General and abdominal adiposity and risk of death in Europe

Intragastric balloon therapy in the management of obesity: why the bad wrap?

For the first time in the history of the United States, in the 21st century, there may be a decline in life expectancy, as a result of the increasing rate of obesity. It is known that even the modest reduction of 10% of excess body weight significantly reduces obesity-associated comorbidities. Conservative measures such as diet and exercise seldom give durable results in the long term. Bariatric surgery has been shown to achieve durable weight loss but is not without significant risks and complications. As a result, greater focus has turned toward minimally invasive endoscopic therapies for the management of obesity. There have been multiple reports of creative endoscopic devices and techniques in the literature, but most have only demonstrated early pilot data. By far, the most widely studied of the minimally invasive endoscopic therapies for obesity is the gastric balloon. Now obsolete, the Garren-Edwards gastric bubble was removed from the market in the United States after several sham-controlled studies showed that diet and behavior modification were equally efficacious and that the device was associated with a prohibitive number of complications. However, the concept and technique of intragastric balloon placement has evolved considerably since that time, and we now have data on nearly 3,000 patients who have undergone placement of the BioEnterics Intragastric Balloon (Carpenteria, CA) worldwide. The balloon is approved as part of a multifaceted approach to obesity in many countries and has been shown to result in at least a 10% excess weight loss durable over 1 year. However, the device is not yet approved for use in the United States. In this article, the authors review the efficacy, indications, complications, and potential uses for the intragastric balloon. The intragastric balloon might be the best start as gastroenterologists in the United States begin to play an increasing role in the treatment of the obesity pandemic.

Effects of low-dose, controlled-release, phentermine plus topiramate combination on weight and associated comorbidities in overweight and obese adults (CONQUER): a randomised, placebo-controlled, phase 3 trial

BACKGROUND

Obesity is associated with a reduction in life expectancy and an increase in mortality from cardiovascular diseases, cancer, and other causes. We therefore assessed the efficacy and safety of two doses of phentermine plus topiramate controlled-release combination as an adjunct to diet and lifestyle modification for weight loss and metabolic risk reduction in individuals who were overweight and obese, with two or more risk factors.

METHODS

In this 56-week phase 3 trial, we randomly assigned overweight or obese adults (aged 18-70 years), with a body-mass index of 27-45 kg/m(2) and two or more comorbidities (hypertension, dyslipidaemia, diabetes or prediabetes, or abdominal obesity) to placebo, once-daily phentermine 7·5 mg plus topiramate 46·0 mg, or once-daily phentermine 15·0 mg plus topiramate 92·0 mg in a 2:1:2 ratio in 93 centres in the USA. Drugs were administered orally. Patients were randomly assigned by use of a computer-generated algorithm that was implemented through an interactive voice response system, and were stratified by sex and diabetic status. Investigators, patients, and study sponsors were masked to treatment. Primary endpoints were the percentage change in bodyweight and the proportion of patients achieving at least 5% weight loss. Analysis was by intention to treat. This study is registered with Clinical Trials.gov, number NCT00553787.

FINDINGS

Of 2487 patients, 994 were assigned to placebo, 498 to phentermine 7·5 mg plus topiramate 46·0 mg, and 995 to phentermine 15·0 mg plus topiramate 92·0 mg; 979, 488, and 981 patients, respectively, were analysed. At 56 weeks, change in bodyweight was -1·4 kg (least-squares mean -1·2%, 95% CI -1·8 to -0·7), -8·1 kg (-7·8%, -8·5 to -7·1; p<0·0001), and -10·2 kg (-9·8%, -10·4 to -9·3; p<0·0001) in the patients assigned to placebo, phentermine 7·5 mg plus topiramate 46·0 mg, and phentermine 15·0 mg plus topiramate 92·0 mg, respectively. 204 (21%) patients achieved at least 5% weight loss with placebo, 303 (62%; odds ratio 6·3, 95% CI 4·9 to 8·0; p<0·0001) with phentermine 7·5 mg plus topiramate 46·0 mg, and 687 (70%; 9·0, 7·3 to 11·1; p<0·0001) with phentermine 15·0 mg plus topiramate 92·0 mg; for ≥10% weight loss, the corresponding numbers were 72 (7%), 182 (37%; 7·6, 5·6 to 10·2; p<0·0001), and 467 (48%; 11·7, 8·9 to 15·4; p<0·0001). The most common adverse events were dry mouth (24 [2%], 67 [13%], and 207 [21%] in the groups assigned to placebo, phentermine 7·5 mg plus topiramate 46·0 mg, and phentermine 15·0 mg plus topiramate 92·0 mg, respectively), paraesthesia (20 [2%], 68 [14%], and 204 [21%], respectively), constipation (59 [6%], 75 [15%], and 173 [17%], respectively), insomnia (47 [5%], 29 [6%], and 102 [10%], respectively), dizziness (31 [3%], 36 [7%], 99 [10%], respectively), and dysgeusia (11 [1%], 37 [7%], and 103 [10%], respectively). 38 (4%) patients assigned to placebo, 19 (4%) to phentermine 7·5 mg plus topiramate 46·0 mg, and 73 (7%) to phentermine 15·0 mg plus topiramate 92·0 mg had depression-related adverse events; and 28 (3%), 24 (5%), and 77 (8%), respectively, had anxiety-related adverse events.

INTERPRETATION

The combination of phentermine and topiramate, with office-based lifestyle interventions, might be a valuable treatment for obesity that can be provided by family doctors.

FUNDING

Vivus.

Menopausal hormone therapy and risk of colorectal cancer in the European Prospective Investigation into Cancer and Nutrition

Menopausal hormone therapy (HT) may influence colorectal cancer risk. A total of 136,275 postmenopausal women from the European Prospective Investigation into Cancer and Nutrition were followed for an average of 9 years, during which time 1,186 colorectal cancers were diagnosed. Hazard ratios (HR) and 95% confidence intervals (CI) were estimated using Cox proportional hazards models stratified by center and age, and adjusted for body mass index, smoking, diabetes, physical activity and alcohol consumption. Compared to never use of HT at study enrollment, current use of estrogen-only (HR, 1.02; 95% CI, 0.79-1.31) or estrogen plus progestin (HR, 0.94; 95% CI, 0.77-1.14) was not significantly associated with the risk of colorectal cancer, and these associations did not vary by recency, duration, route of administration, regimen or specific constituent of HT. Our results show no significant association of estrogen-only or estrogen plus progestin therapy with colorectal cancer risk.

Muscles and their myokines

In the past, the role of physical activity as a life-style modulating factor has been considered as that of a tool to balance energy intake. Although it is important to avoid obesity, physical inactivity should be discussed in a much broader context. There is accumulating epidemiological evidence that a physically active life plays an independent role in the protection against type 2 diabetes, cardiovascular diseases, cancer, dementia and even depression. For most of the last century, researchers sought a link between muscle contraction and humoral changes in the form of an 'exercise factor', which could be released from skeletal muscle during contraction and mediate some of the exercise-induced metabolic changes in other organs such as the liver and the adipose tissue. We have suggested that cytokines or other peptides that are produced, expressed and released by muscle fibres and exert autocrine, paracrine or endocrine effects should be classified as 'myokines'. Given that skeletal muscle is the largest organ in the human body, our discovery that contracting skeletal muscle secretes proteins sets a novel paradigm: skeletal muscle is an endocrine organ producing and releasing myokines, which work in a hormone-like fashion, exerting specific endocrine effects on other organs. Other myokines work via paracrine mechanisms, exerting local effects on signalling pathways involved in muscle metabolism. It has been suggested that myokines may contribute to exercise-induced protection against several chronic diseases.

Body mass index and mortality: is the association explained by genetic factors?

BACKGROUND

Numerous studies have shown that higher body mass index (BMI) is associated with higher mortality. We investigated the extent to which this association might be explained by genetic factors.

METHODS

We used data from the Swedish Twin Registry on twins born 1886-1958 who answered a questionnaire in 1969/1970 or 1972 (n = 44,258). Information on mortality from all-causes (n = 14,217), cardiovascular disease (CVD; n = 9009), and coronary heart disease (CHD; n = 3564) was obtained by linkage to the national Causes of Death Registry for the years 1972-2004. The association between BMI and mortality was studied without control for genetic factors in cohort analyses and with control for genetic factors in co-twin control analyses.

RESULTS

In cohort analyses, there was a clear dose-response relationship between BMI and mortality. Hazard ratios per 1 unit increase in BMI in subjects with BMI ≥18.5 were 1.05 (95% confidence interval = 1.05-1.06) for all-cause mortality, 1.07 (1.07-1.09) for CVD mortality, and 1.09 (1.08-1.10) for CHD mortality. Similar results were seen in co-twin control analyses of dizygotic twins. However, within monozygotic twins, BMI was associated with death from CHD (OR = 1.06; 1.00-1.12), whereas the association with all-cause mortality (1.01, 0.98-1.04) and CVD mortality (1.02, 0.98-1.06) was weak.

CONCLUSIONS

Our findings indicate that there is an association between high BMI and mortality from CHD that is not explained by genetic confounding. However, a large part of the association between BMI and other causes of death may be explained by genes rather than by a causal link between these factors.

Combined influence of lifestyle risk factors on body fat in Spanish adolescents--the Avena study

OBJECTIVE

To examine the combined influence of four lifestyle risk factors related to physical activity, television viewing, sleep duration, and meal frequency on body fat (BF) in adolescents.

METHOD

This cross-sectional study comprised 1,310 Spanish adolescents (age 13-18.5 years). Lifestyle variables were self-reported and BF indicators (weight, height, six skinfold thicknesses, waist circumference) measured during the years 2000-2002. Lifestyle risk factors were: physically inactive, ≥ 3 h/day watching television, <8 h/day sleep duration, and <5 meals a day. The number of lifestyle risk factors was calculated for each participant, ranging from 0 to 4.

RESULTS

The number of lifestyle risk factors was positively associated with sum of six skinfolds, %BF, waist circumference, and waist-height ratio (all p < 0.001). The odds ratios (95% confidence interval) of overweight (including obesity) for groups with 1, 2, and 3-4 lifestyle risk factors compared with those with 0 were 2.86 (1.77-4.62), 3.61 (2.16-6.04), and 5.81 (3.07-10.99), respectively (p for trend <0.001). All the observations were independent of age, gender, race, socioeconomic status, and fat free mass.

CONCLUSION

The combined influence of four lifestyle risk factors is positively associated with BF and an approximately sixfold risk of overweight in adolescents.

Informativeness of indices of blood pressure, obesity and serum lipids in relation to ischaemic heart disease mortality: the HUNT-II study

The informativeness of blood pressure, obesity and serum lipids associated with cardiovascular events may depend on how the indices are expressed, and mid blood pressure, waist-to-hip ratio adjusted for body-mass index (BMI) and the ratio of total to HDL cholesterol may be more informative than other expressions. Our aim was to study the informativeness of indices of blood pressure, obesity and serum lipids associated with ischaemic heart disease mortality in a large, homogeneous population. Blood pressure, weight, height, waist and hip circumference, total and HDL cholesterol, and triglycerides were measured at baseline (1995-1997) in 28,158 men and 32,573 women. Information on deaths from ischaemic heart disease (IHD) was obtained from the Causes of Death Registry in Norway from baseline until the end of 2007. Informativeness was analysed using the difference in twice the log-likelihood of a Cox model with and without each index. During 11 years of follow-up, 597 men and 418 women had died from IHD. Systolic blood pressure in men and pulse pressure in women were the most informative predictors of blood pressure, and waist-to-hip ratio adjusted for BMI was the most informative expression of obesity in both men and women. Among serum lipids, the most informative predictor was the ratio of total cholesterol to HDL cholesterol. Using more informative expressions of conventional risk factors for ischemic heart disease may improve both the validity and precision of estimates of risk, and may be useful both clinically and for preventive purposes.

Comparison of waist-to-hip ratio and other obesity indices as predictors of cardiovascular disease risk in people with type-2 diabetes: a prospective cohort study from ADVANCE

AIMS

The aim of this study was to compare the strength of associations and discrimination capability of body mass index (BMI), waist circumference (WC) and waist-to-hip ratio (WHR) with cardiovascular disease risk in individuals with type-2 diabetes.

METHODS AND RESULTS

Eleven thousand, one hundred and forty men and women were followed for a mean of 4.8 years. The Cox proportional hazard models were used to compute the hazard ratios and 95% confidence intervals (95% CI) for one standard deviation (SD) increase in baseline BMI (SD: 5 kg/m2), WC (SD: 13 cm) and WHR (SD: 0.08) with cardiovascular disease risk. After adjustment, hazard ratio (95% CI) for WC were 1.10 (1.03–1.18) for cardiovascular events, 1.13 (1.03–1.24) for coronary events, and 1.08 (0.98–1.19) for cardiovascular deaths. Estimates for WHR were 1.12 (1.05–1.19), 1.17 (1.08–1.28) and 1.19 (1.09–1.31). BMI was not related to any of these outcomes. Although the receiver operating characteristic curve could not differentiate between anthropometric variables (P values 0.24), the relative integrated discrimination improvement statistic showed an enhancement in the discrimination capabilities of models using WHR for cardiovascular outcomes, except for cerebrovascular events.

CONCLUSION

Strengths of associations and discrimination statistics suggested that WHR was the best predictor of cardiovascular events and mortality in patients with type-2 diabetes and BMI the worst.

Effects of diabetes and obesity on vascular reactivity, inflammatory cytokines, and growth factors

We examined the influences of obesity and diabetes on endothelium-dependent and -independent vasodilation, inflammatory cytokines, and growth factors. We included 258 subjects, age 21-80 years in four groups matched for age and gender: 40 healthy nonobese (BMI <30 kg·m(-2)) nondiabetic subjects, 76 nonobese diabetic patients, 37 obese (BMI >30) nondiabetic subjects, and 105 obese (BMI >30) diabetic patients. The flow-mediated dilation (FMD, endothelium-dependent) and nitroglycerin-induced dilation (NID, endothelium-independent) in the brachial artery, the vascular reactivity at the forearm skin and serum growth factors and inflammatory cytokines were measured. FMD was reduced in the nonobese diabetic patients, obese nondiabetic controls, and obese diabetic patients (P < 0.0001). NID was different among all four groups, being highest in the obese nondiabetic subjects and lowest in the obese diabetic patients (P < 0.0001). The resting skin forearm blood flow was reduced in the obese nondiabetic subjects (P < 0.01). Vascular endothelial growth factor (VEGF) was higher in the obese nondiabetic subjects (P < 0.05), tumor necrosis factor-α was higher in the obese diabetic patients (P < 0.0001) and C-reactive protein was higher in both the obese nondiabetic and diabetic subjects (P < 0.0001). Soluble intercellular adhesion molecule-1 was elevated in the two diabetic groups and the obese nondiabetic subjects (P < 0.05). We conclude that diabetes and obesity affect equally the endothelial cell function but the smooth muscle cell function is affected only by diabetes. In addition, the above findings may be related to differences that were observed in the growth factors and inflammatory cytokines.

The potential of the Internet for health communication: the use of an interactive on-line tool for diabetes risk prediction

OBJECTIVE

The aim of the study is to assess the use of a web-based tool to calculate the 5-year risk of developing type 2 diabetes mellitus, the German Diabetes Risk Score (DRS), in a real-life setting.

METHODS

Recorded web server log information and user entered data (n=24,495) was analyzed. To distinguish information seeking behavior between high- and low-risk DRS records, a sub-sample was created to compare data entries of the highest and lowest risk quintile (n=5046). To learn more on the information seeking behavior of DRS users we created a dataset on the characteristics of those who calculate more than one DRS (n=11,902).

RESULTS

Most users (61%) entered the DRS without a referring website. Forty percent of users did not know their waist circumference. Visit duration among high-risk DRS records was almost 1.5 min longer compared to low-risk DRS records (p-value<0.001). Those who calculated multiple DRS were associated with a higher first DRS and male gender.

CONCLUSION

Understanding users' website utilization is an important step to evaluate risk calculator websites.

PRACTICE IMPLICATIONS

A range of media should be used conjointly to raise type 2 diabetes mellitus risk awareness. Risk websites should be linked to patient information pages.

Physical activity and gain in abdominal adiposity and body weight: prospective cohort study in 288,498 men and women

BACKGROUND

The protective effect of physical activity (PA) on abdominal adiposity is unclear.

OBJECTIVE

We examined whether PA independently predicted gains in body weight and abdominal adiposity.

DESIGN

In a prospective cohort study [the EPIC (European Prospective Investigation into Cancer and Nutrition)], we followed 84,511 men and 203,987 women for 5.1 y. PA was assessed by a validated questionnaire, and individuals were categorized into 4 groups (inactive, moderately inactive, moderately active, and active). Body weight and waist circumference were measured at baseline and self-reported at follow-up. We used multilevel mixed-effects linear regression models and stratified our analyses by sex with adjustments for age, smoking status, alcohol consumption, educational level, total energy intake, duration of follow-up, baseline body weight, change in body weight, and waist circumference (when applicable).

RESULTS

PA significantly predicted a lower waist circumference (in cm) in men (β = -0.045; 95% CI: -0.057, -0.034) and in women (β = -0.035; 95% CI: -0.056, -0.015) independent of baseline body weight, baseline waist circumference, and other confounding factors. The magnitude of associations was materially unchanged after adjustment for change in body weight. PA was not significantly associated with annual weight gain (in kg) in men (β = -0.008; 95% CI: -0.02, 0.003) and women (β = -0.01; 95% CI: -0.02, 0.0006). The odds of becoming obese were reduced by 7% (P < 0.001) and 10% (P < 0.001) for a one-category difference in baseline PA in men and women, respectively.

CONCLUSION

Our results suggest that a higher level of PA reduces abdominal adiposity independent of baseline and changes in body weight and is thus a useful strategy for preventing chronic diseases and premature deaths.

Separate and combined associations of body-mass index and abdominal adiposity with cardiovascular disease: collaborative analysis of 58 prospective studies

BACKGROUND

Guidelines differ about the value of assessment of adiposity measures for cardiovascular disease risk prediction when information is available for other risk factors. We studied the separate and combined associations of body-mass index (BMI), waist circumference, and waist-to-hip ratio with risk of first-onset cardiovascular disease.

METHODS

We used individual records from 58 cohorts to calculate hazard ratios (HRs) per 1 SD higher baseline values (4.56 kg/m(2) higher BMI, 12.6 cm higher waist circumference, and 0.083 higher waist-to-hip ratio) and measures of risk discrimination and reclassification. Serial adiposity assessments were used to calculate regression dilution ratios.

RESULTS

Individual records were available for 221,934 people in 17 countries (14,297 incident cardiovascular disease outcomes; 1.87 million person-years at risk). Serial adiposity assessments were made in up to 63,821 people (mean interval 5.7 years [SD 3.9]). In people with BMI of 20 kg/m(2) or higher, HRs for cardiovascular disease were 1.23 (95% CI 1.17-1.29) with BMI, 1.27 (1.20-1.33) with waist circumference, and 1.25 (1.19-1.31) with waist-to-hip ratio, after adjustment for age, sex, and smoking status. After further adjustment for baseline systolic blood pressure, history of diabetes, and total and HDL cholesterol, corresponding HRs were 1.07 (1.03-1.11) with BMI, 1.10 (1.05-1.14) with waist circumference, and 1.12 (1.08-1.15) with waist-to-hip ratio. Addition of information on BMI, waist circumference, or waist-to-hip ratio to a cardiovascular disease risk prediction model containing conventional risk factors did not importantly improve risk discrimination (C-index changes of -0.0001, -0.0001, and 0.0008, respectively), nor classification of participants to categories of predicted 10-year risk (net reclassification improvement -0.19%, -0.05%, and -0.05%, respectively). Findings were similar when adiposity measures were considered in combination. Reproducibility was greater for BMI (regression dilution ratio 0.95, 95% CI 0.93-0.97) than for waist circumference (0.86, 0.83-0.89) or waist-to-hip ratio (0.63, 0.57-0.70).

INTERPRETATION

BMI, waist circumference, and waist-to-hip ratio, whether assessed singly or in combination, do not importantly improve cardiovascular disease risk prediction in people in developed countries when additional information is available for systolic blood pressure, history of diabetes, and lipids.

FUNDING

British Heart Foundation and UK Medical Research Council.

Body adiposity in later life and the incidence of dementia: the health in men study

Objective

To determine if adiposity in later life increases dementia hazard.

Methods

Cohort study of 12,047 men aged 65–84 years living in Perth, Australia. Adiposity exposures were baseline body mass index (BMI), waist circumference (WC) and waist-to-hip ratio (WHR). We used the Western Australian Data Linkage System (WADLS) to establish the presence of new cases of dementia between 1996 and 2009 according to the International Classification of Diseases (ICD). Crude and adjusted hazard ratio (HR, 95% confidence interval, 95%CI) of dementia for each adiposity marker was calculated using Cox regression models. Other measured factors included age, marital status, education, alcohol use, smoking, diet, physical activity, and prevalent hypertension, diabetes, dyslipidaemia and cardiovascular disease.

Results

Compared with men with BMI<25, participants with BMI between 25–30 had lower adjusted HR of dementia (HR = 0.82, 95% CI = 0.70–0.95). The HR of dementia for men with BMI≥30 was comparable to men with BMI<25 (HR = 0.82, 95%CI = 0.67–1.01). Waist circumference showed no obvious association with dementia hazard. Men with WHR≥0.9 had lower adjusted HR of dementia than men with WHR <0.9 (HR = 0.82, 95%CI = 0.69–0.98). We found a “J” shape association between measures of obesity and the hazard of dementia, with the nadir of risk being in the overweight range of BMI and about 1 for WHR.

Conclusions

Higher adiposity is not associated with incident dementia in this Australian cohort of older men. Overweight men and those with WHR≥0.9 have lower hazard of dementia than men with normal weight and with WHR<0.9.

Obesity, type 2 diabetes and risk of digestive cancer

The frequency of obesity has been increasing worldwide for 20 years. Many epidemiological studies support a correlation between obesity and increased risk of cancer, particularly digestive cancers in both genders, and gynaecological cancer in women. Currently, about 5% of cancers could be directly related to overweight. Carcinogenesis mechanisms induced by obesity involve insulin resistance, adipokine and angiogenic factor secretions, and inflammation. Experimental and clinical evidence suggest that insulin resistance plays a major role in carcinogenesis. Insulin and non-protein banded IGF-1, whose levels are increased in type 2 diabetes, stimulate cellular growth and inhibit apoptosis. Abnormalities in adipokine secretion by the central adipose tissue play a role at different stages of obesity-induced carcinogenesis. Excess of leptin and PAI-1, associated with a decrease in adiponectin secretion in obese people, contributes to carcinogenesis through cellular growth and angiogenesis stimulation. Remodelling of the extracellular matrix due to metalloproteinase stimulation by PAI-1 is also able to promote cell migration. Obesity not only increases cancer frequency, but is also liable to modify the prognosis and the response to antiangiogenic therapy of digestive cancers. This data suggests the need for clinicians to take into account overweight in cancer risk evaluation and to consider obesity and metabolic disorders as confounding factors in designing therapeutic studies.

The association of education with body mass index and waist circumference in the EPIC-PANACEA study

BACKGROUND

To examine the association of education with body mass index (BMI) and waist circumference (WC) in the European Prospective Investigation into Cancer and Nutrition (EPIC).

METHOD

This study included 141,230 male and 336,637 female EPIC-participants, who were recruited between 1992 and 2000. Education, which was assessed by questionnaire, was classified into four categories; BMI and WC, measured by trained personnel in most participating centers, were modeled as continuous dependent variables. Associations were estimated using multilevel mixed effects linear regression models.

RESULTS

Compared with the lowest education level, BMI and WC were significantly lower for all three higher education categories, which was consistent for all countries. Women with university degree had a 2.1 kg/m2 lower BMI compared with women with lowest education level. For men, a statistically significant, but less pronounced difference was observed (1.3 kg/m2). The association between WC and education level was also of greater magnitude for women: compared with the lowest education level, average WC of women was lower by 5.2 cm for women in the highest category. For men the difference was 2.9 cm.

CONCLUSION

In this European cohort, there is an inverse association between higher BMI as well as higher WC and lower education level. Public Health Programs that aim to reduce overweight and obesity should primarily focus on the lower educated population.

Body mass index and all-cause mortality in a large Chinese cohort

BACKGROUND

Obesity is known to be associated with an increased risk of death, but current definitions of obesity are based on data from white populations. We examined the association between body mass index (BMI) and the risk of death in a large population of adult Chinese people.

METHODS

We examined the association between body mass index (BMI) and all-cause mortality prospectively among 58,738 men and 65,718 women aged 20 years and older enrolled in 1998-1999 from four national health screening centres in Taiwan. We used Cox proportional hazards regression analyses to estimate the relative risks of all-cause mortality for different BMI categories during a maximum follow-up of 10 years.

RESULTS

A total of 3947 participants died during the follow-up period. The lowest risk of death was observed among men and women who had a BMI of 24.0-25.9 (mean 24.9). After adjustment for age, smoking status, alcohol intake, betel-nut chewing, level of physical activity, income level and education level, we observed a U-shaped association between BMI and all-cause mortality. Similar U-shaped associations were observed when we analyzed data by age (20-64 or ≥ 65 years), smoking (never, < 10 pack-years or ≥ 10 pack-years) and presence of a pre-existing chronic disease, and after we excluded deaths that occurred in the first three years of follow-up.

INTERPRETATION

BMI and all-cause mortality had a U-shaped association among adult Chinese people in our study. The lowest risk of death was among adults who had a BMI of 24.0-25.9 (mean 24.9). Our findings do not support the use of a lower cutoff value for overweight and obesity in the adult Chinese population.

Obesity induces signs of premature cardiac aging in younger patients: the role of mitochondria

OBJECTIVES

The purpose of the present study was to investigate the influence of obesity on cardiac aging.

BACKGROUND

Obesity is associated with an increased incidence of left ventricular hypertrophy, diastolic dysfunction, heart failure, and atherosclerosis.

METHODS

Sixty male cardiac surgery patients were included in the study according to body mass index (18.5 to 25 kg/m²: normal weight; 30 to 35 kg/m²: obese) and age (<55 years: young; >70 years: old) and divided into 4 groups of 15 patients each. Right atrial cardiomyocytes were analyzed for mitochondrial function, markers of apoptosis, cardiac load or metabolism, and oxidative stress parameters. The metabolic state was further characterized in fasting blood samples.

RESULTS

Obesity resulted in disturbed mitochondrial biogenesis and function (respiratory chain complex I) in the cardiomyocytes of young and old patients. Disturbed mitochondrial function was associated with signs of increased oxidative stress (protein carbonyl content, 8-hydroxy-2'-deoxyguanosine) as well as telomere shortening by up to 30%. Cardiomyocytes from older (obese and normal-weight) and young obese patients demonstrated higher levels of load-induced markers (atrial natriuretic peptide and brain natriuretic peptide) and proapoptotic activation with increased Bax and Bcl-xS expression, cytochrome C release, and caspase 3/9 activation. Disturbances in glucose metabolism and adipocytokine release were detectable in old (obese and normal-weight) and young obese patients. However, only minor deteriorations in most parameters were observed in obese subjects older than 70 years of age compared with normal-weight, age-matched patients.

CONCLUSIONS

These data indicate that obesity results in premature cardiac aging in younger patients, which may contribute to an increased risk for heart failure.

Effects of body size and sociodemographic characteristics on differences between self-reported and measured anthropometric data in middle-aged men and women: the EPIC-Norfolk study

BACKGROUND/OBJECTIVES

To investigate the effects of body size and sociodemographic characteristics on differences between self-reported (SR) and measured anthropometric data in men and women.

SUBJECTS/METHODS

This study comprises 9933 men and 11,856 women aged 39-79 years at baseline survey (1993-1997) in the EPIC-Norfolk study (Norfolk arm of the European Investigation into Cancer and Nutrition Study). The effects of sex, measured height, weight, age group, educational level and social class on differences between SR and measured weight, height, body mass index (BMI), waist, hip and waist-to-hip ratio (WHR) were examined.

RESULTS

There were systematic differences between SR and measured anthropometric measurements by sex, measured height, weight and sociodemographic characteristics. Height was overestimated in both sexes while weight, waist, hip, and consequently, BMI and WHR were underestimated. Being male, shorter, heavier, older, and having no educational qualifications and manual occupation were independently associated with overreporting of height, and underreporting of weight was associated independently with being female, shorter, heavier, younger age, and higher education level and social class. Underreporting of waist circumference was strongly associated with being female and higher measured waist circumference, while underreporting of hip circumference was associated with being male and higher measured hip circumference. Furthermore, there was substantial degree of misclassification of BMI and waist circumference categories for both general and central obesity associated with SR data.

CONCLUSIONS

These findings suggest that errors in SR anthropometric data, especially waist and hip circumference are influenced by actual body size as well as sociodemographic characteristics. These systematic differences may influence associations between SR anthropometric measures and health outcomes in epidemiological studies.

Combined effect of cardiorespiratory fitness and adiposity on mortality in patients with coronary artery disease

BACKGROUND

High cardiorespiratory fitness and body mass index (BMI) are associated with decreased mortality in patients with coronary artery disease. Our objective was to determine the joint impact of fitness and adiposity measures on all-cause mortality in this subgroup.

METHODS

Coronary artery disease patients (n = 855) enrolled in the Mayo Clinic cardiac rehabilitation program from 1993 to 2007 were included. Fitness levels were determined by cardiopulmonary exercise testing. Patients were divided into low and high fitness by sex-specific median values of peak oxygen consumption and total treadmill time. Adiposity was measured through BMI and waist-to-hip ratio (WHR).

RESULTS

There were 159 deaths during 9.7 ± 3.6 years of mean follow-up. After adjusting for potential confounding factors, low fitness, shorter treadmill time, low BMI, and high WHR were significantly associated with increased mortality. Using low WHR-high fitness group as reference, significantly increased mortality was noted in low WHR-low fitness (hazard ratio 4.2, 95% CI, 1.8-9.8), centrally obese-high fitness (2.3, 1.0-5.4), and centrally obese-low fitness (6.1, 2.7-13.6) groups. Overweight-high fitness (2.2, 0.63-7.4), obese-high fitness (3.2, 0.88-11.4), and obese-low fitness (3.3, 0.96-11.4) subjects did not have a significantly different mortality as compared with the reference group of normal weight-high fitness subjects, whereas normal weight-low fitness (9.6, 2.9-31.8) and overweight-low fitness (6.8, 2.1-22.2) groups had significantly increased mortality.

CONCLUSIONS

Low fitness and central obesity were independently and cumulatively associated with increased mortality in coronary artery disease patients attending cardiac rehabilitation. The association of BMI with mortality is complex and altered by fitness levels.

Glycemic status, metabolic syndrome, and cardiovascular risk in children

The metabolic syndrome and adult manifestation of prediabetes and diabetes are major public health problems that begin in childhood. Prevention must be considered as a serious public health issue. Health education and health promotion of school children needs incorporation as a community effort.

Nutrition and human health from a sex-gender perspective

Nutrition exerts a life-long impact on human health, and the interaction between nutrition and health has been known for centuries. The recent literature has suggested that nutrition could differently influence the health of male and female individuals. Until the last decade of the 20th century, research on women has been neglected, and the results obtained in men have been directly translated to women in both the medicine and nutrition fields. Consequently, most modern guidelines are based on studies predominantly conducted on men. However, there are many sex-gender differences that are the result of multifactorial inputs, including gene repertoires, sex steroid hormones, and environmental factors (e.g., food components). The effects of these different inputs in male and female physiology will be different in different periods of ontogenetic development as well as during pregnancy and the ovarian cycle in females, which are also age dependent. As a result, different strategies have evolved to maintain male and female body homeostasis, which, in turn, implies that there are important differences in the bioavailability, metabolism, distribution, and elimination of foods and beverages in males and females. This article will review some of these differences underlying the impact of food components on the risk of developing diseases from a sex-gender perspective.

Effects of testosterone undecanoate on cardiovascular risk factors and atherosclerosis in middle-aged men with late-onset hypogonadism and metabolic syndrome: results from a 24-month, randomized, double-blind, placebo-controlled study

INTRODUCTION

Longitudinal studies have demonstrated that male hypogonadism could be considered a surrogate marker of incident cardiovascular disease.

AIM

To evaluate the effects of parenteral testosterone undecanoate (TU) in outclinic patients with metabolic syndrome (MS) and late-onset hypogonadism (total testosterone (T) at or below 11nmol/L or free T at or below 250pmol/L).

METHODS

This is a randomized, double-blind, double-dummy, placebo-controlled, parallel group, single-center study. Fifty patients (mean age 57±8) were randomized (4:1) to receive TU 1,000mg (every 12 weeks) or placebo (PLB) gel (3-6 g/daily) for 24 months.

MAIN OUTCOME MEASURES

Homeostasis model assessment index of insulin resistance (HOMA-IR), carotid intima media thickness (CIMT), and high-sensitivity C-reactive protein (hsCRP).

RESULTS

At baseline, all patients fulfilled the National Cholesterol Education Program-Third Adult Treatment Panel (NCEP-ATPIII) and International Diabetes Federation (IDF) criteria for the definition of MS. An interim analysis conducted at 12 months showed that TU markedly improved HOMA-IR (P < 0.001), CIMT (P < 0.0001), and hsCRP (P<0.001) compared with PLB; thus, all patients were shifted to TU treatment. After 24 months, 35% (P < 0.0001) and 58% (P < 0.001) of patients still presented MS as defined by NCEP-ATPIII and IDF criteria, respectively. Main determinants of changes were reduction in waist circumference (P<0.0001), visceral fat mass (P<0.0001), and improvement in HOMA-IR without changes in body mass index (BMI).

CONCLUSIONS

TU reduced fasting glucose, waist circumference, and improved surrogate markers of atherosclerosis in hypogonadal men with MS. Resumption and maintenance of T levels in the normal range of young adults determines a remarkable reduction in cardiovascular risk factors clustered in MS without significant hematological and prostate adverse events.

Association between body-mass index and risk of death in more than 1 million Asians

BACKGROUND

Most studies that have evaluated the association between the body-mass index (BMI) and the risks of death from any cause and from specific causes have been conducted in populations of European origin.

METHODS

We performed pooled analyses to evaluate the association between BMI and the risk of death among more than 1.1 million persons recruited in 19 cohorts in Asia. The analyses included approximately 120,700 deaths that occurred during a mean follow-up period of 9.2 years. Cox regression models were used to adjust for confounding factors.

RESULTS

In the cohorts of East Asians, including Chinese, Japanese, and Koreans, the lowest risk of death was seen among persons with a BMI (the weight in kilograms divided by the square of the height in meters) in the range of 22.6 to 27.5. The risk was elevated among persons with BMI levels either higher or lower than that range--by a factor of up to 1.5 among those with a BMI of more than 35.0 and by a factor of 2.8 among those with a BMI of 15.0 or less. A similar U-shaped association was seen between BMI and the risks of death from cancer, from cardiovascular diseases, and from other causes. In the cohorts comprising Indians and Bangladeshis, the risks of death from any cause and from causes other than cancer or cardiovascular disease were increased among persons with a BMI of 20.0 or less, as compared with those with a BMI of 22.6 to 25.0, whereas there was no excess risk of either death from any cause or cause-specific death associated with a high BMI.

CONCLUSIONS

Underweight was associated with a substantially increased risk of death in all Asian populations. The excess risk of death associated with a high BMI, however, was seen among East Asians but not among Indians and Bangladeshis.

Awareness and knowledge about weight status and management: results from the 1 d sensitization campaign 'Obesity Day' in northern Italy

OBJECTIVE

To evaluate the awareness and knowledge about weight status and its management.

DESIGN

A 1 d cross-sectional survey. Basic anthropometric assessments (weight, height, BMI and waist circumference) and a self-administered questionnaire were considered.

SETTING

Nineteen Clinical Nutrition or Endocrinology and Metabolic Disorders Units or Dietetics Services in the Italian region of Lombardy.

SUBJECTS

All adults attending the 'Obesity Day' initiative.

RESULTS

A total of 914 participants (605 female and 309 male) were recruited. Although most of the participants (83·5 %) considered obesity to be a disease, 38·5 % were likely to misperceive their weight status. In particular, 38·8 % of normal-weight adults believed themselves to be overweight, whereas 71·1 % and 37·5 % of classes I and II/III obese adults classified themselves as being overweight and mildly obese, respectively. However, most of the overweight (90·2 %), mildly (96·8 %) and moderately/severely obese adults (99·1 %) recognized the need to lose weight. In all, 37·8 % of the sample underestimated the role of physical activity in weight management. Interestingly, only 17·2 % of dieters (previous or current) declared being advised by their doctor to lose weight. Multivariate models revealed that higher age, low education and higher BMI were important determinants of poor weight control and management. In addition, previous dieting appeared not to provide better knowledge, whereas the role of physical activity was recognized mainly by those practising it.

CONCLUSIONS

The present study suggests that in Italy knowledge about weight management should be improved not only in the general population but also among health-care professionals. To confirm this finding, there is now the rationale for a nationally representative survey. New educational programmes can be designed on the basis of the information collected.

Obesity paradox in elderly patients with cardiovascular diseases

Many elderly people are affected by cardiovascular diseases (CVD) and the majority of CVD patients are elderly people. For both patient populations, studies have shown that a high body mass index (BMI) is associated with lower mortality when compared to normal weight subjects, a fact commonly known as the "obesity paradox". Whether the correlation between obesity and better survival is based on methodological influences and other non-causal factors alone, or whether there is a causal link between obesity and a better survival in these subjects remains widely unexplored. The interrelation between aging, obesity, CVD, frailty and inflammation is a current issue of intensive research. For the elderly, parameters which include measures of body composition, fat and fat-free mass are of greater importance than BMI. Weight management in elderly people with cardiovascular diseases should aim at improvement and maintenance of physical function and quality of life rather than prevention of medical problems associated with obesity in younger and middle aged patients. Although many studies have shown that weight loss in elderly patients is associated with a poor prognosis, recent data demonstrate that intentional weight reduction in obese elderly people ameliorates the cardiovascular risk profile, reduces chronic inflammation and is correlated with an improved quality of life. An individual approach to weight management that includes the participation of the patient, co-morbidity, functional status, and social support should be aspired.

Exercise-induced alterations of retinal vessel diameters and cardiovascular risk reduction in obesity

BACKGROUND

The retinal microcirculation is affected early in the process of atherosclerosis and retinal vessel caliber is an emerging cardiovascular risk factor. Obesity is associated with vascular dysfunction. Here, we investigate the effect of regular exercise on retinal vessel diameters in lean and obese runners. We analyze a possible link to alterations of the nitric oxide (NO)-asymmetric dimethylarginine (ADMA) pathway.

METHODS

Retinal vessel diameters were assessed by means of a static vessel analyzer (SVA-T) in 15 obese athletes (OA), 14 lean amateur athletes (AA) and 17 lean elite athletes (EA) following a 10 week training program. ADMA serum levels were detected by ELISA and dimethylarginine dimethylaminohydrolase (DDAH) -1/-2 mRNA-expression in peripheral mononuclear cells (PBMC) was analyzed by real time PCR.

RESULTS

At baseline, the mean (±SD) arteriolar to venular diameter ratio (AVR) was impaired in obese (OA: 0.81±0.05) compared to lean subjects (AA: 0.87±0.07; EA: 0.94±0.05). The individual fitness levels correlated with AVR (rho=+0.66; P<0.001) and the training program improved AVR in all groups (P<0.001), normalising AVR in the obese (OA: 0.86±0.1). A training-induced arteriolar dilatation was found in OA (P=0.01), which was accompanied by a significant decrease of ADMA levels (0.56±0.12-0.46±0.12 μmoll(-1); P<0.028). DDAH-1 mRNA levels in PBMC increased in all groups (P<0.01).

CONCLUSIONS

Cardiovascular fitness and body composition affect retinal vessel diameters. Regular exercise reverses the subclinical impairment of the retinal microvasculature in obesity by inducing retinal arteriolar dilatation. The NO/ADMA pathway may play a key role in the training-induced improvement of microvascular function, which has the potential to counteract progression of small vessel disease.

Use of reclassification for assessment of improved prediction: an empirical evaluation

BACKGROUND

An increasing number of studies evaluate the ability of predictors to change risk stratification and alter medical decisions, i.e. reclassification performance. We examined the reported design and analysis of recent studies of reclassification and the robustness of their claims for improved reclassification.

METHODS

Two independent investigators searched PubMed and citations to the article that introduced the currently most popular reclassification metric (net reclassification index, NRI) to identify studies performing reclassification analysis (January 2006-January 2010). We focused on articles that included any analyses comparing the performance of a baseline predictive model vs the baseline model plus some additional predictor for a prospectively assessed outcome. We recorded information on the baseline model used, outcomes assessed, choice of risk thresholds and features of reclassification analyses.

RESULTS

Of 58 baseline models used in 51 eligible papers, only 14 (24%) were previously described, used as described and had same outcomes as originally intended. Calibration was examined in 53% of the studies. Sixteen studies (31%) provided a reference for the choice of risk thresholds and only six used the previously proposed categories or justified the use of alternative thresholds. Only 14 studies (27%) stated that the chosen risk thresholds had different therapeutic intervention implications. NRI was calculated in 38 studies and was smaller in studies with adequately referenced or justified risk thresholds vs others (P < 0.0001).

CONCLUSIONS

Reclassification studies would benefit from more rigorous methodological standards; otherwise claims for improved reclassification may remain spurious.

National, regional, and global trends in body-mass index since 1980: systematic analysis of health examination surveys and epidemiological studies with 960 country-years and 9·1 million participants

BACKGROUND

Excess bodyweight is a major public health concern. However, few worldwide comparative analyses of long-term trends of body-mass index (BMI) have been done, and none have used recent national health examination surveys. We estimated worldwide trends in population mean BMI.

METHODS

We estimated trends and their uncertainties of mean BMI for adults 20 years and older in 199 countries and territories. We obtained data from published and unpublished health examination surveys and epidemiological studies (960 country-years and 9·1 million participants). For each sex, we used a Bayesian hierarchical model to estimate mean BMI by age, country, and year, accounting for whether a study was nationally representative.

FINDINGS

Between 1980 and 2008, mean BMI worldwide increased by 0·4 kg/m(2) per decade (95% uncertainty interval 0·2-0·6, posterior probability of being a true increase >0·999) for men and 0·5 kg/m(2) per decade (0·3-0·7, posterior probability >0·999) for women. National BMI change for women ranged from non-significant decreases in 19 countries to increases of more than 2·0 kg/m(2) per decade (posterior probabilities >0·99) in nine countries in Oceania. Male BMI increased in all but eight countries, by more than 2 kg/m(2) per decade in Nauru and Cook Islands (posterior probabilities >0·999). Male and female BMIs in 2008 were highest in some Oceania countries, reaching 33·9 kg/m(2) (32·8-35·0) for men and 35·0 kg/m(2) (33·6-36·3) for women in Nauru. Female BMI was lowest in Bangladesh (20·5 kg/m(2), 19·8-21·3) and male BMI in Democratic Republic of the Congo 19·9 kg/m(2) (18·2-21·5), with BMI less than 21·5 kg/m(2) for both sexes in a few countries in sub-Saharan Africa, and east, south, and southeast Asia. The USA had the highest BMI of high-income countries. In 2008, an estimated 1·46 billion adults (1·41-1·51 billion) worldwide had BMI of 25 kg/m(2) or greater, of these 205 million men (193-217 million) and 297 million women (280-315 million) were obese.

INTERPRETATION

Globally, mean BMI has increased since 1980. The trends since 1980, and mean population BMI in 2008, varied substantially between nations. Interventions and policies that can curb or reverse the increase, and mitigate the health effects of high BMI by targeting its metabolic mediators, are needed in most countries.

FUNDING

Bill & Melinda Gates Foundation and WHO.

Mesodermal developmental gene Tbx15 impairs adipocyte differentiation and mitochondrial respiration

Increased intraabdominal (visceral) fat is associated with a high risk of diabetes and metabolic syndrome. We have previously shown that the mesodermal developmental transcription factor Tbx15 is highly differentially expressed between visceral and subcutaneous (s.c.) fat in both humans and rodents, and in humans visceral fat Tbx15 expression is decreased in obesity. Here we show that, in mice, Tbx15 is 260-fold more highly expressed in s.c. preadipocytes than in epididymal preadipocytes. Overexpression of Tbx15 in 3T3-L1 preadipocytes impairs adipocyte differentiation and decreases triglyceride content. This defect in differentiation can be corrected by stimulating cells with the PPARγ agonist rosiglitazone (Rosi). However, triglyceride accumulation remains decreased by ∼50%, due to a decrease in basal lipogenic rate and increase in basal lipolytic rate. 3T3-L1 preadipocytes overexpressing Tbx15 also have a 15% reduction in mitochondrial mass and a 28% reduction in basal mitochondrial respiration (P = 0.004) and ATP turnover (P = 0.02), and a 45% (P = 0.003) reduction in mitochondrial respiratory capacity. Thus, differential expression of Tbx15 between fat depots plays an important role in the interdepot differences in adipocyte differentiation, triglyceride accumulation, and mitochondrial function that may contribute to the risk of diabetes and metabolic disease.

Development of a risk score for low back pain in office workers--a cross-sectional study

Background

Low back pain (LBP) is common among office workers and is the most common cause of work-related disability in people under 45 years of age. The aetiology of LBP is widely accepted to be multi-factorial. Prognostic research into office workers at risk of developing LBP has received limited attention. The aims of this study were to develop a risk score to identify office workers likely to have LBP and to evaluate its predictive power.

Methods

397 office workers filled out a self-administered questionnaire and underwent physical examination. The questionnaire gathered data on individual, work-related physical and psychosocial data as well as the presence of low back pain in the previous 4 weeks. The physical examination included measurement of body weight, height, waist circumference, hamstrings length, spinal scoliosis, spinal curve, Backache Index and lumbar stability. Logistic regression was used to select significant factors associated with LBP to build a risk score. The coefficients from the logistic regression model were transformed into the components of a risk score.

Results

The model included six items: previous history of working as an office worker, years of work experience, continuous standing for >2 hrs/d, frequency of forward bending during work day, chair having lumbar support and Backache Index outcome. The risk score for LBP in office workers (The Back pain Risk score for Office Workers: The BROW) was built with a risk score ranging from 0 to 9. A cut-off score of ≥4 had a sensitivity of 80% and a specificity of 58%. The positive predictive value and negative predictive values were 70% each.

Conclusions

The BROW is easy and quick to administer. It appears to have reasonable sensitivity, specificity, positive predictive value and negative predictive values for the cut-off point of ≥4. The BROW is a promising tool for use to identify office workers in need of early interventions. Further prospective study is needed to validate the predictive performance of the BROW.

Dose-dependent positive association between cigarette smoking, abdominal obesity and body fat: cross-sectional data from a population-based survey

Background

Although smokers tend to have a lower body-mass index than non-smokers, smoking may favour abdominal body fat accumulation. To our knowledge, no population-based studies have assessed the relationship between smoking and body fat composition. We assessed the association between cigarette smoking and waist circumference, body fat, and body-mass index.

Methods

Height, weight, and waist circumference were measured among 6,123 Caucasians (ages 35-75) from a cross-sectional population-based study in Switzerland. Abdominal obesity was defined as waist circumference ≥102 cm for men and ≥88 cm for women. Body fat (percent total body weight) was measured by electrical bioimpedance. Age- and sex-specific body fat cut-offs were used to define excess body fat. Cigarettes smoked per day were assessed by self-administered questionnaire. Age-adjusted means and odds ratios were calculated using linear and logistic regression.

Results

Current smokers (29% of men and 24% of women) had lower mean waist circumference, body fat percentage, and body-mass index compared with non-smokers. Age-adjusted mean waist circumference and body fat increased with cigarettes smoked per day among smokers. The association between cigarettes smoked per day and body-mass index was non-significant. Compared with light smokers, the adjusted odds ratio (OR) for abdominal obesity in men was 1.28 (0.78-2.10) for moderate smokers and 1.94 (1.15-3.27) for heavy smokers (P = 0.03 for trend), and 1.07 (0.72-1.58) and 2.15 (1.26-3.64) in female moderate and heavy smokers, respectively (P < 0.01 for trend). Compared with light smokers, the OR for excess body fat in men was 1.05 (95% CI: 0.58-1.92) for moderate smokers and 1.15 (0.60-2.20) for heavy smokers (P = 0.75 for trend) and 1.34 (0.89-2.00) and 2.11 (1.25-3.57), respectively in women (P = 0.07 for trend).

Conclusion

Among smokers, cigarettes smoked per day were positively associated with central fat accumulation, particularly in women.

The epidemiology of weight perception: perceived versus self-reported actual weight status among Albertan adults

BACKGROUND

To understand, prevent, and manage weight-related health issues, researchers and clinicians rely on the ability to identify those at risk. Prevention and management strategies may also rely on accurate self-perception of weight and body composition in the general population.

METHODS

We analyzed data from The Tomorrow Project (n = 7,436), a prospective cohort study enrolling adults aged 35-69 years, in Alberta, Canada. Weight perception accuracy was defined based on body mass index (BMI), waist circumference (WC), and a combined (BMI and WC) risk profile.

RESULTS

The majority of participants correctly perceived themselves as overweight. Women were more accurate than men in identifying themselves as overweight. In terms of inaccuracy, more normal-weight women than men perceived themselves to be overweight, while more overweight men than women perceived themselves as about the right weight. When using the combined risk profile, all men with normal weight (BMI) but higher risk WC perceived their weight as about right whereas just under half of men who were overweight (BMI) but lower risk WC perceived their weight as about right. For women, a much higher proportion recognized their weight status as overweight when only BMI was elevated compared to when only WC indicated higher risk.

DISCUSSION

Adults in our sample showed reasonable accuracy in weight perception. Gender differences reveal that women were more accurate than men in identifying themselves as overweight. Incongruence between weight status indicators was noted, indicating the importance of using both BMI and waist circumference as health status measures.

Obesity hypoventilation syndrome

Obesity is becoming a major medical concern in several parts of the world, with huge economic impacts on health- care systems, resulting mainly from increased cardiovascular risks. At the same time, obesity leads to a number of sleep-disordered breathing patterns like obstructive sleep apnea and obesity hypoventilation syndrome (OHS), leading to increased morbidity and mortality with reduced quality of life. OHS is distinct from other sleep- related breathing disorders although overlap may exist. OHS patients may have obstructive sleep apnea/hypopnea with hypercapnia and sleep hypoventilation, or an isolated sleep hypoventilation. Despite its major impact on health, this disorder is under-recognized and under-diagnosed. Available management options include aggressive weight reduction, oxygen therapy and using positive airway pressure techniques. In this review, we will go over the epidemiology, pathophysiology, presentation and diagnosis and management of OHS.

Downregulation of adipose tissue fatty acid trafficking in obesity: a driver for ectopic fat deposition?

OBJECTIVE

Lipotoxicity and ectopic fat deposition reduce insulin signaling. It is not clear whether excess fat deposition in nonadipose tissue arises from excessive fatty acid delivery from adipose tissue or from impaired adipose tissue storage of ingested fat.

RESEARCH DESIGN AND METHODS

To investigate this we used a whole-body integrative physiological approach with multiple and simultaneous stable-isotope fatty acid tracers to assess delivery and transport of endogenous and exogenous fatty acid in adipose tissue over a diurnal cycle in lean (n = 9) and abdominally obese men (n = 10).

RESULTS

Abdominally obese men had substantially (2.5-fold) greater adipose tissue mass than lean control subjects, but the rates of delivery of nonesterified fatty acids (NEFA) were downregulated, resulting in normal systemic NEFA concentrations over a 24-h period. However, adipose tissue fat storage after meals was substantially depressed in the obese men. This was especially so for chylomicron-derived fatty acids, representing the direct storage pathway for dietary fat. Adipose tissue from the obese men showed a transcriptional signature consistent with this impaired fat storage function.

CONCLUSIONS

Enlargement of adipose tissue mass leads to an appropriate downregulation of systemic NEFA delivery with maintained plasma NEFA concentrations. However the implicit reduction in adipose tissue fatty acid uptake goes beyond this and shows a maladaptive response with a severely impaired pathway for direct dietary fat storage. This adipose tissue response to obesity may provide the pathophysiological basis for ectopic fat deposition and lipotoxicity.

Therapeutic prospects of metabolically active brown adipose tissue in humans

The world-wide obesity epidemic constitutes a severe threat to human health and wellbeing and poses a major challenge to health-care systems. Current therapeutic approaches, relying mainly on reduced energy intake and/or increased exercise energy expenditure, are generally of limited effectiveness. Previously believed to be present only in children, the existence of metabolically active brown adipose tissue (BAT) was recently demonstrated also in healthy human adults. The physiological role of BAT is to dissipate chemical energy, mainly from fatty acids, as heat to maintain body temperature in cold environments. Recent studies indicate that the activity of BAT is negatively correlated with overweight and obesity, findings that raise the exciting possibility of new and effective weight reduction therapies based on increased BAT energy expenditure, a process likely to be amenable to pharmacological intervention.

The determinants of misreporting weight and height: The role of social norms

Given the lack of availability of measured anthropometric data for the whole of Spain, this paper combines data from the 2006 Catalan Health and Health Examination Surveys to compute the size of weight and height self-reporting biases. The underlying determinants of these biases are then analyzed, placing special emphasis on the role played by social norms. Our findings show that social norms regarding "ideal" weight (proxied by the average weight of a reference group based on gender and age) tend to affect the self-reporting weight (relative) bias. This finding suggests that the more satisfied individuals feel with their own body image the less prone they are to under-report their weight, although this effect is contingent upon the definition of social norms and the correction of endogeneity. However, we found no evidence of a similar impact caused by the social norms governing height. The relationship found between the measured and self-reported anthropometric data was applied to the Spanish National Health Survey (NHS) so as to correct the self-reported information contained in it. After correcting for self-reporting errors, both the BMI and the prevalence of obesity were found to be significantly underestimated, with instances of misreporting being more prevalent among women.

Differential association of anthropometric parameters with coronary risk in women--data of the CORA study

OBJECTIVE

The predictive value of weight gain, BMI, waist circumference (WC) and waist-to-hip ratio (WHR) as to cardiovascular risk factors and coronary heart disease (CHD) is still controversial.

METHODS

200 consecutive pre- and postmenopausal women with incident CHD (cases) were compared with 255 randomized age-matched population-based controls recruited from corresponding neighborhoods of Hamburg between 1997 and 2001.

RESULTS

At the time of recruitment cases and controls did not differ in BMI, but at any BMI in WC and WHR. Both parameters of central obesity were related to coronary risk. However, after adjustment for conventional risk factors, the odds ratio of WC for CHD lost its significance while the odds ratio of WHR was still 2.20 per 0.1 unit (95% confidence interval 1.48-3.27; p = 0.0001). The pattern of weight gain differed considerably in women with WHR ≥0.85 or <0.85 and closely matched that of women with or without CHD. The dietary pattern did not distinguish women with elevated WC or WHR.

CONCLUSION

In women, an elevated WHR was closely associated with the risk for CHD independent of BMI and conventional risk factors over and above an elevated WC. An increased WC predominantly seems to reflect the presence of components of the metabolic syndrome.

Metabolome-wide association study identifies multiple biomarkers that discriminate north and south Chinese populations at differing risks of cardiovascular disease: INTERMAP study

Rates of heart disease and stroke vary markedly between north and south China. A (1)H NMR spectroscopy-based metabolome-wide association approach was used to identify urinary metabolites that discriminate between southern and northern Chinese population samples, to investigate population biomarkers that might relate to the difference in cardiovascular disease risk. NMR spectra were acquired from two 24-h urine specimens per person for 523 northern and 244 southern Chinese participants in the INTERMAP Study of macro/micronutrients and blood pressure. Discriminating metabolites were identified using orthogonal partial least squares discriminant analysis and assessed for statistical significance with conservative family wise error rate < 0.01 to minimize false positive findings. Urinary metabolites significantly (P < 1.2 × 10(-16) to 2.9 × 10(-69)) higher in northern than southern Chinese populations included dimethylglycine, alanine, lactate, branched-chain amino acids (isoleucine, leucine, valine), N-acetyls of glycoprotein fragments (including uromodulin), N-acetyl neuraminic acid, pentanoic/heptanoic acid, and methylguanidine; metabolites significantly (P < 1.1 × 10(-12) to 2 × 10(-127)) higher in the south were gut microbial cometabolites (hippurate, 4-cresyl sulfate, phenylacetylglutamine, 2-hydroxyisobutyrate), succinate, creatine, scyllo-inositol, prolinebetaine, and trans-aconitate. These findings indicate the importance of environmental influences (e.g., diet), endogenous metabolism, and mammalian-gut microbial cometabolism, which may help explain north-south China differences in cardiovascular disease risk.

Body-mass index and mortality among 1.46 million white adults

BACKGROUND

A high body-mass index (BMI, the weight in kilograms divided by the square of the height in meters) is associated with increased mortality from cardiovascular disease and certain cancers, but the precise relationship between BMI and all-cause mortality remains uncertain.

METHODS

We used Cox regression to estimate hazard ratios and 95% confidence intervals for an association between BMI and all-cause mortality, adjusting for age, study, physical activity, alcohol consumption, education, and marital status in pooled data from 19 prospective studies encompassing 1.46 million white adults, 19 to 84 years of age (median, 58).

RESULTS

The median baseline BMI was 26.2. During a median follow-up period of 10 years (range, 5 to 28), 160,087 deaths were identified. Among healthy participants who never smoked, there was a J-shaped relationship between BMI and all-cause mortality. With a BMI of 22.5 to 24.9 as the reference category, hazard ratios among women were 1.47 (95 percent confidence interval [CI], 1.33 to 1.62) for a BMI of 15.0 to 18.4; 1.14 (95% CI, 1.07 to 1.22) for a BMI of 18.5 to 19.9; 1.00 (95% CI, 0.96 to 1.04) for a BMI of 20.0 to 22.4; 1.13 (95% CI, 1.09 to 1.17) for a BMI of 25.0 to 29.9; 1.44 (95% CI, 1.38 to 1.50) for a BMI of 30.0 to 34.9; 1.88 (95% CI, 1.77 to 2.00) for a BMI of 35.0 to 39.9; and 2.51 (95% CI, 2.30 to 2.73) for a BMI of 40.0 to 49.9. In general, the hazard ratios for the men were similar. Hazard ratios for a BMI below 20.0 were attenuated with longer-term follow-up.

CONCLUSIONS

In white adults, overweight and obesity (and possibly underweight) are associated with increased all-cause mortality. All-cause mortality is generally lowest with a BMI of 20.0 to 24.9.

Intra-individual changes in body weight in population-based cohorts during four decades: the Finnish FINRISK study

BACKGROUND

The aim of the study was to evaluate trends in intra-individual weight changes over the last four decades in Finland.

METHODS

Within the eight FINRISK surveys conducted during the years 1972-2007, we identified individuals who had participated, by chance in at least two surveys. First, individuals aged 25-54 years who had undergone a health examination within 10 years of the first examination (n = 2033) were categorized into five cohorts covering different time periods, and the annual weight change was calculated at follow-up. Second, for each individual aged 25-69 years the longest possible follow-up time (5-35 years) was identified (n = 3443), and the corresponding annual weight change was evaluated.

RESULTS

Comparing the five cohorts from different time periods, the annual increase in body weight among men between 25- and 54-year old remained stable in the range of 0.27-0.47 kg per year over the decades, whereas women belonging to the most recent cohorts (the 1990s) gained weight at 0.53-0.63 kg per year, which is more than double the oldest cohort's weight gain of 0.24 kg. Overall, the annual increase in weight was around 0.3 kg in both sexes. The younger participants had a stronger tendency to gain weight than the older, and those with BMI < 25 kg/m(2) gained more than overweight or obese individuals.

CONCLUSION

The amount of intra-individual annual increase in body weight among men remained stable over the decades, while it increased among women. The tendency to gain weight was most pronounced among the youngest and among those initially leanest.

Body mass index is more strongly associated with hypertension than waist circumference in apparently healthy Japanese men and women

Obesity is associated with hypertension. However, it is controversial which obesity index, body mass index (BMI) or waist circumference (WC), is more strongly associated with hypertension. We compared the cross-sectional associations of BMI and WC with hypertension. Logistic regressions using hypertension as a dependent variable and age, BMI, WC, fasting plasma glucose, triglycerides, high-density lipoprotein cholesterol, smoking status, drinking status, and physical activity as independent variables were performed using data from apparently healthy 1,803 Japanese men aged 49.9 ± 9.0 and 1,150 women aged 49.5 ± 9.0 excluding subjects with a history of cardiovascular disease, or with antidiabetic, antihypertensive and/or antihyperlipidemic medications. The odds ratio [95% confidence interval] of 1 kg/m² increase in BMI and that of 1 cm increase in WC for diagnosing hypertension were 1.23 [1.11-1.36] (p < 0.0001) and 0.99 [0.95-1.02] (p = 0.4) in men and 1.35 [1.16-1.58] (p < 0.0001) and 0.97 [0.91-1.03] (p = 0.4) in women, respectively. Thus, BMI, but not WC, was independently associated with hypertension in apparently healthy Japanese men and women.

The genetics of obesity

Obesity is a result of excess body fat accumulation. This excess is associated with adverse health effects such as CVD, type 2 diabetes, and cancer. The development of obesity has an evident environmental contribution, but as shown by heritability estimates of 40% to 70%, a genetic susceptibility component is also needed. Progress in understanding the etiology has been slow, with findings largely restricted to monogenic, severe forms of obesity. However, technological and analytical advances have enabled detection of more than 20 obesity susceptibility loci. These contain genes suggested to be involved in the regulation of food intake through action in the central nervous system as well as in adipocyte function. These results provide plausible biological pathways that may, in the future, be targeted as part of treatment or prevention strategies. Although the proportion of heritability explained by these genes is small, their detection heralds a new phase in understanding the etiology of common obesity.