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Showing papers by "Claude Bouchard published in 2009"


Journal ArticleDOI
TL;DR: These data demonstrate a dose-response association between sitting time and mortality from all causes and CVD, independent of leisure time physical activity and physicians should discourage sitting for extended periods.
Abstract: KATZMARZYK, P. T., T. S. CHURCH, C. L. CRAIG, and C. BOUCHARD. Sitting Time and Mortality from All Causes, Cardiovascular Disease, and Cancer. Med. Sci. Sports Exerc., Vol. 41, No. 5, pp. 998–1005, 2009. Purpose: Although moderate-tovigorous physical activity is related to premature mortality, the relationship between sedentary behaviors and mortality has not been fully explored and may represent a different paradigm than that associated with lack of exercise. We prospectively examined sitting time and mortality in a representative sample of 17,013 Canadians 18–90 yr of age. Methods: Evaluation of daily sitting time (almost none of the time, one fourth of the time, half of the time, three fourths of the time, almost all of the time), leisure time physical activity, smoking status, and alcohol consumption was conducted at baseline. Participants were followed prospectively for an average of 12.0 yr for the ascertainment of mortality status. Results: There were 1832 deaths (759 of cardiovascular disease (CVD) and 547 of cancer) during 204,732 person-yr of follow-up. After adjustment for potential confounders, there was a progressively higher risk of mortality across higher levels of sitting time from all causes (hazard ratios (HR): 1.00, 1.00, 1.11, 1.36, 1.54; P for trend G0.0001) and CVD (HR: 1.00, 1.01, 1.22, 1.47, 1.54; P for trend G0.0001) but not cancer. Similar results were obtained when stratified by sex, age, smoking status, and body mass index. Age-adjusted all-cause mortality rates per 10,000 person-yr of follow-up were 87, 86, 105, 130, and 161 (P for trend G0.0001) in physically inactive participants and 75, 69, 76, 98, 105 (P for trend = 0.008) in active participants across sitting time categories. Conclusions: These data demonstrate a dose–response association between sitting time and mortality from all causes and CVD, independent of leisure time physical activity. In addition to the promotion of moderate-to-vigorous physical

1,547 citations


Journal ArticleDOI
TL;DR: Bariatric surgery was associated with reduced cancer incidence in obese women but not in obese men, and after exclusion of all cancer cases during the first 3 years of the intervention.
Abstract: Summary Background Obesity is a risk factor for cancer. Intentional weight loss in the obese might protect against malignancy, but evidence is limited. To our knowledge, the Swedish Obese Subjects (SOS) study is the first intervention trial in the obese population to provide prospective, controlled cancer-incidence data. Methods The SOS study started in 1987 and involved 2010 obese patients (body-mass index [BMI] ≥34 kg/m 2 in men, and ≥38 kg/m 2 in women) who underwent bariatric surgery and 2037 contemporaneously matched obese controls, who received conventional treatment. While the main endpoint of SOS was overall mortality, the main outcome of this exploratory report was cancer incidence until Dec 31, 2005. Cancer follow-up rate was 99·9% and the median follow-up time was 10·9 years (range 0–18·1 years). Findings Bariatric surgery resulted in a sustained mean weight reduction of 19·9 kg (SD 15·6 kg) over 10 years, whereas the mean weight change in controls was a gain of 1·3 kg (SD 13·7 kg). The number of first-time cancers after inclusion was lower in the surgery group (n=117) than in the control group (n=169; HR 0·67, 95% CI 0·53–0·85, p=0·0009). The sex–treatment interaction p value was 0·054. In women, the number of first-time cancers after inclusion was lower in the surgery group (n=79) than in the control group (n=130; HR 0·58, 0·44–0·77; p=0·0001), whereas there was no effect of surgery in men (38 in the surgery group vs 39 in the control group; HR 0·97, 0·62–1·52; p=0·90). Similar results were obtained after exclusion of all cancer cases during the first 3 years of the intervention. Interpretation Bariatric surgery was associated with reduced cancer incidence in obese women but not in obese men. Funding Swedish Research Council, Swedish Foundation for Strategic Research, Swedish Federal Government under the LUA/ALF agreement, Hoffmann La Roche, Cederoths, AstraZeneca, Sanofi-Aventis, Ethicon Endosurgery.

680 citations


Journal ArticleDOI
TL;DR: There appears there are gender, age, ethnic, BMI-defined weight status, and income differences in exceeding > or = 2 hours/day in sedentary behavior among youth in the US.
Abstract: Objective. To describe the prevalence of time spent in sedentary behaviors (e.g., TV/video and computer use) among youth in the US. Methods. The National Health and Nutrition Examination Survey (20...

274 citations


Journal ArticleDOI
TL;DR: TheLow prevalence of metabolic syndrome in black adolescents, in parallel with uniformly low prevalence of all 5 risk factors among those with metabolic syndrome, portend ethnic disparities in the time table for early onset of cardiometabolic disorders.
Abstract: Objective To investigate the prevalence of distinct combinations of components of the metabolic syndrome among adolescents. Design A complex, multistage, stratified geographic area design for collecting representative data from the noninstitutionalized US population. Setting The NHANES, an ongoing surveillance of the nation's health conducted by the Centers for Disease Control and Prevention. Participants Two thousand four hundred fifty-six Hispanic, white, and black adolescents aged 12 to 19 years observed in the 2001-2002, 2003-2004, and 2005-2006 NHANES data releases. Main Outcome Measures Metabolic syndrome was defined as having 3 or more disorders in the following measurements: waist circumference, blood pressure, fasting triglycerides, high-density lipoprotein serum cholesterol, and glucose. Results About half of the participants had at least 1 disordered measurement, with an overall metabolic syndrome prevalence of 8.6% (95% confidence interval, 6.5%-10.6%). Prevalence was higher in males (10.8%) than females (6.1%), and in Hispanic (11.2%) and white (8.9%) individuals than in black individuals (4.0%). In black females, there was a high prevalence of a large waist circumference (23.3%), but no component of metabolic syndrome dominated its diagnosis in black adolescents of either sex. A large waist circumference and high fasting triglyceride and low high-density lipoprotein serum cholesterol concentrations were salient factors in Hispanic and white adolescents of both sexes; high glucose concentrations were prominent among Hispanic and white males. Conclusion The low prevalence of metabolic syndrome in black adolescents, in parallel with uniformly low prevalence of all 5 risk factors among those with metabolic syndrome, portend ethnic disparities in the time table for early onset of cardiometabolic disorders.

251 citations


Journal ArticleDOI
TL;DR: In men, high LTSB is associated with higher odds of metabolic syndrome and individual CVD risk factors regardless of meeting physical activity recommendations.
Abstract: Background: This study examines leisure time sedentary behavior (LTSB) and usual occupational/domestic activity (UODA) and their relationship with metabolic syndrome and individual cardiovascular disease (CVD) risk factors, independent of physical activity level. Methods: National Health and Nutrition Examination Survey (NHANES) 2003–2006 data from men (n = 1868) and women (n = 1688) with fasting measures were classified as having metabolic syndrome by the American Heart Association/National Heart, Lung, and Blood Institute (AHA/NHLBI) definition. LTSB was determined from self-reported television viewing and computer usage. UODA was self-reported daily behavior (sitting, standing, walking, carrying loads). Results: LTSB ≥4 hours/day was associated with odds of having metabolic syndrome of 1.94 (95% confidence interval [CI], 1.24, 3.03) in men compared to ≤1 hour/day. LTSB ≥4 hour/day was also associated with higher odds of elevated waist circumference (1.88, CI, 1.03, 3.41), low high-density lipoprotein c...

196 citations


Journal ArticleDOI
TL;DR: The higher CRP concentrations found in women appear to be due to their greater accumulation of subcutaneous fat than that observed in men, and a multivariate model of the whole sample found that both SAT and VAT and the sex x SAT interaction term were significant correlates of CRP and IL-6 concentrations.

185 citations


Journal ArticleDOI
TL;DR: Short and long sleeping times are associated with a higher risk of developing type 2 diabetes/IGT, independent of several covariates, and results suggest that sleep duration may represent a novel risk factor for type 2abetes/IGt.

180 citations


Journal ArticleDOI
01 Oct 2009-Obesity
TL;DR: The results show that excess body weight or weight gain results from a number of obesogenic behaviors that have received considerable attention over the past decade and indicate that the four factors, which have the best predictive potential of variations in BMI, do not have a “caloric value” per se.
Abstract: The aim of this study was to determine the independent contribution of previously reported risk factors for adult overweight and obesity. A cross-sectional (n=537) and a longitudinal (n=283; 6-year follow-up period) analysis was performed for nine risk factors for overweight and obesity assessed in adult participants (aged 18-64 years) of the Quebec Family Study (QFS). The main outcome measure was overweight/obesity, defined as a BMI>or=25 kg/m2. Using logistic regression analysis adjusted for age, sex, and socioeconomic status, short sleep duration, high disinhibition eating behavior, low dietary calcium intake, high susceptibility to hunger behavior, nonparticipation in high-intensity physical exercise, high dietary restraint behavior, nonconsumption of multivitamin and dietary supplements, high dietary lipid intake, and high alcohol intake were all significantly associated with overweight and obesity in the cross-sectional sample. The analysis of covariance adjusted for age, socioeconomic status, and all other risk factors revealed that only individuals characterized by short sleep duration, high disinhibition eating behavior, and low dietary calcium intake had significantly higher BMI compared to the reference category in both sexes. Over the 6-year follow-up period, short-duration sleepers, low calcium consumers, and those with a high disinhibition and restraint eating behavior score were significantly more likely to gain weight and develop obesity. These results show that excess body weight or weight gain results from a number of obesogenic behaviors that have received considerable attention over the past decade. They also indicate that the four factors, which have the best predictive potential of variations in BMI, be it in a cross-sectional or a longitudinal analytical design, do not have a "caloric value" per se.

158 citations


Journal ArticleDOI
TL;DR: Women that were younger, less fit, or exercised more during the DREW trial had greater odds of improving their fitness with training, and the most important finding was that greater volumes of exercise were associated with a lower probability of being a nonresponder.
Abstract: SISSON, S. B., P. T. KATZMARZYK, C. P. EARNEST, C. BOUCHARD, S. N. BLAIR, and T. S. CHURCH. Volume of Exercise and Fitness Nonresponse in Sedentary, Postmenopausal Women. Med. Sci. Sports Exerc., Vol. 41, No. 3, pp. 539-545, 2009. There is a wide individual heterogeneity in the maximal aerobic fitness (VO2max) response to exercise training. Purpose: To examine predictors of VO2max nonresponse after aerobic exercise training in postmenopausal women. Methods: The Dose Response to Exercise in Women (DREW) study was a randomized, controlled trial examining the effects of incremental training doses on sedentary postmenopausal women (45-75 yr). Participants were randomized to one of three exercise treatment groups (4, 8, or 12 kcalIkg j1 Iwk j1 ) for 6 months. Participants exercised 3-4 dIwk j1 at 50% VO2max. Predictors of baseline VO2max were determined by ANOVA. We used a logistic regression analyses with categorical (ethnicity and treatment group) and standardized continuous variables (age, body mass index (BMI), and baseline VO2max) to determine predictors of nonresponse ($ e 0L Imin j1 ). Our analysis included 310 women because the control group was excluded. Results: A total of 44.9%, 23.8%, and 19.3% of the 4-, the 8-, and the 12-kcalIkg j1 Iwk j1 treatment groups (P G 0.0001), respectively, were nonresponders. Maximal effort, BMI, age, and race significantly predicted baseline VO2max. Treatment group (8 and 12 kcalIkg j1 Iwk j1 vs 4 kcalIkg j1 Iwk j1 ; P = 0.0003), baseline VO2max (P G 0.0001), and age (P G 0.05) were significant predictors of nonresponse. Odds ratios and 95% confidence intervals were 2.13 (1.53-2.95) for baseline VO2max; 1.35 (1.00-1.83) for age; 0.45 (0.24-0.85) for the 8- versus the 4-kcalIkg j1 Iwk j1 group; and 0.27 (0.13-0.53) for the 12- versus the 4-kcalIkg j1 Iwk j1 group. Conclusion: Women that were younger, less fit, or exercised more during the DREW trial had greater odds of improving their fitness with training. The most important finding of this study was that greater volumes of exercise were associated with a lower probability of being a nonresponder. Key Words: INDIVIDUAL VARIABILITY, TRAINABILITY, AEROBIC TRAINING, DOSE RESPONSE

144 citations


Journal ArticleDOI
TL;DR: This brief review focuses on the genetic contribution to childhood obesity, and suggests that the prevalence of childhood obesity is increasing across generations as a result of positive assortative mating with obese husbands and wives contributing more obese offspring than normal-weight parents.

125 citations


Journal ArticleDOI
TL;DR: Diabetes-associated variants in CDKAL1, CDKN2B, HHEX/IDE, IGF2BP2, KCNJ11, SLC30A8 and TCF7L2 are associated with physiological alterations leading to T2DM, such as glucose intolerance, impaired insulin secretion or insulin resistance, supporting their role in the disease aetiology.
Abstract: Several single nucleotide polymorphisms (SNPs) for type 2 diabetes mellitus (T2DM) risk have been identified by genome wide association studies (GWAS). The objective of the present study was to investigate the impact of these SNPs on T2DM intermediate phenotypes in order to clarify the physiological mechanisms through which they exert their effects on disease etiology. We analysed 23 SNPs in 9 T2DM genes (CDKAL1, CDKN2B, HHEX/IDE, IGF2BP2, KCNJ11, SLC30A8, TCF2, TCF7L2 and WFS1) in a maximum of 712 men and women from the Quebec Family Study. The participants underwent a 75 g oral glucose tolerance test (OGTT) and were measured for glucose, insulin and C-peptide levels. Indices of insulin sensitivity and insulin secretion were derived from fasting and OGTT measurements. We confirmed the significant associations of variants in CDKAL1, CDKN2B, HHEX/IDE, KCNJ11 and TCF7L2 with insulin secretion and also found associations of some of these variants with insulin sensitivity and glucose tolerance. IGF2BP2 and SLC30A8 SNPs were not associated with insulin secretion but were with insulin sensitivity and glucose tolerance (0.002 ≤ P ≤ 0.02). To examine the joint effects of these variants and their contribution to T2DM endophenotypes variance, stepwise regression models were used and the model R 2 was computed. The variance in the phenotypes explained by combinations of variants ranged from 2.0 to 8.5%. Diabetes-associated variants in CDKAL1, CDKN2B, HHEX/IDE, IGF2BP2, KCNJ11, SLC30A8 and TCF7L2 are associated with physiological alterations leading to T2DM, such as glucose intolerance, impaired insulin secretion or insulin resistance, supporting their role in the disease aetiology. These variants were found to account for 2.0–8.5% of the variance of T2DM-related traits.

Journal ArticleDOI
TL;DR: The data reviewed in this paper reveal that individual differences in the response to alterations in energy balance induced by diet or exercise are ubiquitous and it is likely that genetic variation at several genes contributes to this heterogeneity of responses and thus to the susceptibility to obesity.
Abstract: The data reviewed in this paper reveal that individual differences in the response to alterations in energy balance induced by diet or exercise are ubiquitous. These differences are observed in a variety of obesity-related phenotypes, including body weight, body fatness, and abdominal visceral fat. Although little is known about the causes of the heterogeneity in responsiveness to dietary habits or to regular exercise, the evidence accumulated so far suggests that genetic factors may play an important role in determining the response of body mass and body fat stores to chronic alterations in energy balance. It is likely that genetic variation at several genes contributes to this heterogeneity of responses and thus to the susceptibility to obesity. Research on the genetic and molecular basis of gene-environment interactions has become a major area of investigation. One can, therefore, anticipate that major advances will occur in the coming years with respect to the identification of the genetic and molecular causes of the susceptibility to the most common diseases, including obesity.

Journal ArticleDOI
TL;DR: The data suggested an association with extreme degrees of obesity, and consequently heterogeneous effects from different study designs may mask an underlying association when unaccounted for.
Abstract: The INSIG2 rs7566605 polymorphism was identified for obesity (BMI> or =30 kg/m(2)) in one of the first genome-wide association studies, but replications were inconsistent. We collected statistics from 34 studies (n = 74,345), including general population (GP) studies, population-based studies with subjects selected for conditions related to a better health status ('healthy population', HP), and obesity studies (OB). We tested five hypotheses to explore potential sources of heterogeneity. The meta-analysis of 27 studies on Caucasian adults (n = 66,213) combining the different study designs did not support overall association of the CC-genotype with obesity, yielding an odds ratio (OR) of 1.05 (p-value = 0.27). The I(2) measure of 41% (p-value = 0.015) indicated between-study heterogeneity. Restricting to GP studies resulted in a declined I(2) measure of 11% (p-value = 0.33) and an OR of 1.10 (p-value = 0.015). Regarding the five hypotheses, our data showed (a) some difference between GP and HP studies (p-value = 0.012) and (b) an association in extreme comparisons (BMI> or =32.5, 35.0, 37.5, 40.0 kg/m(2) versus BMI<25 kg/m(2)) yielding ORs of 1.16, 1.18, 1.22, or 1.27 (p-values 0.001 to 0.003), which was also underscored by significantly increased CC-genotype frequencies across BMI categories (10.4% to 12.5%, p-value for trend = 0.0002). We did not find evidence for differential ORs (c) among studies with higher than average obesity prevalence compared to lower, (d) among studies with BMI assessment after the year 2000 compared to those before, or (e) among studies from older populations compared to younger. Analysis of non-Caucasian adults (n = 4889) or children (n = 3243) yielded ORs of 1.01 (p-value = 0.94) or 1.15 (p-value = 0.22), respectively. There was no evidence for overall association of the rs7566605 polymorphism with obesity. Our data suggested an association with extreme degrees of obesity, and consequently heterogeneous effects from different study designs may mask an underlying association when unaccounted for. The importance of study design might be under-recognized in gene discovery and association replication so far.

Journal ArticleDOI
TL;DR: It is suggested that the age-related variation in CRP and IL-6 is largely explained by differences in visceral AT, and matching for visceral AT eliminated the difference between middle-aged men and younger adult men in inflammatory markers.
Abstract: As visceral adipose tissue (AT) accumulation and inflammatory markers are known to increase with age, we examined whether this age-related change in regional AT distribution could contribute to the increase in the concentration of some inflammatory markers found with age. Two hundred eight healthy men aged 18.6 to 72.2 years and covering a wide range of adiposity values (body mass index, 18.5-39.3 kg/m 2 ) were studied. Plasma C-reactive protein (CRP), interleukin-6 (IL-6), and tumor necrosis factor– α (TNF- α ) levels were measured by enzyme-linked immunosorbent assay. Anthropometric characteristics such as height, weight, and waist girth were measured; and body mass index was calculated. Cross-sectional areas of abdominal AT were obtained at L4-L5 by computed tomography. Fasting blood samples were collected to determine a complete lipoprotein lipid profile, and a 75-g oral glucose tolerance test was performed. Overall, visceral AT accumulation was positively correlated with age ( r = 0.51, P r = 0.39, P r = 0.32, P α ( r = 0.14, P r = 0.36, P r = 0.39, P α ( r = 0.15, P P P P

Journal ArticleDOI
TL;DR: It is suggested that the sex dimorphism observed in adipose tissue localization could partly explain the greater cardiovascular risk associated with obesity in men than in women, and those with a "male" distribution of adiposity and with associated metabolic complications greatly benefit from aerobic exercise-training.
Abstract: Obesity has been associated with numerous metabolic complications, such as changes in the concentration and/or composition of plasma lipoproteins, glucose intolerance and hyperinsulinemia leading to diabetes and hypertension. The relation of obesity to cardiovascular disease has not, however, been consistently reported. Recent prospective studies have clearly indicated that the distribution of adipose tissue was a significant cardiovascular risk factor and numerous studies have shown that metabolic disturbances were more closely associated with the level of abdominal fat than excess adiposity per se. As obese men generally store their energy excess in the abdominal region and women in the peripheral fat depots, the metabolic complications of obesity seem to be more closely related to adiposity in men than in women. It is suggested that the sex dimorphism observed in adipose tissue localization could partly explain the greater cardiovascular risk associated with obesity in men than in women. Indeed, obese women with a “male” (abdominal) distribution of body fat have greater metabolic complications than women with lower body fat. When aerobic exercise-training is used to induce weight loss, men generally lose more fat than women. In men, the loss of adipose tissue appears to be central, potentially reducing the risk of cardiovascular disease, whereas a relative resistance to fat loss is observed in women compared to men. Although resistance to fat loss is noted in women, those with a “male” distribution of adipose tissue (high waist-to-hip ratio and high intra-abdominal fat deposition) and with associated metabolic complications greatly benefit from aerobic exercise-training. As a substantial proportion of obese men, as well as women with excess abdominal fat, appear to be the subgroups of obese subjects showing metabolic disturbances, emphasis should be placed on the tracking and the treatment of these subjects. Exercise-training appears to be useful in improving the metabolic profile of these subjects, potentially reducing the risk of cardiovascular disease.

Journal ArticleDOI
TL;DR: A previously reported blood pressure (BP) quantitative trait locus on rat Chromosome 1 was isolated in a short congenic segment spanning 804.6 kb, representing a high resolution positional cloning and translational study for Adamts16 as a candidate gene controlling BP.
Abstract: A previously reported blood pressure (BP) quantitative trait locus on rat Chromosome 1 was isolated in a short congenic segment spanning 804.6 kb. The 804.6 kb region contained only two genes, LOC306664 and LOC306665. LOC306664 is predicted to translate into A Disintegrin-like and Metalloproteinase with Thrombospondin Motifs-16 (Adamts16). LOC306665 is a novel gene. All predicted exons of both LOC306664 and LOC306665 were sequenced. Non-synonymous variants were identified in only one of these genes, LOC306664. These variants were naturally existing polymorphisms among inbred, outbred and wild rats. The full-length rat transcript of Adamts16 was detected in multiple tissues. Similar to ADAMTS16 in humans, expression of Adamts16 was prominent in the kidney. Renal transcriptome analysis suggested that a network of genes related to BP was differential between congenic and S rats. These genes were also differentially expressed between kidney cell lines with or without knock-down of Adamts16. Adamts16 is conserved between rats and humans. It is a candidate gene within the homologous region on human Chromosome 5, which is linked to systolic and diastolic BP in the Quebec Family Study. Multiple variants, including an Ala to Pro variant in codon 90 (rs2086310) of human ADAMTS16, were associated with human resting systolic BP (SBP). Replication study in GenNet confirmed the association of two variants of ADAMTS16 with SBP, including rs2086310. Overall, our report represents a high resolution positional cloning and translational study for Adamts16 as a candidate gene controlling BP.

Journal ArticleDOI
Claude Bouchard1

Journal ArticleDOI
TL;DR: The results suggest that the previously reported association between poor fitness and low-grade inflammation may be largely attributable to increased visceral AT accumulation and its associated state of insulin resistance, conditions frequently observed in subjects with poor cardiorespiratory fitness.
Abstract: The objective of the present study was to determine the respective contributions of visceral adipose tissue (AT) accumulation and cardiorespiratory fitness to variation of inflammatory markers in men and women. Circulating levels of C-reactive protein, tumor necrosis factor-α, interleukin-6, and adiponectin were obtained with visceral AT (computed tomography) and fitness (physical working capacity test) levels in a sample of healthy men (n = 120) and women (n = 152) covering a wide range of adiposity. An inflammation score was developed based on gender-specific percentile values of each inflammatory marker (0 or 1), which yielded a score ranging from 0 (low) to 4 (high). Visceral AT was positively associated with C-reactive protein and interleukin-6 levels (r ≥0.35, p 2 for men and 2 for women), prevalences of participants with an increased inflammation score were 23.9% and 28.0%, respectively, for participants with high and low fitness, whereas in subjects with increased visceral AT, prevalences of a high inflammation score were 60.0% and 61.7%, respectively, for participants with high and low fitness. In conclusion, these results suggest that the previously reported association between poor fitness and low-grade inflammation may be largely attributable to increased visceral AT accumulation and its associated state of insulin resistance, conditions frequently observed in subjects with poor cardiorespiratory fitness.

Journal ArticleDOI
01 Apr 2009-Obesity
TL;DR: It is proposed that weight loss might be expressed as a “percentage of excess body weight loss” (%EBWL), which could complement the use of actual weight loss and facilitate comparison across behavioral, medical, and surgical trials for weight loss.
Abstract: This commentary is written to recommend that we consider modifying the way we express weight change in clinical trials of weight management as well as in the physician’s office. In most cases, weight loss is expressed as pounds (kg in other countries) or as a percent of baseline weight. We are proposing that weight loss might be expressed as a “percentage of excess body weight loss” (%EBWL), which could complement the use of actual weight loss. %EBWL provides a better estimate of the amount of weight loss that has been achieved relative to a defined goal level; however, that may be defined. This method is typically used to express weight change after surgical treatment for obesity. Using a standard metric will facilitate comparison across behavioral, medical, and surgical trials for weight loss, and may thus be beneficial to patients, clients, health-care providers, investigators, and policy-makers. Weight loss has been expressed in many different ways over the past 150 years (1). In his famous pamphlet titled “Letter on Corpulence Addressed to the Public” published in 1863, William Banting expressed his own weight loss in pounds (2). Most others have followed his lead, using either pounds or kilograms of actual weight lost. One problem with this approach is that heavier people tend to lose more weight and thus may appear more successful over short periods of time. Expressing weight loss as a percent of initial body weight will partly correct for this, but will not provide a true assessment of the amount of excess weight a patient or client might expect to lose in relation to a floor or maximal likely weight loss. In 1835, Quetelet introduced what is now known as the BMI as a way of normalizing weight for different heights in his studies of populations (3). A century and a half later, the BMI was adopted, internationally, as a way of evaluating whether an individual is overweight or obese (4,5). The advantage of the BMI is that it minimizes the effect of height better than other height/weight relationships, except possibly weight/height (6). Changes in BMI have also been used as one method of expressing weight loss. Because the height of adults does not change during weight loss, using BMI units can be confusing and provides no advantages over using weight loss alone. Moreover, reporting weight loss as change in BMI units does not reveal how much of the excess weight has been lost. In 1959, a classic article by Stunkard and McLaren-Hume (7) reported on a new method for evaluating weight loss in cohorts. They expressed weight loss as a percentage of patients who lost either 20 or 40 pounds. Because heavier people tend to lose more weight, Trulson (8) introduced a somewhat more sophisticated approach in which both initial body weight and an appropriate weight loss for the degree of overweight were included. A third criterion was developed by Jolliffe and Alpert (9), who proposed the performance index to measure weight loss relative to anticipated or predicted weight loss:

Journal ArticleDOI
TL;DR: The hypothesis that the relationship between low fitness and elevated blood pressure could be related, at least in part, to the higher level of visceral adipose tissue often found among unfit individuals is tested.
Abstract: Individuals with poor cardiorespiratory fitness have higher blood pressure than fit individuals. Individuals with low fitness levels also tend to be characterized by higher visceral adiposity compared with physically fit individuals. We tested the hypothesis that the relationship between low fitness and elevated blood pressure could be related, at least in part, to the higher level of visceral adipose tissue often found among unfit individuals. This study included 407 asymptomatic, nondiabetic participants. Visceral adipose tissue was assessed by computed tomography, and fitness was measured by a progressive submaximal physical working capacity test. Participants in the highest visceral adipose tissue tertile showed the highest systolic and diastolic blood pressures, whereas participants in the highest fitness tertile had the lowest blood pressure values ( P P =0.01), independent of their fitness category. Linear regression analyses showed that age and visceral adipose tissue, but not fitness, predicted systolic blood pressure ( r 2 =0.11 [ P P P value nonsignificant], for age, visceral adipose tissue, and fitness, respectively) and diastolic blood pressure ( r 2 =0.17 [ P P P value nonsignificant], for age, visceral adipose tissue, and fitness, respectively). Individuals with high visceral adipose tissue levels have higher blood pressure, independent of their fitness. Visceral adipose tissue may represent an important clinical target in the management of elevated blood pressure.

Journal ArticleDOI
01 Mar 2009-Obesity
TL;DR: Self‐reported height and weight portend underestimation of obesity prevalence and the effect varies by ethnicity and gender, however, comparisons depend on the true prevalence within ethnicity‐gender groups.
Abstract: As use of self-reported data to classify obesity continues, ethnic differences in reporting errors remain unclear. The objective of this study is to elucidate misreporting disparities between African Americans (AAs) and European Americans (EAs). The Pennington Center Longitudinal Study (PCLS) is an ongoing investigation of environmental, behavioral, and biological factors associated with obesity, diabetes, and other common diseases. Self-reported and measured height and weight were collected during initial screening for eligibility in various studies by telephone and clinic visits. All ethnicity-sex groups (15,656 adults aged 18-65 years, 53% obese, 34% AA, 37% men) misreported heights and weights increasingly as measured values increased (P < 0.0001). More AA vs. EA women (P < 0.001) misreported height and weight, but more EA vs. AA men misreported their weight (P < 0.02). Obesity was underestimated more in AA vs. EA women (self-reported - measured prevalence = -4.0% (AA) vs. -2.6% (EA), P < 0.0001), but less in AA vs. EA men (-3.2% (AA) vs. -4.2% (EA), P < 0.0001)). With measured obesity prevalence equalized at 53% in all groups, the self-reported obesity prevalence in women was 50.4% (AA) vs. 49.6% (EA), and in men 49.8% (AA) vs. 47.3 (EA). Underestimation in women was -2.6% (AA) vs. -3.4% (EA); in men it was -3.2% (AA) vs. -5.7% (EA), P < 0.003. Self-reported height and weight portend underestimation of obesity prevalence and the effect varies by ethnicity and gender. However, comparisons depend on the true prevalence within ethnicity-gender groups. After controlling for obesity prevalence, disparity in underestimation was greater in EA than in AA men (P < 0.003) but not women.

Journal ArticleDOI
Claude Bouchard1
TL;DR: This paper reviews current data concerning the role of the genotype in human variation in fat distribution and its contribution in regulating fat deposition in various regions of the body, primarily the lower trunk area and concludes that the preferential site of fat deposition when exposed to chronic overfeeding is largely determined by one's genotype.
Abstract: This paper reviews current data concerning the role of the genotype in human variation in fat distribution and its contribution in regulating fat deposition in various regions of the body, primarily the lower trunk area. After statistical control over age, gender and total amount of subcutaneous fat, one finds an additive genetic effect of about 20–25 % of remaining human variance in amount of lower trunk fat and in the relative proportion of lower trunk versus extremity fat. In spite of such a moderate genetic effect in fat distribution, the preferential site of fat deposition when exposed to chronic overfeeding is largely determined by one's genotype. Characteristics of regional adipose tissue metabolism and morphology are probably involved in mediating some of these genetic effects but other regulatory mechanisms are undoubtedly implicated.

Journal ArticleDOI
01 Jul 2009-Obesity
TL;DR: The results suggest that the OSBPL11 gene is involved in cholesterol and glucose metabolism in obese individuals.
Abstract: The prevalence of morbid obesity and its associated metabolic complications has risen rapidly in the past decade. Recently, we have established the transcriptome of the visceral adipose tissue of nondiabetic severely obese men with and without metabolic syndrome (MetS) that provided new candidate genes for cardiovascular disease (CVD) risk factors. The oxysterol-binding protein–like protein 11 (OSBPL11) that belongs to the OSBP family of intracellular receptors was one of the genes found to be significantly overexpressed in the MetS group. To determine whether OSBPL11 gene polymorphisms are associated with CVD risk factors and diabetes, OSBPL11 gene promoter and coding regions were sequenced in 25 individuals and six tagging single-nucleotide polymorphisms (SNPs) capturing 85% of gene sequence–derived common genetic variability (minor allele frequency (MAF) > 5%) were genotyped in two samples for a total of 962 obese individuals. Using a multistage experimental design, χ2-tests and logistic regressions were applied to compare genotype frequencies and to compute odds ratios (ORs) for low and high CVD risk groups. Significant associations between rs1055419 and diastolic blood pressure (OR = 0.53; P = 0.01) were found whereas IVS12+95 T>C, a newly discovered SNP, was associated with low-density lipoprotein–cholesterol levels (OR = 1.63; P < 0.001), hyperglycemia/diabetes (OR = 1.48; P < 0.004) as well as with MetS per se (OR = 1.56; P < 0.01). These results suggest that the OSBPL11 gene is involved in cholesterol and glucose metabolism in obese individuals.

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TL;DR: It is suggested that gene-dietary fat interactions may influence glucose homeostasis-related phenotypes and play an important role in determining the increased risk of diabetes associated with the T2DM susceptibility genes.
Abstract: Background/Aims: Genome-wide association studies have led to the identification of several susceptibility genes for type 2 diabetes mellitus (T2DM). The objective of this study was

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TL;DR: A role for the GAD2 gene in determining food intake, eating behaviors and weight gain over time in women is suggested and evidence of association with age- and BMI- adjusted phenotypes is found in men.

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TL;DR: The data suggest that KIF5B is a strong candidate gene for the response of stroke volume to regular exercise, and training-induced changes in submaximal exercise stroke volume may be due to mitochondrial function and variation in Kif5B expression as determined by functional SNPs in its promoter.
Abstract: A genome-wide linkage scan for endurance training-induced changes in stroke volume detected a quantitative trait locus on chromosome 10p11 in white families of the HERITAGE Family Study. Dense micr...

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01 Nov 2009-Obesity
TL;DR: Differences in adiposity between ethnic groups should be considered in disease risk assessment and stratification as they are observed even for a given BMI level.
Abstract: The purpose of this study was to examine ethnic differences in adiposity as measured by sum of skinfolds (SKF) and waist circumference (WC) in children and adolescents, after statistical adjustment for the BMI and age. A cross sectional sample of 3,218 (55% white, 49% male) children and adolescents aged 5-18 years who participated in the Bogalusa Heart Study (1992-1994) were included in these analyses. Sex-specific ANOVAs, adjusted for BMI and age, for each 2-year age group compared measures of adiposity (SKF and WC) between ethnic groups. No significant differences in the proportions of children and adolescents who were overweight and obese by ethnicity or sex were found. Mean SKF in normal weight (P < 0.0001) and overweight (P < 0.0001) categories was higher for white than black children of both sexes. Across most age categories, white boys and girls had significantly higher SKF than black boys and girls, respectively (P

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TL;DR: Severe obesity in Han Chinese was associated with 3 novel common SNPs for ESR1 and PPARgamma, which collectively result in a >5-fold risk of severe obesity.

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TL;DR: The observed associations with resting and submaximal-exercise cardiovascular and metabolic traits in the HERITAGE Family Study are likely due to neither variation in the promoter nor known coding SNPs of SLC4A5.
Abstract: The sodium bicarbonate cotransporter gene SLC4A5, associated earlier with cardiovascular phenotypes, was tested for associations in the HERITAGE Family Study, and possible mechanisms were investigated. Twelve tag-single nucleotide polymorphisms (SNPs) covering the SLC4A5 gene were analyzed in 276 Black and 503 White healthy, sedentary subjects. Associations were tested using a variance components-based (QTDT) method with data adjusted for age, sex and body size. In Whites, rs6731545 and rs7571842 were significantly associated with resting and submaximal exercise pulse pressure (PP) (0.0004

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Claude Bouchard1