Determinants of incident non-insulin-dependent diabetes mellitus among blacks and whites in a national sample. The NHANES I Epidemiologic Follow-up Study

The relationship of body mass index and waist-hip ratio on the 9-year incidence of diabetes and hypertension in a predominantly African-origin population

PURPOSE

To provide 9-year incidence data for diabetes and hypertension and evaluate the relationship of body mass index (BMI) and waist-hip ratio (WHR) on these comorbidities in an African Caribbean population.

METHODS

This was a longitudinal, population-based cohort study, including 4,631 participants at baseline; 2,793 were reexamined at the 9-year follow-up. Diabetes was defined by self-reported history and/or glycosylated hemoglobin measurement; hypertension was defined as systolic blood pressure (BP) >or=140 mm Hg and/or diastolic BP >or=90 mm Hg and/or use of antihypertensive treatment. Incidence rates were based on persons without such conditions at baseline.

RESULTS

The 9-year incidence of hypertension (95% confidence interval) was higher in women (37.5% [34.0-41.2]) than men (30.6% [26.9-34.6]), whereas the incidence of diabetes was similar for both genders (14%). Body size was related to both conditions; however, the incidence of hypertension was more strongly associated with WHR, whereas diabetes had a stronger association with BMI.

CONCLUSIONS

Incidence rates for diabetes and hypertension were high in this cohort, and the relationship of BMI and WHR on these comorbidities was significant. These findings suggest the need to develop tailored interventions and preventive strategies in this African Caribbean and similar high-risk populations.

Sugar-sweetened beverages and incidence of type 2 diabetes mellitus in African American women

BACKGROUND

Type 2 diabetes mellitus is an increasingly serious health problem among African American women. Consumption of sugar-sweetened drinks was associated with an increased risk of diabetes in 2 studies but not in a third; however, to our knowledge, no data are available on African Americans regarding this issue. Our objective was to examine the association between consumption of sugar-sweetened beverages, weight gain, and incidence of type 2 diabetes mellitus in African American women.

METHODS

A prospective follow-up study of 59,000 African American women has been in progress since 1995. Participants reported on food and beverage consumption in 1995 and 2001. Biennial follow-up questionnaires ascertained new diagnoses of type 2 diabetes. The present analyses included 43,960 women who gave complete dietary and weight information and were free from diabetes at baseline. We identified 2713 incident cases of type 2 diabetes mellitus during 338,884 person-years of follow-up. The main outcome measure was the incidence of type 2 diabetes mellitus.

RESULTS

The incidence of type 2 diabetes mellitus was higher with higher intake of both sugar-sweetened soft drinks and fruit drinks. After adjustment for confounding variables including other dietary factors, the incidence rate ratio for 2 or more soft drinks per day was 1.24 (95% confidence interval, 1.06-1.45). For fruit drinks, the comparable incidence rate ratio was 1.31 (95% confidence interval, 1.13-1.52). The association of diabetes with soft drink consumption was almost entirely mediated by body mass index, whereas the association with fruit drink consumption was independent of body mass index.

CONCLUSIONS

Regular consumption of sugar-sweetened soft drinks and fruit drinks is associated with an increased risk of type 2 diabetes mellitus in African American women. While there has been increasing public awareness of the adverse health effects of soft drinks, little attention has been given to fruit drinks, which are often marketed as a healthier alternative to soft drinks.

Periodontal disease and incident type 2 diabetes: results from the First National Health and Nutrition Examination Survey and its epidemiologic follow-up study

OBJECTIVE

Type 2 diabetes and periodontal disease are known to be associated, but the temporality of this relationship has not been firmly established. We investigated whether baseline periodontal disease independently predicts incident diabetes over two decades of follow-up.

RESEARCH DESIGN AND METHODS

A total of 9,296 nondiabetic male and female National Health and Nutrition Examination Survey (NHANES I) participants aged 25-74 years who completed a baseline dental examination (1971-1976) and had at least one follow-up evaluation (1982-1992) were studied. We defined six categories of baseline periodontal disease using the periodontal index. Of 7,168 dentate participants, 47% had periodontal index = 0 (periodontally healthy); the remaining were classified into periodontal index quintiles. Incident diabetes was defined by 1) death certificate (ICD-9 code 250), 2) self-report of diabetes requiring pharmacological treatment, or 3) health care facility stay with diabetes discharge code. Multivariable logistic regression models assessed incident diabetes odds across increasing levels of periodontal index in comparison with periodontally healthy participants.

RESULTS

The adjusted odds ratios (ORs) for incident diabetes in periodontal index categories 1 and 2 were not elevated, whereas the ORs in periodontal index categories 3 through 5 were 2.26 (95% CI 1.56-3.27), 1.71 (1.0-2.69), and 1.50 (0.99-2.27), respectively. The OR in edentulous participants was 1.30 (1.00-1.70). Dentate participants with advanced tooth loss had an OR of 1.70 (P < 0.05) relative to those with minimal tooth loss.

CONCLUSIONS

Baseline periodontal disease is an independent predictor of incident diabetes in the nationally representative sample of NHANES I.

Childhood socioeconomic position, gender, adult body mass index, and incidence of type 2 diabetes mellitus over 34 years in the Alameda County Study

OBJECTIVES

We examined the association between childhood socioeconomic position and incidence of type 2 diabetes and the effects of gender and adult body mass index (BMI).

METHODS

We studied 5913 participants in the Alameda County Study from 1965 to 1999 who were diabetes free at baseline (1965). Cox proportional hazards models estimated diabetes risk associated with childhood socioeconomic position and combined childhood socioeconomic position-adult BMI categories in pooled and gender-stratified samples. Demographic confounders and potential pathway components (physical inactivity, smoking, alcohol consumption, hypertension, depression, health care access) were included as covariates.

RESULTS

Low childhood socioeconomic position was associated with excess diabetes risk, especially among women. Race and body composition accounted for some of this excess risk. The association between childhood socioeconomic position and diabetes incidence differed by adult BMI category in the pooled and women-only groups. Adjustment for race and behaviors attenuated the risk attributable to low childhood socioeconomic position among the obese group only.

CONCLUSIONS

Childhood socioeconomic position was a robust predictor of incident diabetes, especially among women. A cumulative risk effect was observed for both childhood socioeconomic position and adult BMI, especially among women.

Reduced diabetic, hypertensive, and cholesterol medication use with walking

PURPOSE

To assess the relationships of walking distance, frequency, and intensity to the prevalence of antidiabetic, antihypertensive, and LDL cholesterol-lowering medications use.

METHODS

Cross-sectional analyses of 32,683 female and 8112 male participants of the National Walkers' Health Study, of whom 2.8% and 7.4% reported antidiabetic, 14.3% and 29.0% reported antihypertensive, and 7.3% and 21.5% reported LDL cholesterol-lowering medication use, respectively.

RESULTS

Weekly walking distance, longest walk, and walking intensity were inversely related to the prevalence of antidiabetic (males: P < 0.001, females: P < 0.0001), antihypertensive (males: P < 0.01, females: P < 0.0001), and LDL cholesterol-lowering medications (males: P < 0.01, females: P < 0.0001). Each medication remained significantly related to both walking intensity and longest weekly walk when adjusted for total weekly distance. Compared with men and women who walked at a speed of < 1.2 m.s, those who walked > 2.1 m.s had 48% and 52% lower odds for antihypertensive, 68% and 59% lower odds for antidiabetic, and 53% and 40% lower odds for LDL cholesterol-lowering medications, respectively, when adjusted for age, smoking, and diet. The longest usual weekly walk was a better discriminator of medication status than the total cumulative distance per week, particularly in men.

CONCLUSION

These results are consistent with the hypothesis that antidiabetic, antihypertensive, and LDL cholesterol-lowering medication use may be reduced substantially by walking more intensely and farther each week, and by including longer walks.

Diabetes and lipid screening among patients in primary care: a cohort study

BACKGROUND

Obesity is associated with increased cardiovascular diseases and diabetes mellitus. Guidelines call for intensified glucose and lipid screening among overweight and obese patients. Data on compliance with these guidelines are scarce. The purpose of this study was to assess rates of diabetes and lipid screening in primary care according to demographic variables and weight status.

METHODS

Over a 3-year follow-up period, we assessed screening rates for blood glucose, triglycerides, and HDL- and LDL-cholesterol among 5025 patients in primary care. From proportional hazards models we estimated screening rates among low, moderate, high, and very-high risk patients and compared them with recommendations of the American Diabetes Association (ADA), National Cholesterol Education Program (ATP III) and U.S. Preventive Services Task Force (USPSTF).

RESULTS

Mean (SD) age was 47.4 (15.6); 69% were female, 21% were non-white, and 30% of males and 25% of females were obese (BMI > or = 30 kg/m2). For both diabetes and lipid screening, the adjusted hazard was 260-330% higher among > or = 65 than < 35 year-olds, 50-90% higher in persons with BMI > or = 35 than < 25 kg/m2, 10-30% lower for females than males, and not lower among racial/ethnic minorities. Screening rates were at least 80% among very-high risk persons, which we defined as 55-64 years old, BMI > or = 35 kg/m2, non-white, with baseline hypertension. In contrast, high-risk persons who were younger (35-44 years old) and less obese (BMI 30-<35 kg/m2) were screened less often (43% for LDL-cholesterol among females to 83% for diabetes among males) even though ADA, ATP III and USPSTF recommend diabetes and lipid screening among them.

CONCLUSION

Patients with higher BMI or age were more likely to be screened for cardiometabolic risk factors. Women were screened at lower rates than men. Even in a highly structured medical group practice, some obese patients were under-screened for diabetes and dyslipidemia.

Comparing diabetes prevalence between African Americans and Whites of similar socioeconomic status

OBJECTIVES

We investigated whether racial disparities in the prevalence of type 2 diabetes exist beyond what may be attributable to differences in socioeconomic status (SES) and other modifiable risk factors.

METHODS

We analyzed data from 34331 African American and 9491 White adults aged 40 to 79 years recruited into the ongoing Southern Community Cohort Study. Participants were enrolled at community health centers and had similar socioeconomic circumstances and risk factor profiles. We used logistic regression to estimate the association between race and prevalence of self-reported diabetes after taking into account age, SES, health insurance coverage, body mass index, physical activity, and hypertension.

RESULTS

Multivariate analyses accounting for several diabetes risk factors did not provide strong support for higher diabetes prevalence rates among African Americans than among Whites (men: odds ratio [OR]=1.07; 95% confidence interval [CI]=0.95, 1.20); women: OR=1.13, 95% CI=1.04, 1.22).

CONCLUSIONS

Our findings suggest that major differences in diabetes prevalence between African Americans and Whites may simply reflect differences in established risk factors for the disease, such as SES, that typically vary according to race.

Association of gender and education with blood lipids and fasting glucose levels in a sample of Iranian obese adults

This study aimed to assess the relationship between gender and educational level with obesity related conditions in a sample of adult obese subjects in Rasht, northern Iran. A total of 1113 of men and 1279 women took part in this study. Data on age, original body weight, and educational level were collected. Blood lipids, fasting serum sugar (FBS), waist circumference, body weight and height were measured. The findings showed that the men had significantly higher serum triglyceride levels (270.0+/-202.2 vs. 203.4+/-180.1 P=0.0001) and FBS (126.5+/-103.8 vs. 118.2+/-53.8 P=0.03) and they had lower serum HDL-cholesterol levels than the women when differences in severity of obesity, age, original weight, waist circumference, and educational levels were taken into account. These findings showed that blood lipid levels and FBS were not different between educational groups in men. In women, serum HDL-cholesterol was lower, and serum triglyceride and FBS levels were higher in lower educational groups than higher educational ones.

Overall and central obesity and risk of type 2 diabetes in U.S. black women

OBJECTIVE

Obesity has risen to epidemic proportions in the United States, leading to an emerging epidemic of type 2 diabetes. African-American women are disproportionately affected by both conditions. While an association of overall obesity with increasing risk of diabetes has been documented in black women, the effect of fat distribution, specifically abdominal obesity, has not been studied. We examined the association of BMI, abdominal obesity, and weight gain with risk of type 2 diabetes.

RESEARCH METHODS AND PROCEDURES

During eight years of follow-up of 49,766 women from the Black Women's Health Study, 2472 incident cases of diabetes occurred. Cox proportional hazard models were used to estimate incidence rate ratios (IRRs), with control for age, physical activity, family history of diabetes, cigarette smoking, years of education, and time period of data collection.

RESULTS

Sixty-one percent of participants had a BMI>or=25 kg/m2 (WHO definition of overweight). Compared with a BMI of <23 kg/m2, the IRR for a BMI of >45 kg/m2 was 23 (95% confidence interval, 17.0 to 31.0). The IRR for the highest quintile of waist-to-hip ratio relative to the lowest was 2.3 (95% confidence interval, 2.0 to 2.7) after control for BMI. Furthermore, at every level of BMI, an increased risk was observed for high waist-to-hip ratio relative to low.

DISCUSSION

Central obesity, as well as overall obesity, is a strong risk factor for diabetes in African-American women. Efforts to reduce the prevalence of obesity in African-American women are of paramount importance.

Family history of diabetes, awareness of risk factors, and health behaviors among African Americans

OBJECTIVES

We examined the role of family history of diabetes in awareness of diabetes risk factors and engaging in health behaviors.

METHODS

We conducted a cross-sectional analysis of 1122 African American adults without diabetes who were participants in Project DIRECT (Diabetes Interventions Reaching and Educating Communities Together).

RESULTS

After adjustment for age, gender, income, education, body mass index, and perceived health status, African Americans with a family history of diabetes were more aware than those without such a history of several diabetes risk factors: having a family member with the disease (relative risk [RR]=1.09; 95% confidence interval [CI]=1.03, 1.15), being overweight (RR=1.12; 95% CI=1.05, 1.18), not exercising (RR=1.17; 95% CI=1.07, 1.27), and consuming energy-dense foods (RR=1.10; 95% CI=1.00, 1.17). Also, they were more likely to consume 5 or more servings of fruits and vegetables per day (RR=1.31; 95% CI=1.02, 1.66) and to have been screened for diabetes (RR=1.21; 95% CI=1.12, 1.29).

CONCLUSIONS

African Americans with a family history of diabetes were more aware of diabetes risk factors and more likely to engage in certain health behaviors than were African Americans without a family history of the disease.

Achieving healthy weight in African-American communities: research perspectives and priorities

The longstanding high burden of obesity in African-American women and the more recent, steeper than average rise in obesity prevalence among African-American children constitute a mandate for an increased focus on obesity prevention and treatment research in African-American communities. The African-American Collaborative Obesity Research Network (AACORN) was formed to stimulate and support greater participation in framing and implementing the obesity research agenda by investigators who have both social and cultural grounding in African-American life experiences and obesity-related scientific expertise. AACORN's examination of obesity research agenda issues began in 2003 in conjunction with the Think Tank on Enhancing Obesity Research at the National Heart, Lung, and Blood Institute (NHLBI). The assessment was subsequently expanded to take into account the overall NIH strategic plan for obesity research, literature reviews, and descriptions of ongoing studies. In identifying priorities, AACORN members considered the quality, quantity, focus, and contextual relevance of published research relevant to obesity prevention and treatment in African-American adults or children. Fifteen recommended research priorities are presented in five categories adapted from the NHLBI Think Tank proceedings: health effects, social and environmental context, prevention and treatment, research methods, and research training and funding. These recommendations from an African-American perspective build on and reinforce certain aspects of the NHLBI and overall NIH research agendas by providing more specific rationale and directions on areas for enhancement in the type of research being done or in the conceptualization and implementation of that research.

A worksite diabetes prevention program: two-year impact on employee health

The purpose of this study was to determine the 2-year impact of a worksite-based diabetes prevention program. Thirty-seven pre-diabetic and previously undiagnosed diabetic employees participating in a 12-month worksite diabetes prevention program were included. Weight, body mass index, waist circumference, oral glucose tolerance testing, fasting insulin, blood lipids, and aerobic fitness had improved significantly after 6 months. Much of this improvement continued through 12 months. One year following the intervention, oral glucose tolerance and aerobic fitness had improved significantly. Of the 22 employees remaining in the study through 24 months, more than half had normal results on glucose tolerance testing. Worksite diabetes prevention programs may reduce blood glucose below pre-diabetic and diabetic levels. Improvements in diabetes risk factors persisted for at least 2 years in most of these employees.

Measuring the full economic costs of diet, physical activity and obesity-related chronic diseases

Most studies that have focused on the costs of obesity have ignored the direct effects of obesity-related patterns of diet and physical activity. This study reviews the full effects of each component--poor dietary and physical activity patterns and obesity--on morbidity, mortality and productivity. The direct healthcare costs are based on a review of the effects of these factors on key diseases and the related medical care costs of each disease. The indirect costs on reduced disability, mortality and sickness during the period of active labour force participation prior to retirement are also examined. A case study is prepared for China to provide some guidance in the utilization of this review for economic analysis of obesity. The case study shows that the indirect costs are often far more important than the direct medical care costs. The Chinese case study found that the indirect effects of obesity and obesity-related dietary and physical activity patterns range between 3.58% and 8.73% of gross national product (GNP) in 2000 and 2025 respectively.

Ethnicity, obesity, and risk of type 2 diabetes in women: a 20-year follow-up study

OBJECTIVE

To examine ethnic differences in risk of type 2 diabetes, taking dietary and lifestyle risk factors into account.

RESEARCH DESIGN AND METHODS

A prospective (1980-2000) cohort (from The Nurses' Health Study) including 78,419 apparently healthy women (75,584 whites, 801 Asians, 613 Hispanics, and 1,421 blacks) was studied. Detailed dietary and lifestyle information for each participant was repeatedly collected every 4 years.

RESULTS

During 1,294,799 person-years of follow-up, we documented 3,844 incident cases of diabetes. Compared with whites, the age-adjusted relative risks (RRs) were 1.43 (95% CI 1.08-1.90) for Asians, 1.76 (1.32-2.34) for Hispanics, and 2.18 (1.82-2.61) for blacks. After adjustment for BMI, the RRs changed to 2.26 (1.70-2.99) for Asians, 1.86 (1.40-2.47) for Hispanics, and 1.34 (1.12-1.61) for blacks. For each 5-unit increment in BMI, the multivariate RR of diabetes was 2.36 (1.83-3.04) for Asians, 2.21 (1.75-2.79) for Hispanics, 1.96 (1.93-2.00) for whites, and 1.55 (1.36-1.77) for blacks (P for interaction <0.001). For each 5-kg weight gain between age 18 and the year 1980, the risk of diabetes was increased by 84% (95% CI 58-114) for Asians, 44% (26-63) for Hispanics, 38% (28-49) for blacks, and 37% (35-38%) for whites. A healthy diet high in cereal fiber and polyunsaturated fat and low in trans fat and glycemic load was more strongly associated with a lower risk of diabetes among minorities (RR 0.54 [95% CI 0.39-0.73]) than among whites (0.77 [0.72-0.84]).

CONCLUSIONS

The risk of diabetes is significantly higher among Asians, Hispanics, and blacks than among whites before and after taking into account differences in BMI. Weight gain is particularly detrimental for Asians. Our data suggest that the inverse association of a healthy diet with diabetes is stronger for minorities than for whites.

Combining risk estimates from observational studies with different exposure cutpoints: a meta-analysis on body mass index and diabetes type 2

Studies on a dose-response relation often report separate relative risks for several risk classes compared with a referent class. When performing a meta-analysis of such studies, one has to convert these relative risks into an overall relative risk for a continuous effect. Apart from taking the dependence between separate relative risks into account, this implies assigning an exposure level to each risk factor class and allowing for the nonlinearity of the dose-response relation. The authors describe a relatively simple method solving these problems. As an illustration, they applied this method in a meta-analysis of the association between body mass index and diabetes type 2, restricted to results of follow-up studies (n=31). Results were compared with a more ad hoc method of assigning exposure levels and with a method in which the nonlinearity of the dose-response method was not taken into account. Differences with the ad hoc method were larger in studies with fewer categories. Not incorporating the nonlinearity of the dose response leads to an overestimation of the pooled relative risk, but this bias is relatively small.

Changes in incidence of diabetes in U.S. adults, 1997-2003

BACKGROUND

The incidence of self-reported diagnosed diabetes may be increasing because of recent changes in the diagnostic criteria for diabetes, enhanced case detection, and a true increase in disease incidence. These factors may also be changing the characteristics of newly diagnosed cases. Therefore, we examined recent trends in the incidence of diagnosed diabetes, changes to the characteristics of incident cases, and factors associated with incidence.

METHODS

First, National Health Interview Survey data for 1997 to 2003 were used to examine 7-year trends in the incidence of diagnosed diabetes among U.S. adults aged 18 to 79 years. Second, among 1997-1998 and 2002-2003 incident cases, differences in sociodemographic characteristics, risk factors, and indicators of health status were examined. Lastly, multivariate-adjusted incidence from multiple logistic regression of 2001-2003 survey data were derived.

RESULTS

From 1997 to 2003, the incidence of diagnosed diabetes increased 41% from 4.9 to 6.9 per 1,000 population (p <0.01). Incidence increased among men and women, non-Hispanic whites, persons with at least a high school education, nonsmokers, active and inactive persons, and among obese persons (p <0.05). Obesity was more prevalent (p <0.01) and physical limitation was less prevalent (p =0.03) in 2002-2003 versus 1997-1998 incident cases. Multivariate-adjusted incidence increased with age and BMI category, and decreased with education level (p <0.05).

CONCLUSIONS

Obesity was a major factor in the recent increase of newly diagnosed diabetes. Lifestyle interventions that reduce or prevent the prevalence of obesity among persons at risk for diabetes are needed to halt the increasing incidence of diabetes.

Epidemiological evidence for the role of physical activity in reducing risk of type 2 diabetes and cardiovascular disease

Epidemiological studies suggest that physically active individuals have a 30-50% lower risk of developing type 2 diabetes than do sedentary persons and that physical activity confers a similar risk reduction for coronary heart disease. Risk reductions are observed with as little as 30 min of moderate-intensity activity per day. Protective mechanisms of physical activity include the regulation of body weight; the reduction of insulin resistance, hypertension, atherogenic dyslipidemia, and inflammation; and the enhancement of insulin sensitivity, glycemic control, and fibrinolytic and endothelial function. Public health initiatives promoting moderate increases in physical activity may offer the best balance between efficacy and feasibility to improve metabolic and cardiovascular health in largely sedentary populations.

Education, income, occupation, and the 34-year incidence (1965-99) of Type 2 diabetes in the Alameda County Study

BACKGROUND

Lower socioeconomic position (SEP) is related to higher prevalence of Type 2 diabetes, yet little is known about the relationship of SEP with incident diabetes.

METHODS

The association between SEP, measured by self-reported education, income, and occupation, and Type 2 diabetes incidence was examined in a community sample of 6147 diabetes-free adults from Alameda County, CA. Cox proportional hazards models estimated the effect of baseline (1965) and time-dependent (value changes over time) measures of SEP on incident diabetes over a 34-year study period (1965-99). Demographic confounders (age, gender, race, and marital status) and potential components of the causal pathway (physical inactivity, smoking, alcohol consumption, body composition, hypertension, depression, and health care access) were included as fixed or time-dependent covariates.

RESULTS

Education, income, and occupation were associated with increased diabetes risk in unadjusted models. In baseline models adjusted for demographics, respondents with <12 years of education had 50% excess risk compared with those with more education [hazard ratio (HR) = 1.5, 95% confidence interval (95% CI) 1.11-2.04], but income and occupation were no longer significantly associated with increased risk. Further adjustment minimized the significance of all associations. Time-dependent effects were consistently elevated for low education and male blue-collar occupation, but non-significant after full adjustment (HR = 1.1, 95% CI 0.79-1.47 and HR = 1.3, 95% CI 0.91-1.89, respectively).

CONCLUSIONS

Socioeconomic disadvantage, especially with low educational attainment, is a significant predictor of incident Type 2 diabetes, although associations were largely eliminated after covariate adjustment. Obesity and overweight appear to mediate these associations.

Socioeconomic status and diagnosed diabetes incidence

AIMS

To investigate the association between socioeconomic status (SES) and incidence of diabetes.

METHODS

We investigated three measures of SES and incidence of diagnosed diabetes among women and men in the NHANES I Epidemiologic Followup Study, 1971-1992, who were free of diagnosed diabetes in 1980.

RESULTS

Among women, diabetes incidence was inversely associated with income (measured as percent of the poverty level), education, and occupational status, adjusting for age and race/ethnicity. The hazard ratio (HR) for women with > 16 years education was 0.26 (95% confidence interval (CI) 0.13-0.54) relative to those with < 9 years of education. Adjustment for potential mediators, including body size variables, diet, physical activity, and alcohol and tobacco use, substantially attenuated the associations with income and education. Among men a trend toward lower diabetes incidence with higher income and higher education was evident (the HR for men with household income > 5 times the poverty level was 0.44 (95% CI 0.19-0.98) relative to those under the poverty line), but there was no inverse association of diabetes incidence with occupational status.

CONCLUSIONS

SES, assessed with any of three common measures, is a risk factor for diagnosed diabetes in women. Among men these associations are less consistent.

Do centrally obese Chinese with normal BMI have increased risk of metabolic disorders?

BACKGROUND

Body mass index (BMI) and waist circumference are highly correlated. One or the other predicts the metabolic syndromes better, depending on characteristic of the population studied, such as age, gender, and ethnicity. We examined the impact of isolated central obesity, isolated BMI elevation, and the combined type of obesity on metabolic disorders, in order to shed lights on the strategy of obesity screening.

METHODS

The study subjects were Chinese aged 20 or above residing in Taiwan. Their data were derived from two large-scale studies: the Nutrition and Health Survey in Taiwan (NAHSIT 1993-1996) and the Cardiovascular Disease Risk Factor Two-township Study (CVDFACTS, 1994-1997). In evaluating the relations between obesity and health risks, the cut-points of BMI (> or =24 kg/m(2) for overweight) and waist circumference (> or =80 cm for women and > or =90 cm for men) recommended by Department of Health in Taiwan for Taiwanese people were used to define various types of obesity.

RESULTS

We found that there was a small but nontrivial proportion (1.7% for men and 4.0% for women) of Taiwanese people for whom BMI was in the normal range but their waist circumferences were above normal. These people were at a higher risk of developing metabolic syndromes than those with isolated BMI elevation. Their risks were close to that of the combined type.

CONCLUSIONS

In order to screen out high-risk obese individuals, isolated centrally obese subjects should not be overlooked. Therefore, we recommend to assess waist circumference in parallel to, not just sequential to the measurement of BMI in Chinese.

Is central obesity associated with cirrhosis-related death or hospitalization? A population-based, cohort study

BACKGROUND & AIMS

We aimed to determine the interaction between body fat distribution (central versus peripheral) and increased body mass index (BMI) with regards to the risk of cirrhosis-related death or hospitalization.

METHODS

Participants included 11,434 persons aged 25-74 years without evidence of cirrhosis at entry into the study or during the first 5 years of follow-up who were subsequently followed for a mean of 12.9 years as part of the first National Health and Nutrition Examination Survey. Participants were categorized into "normal-weight" (BMI < 25 kg/m 2 , N = 5750), "overweight" (BMI 25 to < 30 kg/m 2 , N = 3770), and "obese" (BMI > or = 30 kg/m 2 , N = 1914). The subscapular to triceps skinfold thickness ratio (SFR) was used to categorize body fat distribution into central (SFR > 1, N = 5211) and peripheral (SFR < or = 1, N = 6223).

RESULTS

Cirrhosis resulted in death or hospitalization of 88 participants during 149,888 person-years of follow-up (59/100,000 person-years). Among persons with a central body fat distribution, cirrhosis-related deaths or hospitalizations were more common in obese persons (115/100,000 person-years, adjusted hazard ratio 2.2, 95% confidence interval [CI] 1.1-4.6) and in overweight persons (94/100,000 person-years, adjusted hazard ratio 1.5, 95% CI 0.8-3.0) compared to normal-weight persons (59/100,000 person-years). However, among persons with a peripheral fat distribution, there was no association between obesity (adjusted hazard ratio 0.7, 95% CI 0.3-1.6) or overweight (adjusted hazard ratio 0.8, 95% CI 0.2-2.8) and cirrhosis-related death or hospitalization.

CONCLUSIONS

The risk of cirrhosis-related death or hospitalization appears to be increased in the presence of cirrhosis, but only among persons with a central fat distribution. The excess risk associated with central obesity might be related to insulin resistance and hepatic steatosis.

Statins and newly diagnosed diabetes

AIMS

In order to evaluate a hypothesized protective effect of the use of HMG Co-A reductase inhibitors (statins) on the development of Type 2 diabetes, we conducted a nested case-control study based on data from the UK-based General Practice Research Database (GPRD).

METHODS

We identified a population of adults 30-79 years of age between 1 January 1991 and 31 March 2002, who were being treated with a statin or who were diagnosed with hyperlipidaemia but were not being treated with a lipid-lowering drug. From this population we identified all incident cases of Type 2 diabetes. We conducted a nested case-control study encompassing 588 cases and 2063 matched controls.

FINDINGS

We observed an adjusted odds ratio (OR) of 1.1 [95% confidence interval (CI) 0.8, 1.4] for current statin users compared with non-exposed subjects and adjusted ORs for pravastatin use alone and simvastatin use alone compared with non-exposed of 0.7 (95% CI 0.4, 1.2) and 1.0 (95% CI 0.7, 1.3), respectively. There was little evidence for a duration effect for simvastatin in these data, though there is a slight suggestion of a long-term protective effect with pravastatin.

CONCLUSION

The current study results are most consistent with the conclusion that there is little if any protective effect of statins on the development of Type 2 diabetes.

A randomized controlled trial of the effects of nurse case manager and community health worker team interventions in urban African-Americans with type 2 diabetes

The objective of the study was to determine the effectiveness and cost-effectiveness of primary care and community-oriented interventions in managing HbA1c, blood pressure, and lipids, and reducing hospitalizations and emergency room visits over 2 years. We describe an ongoing, randomized controlled trial of 542 urban African-Americans with type 2 diabetes ages 25 years and older who are members of a university-affiliated managed-care organization in Baltimore, MD. The participants are 74% female, have a mean age of 58 years, and 35% have yearly incomes greater than 7500 US dollars. Participants were randomized to one of two intervention groups for a period of 2 years: (1) usual medical care plus minimal telephone intervention implemented by a trained lay health educator (control group) or (2) usual medical care plus intensive intervention implemented by a nurse case manager (NCM)/community health worker (CHW) team. The intensive NCM/CHW team executes individual plans of care using evidence-based algorithms that focus on traditional diabetes self-management, screening and management of diabetes-related complications, and social issues surrounding diabetes care. Face-to-face NCM visits are conducted in the clinic once per year and CHW visits are conducted in the participant's home one to three times per year, both with additional follow-up contacts as needed. Written and verbal feedback (when necessary) is provided to the participant's primary care physician. All participants are expected to attend a 24-month follow-up visit where data are collected by interviewers blinded to intervention assignment. As of May 1, 2003, recruitment is complete, interventions are being fully implemented, and 24-month follow-up visits are beginning. Baseline sociodemographic characteristics, health-care utilization, health behaviors, and clinical characteristics of the study population are reported. This study is designed to test the hypothesis that a primary-care-based NCM plus CHW team approach is an effective, practical, and economically feasible strategy for translating current knowledge about type 2 diabetes into high-quality health care for urban African-Americans.

High incidence of type 2 diabetes and increasing conversion rates from impaired fasting glucose and impaired glucose tolerance to diabetes in Mauritius

OBJECTIVE

To describe the incidence of different stages of glucose intolerance in a population from Mauritius followed over 11 years. RESEARCH DESIGN, METHODS AND SUBJECTS: Population-based surveys were undertaken in the multi-ethnic nation of Mauritius in 1987, 1992 and 1998 with 5083, 6616 and 6291 participants, respectively. Questionnaires, anthropometric measurements, and a 2-h 75-g oral glucose tolerance test were included. Three cohorts aged between 25 and 79 years with classifiable glucose tolerance data were identified; 3680 between 1987 and 1992, 4178 between 1992 and 1998, and 2631 between 1987 and 1998. Glucose tolerance was classified according to WHO 1999 criteria.

RESULTS

The incidence rate of type 2 diabetes was higher between 1992 and 1998 than between 1987 and 1992. In men, the incidence was similar between cohorts (24.5 and 25.4 per 1000 person-years) whereas the incidence increased in women (23.3 and 16.4 per 1000 person-years). The incidence of diabetes peaked in the 45-54 year age group and then plateaued or fell. The incidences of impaired glucose tolerance (IGT) and impaired fasting glucose (IFG) decreased in both men and women. Of normoglycaemic subjects at baseline, more women than men developed IGT and more men than women developed IFG. Of those labelled as IFG in 1987, 38% developed diabetes after 11 years. The corresponding figure for IGT was 46%.

CONCLUSIONS

In this study, we report changes in incidence rates of glucose intolerance over a 11-year period. In particular, differences between men and women were observed. The increased incidence of IGT in women compared with men, and increased incidence of IFG in men compared with women was consistent with, and explains the sex biases seen in the prevalences of these states.

Population-based incidence rates and risk factors for type 2 diabetes in white individuals: the Bruneck study

Incidence rates and risk factors for type 2 diabetes in low-risk populations are not well documented. We investigated these in white individuals who were aged 40-79 years and from the population of Bruneck, Italy. Of an age- and sex-stratified random sample of 1,000 individuals who were identified in 1990, 919 underwent an oral glucose tolerance test (OGTT) and an assessment of physiological risk factors for diabetes, including insulin resistance (homeostasis model assessment, HOMA-IR), and postchallenge insulin response (Sluiter's Index). Diabetes at baseline by fasting or 2-h OGTT plasma glucose (World Health Organization criteria, n = 82) was excluded, leaving 837 individuals who were followed for 10 years. Incident cases of diabetes were ascertained by confirmed diabetes treatment or a fasting glucose >or=7.0 mmol/l. At follow-up, 64 individuals had developed diabetes, corresponding to a population-standardized incidence rate of 7.6 per 1,000 person-years. Sex- and age-adjusted incidence rates were elevated 11-fold in individuals with impaired fasting glucose at baseline, 4-fold in those with impaired glucose tolerance, 3-fold in overweight individuals, 10-fold in obese individuals, and approximately 2-fold in individuals with dyslipidemia or hypertension. Incidence rates increased with increasing HOMA-IR and decreasing Sluiter's Index. As compared with normal insulin sensitivity and normal insulin response, individuals with low insulin sensitivity and low insulin response had a sevenfold higher risk of diabetes. Baseline impaired fasting glucose, BMI, HOMA-IR, and Sluiter's Index were the only independent predictors of incident diabetes in multivariate analyses. We conclude that approximately 1% of European white individuals aged 40-79 years develop type 2 diabetes annually and that "subdiabetic" hyperglycemia, obesity, insulin resistance, and impaired insulin response to glucose are independent predictors of diabetes.

An assessment of racial differences in clinical practices for hypertension at primary care sites for medically underserved patients

Ethnic disparities in hypertension-related outcomes may relate to differences in medical care. This study assessed primary care sites serving low-income patients to determine if differences in process and treatment indicators might contribute to disparities in outcomes. Eight sites were enrolled with 100,000 patients, collectively. Trained nurses abstracted a random sample of medical records for diagnoses, laboratory data, medications, and demographic variables. Data were obtained on 1250 white and 2786 African-American adults. African Americans were more likely (p<0.01) to be hypertensive (44% vs. 23%) and diabetic (16% vs. 8%) than whites. African Americans were more likely to have serum creatinine, potassium, lipid, and glycosylated hemoglobin values recorded in the medical record than whites (p<0.01). African-American hypertensives were more likely (p<0.05) than white hypertensives to receive calcium channel blockers, angiotensin-converting enzyme inhibitors, diuretics, and combination therapy. Thus, there appeared to be little difference in the level of care between the two groups. Based on the sites examined, ethnic variations in important process and treatment indicators do not explain racial differences in cardiovascular and renal outcomes.

The Economic Costs Associated With Physical Inactivity and Obesity in Canada: An Update

The purpose of this analytical review was to estimate the direct and indirect economic costs of physical inactivity and obesity in Canada in 2001. The relative risks of diseases associated with physical inactivity and obesity were determined from a meta-analysis of existing prospective studies and applied to the health care costs of these diseases in Canada. Estimates were derived for both the direct health care expenditures and the indirect costs, which included the value of economic output lost because of illness, injury-related work disability, or premature death. The economic burden of physical inactivity was $5.3 billion ($1.6 billion in direct costs and $3.7 billion in indirect costs) while the cost associated with obesity was $4.3 billion ($1.6 billion of direct costs and $2.7 billion of indirect costs). The total economic costs of physical inactivity and obesity represented 2.6% and 2.2%, respectively, of the total health care costs in Canada. The results underscore the importance of public health efforts aimed at combating the current epidemics of physical inactivity and obesity in Canada. Key words: overweight, lifestyle, meta analysis, population attributable risk, cost-of-illness

Snoring, hypertension and Type 2 diabetes in obesity. Protection by physical activity

Sleep-related breathing disorders are recognized as major health problems in obesity. They are involved in both hypertension and Type 2 diabetes, through mechanisms possibly related to increased sympathetic tone. We studied the association of habitual snoring with diabetes, hypertension, weight cycling and physical activity in a large Italian database of treatment-seeking obese subjects. Clinical and behavioral data were assessed by standardized questionnaires. Consecutive data of 1890 obese patients were analyzed [average body mass index (BMI), 38.2 kg/m2, median age: 46 yr, 78% females], from 25 obesity Italian centers, with low prevalence of clinical manifestations of cardiovascular disease. Habitual snoring was reported in 56% of the cases, and was associated with day-time sleepiness. The prevalence increased with obesity class and waist circumference, and was positively associated with weight cycling and weight gain since the age of 20, and smoking. Regular physical activity had a protective effect. Snoring was associated with diabetes and hypertension at univariate analysis, but in multivariate analysis an independent effect was only observed for hypertension. After adjustment for age, gender and BMI, physical activity maintained an independent, protective effect on both snoring (odds ratio 0.65, 95% confidence interval 0.49-0.84; p=0.001), diabetes (0.50, 0.30-0.86; p=0.011) and hypertension (0.71, 0.53-0.95; p=0.023). We conclude that in treatment-seeking, obese subjects with low prevalence of cardiovascular disease, snoring independently increases the risk of hypertension, whereas physical activity exerts a protection on both snoring and complications. These data underline the importance of lifestyle interventions to limit the burden of obesity and associated diseases.

Ethnic differences in adiponectin levels

Adiponectin levels were measured in African American and Caucasian women of varying body mass index (BMI). Plasma adiponectin levels were compared and the relationship between adiponectin and insulin sensitivity was assessed. Adiponectin levels were similar in the Caucasian obese (7.0 +/- 0.8 microg/mL), African American obese (7.3 +/- 3.5 microg/mL), and African American non-obese women (7.1 +/- 1.2 microg/mL), but were significantly higher in Caucasian non-obese women (12.2 +/- 1.4 microg/mL). Correlational analyses demonstrated that BMI, insulin, and homeostasis model assessment (HOMA) correlated significantly with adiponectin levels in only the Caucasian women. These results provide support for the notion that what applies to other ethnic populations might not apply to the African American population, and that the association between adiponectin and insulin sensitivity needs to be clarified in the African American population.

Racial comparisons of health care and glycemic control for African American and white diabetic adults in an urban managed care organization

The excess risk of diabetic complications in African Americans may be due to poor glycemic control arising from suboptimal use and/or quality of diabetes-related health care. However, little is known about racial differences in these factors, particularly in urban populations. We conducted a cross-sectional study using medical claims and encounter data on 1,106 adults with diabetes aged > or =30 years who were members of an urban managed care organization in capitated health plans. We examined health care and routine hemoglobin A(1c) (HbA(1c)) testing in a biracial cohort for 12 months. We then followed individuals for an additional 12 months, using a retrospective cohort design, to determine how this health care predicted subsequent emergency room visits. On average, compared with their white counterparts, African Americans had fewer primary care visits (85% vs. 91% with four or more visits) and fewer HbA(1c) tests (56% vs. 68% with two or more HbA(1c) tests) (all P < 0.05). Likewise, in the subset who underwent one or more HbA(1c) measurement (n = 855), African Americans displayed poorer glycemic control (HbA(1c) 9.1 +/- 2.9%) than whites (8.5 +/- 2.2%; P = 0.001). In multivariate analyses, racial differences in visit frequency and HbA(1c) testing were attenuated by adjustment for age, sex, and type of capitated plan and did not remain statistically significant. The relationship of health care to subsequent emergency room visits differed by race; in African Americans, fewer primary care visits and HbA(1c) tests predicted greater risk of emergency room visits. Even in a capitated, managed care setting, urban African Americans with diabetes are less likely than their white counterparts to undergo routine primary care visits and laboratory testing and are more likely to have suboptimal glycemic control. Differences in age, sex, and insurance type seemed to explain some of the disparities. Future research should determine the individual contributions of physician, patient, and system factors to the racial disparities in health care.

Cardiorespiratory fitness and the incidence of type 2 diabetes: prospective study of Japanese men

OBJECTIVE

To investigate the association between cardiorespiratory fitness and the incidence of type 2 diabetes among Japanese men.

RESEARCH DESIGN AND METHODS

This prospective cohort study was conducted in 4747 nondiabetic Japanese men, aged 20-40 years at baseline, enrolled in 1985 with follow-up to June 1999. Cardiorespiratory fitness was measured using a cycle ergometer test, and Vo(2max) was estimated. During a 14-year follow-up, 280 men developed type 2 diabetes.

RESULTS

The age-adjusted relative risks of developing type 2 diabetes across quartiles of cardiorespiratory fitness (lowest to highest) were 1.0 (referent), 0.56 (95% CI 0.42-0.75), 0.35 (0.25-0.50), and 0.25 (0.17-0.37) (for trend, P < 0.001). After further adjustment for BMI, systolic blood pressure, family history of diabetes, smoking status, and alcohol intake, the association between type 2 diabetes risk and cardiorespiratory fitness was attenuated but remained significant (1.0, 0.78, 0.63, and 0.56, respectively; for trend, P = 0.001).

CONCLUSIONS

These results indicate that a low cardiorespiratory fitness level is an important risk factor for incidence of type 2 diabetes among Japanese men.

Diabetes and Vascular Disease

The incidence of diabetes is on the rise; most of this increase is accounted for by type 2 diabetes and is secondary to the growing prevalence of obesity. Most of the late complications of both type 1 and type 2 diabetes are secondary to microvascular and macrovascular complications. Microvascular complications include retinopathy, neuropathy, and nephropathy. Nephropathy is strongly linked to the complications of macrovascular disease, which include cardiovascular, cerebrovascular, and peripheral vascular disease. Hence, once microalbuminuria (an early marker of nephropathy) is present, the patient is at a greater risk of cardiovascular disease and other microvascular complications, including retinopathy. A number of cellular mechanisms are altered secondary to hyperglycemia, and recently, a common pathway linking these mechanisms has been proposed, ultimately leading to oxidative damage and thus end-organ or tissue damage. Due to the increased risk of vascular complications, many diabetic patients undergo surgical procedures, including revascularization and bypass. Recent studies have highlighted the importance of strict glycemic control during the perioperative and postoperative period, even in the nondiabetic patient. The results of these studies have shown a decrease in morbidity, mortality, and hospital stay with strict glycemic control. Glycemic control has been directly linked to decreased microvascular complications. Macrovascular disease, however, has not been clearly linked to glucose levels alone, and although it certainly plays a role, other components of the metabolic syndrome, including blood pressure and lipid status, are equally important.

Insulin resistance and the sympathetic nervous system

The obesity epidemic is driving metabolic (insulin resistance) syndrome-related health problems including an approximately threefold increased coronary heart disease risk. Sympathetic hyperfunction may participate in the pathogenesis and complications of the metabolic syndrome including higher blood pressure, a more active renin-angiotensin system, insulin resistance, faster heart rates, and excess cardiovascular disease including sudden death. Possible factors augmenting sympathetic activation in the metabolic syndrome include alterations of insulin, leptin, nonesterified fatty acids (NEFAs), cytokines, tri-iodothyronine, eicosanoids, sleep apnea, nitric oxide, endorphins, and neuropeptide Y. Of note, high plasma NEFAs are a risk factor for hypertension and sudden death. In short-term human studies, NEFAs can raise blood pressure, heart rate, and a(1)-adrenoceptor vasoreactivity, while reducing baroreflex sensitivity, endothelium-dependent vasodilatation, and vascular compliance. Efforts to further identify the mechanisms and consequences of sympathetic dysfunction in the metabolic syndrome may provide insights for therapeutic advances to ameliorate the excess cardiovascular risk and adverse outcomes.

Depressive symptoms and the risk of type 2 diabetes mellitus in a US sample

OBJECTIVE

There is some evidence to suggest that individuals with depression are at an almost twofold increased risk of developing type 2 diabetes mellitus, but results are far from conclusive. Therefore, to determine if depressive symptoms increased the risk of type 2 diabetes, we conducted longitudinal analyses using data from the NHANES I Epidemiologic Follow-up Survey (NHEFS).

RESEARCH DESIGN AND METHODS

Participants included individuals who were white or African-American, did not report previous diagnosis of diabetes, and who completed the Centers for Epidemiologic Studies Depression (CES-D) questionnaire in the 1982-1984 study (n = 8870). Participants were followed up for incident-diagnosed diabetes through 1992 (mean follow-up 9.0 years).

RESULTS

There were 1444 (15.9%) participants with high depressive symptoms in the 1982-1984 study (CES-D score > or = 16). During follow-up, there were 465 incident cases of diabetes. Incidence of diabetes was 6.9/1000 person years among those with high depressive symptoms, 6.0/1000 person years among those with moderate symptoms, and 5.0/1000 person years among those with no symptoms. After adjusting for age, sex, and race, the relative hazard (RH) of diabetes among those with high depressive symptoms was 1.27 (95% CI: 0.93 to 1.73) compared to those without symptoms. Further adjustment for education and known diabetes risk factors (body mass index and physical activity) further attenuated the relationship (RH 1.11, 95% CI: 0.79 to 1.56).

CONCLUSIONS

There was no increased incidence of diabetes for those with high or moderate depressive symptoms compared to those with no depressive symptoms. These results do not support the etiologic relationship of depression predisposing individuals to diabetes.

Protease inhibitor use and the incidence of diabetes mellitus in a large cohort of HIV-infected women

OBJECTIVE

To assess the association between protease inhibitor (PI) use and the incidence of diabetes mellitus (DM) among participants in the Women's Interagency HIV Study.

DESIGN

Prospective multicenter cohort study. The diagnosis of DM was based on self-report at semiannual interviews conducted from 1994 to 1998.

SETTING

Six inner-city clinical sites in the United States (Brooklyn, NY; Bronx, NY; Washington, DC; Chicago, IL; San Francisco, CA; and Los Angeles, CA).

PARTICIPANTS

A total of 1785 nonpregnant women who had no history of prior DM. The women made up four groups: 1) PI users (n = 609, person-years [PY] at risk = 707); 2) reverse transcriptase inhibitor (RTI)-only users (n = 932, PY = 1486); 3) HIV-infected women reporting no antiretroviral therapy (ART) ever (n = 816, PY = 1480); and 4) HIV-uninfected women (n = 350, PY = 905).

MAIN OUTCOMES

Incidence of DM and median body mass index (BMI) from 1995 to 1998 were compared among the four groups.

RESULTS

Sixty-nine incident cases of DM occurred among 1785 women (1.5 cases per 100 PY; 95% CI: 1.2-1.9). The incidence of DM among PI users was 2.8 cases per 100 PY (2.8%) versus 1.2% among both RTI users and women on no ART (95% CI: 1.6-4.1 [PI]; 0.7-1.8 [RTI and no ART]; P = 0.01 for comparison of the PI group with the RTI group) and 1.4% among HIV-uninfected women (95% CI: 0.7-2.2, P = 0.06 for comparison with PI group). Weight gain was not associated with either PI or RTI use. Multivariate models identified PI use (hazard ratio [HR] = 2.90 [95% CI: 1.50-5.60]; P = 0.002), age (HR = 1.75 per 10 years [95% CI: 1.31-2.34]; P = 0.0002) and BMI as independent risk factors for DM.

CONCLUSIONS

PI use was associated with a threefold increase in the risk of reporting incident DM. Routine screening for diabetes, particularly among older and heavier patients using PI therapy, is advisable.

Neighborhood characteristics and components of the insulin resistance syndrome in young adults: the coronary artery risk development in young adults (CARDIA) study

OBJECTIVE

To examine associations of neighborhood characteristics with six components of the insulin resistance syndrome (IRS) in young adults.

RESEARCH DESIGN AND METHODS

Cross-sectional data from the Coronary Artery Risk Development in Young Adults (CARDIA) Study were used to examine associations of neighborhood characteristics with the IRS in 3,093 nondiabetic adults aged 28-40 years. Measures of BMI, fasting HDL cholesterol, triglycerides, insulin, glucose, and systolic blood pressure were combined into an IRS score. U.S. Census-derived neighborhood characteristics were summarized into a neighborhood socioeconomic score, with an increasing score signifying increasing socioeconomic advantage.

RESULTS

Among white men and women, the IRS score was inversely related to neighborhood socioeconomic score. Neighborhood characteristics remained associated with the IRS score after controlling for personal income and education (adjusted mean differences for 95th vs. 5th percentile of neighborhood score: -0.24 standard deviation units [SE = 0.12] in men and -0.56 standard deviation units [SE = 0.10] in women). Among black participants, neighborhood score was inversely associated with IRS score in persons of high income and education (mean differences 95th vs. 5th percentile -0.54 [SE 0.26] in men and -0.52 [SE 0.26] in women) but positively associated or not associated with IRS score in persons of low income and education (mean differences 0.60 [SE 0.21] in men and 0.00 [SE 0.16] in women).

CONCLUSIONS

The IRS score is associated with neighborhood characteristics as early as young adulthood. Features of residential environments may be related to the development of insulin resistance.

The evaluation of screening policies for diabetic retinopathy using simulation

AIMS

To develop a model for evaluating screening strategies and to use it to determine the cost effectiveness of varying the screening method and the screening interval.

METHODS

A discrete event simulation was designed, validated and run for a population of 500000. Most parameters were derived from peer-reviewed publications.

RESULTS

Standard methods of screening save up to 50% of the potential sight years lost. They give up to 85% of the sight years saved by an idealized gold standard programme using mydriatic seven-field photography reported by an ophthalmologist. The mobile camera, used for annual screening and 6-month follow-up after the detection of background retinopathy, had an estimated cost of pound 449200 per year with pound 2842 per sight year saved. It is less efficient to screen Type 2, rather than Type 1 diabetes mellitus patients, but they contributed to almost three-quarters of the sight years saved.

CONCLUSIONS

The model can evaluate screening intervals and methods on a national or health authority basis. Results indicate that it appears more cost effective to continue to screen outside an ophthalmology clinic, until treatment is needed. Programmes with annual screening, and more frequent screening for those with background retinopathy, are robust to realistic fluctuations in compliance and screening sensitivity.

The relation of gender, race and socioeconomic status to obesity and obesity comorbidities in a sample of US adults

OBJECTIVE

To examine the obesity-related chronic diseases in the US adult population according to gender, race and socioeconomic status.

METHODS

Data from the 1994-1996 Continuing Survey of Food Intakes by Individuals (1994-1996 CSFII) conducted by the US Department of Agriculture/Agricultural Research Service (USDA/ARS) were used in the analysis. Relevant data included self-reported weight and height, self-reported physician-diagnosed diabetes mellitus, hypertension, heart disease and high serum cholesterol. Analysis was conducted according to gender, race, income level and education level.

RESULTS

There was a graded increase in diabetes, hypertension and high serum cholesterol with increasing body weight in nearly all gender, racial and socioeconomic groups. Among the obese individuals, the prevalence of hypertension was higher in black subjects and the prevalence of diabetes, hypertension and heart disease was higher in individuals with lower education compared to their counterparts. The odds of having diabetes, hypertension, heart disease and high serum cholesterol increased with increasing body weight after adjusting for age, gender, race, income, education and smoking.

CONCLUSION

Although cross-sectional in nature, our results suggest that the disease burden associated with obesity in the population may be substantial. This burden increases with increasing severity of obesity. Our findings support the current opinion that, although the nature of obesity-related health risks is similar in all populations, the specific level of risk associated with a given level of obesity may be different depending on gender, race and socioeconomic condition.

Predicting incident diabetes in Jamaica: the role of anthropometry

OBJECTIVE

To evaluate the performance of the body mass index (BMI), waist circumference, waist-to-hip ratio (WHR), and waist-to-height ratio (WHTR) in predicting incident diabetes in Jamaica.

RESEARCH METHODS AND PROCEDURES

A cohort of 728 nondiabetic adults (290 men and 438 women), ages 25 to 74 years and residents of Spanish Town, Jamaica, were followed for a mean of 4 years. Participants had fasting and 2-hour postchallenge glucose concentrations measured at baseline and follow-up.

RESULTS

There were 51 cases of incident diabetes (17 men and 34 women). All indices were independent predictors of diabetes, and none was clearly superior. The area under the receiver operating characteristics curves (95% confidence interval) for BMI was 0.74 (0.59 to 0.88) for men and 0.62 (0.51 to 0.72) for women. For waist circumference, these values were 0.78 (0.65 to 0.91) in men and 0.61 (0.50 to 0.71) in women. Similar results were obtained for WHR and WHTR. "Optimal" cut-off points for BMI were 24.8 kg/m(2) (men) and 29.3 kg/m(2) (women). For waist circumference, these were 88 cm and 84.5 cm for men and women, respectively. Corresponding values for WHR were 0.87 and 0.80 and for WHTR were 0.51 and 0.54, respectively.

DISCUSSION

Cut-off points for waist circumference and WHR were similar to those proposed in developed countries for women but lower in men. Waist circumference could be useful in health promotion as an alternative to BMI.

Diabetes and impaired glucose tolerance in Aboriginal Australians: prevalence and risk

The prevalence and risk of having impaired glucose tolerance (IGT) and diabetes was estimated relative to body mass index (BMI) among Australian Aboriginal people. A stratified analysis was undertaken of community screening data. Measures included fasting and 2-h glucose concentrations, and BMI (five strata: <22, 22-24.9, 25-29.9, 30-34.9 and >/=35 kg/m(2)). Age was stratified into three groups: 15-34.9, 35-44.9, and >/=45 years. Participants were men and women, ages 15-94 years (n=2626). The prevalence of IGT and diabetes, respectively, adjusted for age and BMI, was 139 and 142 cases/1000 persons among men, and 157 and 152 cases/1000 persons among women. Odds ratios (95% CI) for IGT and diabetes for increasing BMI strata >/=22 kg/m(2) ranged from 1.7 (1.0 to 2.9) to 5.1 (2.4-10.5) for IGT, and from 2.0 (1.2-3.5) to 6.1 (3.3-11.1) for diabetes. For IGT and diabetes, across genders, the population attributable risk percentages (95% CI) for BMI >/=22 kg/m(2) were 34.1% (26.2-41.9%) for IGT, and 46.4% (38.5-54.5%) for diabetes. Diabetes and IGT have reached epidemic proportions among Australian Aboriginal people. An urgent need exists for programmes to reduce the prevalence of diabetes risk factors, especially BMI of 22 kg/m(2) or more, a limit lower than advocated for Euro-American populations.

Racial differences in insulin resistance and mid-thigh fat deposition in postmenopausal women

OBJECTIVE

To determine whether racial differences in insulin resistance between African American (AA) and white women exist in postmenopausal women and whether they are related to physical fitness and/or obesity.

RESEARCH METHODS AND PROCEDURES

We studied 35 obese AA (n = 9) and white (n = 26) women of comparable maximal oxygen consumption, obesity, and age. Total body fat was measured by DXA. Abdominal and mid-thigh low-density lean tissue (a marker of intramuscular fat) were determined with computed tomography. Glucose utilization (M) was measured during the last 30 minutes of a 3-hour hyperinsulinemic-euglycemic clamp. Insulin sensitivity was estimated from the relationship of M to the concentration of insulin during the last 30 minutes of the clamp.

RESULTS

The percentage of fat and total body fat mass were similar between AA and white women, whereas fat-free mass was higher in African American women. Visceral adipose tissue was not different between groups, but subcutaneous abdominal fat was 17% higher in the AA than in the white women. AA women had an 18% greater mid-thigh muscle area (p < 0.01) and a 34% greater mid-thigh low-density lean tissue area than the white women. Fasting glucose concentrations were not different, but fasting insulin concentrations were 29% higher in AA women. Glucose utilization was 60% lower in the AA women because of a lower non-oxidative glucose disposal. Insulin sensitivity was 46% lower in the AA women.

DISCUSSION

AA postmenopausal women have more mid-thigh intramuscular fat, lower glucose utilization, and are less insulin sensitive than white women despite comparable fitness and relative body fat levels.

Sensitivity and specificity of anthropometrics for the prediction of diabetes in a biracial cohort

OBJECTIVE

To evaluate the ability of body mass index, waist circumference, waist-to-hip ratio, and combinations of these variables to discriminate individuals who will develop diabetes in adulthood.

RESEARCH METHODS AND PROCEDURES

Data were from 45- to 64-year-old men and women who were members of the Atherosclerosis Risk in Communities cohort. The analysis sample consisted of 12,814 African American and white participants who were free of diabetes at baseline. Body mass index, waist circumference, waist-to-hip ratio, and diabetes incidence (defined as one glucose measure > or =126 mg/dL after fasting for at least 8 hours, one nonfasting glucose measure > or =200 mg/dL, and self-report of diabetes or report of taking medication for diabetes).

RESULTS

1515 new cases of diabetes were identified over the 9-year follow-up. Areas under receiver operating characteristic curves ranged from 0.66 to 0.73 for single measures. The curves were smooth, with no indication of a threshold. Waist tended to have the highest receiver operating characteristic statistic in all groups, but differences were small.

DISCUSSION

The three anthropometric indices tested were approximately equivalent in their ability to predict diabetes. Sensitivity and specificities differed among ethnic and gender groups.

Associação da cor da pele com diabetes mellitus tipo 2 e intolerância à glicose em mulheres obesas de Salvador, Bahia

Fora do Brasil a prevalência de diabetes mellitus (DM) tipo 2 é maior em negros do que em brancos. Mulheres do ambulatório de obesidade do Hospital Universitário Professor Edgard Santos, Salvador - BA, foram estudadas para avaliar se a cor de pele escura tem prevalência mais alta de DM tipo 2 e de intolerância à glicose (ITG), com diagnóstico baseado nos critérios da Organização Mundial da Saúde, independentemente da idade e do índice de massa corporal (IMC). A cor da pele foi classificada como clara (n= 166), intermediária (n= 186) ou escura (n= 128). Determinou-se o nível de glicose plasmática pelo método da glicose-oxidase. O teste de tolerância à glicose oral foi realizado em todas as pacientes, com exceção de 14 que já sabiam ser diabéticas. Pacientes com pele clara, intermediária e escura foram semelhantes em idade, IMC e relação cintura/quadril. A prevalência de DM, contudo, foi significantemente maior (p< 0,05) nas de pele escura (13,3%) quando comparadas com as de pele clara (7,2%). A prevalência de ITG foi também maior, embora estatisticamente não significante (p= 0,088), nas de pele escura (18,8%) do que nas de pele clara (12,7%). A relação entre o número de pacientes com e sem o diagnóstico de DM ou ITG foi 1,9 vezes maior no grupo pele escura, comparado com clara [odds ratio (OR)= 1,9; intervalo de confiança (IC) 95%= 1,1-3,2; p< 0,05]. Esta associação não foi alterada (OR= 1,7; IC 95%= 1,0-2,9) e permaneceu moderadamente significante (p= 0,069), mesmo após o ajuste para idade e IMC, através de regressão logística. Neste estudo, as mulheres obesas com pele escura tiveram maior associação com DM e ITG, independentemente da idade e IMC.

A case-control study of physical activity and non-insulin dependent diabetes mellitus (NIDDM). the San Luis Valley Diabetes Study

PURPOSE

The purpose of this study was to examine the association between physical activity and non-insulin dependent diabetes mellitus (NIDDM).

METHODS

We conducted a population-based case-control study in Hispanic and non-Hispanic white men and women, ages 20-74. A total of 167 cases with NIDDM and 1100 controls with normal glucose tolerance were included. All subjects completed an oral glucose tolerance test.

RESULTS

Persons with recently diagnosed NIDDM reported significantly lower levels of physical activity than control subjects. For total metabolic units, the odds ratio for subjects in the highest tertile compared to those in the lowest tertile was 0.60 (95% confidence interval (CI) = 0.37-0.98) after adjusting for age, sex, ethnicity, and family history of diabetes. The adjusted odds ratio for persons reporting high levels of vigorous activity (at least three times per week for 20 minutes) was also less than 1, but was not statistically significant (odds ratio (OR) = 0.73, 95% CI = 0.47-1.14). Similar adjusted odds ratios were observed for high versus low levels of self-assessed work activity (OR = 0.50, 95% CI = 0.34-0.74) and leisure time physical activity (OR = 0.62, 95% CI = 0.44-0.90). Further adjustments for body mass index attenuated the strength of the association between physical activity and NIDDM. This is consistent with the hypothesis that obesity is one consequence of physical inactivity that puts individuals at increased risk for NIDDM. The association of physical activity and NIDDM was stronger in Hispanic than in non-Hispanic white subjects, although this difference was not statistically significant.

CONCLUSIONS

High levels of physical activity are associated with lower odds of NIDDM and this relationship may be stronger in Hispanic subjects.

Modest lifestyle intervention and glucose tolerance in obese African Americans

OBJECTIVE

Previous studies have demonstrated the benefit of short-term diets on glucose tolerance in obese individuals. The purpose of this study was to evaluate the effectiveness of modest lifestyle changes in maintaining improvements in glucose tolerance induced by short-term energy restriction in obese African Americans with impaired glucose tolerance or type 2 diabetes mellitus.

RESEARCH METHODS AND PROCEDURES

An intervention group (n = 45; 47 +/- 1 year [mean +/- SE]), 105 +/- 4 kg; body mass index: 39 +/- 1 kg/m(2)) received an energy-restricted diet (943 +/- 26 kcal/d) for 1 week, followed by a lifestyle program of reduced dietary fat (-125 kcal/d) and increased physical activity (+125 kcal/d) for 1 year. Body weight and plasma concentrations of glucose, insulin, and C-peptide during an oral glucose tolerance test were measured at baseline, 1-week, and 4-month intervals. A control group (n = 24; 48 +/- 1 year; 110 +/- 5 kg; body mass index: 41 +/- 2 kg/m(2)) underwent these measurements at 4-month intervals.

RESULTS

No changes in weight or glucose tolerance were observed in the control group. The intervention group had significant (p < 0.05) improvements in body weight and glucose tolerance in response to the 1-week diet, which persisted for 4 months (p < 0.001 vs. control for change in weight). A total of 19 subjects (42%) continued the intervention program for 1 year, with sustained improvements (weight: -4.6 +/- 1.0 kg; p < 0.001 vs. control; oral glucose tolerance test glucose area: -103 +/- 44 mM. min; p < 0.05 vs. control).

DISCUSSION

A modest lifestyle program facilitates weight loss and enables improvements in glucose tolerance to be maintained in obese individuals with abnormal glucose tolerance. However, attrition was high, despite the mild nature of the program.

The association between physical activity, physical fitness, and type 2 diabetes mellitus

Recent studies have shown that cardiorespiratory fitness--an objective measurement of physical activity--is a strong predictor of type 2 diabetes. Self-reported physical activity is also associated with decreased risk of developing diabetes.

Nutritional consequences of the African diaspora

Along with their foods and dietary customs, Africans were carried into diaspora throughout the Americas as a result of the European slave trade. Their descendants represent populations at varying stages of the nutrition transition. West Africans are in the early stage, where undernutrition and nutrient deficiencies are prevalent. Many Caribbean populations represent the middle stages, with undernutrition and obesity coexisting. African-Americans and black populations in the United Kingdom suffer from the consequences of caloric excess and diets high in fat and animal products. Obesity, non-insulin-dependent diabetes mellitus, hypertension, coronary heart disease, and certain cancers all follow an east-to-west gradient of increasing prevalence. Public health efforts must focus not only on eradicating undernutrition in West Africa and the Caribbean but also on preventing obesity, hypercholesterolemia, and their consequences. Fortunately, a coherent and well-supported set of recommendations exists to promote better nutrition. Implementation of it founders primarily as a result of the influence of commercial and political interests.