared with pattern 1, patterns 4 and 5, characterized by a lasting late insulin response, were associated with significantly less insulin sensitivity as measured by the Matsuda index and lower early insulin response by the disposition index. The multiple-adjusted odds ratios of type 2 diabetes were 12.55 (95% CI 4.79-32.89) for pattern 4 and 8.34 (2.38-29.27) for pattern 5 compared with patterns 1 and 2. This association was independent of insulin secretion and sensitivity. CONCLUSIONS: The patterns of insulin concentration during an OGTT strongly predict the development of type 2 diabetes.

Impact of differences in glucose tolerance on the prevalence of a negative insulinogenic index.

OBJECTIVE: To determine the prevalence of a negative insulinogenic index (change in plasma insulin/change in plasma glucose from 0 to 30 min) from an oral glucose tolerance test according to glucose tolerance category. MATERIALS AND METHODS: Data from the San Antonio Heart Study (n=2494), Japanese American Community Diabetes Study (JACDS; n=594) and Genetics of NIDDM Study (n=1519) were examined. Glucose tolerance was defined by ADA criteria. RESULTS: In the combined cohort, the prevalence of a negative insulinogenic index was significantly higher in diabetes 20/616 (3.2%) compared to normal glucose tolerance 43/2667 (1.6%) (p<0.05). Longitudinally, in the JACDS cohort, the prevalence did not change from baseline (3/594; 0.5%) to 5 (4/505; 0.7%) and 10 years (8/426; 1.9%) (p=0.9) and no subject had a repeat negative insulinogenic index. CONCLUSIONS: A negative insulinogenic index occurs at a low prevalence across glucose tolerance categories although more often in diabetes, but without recurrence over time.