Body mass index and waist circumference correlate to the same degree with insulin-mediated glucose uptake

Overall and abdominal obesity and risks of all-cause and cause-specific mortality in Korean adults: a pooled analysis of three population-based prospective cohorts

BACKGROUND

Studies found a J-shaped association between body mass index (BMI) and mortality. However, it is unclear whether the association is driven by biases, particularly confounding by fat-free mass.

METHODS

We conducted an individual-level pooled analysis of three cohorts of Korean adults (aged ≥ 40 years; n = 153 248). Mortality was followed up through December 2019. Anthropometric data were directly measured at baseline. Fat and fat-free mass were predicted using validated prediction models. Using Cox proportional hazards models, we estimated the associations of BMI and waist circumference (WC) with all-cause and cause-specific mortality. To account for biases, we excluded participants aged ≥ 70 years, deaths that occurred within 5 years of follow-up and ever smokers, and adjusted for fat-free mass index (FFMI).

RESULTS

During the follow-up of up to 18 years, 6061 deaths were identified. We observed J-shaped association of BMI (nadir at 22-26) and monotonically positive association of WC with all-cause, cardiovascular, and cancer mortality among Korean adults without a history of cancer or cardiovascular disease. In the BMI analysis, excluding ever smokers and adjusting for FFMI attenuated the excess mortality in underweight participants and transformed the J-shaped association into a monotonically positive shape, suggesting an increased mortality at BMI > 22.0. Excluding participants aged ≥ 70 years and deaths that occurred within 5 years of follow-up did not change the results. In the WC analysis, the monotonic positive associations did not change after the control. Similar results were observed among participants with a history of cancer or cardiovascular disease.

CONCLUSIONS

Our data suggest that both overall and abdominal body fat are associated with increased mortality in Korean adults.

Banting Memorial Lecture 2021-Banting, banting, banter and bravado: Convictions meet evidence in the scientific process: Diabetes UK Professional Conference, 27 April 2021

This personal account presents some glimpses into the clinical research processes which have made radical changes to our understanding of disease and treatment, and some characteristics of researchers, drawn from history and personal experiences around obesity and type 2 diabetes. Some summary messages emerge: The history of clinical diabetes research has shown how, perhaps through skilful leadership, combining very different personalities, skills and motivation can solve great challenges: Type 2 diabetes is a primary nutritional disease, secondary to the disease-process of obesity, not a primary endocrine disease. Type 2 diabetes is a manifestation of the disease-process of obesity, revealed by weight gain in people with underlying metabolic syndrome genetics/diathesis, mediated in large part at least by reversible ectopic fat accumulation impairing function of organs (liver, pancreas, brown adipose tissue). Treat overweight/obesity more seriously (defined as a disease-process with multiple organ-specific complications-not as a disease-state or BMI cut-off). Discuss the complications and risks of T2D openly: remission is as important as for cancers. Offer and support an optimal dietary weight management program as soon as possible from diagnosis, specifically aiming for remission: (a) Warn against non-evidence-based programs that look similar or claim to have similar potential: we have fully evidence-based programs; (b) Target sustained loss of >15 kg for Europeans (possibly less, e.g. >10 kg for Asians?). Increase future research support to enhance long-term weight loss maintenance. Several approaches need consideration: (a) Personalise diet compositions (recognising there is no intrinsic advantage from different carbohydrate/fat content). (b) Novel diet strategies (e.g. 5:2, time-restricted, flexible diet compositions). (c) New pharmaceutical agents as adjuncts to diet if necessary. (d) Novel food supplements to increase endogenous GLP-1 secretion.

Secular trends in the prevalence of abdominal obesity among Chinese adults with normal weight, 1993-2015

A considerable chronic disease burden existed in people with normal body mass index (BMI), it is imperative to study the prevailing trends in abdominal obesity among Chinese people with normal BMI. Hence, we aimed to analyze updated prevalence data on abdominal obesity trends among Chinese adults with a normal BMI. We used data from the China Health and Nutrition Survey (CHNS) conducted between 1993 and 2015. Abdominal obesity is defined as waist circumference (WC) ≥ 90 cm for men and ≥ 80 cm for women following the International Diabetes Federation recommendations for Asians. Over the 23-year period, the age-standardized mean WC values showed a significant increasing trend among Chinese adults with BMI < 25 kg/m², with the mean value increased from 74.0 cm to 78.5 cm (P for trend < 0.0001). During the period of 1993-2015, the age-standardized prevalence of abdominal obesity increased from 12.1 to 26.0% (P for trend < 0.0001). Significant increases were observed in both sexes, all age groups, rural and urban residents, and all educational attainment groups (all P for trends < 0.0001), with a greater relative increase noted among men, younger participants, and rural residents. Similar significant trends were noted when a more stringent BMI < 23 kg/m² cut point (Asian cut point) was applied. A low magnitude of overlap existed between abdominal obesity and general obesity, irrespective of the criteria used. The mean WC and the prevalence of abdominal obesity among Chinese adults with normal BMI increased continuously from 1993 to 2015. The upward trends were noted in both sexes, all age groups, rural and urban regions, and all educational attainment groups. Our estimates emphasize the importance of adding WC in addition to BMI as measures to monitor obesity prevalence.

Myths about Insulin Resistance: Tribute to Gerald Reaven

Gerald Reaven was often called the "father of insulin resistance." On the 1-year anniversary of his death in 2018, we challenge three myths associated with insulin resistance: metformin improves insulin resistance; measurement of waist circumference predicts insulin resistance better than body mass index; and insulin resistance causes weight gain. In this review, we highlight Reaven's relevant research that helped to dispel these myths associated with insulin resistance.

Waist Circumference and All-Cause Mortality Independent of Body Mass Index in Korean Population from the National Health Insurance Health Checkup 2009⁻2015

BACKGROUND

Waist circumference (WC) is an index of abdominal obesity and associated with co-morbidities and mortality. Higher WC is positively associated with increased mortality; therefore, we examined the relationship between WC and mortality in Korean populations with the interaction of body mass index (BMI) and WC for mortality.

METHODS

A total of 23,263,878 subjects (men = 11,813,850 and women = 11,450,028) who were older than 20 years and underwent the National Health Insurance Service health checkup were included. WC was divided into six categories by 5 cm increments and level 3 (85⁻90 cm in men and 80⁻85 cm in women) was referenced. Multivariable Cox proportional hazard models were used to obtain the hazard ratios (HRs) and 95% confidence intervals for all-cause mortality according to the six levels of WC.

RESULTS

WC in 5 cm increments showed a positively increased all-cause mortality after adjusting for all covariates including BMI. Men showed higher HRs for mortality than women as WC increased, and the HRs were higher in the lower WC levels, but lower in the higher WC levels among the subjects aged 65⁻85 years than subjects aged 40⁻65 years. Even in subjects with normal weight and overweight, increased WC (levels 4, 5, and 6) showed increased HRs for mortality (HRs = 1.156, 1.412, and 1.614 in normal BMI and 1.145, 1.401, and 1.909 in overweight, respectively).

CONCLUSION

There was a linear association between WC and all-cause mortality across all BMI categories even in the subjects with normal or overweight BMI. Physicians should check WC routinely even in the subjects with normal weight or overweight.

Cardiometabolic Risk in South Asian Inhabitants of California: Hypertriglyceridemic Waist vs Hypertriglyceridemic Body Mass Index

OBJECTIVE

Hypertriglyceridemic waist (HTG-waist), an increased waist circumference (WC) with an elevated triglyceride (TG) concentration, can identify increased cardiometabolic risk in apparently healthy individuals. Since WC and BMI are highly correlated, we examined whether an HTG-BMI would be as effective as an HTG-waist in identifying cardiometabolic risk in apparently healthy South Asians.

DESIGN SETTING AND PARTICIPANTS

In this cross-sectional study, we classified South Asian women (n=1156) and men (n=1842) without diabetes mellitus as having an HTG-waist (TG ≥150 mg/dL and a WC ≥80 cm in women or ≥ 90 cm in men) and an HTG-BMI (TG ≥150 mg/dL and a BMI ≥23 kg/m²).

OUTCOME MEASURES

We measured cardiometabolic risk factors, including blood pressure and fasting lipid profile, glucose, insulin, fibrinogen, and high-sensitivity C-reactive protein.

RESULTS

An HTG-waist was present in 670 individuals, of whom 648 (97%) had an HTG-BMI. The cardiometabolic profile was significantly more adverse in those in whom an HTG-waist was present vs absent; and the same was true when individuals with an HTG-BMI were compared with those without.

CONCLUSIONS

Essentially every individual with an HTG-waist also had an HTG-BMI. An HTG-BMI identified cardiometabolic risk as effectively as an HTG-waist in a population composed entirely of South Asians.

Central adiposity, obesity during early adulthood, and pancreatic cancer mortality in a pooled analysis of cohort studies

BACKGROUND

Body mass index (BMI), a measure of obesity typically assessed in middle age or later, is known to be positively associated with pancreatic cancer. However, little evidence exists regarding the influence of central adiposity, a high BMI during early adulthood, and weight gain after early adulthood on pancreatic cancer risk.

DESIGN

We conducted a pooled analysis of individual-level data from 20 prospective cohort studies in the National Cancer Institute BMI and Mortality Cohort Consortium to examine the association of pancreatic cancer mortality with measures of central adiposity (e.g. waist circumference; n = 647 478; 1947 pancreatic cancer deaths), BMI during early adulthood (ages 18-21 years) and BMI change between early adulthood and cohort enrollment, mostly in middle age or later (n = 1 096 492; 3223 pancreatic cancer deaths). Multivariable hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated using Cox proportional hazards regression models.

RESULTS

Higher waist-to-hip ratio (HR = 1.09, 95% CI 1.02-1.17 per 0.1 increment) and waist circumference (HR = 1.07, 95% CI 1.00-1.14 per 10 cm) were associated with increased risk of pancreatic cancer mortality, even when adjusted for BMI at baseline. BMI during early adulthood was associated with increased pancreatic cancer mortality (HR = 1.18, 95% CI 1.11-1.25 per 5 kg/m(2)), with increased risk observed in both overweight and obese individuals (compared with BMI of 21.0 to <23 kg/m(2), HR = 1.36, 95% CI 1.20-1.55 for BMI 25.0 < 27.5 kg/m(2), HR = 1.48, 95% CI 1.20-1.84 for BMI 27.5 to <30 kg/m(2), HR = 1.43, 95% CI 1.11-1.85 for BMI ≥30 kg/m(2)). BMI gain after early adulthood, adjusted for early adult BMI, was less strongly associated with pancreatic cancer mortality (HR = 1.05, 95% CI 1.01-1.10 per 5 kg/m(2)).

CONCLUSIONS

Our results support an association between pancreatic cancer mortality and central obesity, independent of BMI, and also suggest that being overweight or obese during early adulthood may be important in influencing pancreatic cancer mortality risk later in life.

Inadequate control of diabetes and metabolic indices among diabetic patients: A population based study from the Kerman Coronary Artery Disease Risk Study (KERCADRS)

BACKGROUND

The goal of diabetes control should be feasible in order to minimize the risk of its adverse events and to reduce its burden and cost on patients. The current study aimed to assess the status of glycemic control in male and female patients with Type 2 Diabetes Mellitus (T2DM) in Kerman, Iran.

METHODS

In the present study, 500 T2DM (300 women and 200 men) from the Kerman Coronary Artery Disease Risk Study (KERCADRS), a population-based study from 2009 to 2011, were selected. Patients were >18 years old, had Fasting Blood Sugar (FBS) higher than 126 mg/dl, and had been through treatment for their diagnosed disease. All participants underwent Glycosylated Hemoglobin (HbA1c) analysis. HbA1c less than 7% was considered as good glucose control. Other metabolic indices based on American Diabetes Association (ADA) target recommendations were considered.

RESULTS

The mean level of HbA1c in total subjects was 8.56 ± 4.72% that only 31.66% of men and 26.00% of women had controlled level of HbA1c. Total cholesterol less than 200 mg/dl was reported in 64.50% of men and 44.00% of women, High Density Lipoprotein (HDL) more than 40 mg/dl was revealed in 20.50% of men and 34.67% of women, and Low Density Lipoprotein (LDL) less than 100 mg/dl was reported in 41.50% of men and 25.33% of women. In multivariate logistic regression model, longer duration of disease and higher Waist Circumference (WC) were positively associated with uncontrolled diabetes status.

CONCLUSION

The findings of the present study revealed that diabetes control in T2DM was inadequate. Changing the policy of treatment in individual patient and establishing better diabetes clinic to decrease the frequency of uncontrolled T2DM are crucial. Paying attention to other affecting metabolic components such as WC in the process of T2DM management is important.

Does waist circumference uncorrelated with BMI add valuable information?

BACKGROUND

Estimation of relative contribution of Body Mass Index (BMI) and waist circumference (WC) on health outcomes requires a regression model that includes both obesity metrics. But, multicollinearity could yield biased estimates.

METHODS

To address the multicollinearity issue between BMI and WC, we used the residual model approach. The standard WC (Y-axis) was regressed on the BMI (X-axis) to obtain residual WC. Data from two adult population surveys (Nunavik Inuit and James Bay Cree) were analysed to evaluate relative effect of BMI and WC on four cardiometabolic risk factors: insulin, triglycerides, systolic blood pressure and high-density lipoprotein levels.

RESULTS

In multivariate models, standard WC and BMI were significantly associated with cardiometabolic outcomes. Residual WC was not linked with any outcomes. The BMI effect was weakened by including standard WC in the model, but its effect remained unchanged if residual WC was considered.

CONCLUSIONS

The strong correlation between standard WC and BMI does not allow assessment of their relative contributions to health in the same model without a risk of making erroneous estimations. By contrast with BMI, fat distribution (residual WC) does not add valuable information to a model that already contains overall adiposity (BMI) in Inuit and Cree.

Long-term progression of abnormal glucose tolerance and its relationship with the metabolic syndrome after kidney transplantation

BACKGROUND

Metabolic syndrome (MS) diagnosed early after kidney transplantation is a risk factor for developing new-onset diabetes. The aim of this study was to examine whether glucose intolerance and MS identified late after transplantation influence the progression of glycemic abnormalities in kidney transplant recipients.

METHODS

This is a retrospective study in which 76 non-diabetic renal transplant recipients underwent oral glucose tolerance tests (OGTT) in 2005 to 2006 (baseline) and then in 2011 to 2012 (follow-up). MS was identified using the International Diabetes Federation criteria and OGTT was interpreted according to the WHO classification.

RESULTS

At follow-up, median time from transplantation was 11.1 years (range 6.2-23.8). Mean 0-hour and 2-hour plasma glucose levels were significantly higher at follow-up compared to baseline (5.7 ± 0.7 vs. 5.9 ± 0.9 mmol/L, P=0.03 and 6.7 ± 1.9 vs. 7.5 ± 2.8 mmol/L, P=0.03, respectively). The proportion of patients with an abnormal OGTT increased from 42% at baseline to 61% at follow-up (P=0.007). Patients with MS were more likely to progress to a higher degree of glucose intolerance compared to those without MS (58% vs. 27%, P=0.01). On multivariable logistic regression adjusted for age and gender, MS was significantly associated with the progression of glucose intolerance (OR 3.5, CI 1.2-9.9, P=0.01), as was a fasting glucose greater than 5.6 mmol/L (OR 4.8, CI 1.6-14.8, P=0.006).

CONCLUSION

MS is a risk factor for the progression of glucose intolerance in renal transplant recipients in the late posttransplant period. Therefore, MS has to be considered in tandem with OGTT results to assess cardiovascular risk.

The comparison of glucose and lipid metabolism parameters in drug-naïve, antipsychotic-treated, and antipsychotic discontinuation patients with schizophrenia

BACKGROUND

Although many studies have reported that glucose and lipid metabolism disorders are a significant side effect associated with the use of antipsychotic drugs, the characteristics of glucose and lipid metabolism disorders in patients with schizophrenia who are taking antipsychotic drugs remain poorly understood, and the possible effects that antipsychotic discontinuation may have on glucose and lipid metabolism remain unclear.

METHODS

The sample consisted of 131 Chinese patients with schizophrenia, including 70 first-episode, drug-naïve patients; 33 patients who had received continuous antipsychotic drug treatment for ≥1 year prior to the beginning of the study; and 28 patients who had discontinued antipsychotic drug treatment for ≥3 months prior to the beginning of study. We compared the glucose and lipid metabolic parameter levels among the three groups of patients with schizophrenia. All assessments were performed upon hospital admission.

RESULTS

The characteristics of glucose and lipid metabolism disorders in Chinese patients with schizophrenia who are taking antipsychotic drugs included significant augmentation of the body mass index and waist circumference, significantly higher levels of fasting plasma insulin and insulin resistance, and significantly lower plasma high-density lipoprotein cholesterol levels. Antipsychotic discontinuation appeared to not significantly improve any plasma glucose and lipid metabolic parameter levels.

CONCLUSION

The results suggest that antipsychotic drugs aggravate glucose and lipid metabolism disorders and that antipsychotic discontinuation is generally not associated with improvements in the parameters that indicate glucose and lipid metabolism disorders in Chinese patients with schizophrenia.

Body composition is the main determinant for the difference in type 2 diabetes pathophysiology between Japanese and Caucasians

OBJECTIVE This cross-sectional clinical study compared the pathophysiology of type 2 diabetes in Japanese and Caucasians and investigated the role of demographic, genetic, and lifestyle-related risk factors for insulin resistance and β-cell response. RESEARCH DESIGN AND METHODS A total of 120 Japanese and 150 Caucasians were enrolled to obtain comparable distributions of high/low BMI values across glucose tolerance states (normal glucose tolerance, impaired glucose tolerance, and type 2 diabetes), which were assessed by oral glucose tolerance tests. BMI in the two cohorts was distributed around the two regional cutoff values for obesity. RESULTS Insulin sensitivity was higher in Japanese compared with Caucasians, as indicated by the homeostatic model assessment of insulin resistance and Matsuda indices, whereas β-cell response was higher in Caucasians, as measured by homeostatic model assessment of β-cell function, the insulinogenic indices, and insulin secretion ratios. Disposition indices were similar for Japanese and Caucasians at all glucose tolerance states, indicating similar β-cell response relative to the degree of insulin resistance. The main determinants for differences in metabolic indices were measures of body composition, such as BMI and distribution of adipose tissue. Differences in β-cell response between Japanese and Caucasians were not statistically significant following adjustment by differences in BMI. CONCLUSIONS Our study showed similar disposition indices in Japanese and Caucasians and that the major part of the differences in insulin sensitivity and β-cell response between Japanese and Caucasians can be explained by differences in body composition.

Metabolic syndrome in the prevention of cardiovascular diseases and diabetes--still a matter of debate?

After metabolic syndrome was first introduced to identify persons at greater cardiovascular disease (CVD) risk, it has been associated with an increased risk of CVD and type 2 diabetes (T2D). Obesity has been considered as the fundamental factor in metabolic syndrome and it is thought to be mediated, at least in part by the role of the adipocyte in controlling circulating free fatty acids and the development of insulin resistance. However, the obese population is not perfectly overlapped with the population with metabolic syndrome. Is metabolic syndrome a better predictor than obesity to prevent CVD and T2D? Has metabolic syndrome been considered as a cluster of risk factors or an additional independent risk factor to assess CVD and T2D risk? The debate on the necessity of metabolic syndrome diagnosis seems not to be ended. Various definitions of metabolic syndrome were advocated by different organizations with emphasis on different components, and these definitions have different abilities to predict CVD and T2D among different populations because of fundamental philosophical differences. In the definitions of metabolic syndrome, only the cutoffs of each component were presented but rather continuous values or the degree of the severity of the syndrome with multiple cutoffs. Moreover, metabolic syndrome did not incorporate all the risk factors as known for CVD and T2D, such as physical activity. Future prospective studies with the measurement of sophisticated metabolic markers and of abdominal visceral and subcutaneous adiposity are needed to examine if the metabolic syndrome is a good CVD and T2D risk predictor over obesity and other risk factors. In practice, prevention action should be taken at the stage of obesity and providers need to pay attention to any components in the definition of metabolic syndrome even if the number of positive components has not achieved three or more.

Waist circumference is positively correlated with markers of inflammation and negatively with adiponectin in women with metabolic syndrome

The purpose of this study was to correlate biomarkers of metabolic syndrome (MetS), with markers of inflammation and macronutrient intake in 89 women (25-72 years) with MetS. We hypothesized that waist circumference (WC) would have the stronger correlations with inflammatory parameters and would correlate with carbohydrate intake. Values for WC (108.7 ± 11.1 cm) and plasma triglycerides (202.7 ± 52.1 mg/dL) were elevated, whereas plasma glucose levels varied from 66 to 179 mg/dL, with 42% of women having insulin resistance. Plasma levels of interleukin 6 (0.2-15.9 mg/L), tumor necrosis factor α (1.47-12.3 mg/L), and high-sensitivity C-reactive protein (0.06-3.08 mg/dL) varied widely, with most women being above values considered normal. Subjects had high intake of total sugar (92.3 ± 56.4 g/d), high glycemic index (59.8 ± 6.5), and glycemic load (127.2 ± 56.1), whereas dietary fiber (17.1 ± 9.1 g/d) was below recommended intake. Waist circumference was positively correlated with insulin (r = 0.275, P < .01) and with the inflammatory markers interleukin 6 (r = 0.307, P < .01) and tumor necrosis factor α (r = 0.228, P < .05) and negatively correlated with plasma adiponectin (r = -0.309, P < .0001). In addition, WC was positively correlated with total carbohydrate, added sugar, and glycemic load (P < .05) but not with fat or protein. These results are consistent with central obesity being a key marker of the inflammatory state, and they also suggest that carbohydrates, particularly those that are digested rapidly, contribute to increased risk of central obesity and development of MetS.

Relationship between white blood cell count and components of metabolic syndrome among young adolescents

Components of metabolic syndrome (MetS) have been associated with several inflammatory factors, including white blood cell count (WBCC). In the present study, the relationships between WBCC and aspects of MetS in young adolescents were investigated. We enrolled 596 participants (328 males and 268 females) from 10 to 13 years of age and with normal WBCC in this study. They were divided into four quartiles according to WBCC (WBCC1-4, from lowest to highest WBCC). The mean values of MetS components for each group were compared in males and females separately. Multivariate linear regression analysis between the WBCC and the components of MetS after adjusted for age and body mass index (BMI) were also evaluated. In the male group, the BMI of WBCC1 and WBCC2 was significantly lower than WBCC4. The total cholesterol and low-density lipoprotein-cholesterol (LDL-C) of WBCC2 were significantly higher than WBCC1 and WBCC4. Triglyceride (TG) levels of WBCC1 were significantly lower than WBCC3 and WBCC4, and TG levels of WBCC2 were significantly lower than WBCC4. Alternatively, the BMI of WBCC1 and WBCC2 were significantly lower than WBCC3 in the female group. Finally, the TG and fasting plasma glucose (FPG) levels of WBCC1 were significantly lower than WBCC3 or WBCC4, respectively. After multivariate linear regression, WBCC was positively correlated to BMI and TG, but negatively correlated to FPG in males whereas in young adolescent females, WBCC was positively correlated to BMI and FPG. In conclusion BMI was positively correlated with WBCC in young adolescent females and males. Thus, BMI is the most important component of MetS in this age group. In addition, TG levels in males and FPG in females were significantly related to WBCC. These findings could be regarded an early indication for the future development of full-blown MetS or cardiovascular diseases.

Waist circumference is the best anthropometric predictor for insulin resistance in nondiabetic patients with schizophrenia treated with clozapine but not olanzapine

OBJECTIVE

The goal of this study was to evaluate which anthropometric measure (human body measurement) best predicts insulin resistance measured by the insulin sensitivity index (SI) and the homeostasis model of assessment of insulin resistance (HOMA-IR) in nondiabetic patients with schizophrenia treated with clozapine or olanzapine.

METHODS

We conducted a cross-sectional study of nondiabetic subjects with schizophrenia being treated with olanzapine or clozapine using a frequently sampled intravenous glucose tolerance test, nutritional assessment, and anthropometric measures, to assess the relationship between anthropometric measures and insulin resistance.

RESULTS

No difference was found between the groups treated with clozapine and olanzapine in age, gender, race, body mass index (BMI), waist circumference (WC), lipid levels, HOMA-IR, or SI. The disposition index (SI x the acute insulin response to glucose), which measures how the body compensates for insulin resistance to maintain a normal glucose level, was significantly lower in the group treated with clozapine than in the group treated with olanzapine (1067+/-1390 vs. 2521+/-2805; P=0.013), suggesting that the subjects treated with clozapine had a reduced compensatory response to IR compared with the subjects treated with olanzapine. In the clozapine group, both higher WC and BMI were significantly associated with elevated HOMA-IR and lower SI; however, WC was a stronger correlate of IR than BMI, as measured by SI (-0.50 vs. -0.40). In the olanzapine group, neither WC nor BMI was significantly associated with any measure of glucose metabolism.

CONCLUSIONS

In this study, WC was the single best anthropometric surrogate for predicting IR in patients treated with clozapine but not olanzapine. The results suggest that WC may be a valuable screening tool for predicting IR in patients with schizophrenia being treated with clozapine who are at relatively higher risk of developing the metabolic syndrome, type 2 diabetes mellitus, and associated cardiovascular disease.

Comparison of waist circumference versus body mass index in diagnosing metabolic syndrome and identifying apparently healthy subjects at increased risk of cardiovascular disease

The goal of this study was to compare the impact of differences in waist circumference (WC) defined according to the International Diabetes Federation (IDF) and the Adult Treatment Panel III (ATP III) and body mass index (BMI) on cardiovascular disease risk factors in 402 apparently healthy volunteers of European ancestry. Consequently, measurements were made of the WC, BMI, blood pressure, glucose, and lipid components of metabolic syndrome (MS) and insulin-mediated glucose uptake. Subjects were divided according to WC (IDF and ATP III criteria) and by normal weight, overweight, or obesity using BMI, and comparisons were made of the effect of these different indexes of adiposity on cardiovascular disease risk factors. The results indicated that WC and BMI significantly correlated (p <0.001) and were associated with differences in insulin-mediated glucose uptake to a similar degree in men (r = 0.57 and r = 0.59) and women (r = 0.53 and r = 0.52). Prevalences of MS were essentially identical irrespective of the measure of WC used (ATP III vs IDF), as were metabolic characteristics of those classified using IDF or ATP III criteria. Cardiovascular disease risk factor status did not vary substantially when subjects were divided on the basis of WC or BMI. In conclusion, prevalences of MS or cardiovascular disease risk factors did not vary as a function of differences in IDF and ATP III criteria for WC. BMI identified individuals at increased cardiovascular disease risk as effectively as determination of WC.

Waist circumference, not the metabolic syndrome, predicts glucose deterioration in type 2 diabetes

We sought to assess the relationship between the metabolic syndrome, abdominal obesity, and glucose deterioration amongst patients with type 2 diabetes. Our prospective cohort consisted of 164 adult patients with established diabetes who have a history of poor glycemic control, have just completed an intensive intervention aimed at improved control, and have demonstrated reduced HbA1c prior to enrollment. Waist circumference and presence of metabolic syndrome were assessed at baseline, and patients were followed up (median 24 months) for assessment of the study outcome, namely, time-to-hyperglycemic relapse, predefined as HbA1c >8% and >1% rise over baseline. Kaplan-Meier estimates of relapse-free glucose maintenance and multivariable Cox regression models were used for quantifying the independent effects of the metabolic syndrome and waist circumference on risk of glucose deterioration. The mean baseline waist circumference was 42.9 5.5 inches. Prevalence of the metabolic syndrome was 80%. During follow-up, 39 patients (24%) experienced hyperglycemic relapse. The metabolic syndrome was not associated with time-to-relapse (P = 0.15). The waist circumference component by itself, however, was associated with increased likelihood of hyperglycemic relapse with an unadjusted hazard ratio of 3.4 (95% confidence interval (CI) 1.2-9.7) and a hazard ratio of 3.2 (95% CI 1.1-9.1) after adjusting for age, gender, insulin use, weight change, and physical activity level. The National Cholesterol Education Program Adult Treatment Panel III (NCEP ATPIII) metabolic syndrome had limited ability to predict glucose deterioration in this type 2 diabetes cohort. Waist circumference by itself, however, is a strong predictor of future glucose control, and may be a parsimonious tool for risk stratification. BMI may also be a useful predictive tool.

Abdominal obesity and the metabolic syndrome: contribution to global cardiometabolic risk

There is currently substantial confusion between the conceptual definition of the metabolic syndrome and the clinical screening parameters and cut-off values proposed by various organizations (NCEP-ATP III, IDF, WHO, etc) to identify individuals with the metabolic syndrome. Although it is clear that in vivo insulin resistance is a key abnormality associated with an atherogenic, prothrombotic, and inflammatory profile which has been named by some the "metabolic syndrome" or by others "syndrome X" or "insulin resistance syndrome", it is more and more recognized that the most prevalent form of this constellation of metabolic abnormalities linked to insulin resistance is found in patients with abdominal obesity, especially with an excess of intra-abdominal or visceral adipose tissue. We have previously proposed that visceral obesity may represent a clinical intermediate phenotype reflecting the relative inability of subcutaneous adipose tissue to act as a protective metabolic sink for the clearance and storage of the extra energy derived from dietary triglycerides, leading to ectopic fat deposition in visceral adipose depots, skeletal muscle, liver, heart, etc. Thus, visceral obesity may partly be a marker of a dysmetabolic state and partly a cause of the metabolic syndrome. Although waist circumference is a better marker of abdominal fat accumulation than the body mass index, an elevated waistline alone is not sufficient to diagnose visceral obesity and we have proposed that an elevated fasting triglyceride concentration could represent, when waist circumference is increased, a simple clinical marker of excess visceral/ectopic fat. Finally, a clinical diagnosis of visceral obesity, insulin resistance, or of the metabolic syndrome is not sufficient to assess global risk of cardiovascular disease. To achieve this goal, physicians should first pay attention to the classical risk factors while also considering the additional risk resulting from the presence of abdominal obesity and the metabolic syndrome, such global risk being defined as cardiometabolic risk.

A prospective study of waist circumference and body mass index in relation to colorectal cancer incidence

OBJECTIVES

To study the association between waist circumference and colorectal cancer, and whether it is independent of body mass index (BMI).

METHODS

Between 1997 and 2005, 953 incident colorectal cancer cases (546 men and 407 women) were identified among 95,151 participants (44,068 men and 51,083 women) from the Cancer Prevention Study-II Nutrition Cohort.

RESULTS

Waist circumference was associated with increased colorectal cancer incidence in both men (multivariable adjusted rate ratio (RR) 1.68, 95% confidence interval (CI) 1.12-2.53 for waist circumference > or =120 cm compared to <95 cm, p trend = 0.006) and women (RR 1.75, 95% CI 1.20-2.54 for > or =110 compared to <85 cm, p trend = 0.003). High levels of BMI were also associated with increased risk. After adjustment for BMI, waist circumference remained associated with a nonstatistically significant increase in colorectal cancer incidence in both men (RR 1.41, 95% CI 0.81-2.45 for > or =120 compared to <95 cm, p trend = 0.10) and women (RR 1.48, 95% CI 0.89-2.48 for > or =110 compared to <85 cm, p trend = 0.13).

CONCLUSIONS

Our results confirm that waist circumference is associated with increased colorectal cancer incidence, possibly partially independent of BMI.

Non-dipping blood pressure in the metabolic syndrome among Arabs of the Oman family study

OBJECTIVE

The objective was to examine the circadian changes in blood pressure and their relation to the metabolic syndrome and its components in Omani Arabs.

RESEARCH METHODS AND PROCEDURES

Ambulatory blood pressure (ABPM) was recorded in 1124 subjects from 5 large, extended, consanguineous, and young Arab pedigrees. According to the International Diabetes Federation's definition, 264 subjects had the metabolic syndrome, a prevalence of 23%. Subjects were defined as non-dippers when their nocturnal systolic blood pressure (SBP) fell by <10% from daytime SBP.

RESULTS

Non-dippers with the metabolic syndrome were 131 of 264 (50%), compared with 265 of 860 (31%) without the metabolic syndrome. Of the non-dippers, 99 of 131 (76%) were females and 32 of 131 (24%) were males. Daytime and nighttime SBP and DBP and nighttime pulse pressure were significantly higher in non-dipper subjects with the metabolic syndrome. The important determinants of a non-dipping BP in this cohort were high BMI and high serum triglycerides.

DISCUSSION

We hypothesize that obesity and nocturnal volume-dependent hypertension may be involved in the pathophysiology of non-dipping in the metabolic syndrome. This study showed that non-dipping BP was common in subjects with the metabolic syndrome. Higher 24-hour blood pressure load may add to the indices of the overall cardiovascular burden already associated with the metabolic syndrome.

Relationship between obesity and several cardiovascular disease risk factors in apparently healthy Korean individuals: comparison of body mass index and waist circumference

Recent versions of the criteria for diagnosing the metabolic syndrome have emphasized the superiority of abdominal obesity, as measured by waist circumference (WC), in identifying individuals at increased risk for cardiovascular disease (CVD). On the other hand, there is evidence that body mass index (BMI), an estimate of overall obesity, fulfills this function as effectively as does WC. The present analysis was performed to compare the relative use of these 2 indices of obesity to identify multiple CVD risk factors. The study population consisted of 19584 apparently healthy men and women of Korean ethnicity, and the CVD risk factors measured included fasting plasma concentrations of the following variables: glucose, insulin, total, low-density lipoprotein, and high-density lipoprotein cholesterol, triglycerides, apolipoproteins A-I and B, and high-sensitivity C-reactive protein. The univariate relationships between the 2 indices of obesity and the 9 CVD risk factors were relatively modest (the highest r value was 0.45), but they were all statistically significant, and the magnitude of the relationships between the CVD risk factors and BMI and WC were comparable. When multivariate analysis was performed, adjusting for age and either BMI or WC, each index of obesity continued to have an independent relationship, albeit reduced in magnitude, with the CVD risk factors. These findings suggest that measurements of BMI provide as much clinical insight as do determinations of WC in identifying multiple CVD risk factors in a large population of apparently healthy Korean men and women, and that the use of both indices would provide the most information.

The Fatty Liver Index: a simple and accurate predictor of hepatic steatosis in the general population

Background

Fatty liver (FL) is the most frequent liver disease in Western countries. We used data from the Dionysos Nutrition & Liver Study to develop a simple algorithm for the prediction of FL in the general population.

Methods

216 subjects with and 280 without suspected liver disease were studied. FL was diagnosed by ultrasonography and alcohol intake was assessed using a 7-day diary. Bootstrapped stepwise logistic regression was used to identify potential predictors of FL among 13 variables of interest [gender, age, ethanol intake, alanine transaminase, aspartate transaminase, gamma-glutamyl-transferase (GGT), body mass index (BMI), waist circumference, sum of 4 skinfolds, glucose, insulin, triglycerides, and cholesterol]. Potential predictors were entered into stepwise logistic regression models with the aim of obtaining the most simple and accurate algorithm for the prediction of FL.

Results

An algorithm based on BMI, waist circumference, triglycerides and GGT had an accuracy of 0.84 (95%CI 0.81–0.87) in detecting FL. We used this algorithm to develop the "fatty liver index" (FLI), which varies between 0 and 100. A FLI < 30 (negative likelihood ratio = 0.2) rules out and a FLI ≥ 60 (positive likelihood ratio = 4.3) rules in fatty liver.

Conclusion

FLI is simple to obtain and may help physicians select subjects for liver ultrasonography and intensified lifestyle counseling, and researchers to select patients for epidemiologic studies. Validation of FLI in external populations is needed before it can be employed for these purposes.

The metabolic syndrome: is this diagnosis necessary?

Values of insulin-mediated glucose disposal vary continuously throughout a population of apparently healthy persons, and a difference of > or = 600% exists between the most insulin-sensitive and the most insulin-resistant persons. Approximately 50% of this variability can be attributed to differences in adiposity (25%) and fitness (25%), with the remaining 50% likely of genetic origin. The more insulin-resistant a person, the more likely that he or she will develop some degree of glucose intolerance, high triacylglycerol and low HDL concentrations, essential hypertension, and procoagulant and proinflammatory states, all of which increase the risk of cardiovascular disease (CVD). To identify persons at greater CVD risk because of these abnormalities, the World Health Organization, the Adult Treatment Panel III, and the International Diabetes Federation created a new diagnostic category, the metabolic syndrome. Although the components of the 3 versions of the metabolic syndrome are similar, the specific values for those components that define an abnormality are somewhat different, and the manner in which the abnormalities are used to make a positive diagnosis varies dramatically from version to version. This review will summarize the similarities in and differences between the 3 versions of the metabolic syndrome, point out that the clustering of components that make up all 3 definitions of the metabolic syndrome is not accidental and occurs only in insulin-resistant persons, develop the argument that diagnosing the metabolic syndrome in a person has neither pedagogical nor clinical utility, and suggest that the clinical emphasis should be on treating effectively any CVD risk factor that is present.

All obese individuals are not created equal: insulin resistance is the major determinant of cardiovascular disease in overweight/obese individuals

The ability of insulin to mediate glucose disposal varies more than six-fold in an apparently healthy population, and approximately one third of the most insulin-resistant of these individuals are at increased risk to develop cardiovascular disease. Differences in degree of adiposity account for approximately 25% of this variability, and another 25% varies as a function of level of physical fitness. The more overweight/obese the person, the more likely they are to be insulin-resistant and at increased risk of cardiovascular disease, but substantial numbers of overweight/obese individuals remain insulin-sensitive, and not all insulin-resistant persons are obese. Of greater clinical relevance is evidence that the metabolic benefit and decrease in risk of cardiovascular disease following weight loss occurs primarily in those overweight/obese individuals that are also insulin-resistant. The relationship between insulin resistance and overall obesity, as assessed by measurement of body mass index, is essentially the same as the relationship between insulin action and abdominal obesity as quantified by determining waist circumference. Finally, there appears to be a comparable relationship between insulin-mediated glucose disposal and amount of visceral fat, subcutaneous fat, and total fat as quantified by various imaging techniques, and the magnitude of these relationships is no greater than that between insulin action and simple measure of body mass index.