Biomedical subjects

E J Boyko

Publications and source records attributed to E J Boyko.

At least 19 recordsLinked to original sources

PubMed2006

Racial and ethnic differences in incident myocardial infarction in end-stage renal disease patients: The USRDS.

African Americans have a greater risk of cardiovascular disease (CVD) than Caucasians in early chronic kidney disease; however, limited data describe racial and ethnic differences in the risk of incident myocardial infarction (MI) among patients with end-stage renal disease (ESRD). We conducted a prospective, observational cohort study among 271 102 incident dialysis patients receiving renal replacement therapy enrolled in the United States Renal Data System (USRDS) for whom Medicare was the primary insurer between 1995 and 2000. The incidence and risk of any MI (non-fatal or fatal) estimated by Cox proportional hazards models was the primary outcome of interest. Of those with prevalent CVD at baseline (118 708), 14 849 had an incident non-fatal MI compared with 9926 events for those without prevalent CVD (152 394). Patients with prevalent CVD had higher crude rates of combined fatal and non-fatal MI (99.3/1000 person-years vs 42.9/1000 person-years) compared with those without prevalent CVD. Among those with prevalent CVD, African Americans (adjusted relative risk (aRR)=0.65, 95% confidence interval (CI):0.62-0.68), Asian Americans (aRR=0.74, 95% CI: 0.66-0.83), and Hispanics (aRR=0.72, 95% CI: 0.68-0.77) were 26-35% less likely to have an incident MI compared to Caucasians. Similarly, among those without prevalent CVD, racial/ethnic minorities were 26-42% less likely to have an incident MI compared to Caucasians. We conclude that in a national setting where comparable access to dialysis and associated medical care, exist, racial/ethnic minorities were found to have a lower risk of non-fatal and fatal MI than Caucasians.

Adult↗

PubMed2003

Relationship of adiponectin to body fat distribution, insulin sensitivity and plasma lipoproteins: evidence for independent roles of age and sex.

AIMS/HYPOTHESIS: Increased intra-abdominal fat is associated with insulin resistance and an atherogenic lipoprotein profile. Circulating concentrations of adiponectin, an adipocyte-derived protein, are decreased with insulin resistance. We investigated the relationships between adiponectin and leptin, body fat distribution, insulin sensitivity and lipoproteins. METHODS: We measured plasma adiponectin, leptin and lipid concentrations, intra-abdominal and subcutaneous fat areas by CT scan, and insulin sensitivity index (S(I)) in 182 subjects (76 M/106F). RESULTS: Adiponectin concentrations were higher in women than in men (7.4+/-2.9 vs 5.4+/-2.3 micro g/ml, p<0.0001) as were leptin concentrations (19.1+/-13.7 vs 6.9+/-5.1 ng/ml, p<0.0001). Women were more insulin sensitive (S(I): 6.8+/-3.9 vs 5.9+/-4.4 x 10(-5) min(-1)/(pmol/l), p<0.01) and had more subcutaneous (240+/-133 vs 187+/-90 cm(2), p<0.01), but less intra-abdominal fat (82+/-57 vs 124+/-68 cm(2), p<0.0001). By simple regression, adiponectin was positively correlated with age ( r=0.227, p<0.01) and S(I) ( r=0.375, p<0.0001), and negatively correlated with BMI ( r=-0.333, p<0.0001), subcutaneous ( r=-0.168, p<0.05) and intra-abdominal fat ( r=-0.35, p<0.0001). Adiponectin was negatively correlated with triglycerides ( r=-0.281, p<0.001) and positively correlated with HDL cholesterol ( r=0.605, p<0.0001) and Rf, a measure of LDL particle buoyancy ( r=0.474, p<0.0001). By multiple regression analysis, adiponectin was related to age ( p<0.0001), sex ( p<0.005) and intra-abdominal fat ( p<0.01). S(I) was related to intra-abdominal fat ( p<0.0001) and adiponectin ( p<0.0005). Both intra-abdominal fat and adiponectin contributed independently to triglycerides, HDL cholesterol and Rf. CONCLUSION/INTERPRETATION: These data suggest that adiponectin concentrations are determined by intra-abdominal fat mass, with additional independent effects of age and sex. Adiponectin could link intra-abdominal fat with insulin resistance and an atherogenic lipoprotein profile.

Abdominal Wall↗

PubMed2001

Intramuscular testosterone esters and plasma lipids in hypogonadal men: a meta-analysis.

PURPOSE: It is unclear whether intramuscular administration of testosterone esters to hypogonadal men is associated with changes in plasma lipids. We therefore analyzed 19 studies published between 1987 and 1999 that focused on male subjects with nonexperimental hypogonadism, treated subjects with an intramuscular testosterone ester and reported pretreatment and post-treatment concentrations of total cholesterol, low-density lipoprotein (LDL), high-density lipoprotein (HDL) cholesterol, or total triglyceride. METHODS: We calculated study-specific, post-treatment minus pretreatment differences in each plasma lipid concentration (mean [95% confidence interval]). After testing of between-study homogeneity, we combined the study-specific differences. We then determined whether heterogeneity of differences could be explained in models of the differences on study and patient characteristics (mean +/- SE) before and after excluding extreme values using a multiple outlier procedure. RESULTS: The studies represented 272 hypogonadal men (age 44 +/- 4 years; 20% with hypergonadotropic hypogonadism; total testosterone 0.5 +/- 0.2 ng/mL) who received, on average, 179 +/- 13 mg intramuscular testosterone ester every 16 +/- 1 days for 6 +/- 1 months. Fixed-effects estimates of post-treatment minus pretreatment differences were -14 [-17 to -11] mg/dL (total cholesterol), -5 [-8 to -1] mg/dL (LDL cholesterol), -4 [-5 to -2] mg/dL (HDL cholesterol), and -1 [-6 to + 4] mg/dL (triglyceride). Decreases in HDL cholesterol were larger at lower dosages of testosterone ester (r = -0.54, P = 0.055), but were not explained by attrition, regression to the mean, dosing frequency or duration, concomitant elevation of plasma total testosterone, aromatization of testosterone to estradiol, or other study and patient characteristics. CONCLUSION: Intramuscular administration of testosterone esters to hypogonadal men is associated with a small, dosage-dependent decrease in HDL cholesterol and concomitant declines in total cholesterol and LDL cholesterol. The aggregate effect of these changes on cardiovascular risk remains unknown but deserves further study.

Cholesterol, HDL↗

PubMed2001

Assessment of vital status in Department of Veterans Affairs national databases. comparison with state death certificates.

PURPOSE: To determine the extent to which Department of Veterans Affairs (VA) database vital status information agrees with Washington state death certificates. METHODS: Using each data source, vital status was determined for 19,481 Washington state resident veterans hospitalized in Washington VA hospitals from 1994 to 1997, and for 33,602 Washington state resident veterans who were seen as outpatients during 1997. RESULTS: The agreement between VA and Washington state records was excellent for hospitalized veterans (kappa = 0.91, p < 0.0001). Three thousand one hundred-eight individuals (86.2% of all deaths) appeared in both files. Of those deaths missing in the VA files, 71% had no service-connected disability, VA pension, or other compensation. Among outpatients, agreement between the death files was very good (kappa = 0.82, p < 0.001). Three hundred seventy-two individuals (69.8% of all deaths) appeared in both files. Of those deaths missing in the VA files, 63% had no service-connected disability or VA pension or other compensation. CONCLUSIONS: The VA death files are a valid source of vital status information for veterans hospitalized in recent years. For veterans having exclusively outpatient visits, however, the VA files miss a substantial proportion of deaths. For these patients, alternative means of vital status ascertainment are warranted.

Aged↗

PubMed2001

Genetic variation and obesity in Australian women: a prospective study.

OBJECTIVE: A number of candidate genes have been implicated in the pathogenesis of obesity in humans. This study examines associations between longitudinal changes in body mass and composition and the presence of polymorphisms in the beta-3 adrenergic receptor, tumor necrosis factor-alpha, leptin, and leptin receptor (Lepr) in a cohort of Australian women. RESEARCH METHODS AND PROCEDURES: Healthy white Australian women (n = 335) were randomly selected from the Barwon region of Victoria and underwent baseline anthropometry and double-energy X-ray absorptiometry for assessment of body mass and adiposity. These measurements were repeated again at 2-year follow-up. Genomic DNA was extracted and used for polymerase chain reaction-based genotyping of all polymorphisms. RESULTS: The Pro1019Pro Lepr polymorphism was associated with longitudinal increases in body weight (p = 0.02), fat mass (p = 0.05), and body mass index (p = 0.01) in this study, and individuals homozygous for the A allele at this locus had a greater propensity to gain body fat over time. The largest effects on body composition seemed to be in individuals already obese at baseline. Changes in body weight, fat mass, percent body fat, and body mass index over a 2-year period were not associated with genetic variation in the beta-3 adrenergic receptor (Trp64Arg), tumor necrosis factor-alpha promoter, or leptin genes in non-obese or obese women. DISCUSSION: These results suggest that a Lepr polymorphism is involved in the regulation of body mass and adiposity in obese Australian white women, which may have implications for the treatment of obesity in this population.

Absorptiometry, Photon↗

PubMed2001

Leptin and other components of the Metabolic Syndrome in Mauritius--a factor analysis.

OBJECTIVE: To use factor analysis to examine the putative role of leptin in the Metabolic Syndrome, and to define better the associations among observed variables and the identified factors. DESIGN: Factor analysis of cross-sectional data from a 1987 survey. SUBJECTS: Non-diabetic residents of Mauritius who participated in population-based surveys in 1987 and 1992 (1414 men and 1654 women). MEASUREMENTS: Fasting and 2 h plasma glucose and insulin following a 75 g oral glucose load; seated blood pressure; body mass index (BMI); waist-to-hip ratio (WHR); and fasting serum triglycerides, HDL-cholesterol, leptin and uric acid concentrations. RESULTS: Principal components factor analysis revealed three factors for men and women that explained between 54 and 55% of the observed variance of the 12 measured variables. General features of these factors were as follows: factor 1, WHR, BMI, leptin, fasting and 2 h insulin, triglycerides, and HDL-cholesterol; factor 2, systolic and diastolic blood pressure, uric acid (men only), and fasting glucose (women only); and factor 3, fasting and 2 h glucose and insulin. Only three variables loaded on more than one factor with a loading > or = 0.4 (fasting and 2 h insulin, fasting glucose in women only). Leptin loaded on one factor only in both men and women. CONCLUSIONS: Since multiple factors underlie the Metabolic Syndrome, and since no observed variable loads on all three factors, more than one mechanism might account for the observed clustering of risk characteristics. Leptin does not unite features of this syndrome due to its loading on one factor only. Uric acid is related to a different factor in men and women. The absence of gender differences in factor loadings argues for similar mechanisms for the Metabolic Syndrome in men and women in Mauritius. International Journal of Obesity (2001) 25, 126-131

Adult↗

PubMed2001

Standard definitions of overweight and central adiposity for determining diabetes risk in Japanese Americans.

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 nondiabetic Japanese Americans [age: 52.2 +/- 0.6 y; BMI (in kg/m(2)): 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 < or = 55 y, incident diabetes was strongly associated with overweight (BMI > or = 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 > or = 88 cm for women and > or = 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.

Adipose Tissue↗

PubMed2001

Tissue oxygenation and skin blood flow in the diabetic foot: responses to cutaneous warming.

We previously reported an unexpected statistically significant decline in the mean transcutaneous partial pressure of oxygen (TcPO2) with cutaneous warming from 37 degrees C to 44 degrees C on the plantar diabetic foot, as opposed to the expected increase seen at the dorsal sites. To elucidate this relationship we compared changes with cutaneous warming in TcPO2 and skin circulation measured by laser Doppler flowmetry on the right plantar foot surface of 20 consecutive subjects. Neuropathy by monofilament testing was present in 55% of the cases. Right dorsal foot TcPO2 increased with cutaneous warming from 37 degrees C to 44 degrees by a mean change of +43.6+/-20.7 mmHg (+/- standard deviation) in 95% of the cases. In 42% of cases right plantar first metatarsal head TcPO2 fell with warming from 37 degrees C to 44 degrees C by a mean change of -10.7+/-7.6 mmHg. In the remaining 58% of cases right plantar first metatarsal head TcPO2 rose by 6.8+/-6.3 mmHg. In 95% of cases right plantar great toe laser Doppler perfusion units (LDPU) increased with warming from 36 degrees C to 44 degrees C by a mean change of +50.4+/-37.1. Blood flow measured by laser Doppler flowmetry increased in 95% of the subjects with heating. The finding that blood flow was increased with warming contradicts the hypothesis that arterioles in the plantar great toe cannot vasodilate in response to thermal stimuli. This finding supports the hypothesis that the decline in TcPO2 with warming might be due to an increase in epidermal oxygen consumption that exceeds the increase in oxygen delivery due to increased blood flow. The pathological mechanisms behind microvascular dysfunction in skin microcirculation in the diabetic foot need further investigation.

Aged↗

PubMed2001

Abnormal glucose tolerance and increased risk for cardiovascular disease in Japanese-Americans with normal fasting glucose.

OBJECTIVE: To compare the American Diabetes Association (ADA) fasting glucose and the World Health Organization (WHO) oral glucose tolerance test (OGTT) criteria for diagnosing diabetes and detecting people at increased risk for cardiovascular disease (CVD). RESEARCH DESIGN AND METHODS: Study subjects were 596 Japanese-Americans. Fasting insulin, lipids, and C-peptide levels; systolic and diastolic blood pressures (BPs); BMI (kg/m2); and total and intra-abdominal body fat distribution by computed tomography (CT) were measured. Study subjects were categorized by ADA criteria as having normal fasting glucose (NFG), impaired fasting glucose (IFG), and diabetic fasting glucose and by WHO criteria for a 75-g OGTT as having normal glucose tolerance (NGT), impaired glucose tolerance (IGT), and diabetic glucose tolerance (DGT). RESULTS: Of 503 patients with NFG, 176 had IGT and 20 had DGT These patients had worse CVD risk factors than those with NGT . The mean values for NGT, IGT, and DGT, respectively, and analysis of covariance P values, adjusted for age and sex, are as follows; intra-abdominal fat area by CT 69.7, 95.0, and 101.1 cm2 (P < 0.0001); total CT fat area 437.7, 523.3, and 489.8 cm2 (P < 0.0001); fasting triglycerides 1.40, 1.77, and 1.74 mmol/l (P = 0.002); fasting HDL cholesterol 1.56, 1.50, and 1.49 mmol/l (P = 0.02); C-peptide 0.80, 0.90, 0.95 nmol/l (P = 0.002); systolic BP 124.9, 132.4, and 136.9 mmHg (P = 0.0035); diastolic BP 74.8, 77.7, and 78.2 mmHg (P = 0.01). CONCLUSIONS: NFG patients who had IGT or DGT had more intra-abdominal fat and total adiposity; higher insulin, C-peptide, and triglyceride levels; lower HDL cholesterol levels; and higher BPs than those with NGT. Classification by fasting glucose misses many Japanese-Americans with abnormal glucose tolerance and less favorable cardiovascular risk profiles.

Adult↗

PubMed2000

US Department of Veterans Affairs medical care system as a resource to epidemiologists.

Epidemiologists have utilized several health care systems with large numbers of enrollees and centralized databases to achieve their research aims. Although containing many of the features that have made certain health care systems valuable to the conduct of epidemiologic research, the US Department of Veterans Affairs (VA) medical care system has not been well utilized by epidemiologists. This article will describe existing and planned features of this health care system that should be of interest to epidemiologists, including centralized databases that capture hospital discharge and outpatient clinic diagnostic data, a planned enrollment file that would contain all persons eligible for VA medical care, and the size and national dispersion of VA medical care facilities. Also, VA leadership has demonstrated an interest in the promotion of epidemiologic research by initiating several new programs, including the creation of three Epidemiologic Research and Information Centers (ERICs) to foster VA epidemiologic research, and announcing a program to support investigator-initiated epidemiologic research projects with VA funding. Epidemiologists with interests in medical problems that afflict veterans should consider partnerships with VA investigators to achieve their research aims.

Epidemiologic Methods↗

PubMed2000

A randomized controlled trial of a clinic-based support staff intervention to increase the rate of fecal occult blood test ordering.

BACKGROUND: Colorectal cancer is the second most common fatal malignancy in the United States. Early detection using fecal occult blood tests has been shown to reduce mortality, but these tests are underutilized among those eligible for this screening. Attempts to increase use of fecal occult blood tests in eligible populations have focused on the provider, patient, or system. But none have examined whether a support-staff intervention is effective in achieving this aim. We therefore conducted a randomized controlled trial to test the impact of authorizing support staff to order fecal occult blood tests in a general internal medicine clinic organized into four teams. METHODS: A total of 1,109 patients were included in the study, 545 of whom were in the two teams randomized to treatment. Univariate and multivariate regression analyses were used to evaluate the impact of the intervention. RESULTS: The intervention resulted in significantly more fecal occult blood test ordering in the treatment group than in the control group for all patients (52% vs 15%, P < 0.001). Treatment fecal occult blood test cards were returned as frequently as the control cards for all patients (44% vs 48%, P = 0.571). CONCLUSION: Delegation of selected screening tasks to support staff can enhance patient access to preventive care.

Colorectal Neoplasms↗

PubMed2000

Type 2 diabetes and the metabolic syndrome in Japanese Americans.

Japanese Americans have experienced a higher prevalence of type 2 diabetes than in Japan. Research conducted in Seattle suggests that lifestyle factors associated with 'westernization' play a role in bringing out this susceptibility to diabetes. These lifestyle factors include consumption of a diet higher in saturated fat and reduced physical activity. A consequence of this is the development of central (visceral) adiposity, insulin resistance, and other features associated with this insulin resistance metabolic syndrome, such as dyslipidemia (high triglycerides, low HDL-cholesterol, and small and dense LDL particles), hypertension, and coronary heart disease. We have postulated that the superimposition of insulin resistance upon a genetic background of reduced beta-cell reserve results in hyperglycemia and diabetes among Japanese Americans. This article reviews evidence that support this view.

Adipose Tissue↗

PubMed2000

Low serum testosterone level as a predictor of increased visceral fat in Japanese-American men.

OBJECTIVE: To examine the association between baseline testosterone levels and changes in visceral adiposity in Japanese-American men. DESIGN: Prospective observational study. SUBJECTS: Second-generation Japanese-American males enrolled in a community-based population study. MEASUREMENTS: At baseline, 110 men received a 75g oral glucose tolerance test (OGTT), and an assessment of body mass index (BMI); visceral adiposity measured as intra-abdominal fat area (IAF) using computed tomography (CT); fasting insulin and C-peptide levels; and total testosterone levels. IAF was re-measured after 7.5 y. Subcutaneous fat areas were also measured by CT in the abdomen, thorax and thigh. The total fat (TF) was calculated as the sum of IAF and total subcutaneous fat areas (SCF). RESULTS: After 7.5y, IAF increased by a mean of 8.0 cm2 (95% CI: 0.8, 15.3). Baseline total testosterone was significantly correlated with change in IAF (r= -0.26, P= 0.006), but not to any appreciable degree with change in BMI, TF, or SCF. In a linear regression model with change in IAF as the dependent variable, baseline testosterone was significantly related to this outcome while adjusting for baseline IAF, SCF, BMI, age, diabetes mellitus status (OGTT by the WHO diagnostic criteria) and fasting C-peptide (regression coefficient for baseline testosterone [nmol/l] = -107.13, P = 0.003). CONCLUSIONS: In this Japanese-American male cohort, lower baseline total testosterone independently predicts an increase in IAF. This would suggest that by predisposing to an increase in visceral adiposity, low levels of testosterone may increase the risk of type 2 diabetes mellitus.

Abdomen↗

PubMed2000

Preventing diabetes--applying pathophysiological and epidemiological evidence.

This is a review of research carried out in Japanese Americans that points towards possible approaches to prevention of type 2 diabetes mellitus. The natural history of type 2 diabetes usually includes both insulin resistance and beta-cell dysfunction. Insulin secretion may compensate for insulin resistance. Alternatively, enhanced insulin sensitivity may mask an insulin secretory defect. Epidemiological data support the view that in the vast majority of cases of type 2 diabetes, insulin resistance is essential to the pathogenesis of hyperglycemia. Increased diabetes prevalence as ethnic groups migrate to more urban or westernized regions has been attributed to increased occurrence of insulin resistance. Research among Japanese Americans in Seattle, Washington, showed a higher prevalence of type 2 diabetes than in Japan, which suggested that factors associated with 'westernization' might be playing a role in bringing out underlying susceptibility to diabetes. Our research has shown that these impressions were correct and that the abnormalities that characterize the metabolic syndrome play a significant role. Due to increased intra-abdominal fat deposition, Japanese Americans were likely to be 'metabolically obese' despite relatively normal BMI. A diet higher in animal fat and lower levels of physical activity were risk factors leading to increased intra-abdominal fat deposition, insulin resistance, and diabetes. Information from epidemiological studies such as these may be used to determine whether diabetes may be prevented through changes in lifestyle or application of specific therapies targeted towards identified metabolic abnormalities.

Adult↗

PubMed2000

Reassessing the role of QTc in the diagnosis of autonomic failure among patients with diabetes: a meta-analysis.

OBJECTIVE: A 1992 consensus statement on autonomic testing portrayed Bazett's heart rate-corrected QT interval (QT) prolongation as a specific yet insensitive indicator of diabetic autonomic failure. At that time, only a few small studies had evaluated the accuracy of QTc. To date, even fewer studies have evaluated whether its accuracy is influenced by patient characteristics. RESEARCH DESIGN AND METHODS: We critically appraised 17 studies reporting the sensitivity and specificity of QTc for diabetic autonomic failure. The studies represented 4,584 patients with diabetes (mean age 34.9 years, 46% female, 92% with type 1 diabetes, mean duration of diabetes 14.5 years). We summarized the accuracy of QTc prolongation for diabetic autonomic failure as an odds ratio (OR) (95% CI) and determined whether patient and study design characteristics influenced the accuracy of QTc prolongation by comparing summary receiver operating characteristic curves. RESULTS: Autonomic failure, defined as > or =1.2+/-0.4 (mean +/- SD) abnormal of 2.0+/-1.6 administered cardiovascular reflex tests, was found in 26% (25-28) of patients. The pooled sensitivity and specificity of QTc > 441+/-8 ms for autonomic failure were 28% (26-29) and 86% (85-87), respectively. Autonomic failure was 2.26 times (1.90-2.70) more likely to be present in patients with than in patients without QTc prolongation. At 86% specificity, the sensitivity of QTc prolongation was 46 vs. 12% for men versus women (P = 0.0077), respectively, and, after adjustment for sex, 66 vs. 17% among patients aged 25 vs. 55 years (P = 0.1902) and 61 vs. 27% at thresholds of >420 vs. >460 ms, respectively (P = 0.2964). CONCLUSIONS: QTc prolongation is a specific albeit insensitive indicator of autonomic failure. Although QTc prolongation is relatively accurate for men, accuracy may be even greater for young men at low QTc thresholds.

Adult↗

PubMed2000

Visceral adiposity and risk of type 2 diabetes: a prospective study among Japanese Americans.

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.

Adipose Tissue↗

PubMed2000

Features of the metabolic syndrome predict higher risk of diabetes and impaired glucose tolerance: a prospective study in Mauritius.

OBJECTIVE: To assess the independent and joint effects of the components of the metabolic syndrome, including leptin, which is a recently proposed addition to this syndrome, in predicting the cumulative incidence of impaired glucose tolerance (IGT) and diabetes among individuals with normal glucose tolerance. RESEARCH DESIGN AND METHODS: This prospective study involved 2,605 residents of Mauritius with normal glucose tolerance who were followed for 5 years for IGT or diabetes onset in relation to total and regional adiposity (BMI, waist-to-hip ratio [WHR]), fasting and 2-h 75-g oral glucose load glucose and insulin, total and HDL cholesterol, blood pressure, serum uric acid, triglyceride, and leptin levels. RESULTS: A multivariate logistic regression model adjusted for age, sex, ethnicity, and diabetes family history showed a significantly higher linear increase in risk of IGT and diabetes in association with the following variables only: fasting glucose (odds ratio 1.89 [95% CI 1.51-2.34]), 2-h glucose (1.68 [1.50-1.88]), WHR (1.30 [1.10-1.52]), BMI (1.04 [1.00-1.08]), and serum uric acid (1.37 [1.20-1.57]). However, a nonlinear increase was seen with serum triglyceride and plasma leptin concentrations. No risk factors resulted in joint effects that were greater than expected from combining individual effects. CONCLUSIONS: Metabolic syndrome features independently predict a higher risk of diabetes or IGT in normoglycemic subjects but in combination confer no higher-than-expected risk of these outcomes. At higher concentrations of triglycerides and leptin, risk plateaus and even declines slightly.

Adult↗

PubMed2000

Proportion of type 2 diabetes cases resulting from impaired fetal growth.

OBJECTIVE: During the past decade, several researchers have demonstrated a higher risk of type 2 diabetes in relation to lower birth weight. This theory, referred to as the "thrifty phenotype" hypothesis, postulates that impaired fetal growth predisposes individuals to the development of diabetes and other metabolic abnormalities. This article examines the importance of fetal growth in the etiology of diabetes by estimating the proportion of diabetes cases associated with this exposure. RESEARCH DESIGN AND METHODS: The importance of an exposure or its correlate as a potential cause of a disease can be assessed by estimating the proportion of cases that could be prevented if the exposure was eliminated from a defined population. This proportion is referred to as the population-attributable fraction (PAF). Published studies of the association between diabetes and birth weight were reviewed and selected for further analysis if data were presented that enabled PAF calculation. In addition, PAFs were calculated for higher birth weight cutoffs because researchers have postulated that the lowest birth weight category may not capture all cases of fetal growth retardation. Studies have shown that exposure classified in this broader manner can produce unbiased PAF estimates, even if many subjects are falsely classified as exposed. RESULTS: PAFs for the lowest birth weight category ranged from 0.01 to 0.25. In this analysis, PAFs for diabetes did not exceed 0.35. In contrast, >50% of diabetes cases in the First National Health and Nutrition Examination Survey Epidemiologic Follow-Up Study were attributable to excess adiposity as reflected by a BMI of > or =26 kg/m2 (PAF >0.50). CONCLUSIONS: Impaired fetal growth or its correlates account for a minority (<0.50) of type 2 diabetes cases.

Birth Weight↗