Showing papers in "International Journal of Obesity in 2002"
TL;DR: The complexity of the leptin axis indicates that it is unlikely that effective treatments for obesity will be simply derived, but improving knowledge and understanding of these complex interactions may point the way to the underlying physiology which predisposes some individuals to apparently unregulated weight gain.
Abstract: Following the discovery of leptin in 1994, the scientific and clinical communities have held great hope that manipulation of the leptin axis may lead to the successful treatment of obesity. This hope is not yet dashed; however the role of the leptin axis is now being shown to be ever more complex than was first envisaged. It is now well established that leptin interacts with pathways in the central nervous system and through direct peripheral mechanisms. In this review, we consider the tissues in which leptin is synthesized and the mechanisms which mediate leptin synthesis, the structure of leptin and the knowledge gained from cloning leptin genes in aiding our understanding of the role of leptin in the periphery. The discoveries of expression of leptin receptor isotypes in a wide range of tissues in the body have encouraged investigation of leptin interactions in the periphery. Many of these interactions appear to be direct, however many are also centrally mediated. Discovery of the relative importance of the centrally mediated and peripheral interactions of leptin under different physiological states and the variations between species is beginning to show the complexity of the leptin axis. Leptin appears to have a range of roles as a growth factor in a range of cell types: as be a mediator of energy expenditure; as a permissive factor for puberty; as a signal of metabolic status and modulation between the foetus and the maternal metabolism; and perhaps importantly in all of these interactions, to also interact with other hormonal mediators and regulators of energy status and metabolism such as insulin, glucagon, the insulin-like growth factors, growth hormone and glucocorticoids. Surely, more interactions are yet to be discovered. Leptin appears to act as an endocrine and a paracrine factor and perhaps also as an autocrine factor. Although the complexity of the leptin axis indicates that it is unlikely that effective treatments for obesity will be simply derived, our improving knowledge and understanding of these complex interactions may point the way to the underlying physiology which predisposes some individuals to apparently unregulated weight gain.
1,013 citations
TL;DR: Irrespective of the pathogenetic mechanism involved, obese PCOS women have more severe hyperandrogenism and related clinical features (such as hirsutism, menstrual abnormalities and anovulation) than normal-weight PCos women.
Abstract: The polycystic ovary syndrome (PCOS) is a condition characterized by hyperandrogenism and chronic oligo-anovulation. However, many features of the metabolic syndrome are inconsistently present in the majority of women with PCOS. Approximately 50% of PCOS women are overweight or obese and most of them have the abdominal phenotype. Obesity may play a pathogenetic role in the development of the syndrome in susceptible individuals. In fact, insulin possesses true gonadotrophic function and an increased insulin availability at the level of ovarian tissue may favour excess androgen synthesis. Obesity, particularly the abdominal phenotype, may be partly responsible for insulin resistance and associated hyperinsulinemia in women with PCOS. Therefore, obesity-related hyperinsulinemia may play a key role in favouring hyperandrogenism in these women. Other factors such as increased estrogen production rate, increased activity of the opioid system and of the hypothalamic-pituitary-adrenal axis, decreased sex hormone binding globulin synthesis and, possibly, high dietary lipid intake, may be additional mechanisms by which obesity favours the development of hyperandrogenism in PCOS. Irrespective of the pathogenetic mechanism involved, obese PCOS women have more severe hyperandrogenism and related clinical features (such as hirsutism, menstrual abnormalities and anovulation) than normal-weight PCOS women. This picture tends to be more pronounced in obese PCOS women with the abdominal phenotype. Body weight loss is associated with beneficial effects on hormones, metabolism and clinical features. A further clinical and endocrinological improvement can also be achieved by adding insulin-sensitizing agents and/or antiandrogens to weight reduction programmes. These obviously emphasize the role of obesity in the pathophysiology of PCOS.
730 citations
TL;DR: Many adolescents, in particular those who are overweight, report being teased about their weight and being bothered by the teasing, which is associated with disordered eating behaviors that may place overweight youth at increased risk for weight gain.
Abstract: OBJECTIVES: This study aimed to assess the prevalence of perceived weight-teasing and associations with unhealthy weight-control behaviors and binge eating in a population-based sample of youth. Particular focus was placed on overweight youth, who may be most vulnerable to weight-teasing. METHODS: The study population included 4746 adolescents from St Paul/Minneapolis public schools who completed surveys and anthropometric measurements as part of Project EAT, a population-based study of eating patterns and weight concerns among teens. RESULTS: There were statistically significant associations between perceived weight-teasing and weight status; both overweight and underweight youth reported higher levels of teasing than average weight youth. Very overweight youth (body mass index (BMI) ≥95th percentile) were most likely to be teased about their weight; 63% of very overweight girls, and 58% of very overweight boys reported being teased by their peers, while weight-teasing by family members was reported by 47% of these girls and 34% of these boys. Youth who were teased about their weight, particularly overweight girls, reported that it bothered them. Perceived weight-teasing was significantly associated with disordered eating behaviors among overweight and non-overweight girls and boys. For example, among overweight youth, 29% of girls and 18% of boys who experienced frequent weight-teasing reported binge-eating as compared to 16% of girls and 7% of boys who were not teased. CONCLUSIONS: Many adolescents, in particular those who are overweight, report being teased about their weight and being bothered by the teasing. Weight-teasing is associated with disordered eating behaviors that may place overweight youth at increased risk for weight gain. Educational interventions and policies are needed to curtail weight-related mistreatment among youth.
720 citations
TL;DR: Reference intervals for FFMI and FMI could be of practical value for the clinical evaluation of a deficit in fat-free mass with or without excess fat mass (sarcopenic obesity) for a given age category, complementing the classical concept of body mass index (BMI) in a more qualitative manner.
Abstract: Objective: To determine reference values for fat-free mass index (FFMI) and fat mass index (FMI) in a large Caucasian group of apparently healthy subjects, as a function of age and gender and to develop percentile distribution for these two parameters. Design: Cross-sectional study in which bioelectrical impedance analysis (50 kHz) was measured (using tetrapolar electrodes and cross-validated formulae by dual-energy X-ray absorptiometry in order to calculate FFMI (fat-free mass/height squared) and FMI (fat mass/height squared). Subjects: A total of 5635 apparently healthy adults from a mixed non-randomly selected Caucasian population in Switzerland (2986 men and 2649 women), varying in age from 24 to 98 y. Results: The median FFMI (18–34 y) were 18.9 kg/m2 in young males and 15.4 kg/m2 in young females. No difference with age in males and a modest increase in females were observed. The median FMI was 4.0 kg/m2 in males and 5.5 kg/m2 in females. From young to elderly age categories, FMI progressively rose by an average of 55% in males and 62% in females, compared to an increase in body mass index (BMI) of 9 and 19% respectively. Conclusions: Reference intervals for FFMI and FMI could be of practical value for the clinical evaluation of a deficit in fat-free mass with or without excess fat mass (sarcopenic obesity) for a given age category, complementing the classical concept of body mass index (BMI) in a more qualitative manner. In contrast to BMI, similar reference ranges seems to be utilizable for FFMI with advancing age, in particular in men.
622 citations
TL;DR: The data showed a race effect for women, but not men, and the failure to adjust for these sources of bias resulted in substantial differences in the proportion of subjects defined as obese by measured %fat.
Abstract: Objective To study the effects of sex, age and race on the relation between body mass index (BMI) and measured percent body fat (%fat) Design Cross-sectional validation study of sedentary individuals Subjects The Heritage Family Study cohort of 665 black and white men and women who ranged in age from 17 to 65 y Measurements Body density determined from hydrostatic weighing Percentage body fat determined with gender and race-specific, two-compartment models BMI determined from height and weight, and sex and race in dummy coded form Results Polynomial regression showed that the relationship between %fat and BMI was quadratic for both men and women A natural log transformation of BMI adjusted for the non-linearity Test for homogeneity of log transformed BMI and gender showed that the male-female slopes were within random variance, but the intercepts differed For the same BMI, the %fat of females was 104% higher than that of males General linear models analysis of the women's data showed that age, race and race-by-BMI interaction were independently related to %fat The same analysis applied to the men's data showed that %fat was not just a function of BMI, but also age and age-by-BMI interaction Multiple regression analyses provided models that defined the bias Conclusions These data and results published in the literature show that BMI and %fat relationship are not independent of age and gender These data showed a race effect for women, but not men The failure to adjust for these sources of bias resulted in substantial differences in the proportion of subjects defined as obese by measured %fat
616 citations
TL;DR: It is suggested that long-term consumption of tea catechins is beneficial for the suppression of diet-induced obesity, and it may reduce the risk of associated diseases including diabetes and coronary heart disease.
Abstract: OBJECTIVE: Obesity has increased at an alarming rate in recent years and is now a worldwide health problem. We investigated the effects of long-term feeding with tea catechins, which are naturally occurring polyphenolic compounds widely consumed in Asian countries, on the development of obesity in C57BL/6J mice. DESIGN: We measured body weight, adipose tissue mass and liver fat content in mice fed diets containing either low-fat (5% triglyceride (TG)), high-fat (30% TG), or high-fat supplemented with 0.1–0.5% (w/w) tea catechins for 11 months. The β-oxidation activities and related mRNA levels were measured after 1 month of feeding. RESULTS: Supplementation with tea catechins resulted in a significant reduction of high-fat diet-induced body weight gain, visceral and liver fat accumulation, and the development of hyperinsulinemia and hyperleptinemia. Feeding with tea catechins for 1 month significantly increased acyl-CoA oxidase and medium chain acyl-CoA dehydrogenase mRNA expression as well as β-oxidation activity in the liver. CONCLUSION: The stimulation of hepatic lipid metabolism might be a factor responsible for the anti-obesity effects of tea catechins. The present results suggest that long-term consumption of tea catechins is beneficial for the suppression of diet-induced obesity, and it may reduce the risk of associated diseases including diabetes and coronary heart disease.
501 citations
TL;DR: Obesity and the global burden of disease and the action agenda, prevalence, trends and economics, and potential solutions are presented.
Abstract: Contents 1. Obesity and the global burden of disease 2. Prevalence, trends and economics 3. Targets for action 4. The action agenda 5. Potential solutions 6. Tracking outcomes 7. Glossary of terms 8. Key references and further reading 9. Case studies: Available on Nature website at www.naturesj.com/ijo/index.html
495 citations
TL;DR: These mean body composition estimates for TBW, FFM, TBF and %BF based upon NHANES III BIA data provide a descriptive reference for non-Hispanic whites, non- Hispanic blacks and Mexican Americans in the US population.
Abstract: BACKGROUND: Body composition estimates for the US population are important in order to analyze trends in obesity, sarcopenia and other weight-related health conditions. National body composition estimates have not previously been available. OBJECTIVE: To use transformed bioelectrical impedance analysis (BIA) data in sex-specific, multicomponent model-derived prediction formulae, to estimate total body water (TBW), fat-free mass (FFM), total body fat (TBF), and percentage body fat (%BF) using a nationally representative sample of the US population. DESIGN: Anthropometric and BIA data were from the third National Health and Nutrition Examination Survey (NHANES III; 1988–1994). Sex-specific BIA prediction equations developed for this study were applied to the NHANES data, and mean values for TBW, FFM, TBF and %BF were estimated for selected age, sex and racial-ethnic groups. RESULTS: Among the non-Hispanic white, non-Hispanic black, and Mexican-American participants aged 12–80 y examined in NHANES III, 15 912 had data available for weight, stature and BIA resistance measures. Males had higher mean TBW and FFM than did females, regardless of age or racial-ethnic status. Mean TBW and FFM increased from the adolescent years to mid-adulthood and declined in older adult age groups. Females had higher mean TBF and %BF estimates than males at each age group. Mean TBF also increased with older age groups to approximately 60 y of age after which it decreased. CONCLUSIONS: These mean body composition estimates for TBW, FFM, TBF and %BF based upon NHANES III BIA data provide a descriptive reference for non-Hispanic whites, non-Hispanic blacks and Mexican Americans in the US population.
490 citations
TL;DR: Dramatic increases in the prevalence of both overweight and obesity in Canada over the last 15 y are indicated, and the problem is particularly pronounced among children.
Abstract: OBJECTIVE: To assess changes in the prevalence of overweight and obesity among Canadian children and adults between 1981 and 1996 using recent recommendations for the classification of overweight and obesity. DESIGN: Epidemiological study comparing the prevalence of overweight and obesity from the 1981 Canada Fitness Survey (CFS) to the 1996 National Longitudinal Survey of Children and Youth (NLSCY) and the 1996 National Population Health Survey (NPHS). SUBJECTS: Adults 20–64 y of age and children 7–13 y of age from the CFS, NLSCY and NPHS. MEASUREMENTS: BMI was calculated from directly measured or self-reported body mass and height. For adults 20–64 y of age, overweight and obesity were defined as BMI≥25 kg/m2 and BMI≥30 kg/m2, respectively. Age- and sex-specific cut-off points for children that correspond to the adulthood categories were used to define overweight and obesity for children 7–13 y of age. RESULTS: The prevalence of overweight increased from 48 to 57% among men and from 30 to 35% among women, while the prevalence of obesity increased from 9 to 14% in men and from 8 to 12% in women. The corresponding increases were from 11 to 33% in boys and from 13 to 27% in girls for overweight and from 2 to 10% in boys and from 2 to 9% in girls for obesity. CONCLUSION: The results indicate dramatic increases in the prevalence of both overweight and obesity in Canada over the last 15 y, and the problem is particularly pronounced among children.
486 citations
TL;DR: The intervention significantly decreased the percentage of normal-weight women who exceeded the IOM recommendations and postpartum weight retention was strongly related to weight gain during pregnancy (r=0.89).
Abstract: BACKGROUND: The Institute of Medicine (IOM) recommends that normal‐weight women (BMI (body mass index) of 198–260) gain 25–35 lb (114–159 kg) during pregnancy, and that overweight women (BMI of 261–290) gain 15–25 lbs (68–114 kg) A significant number of normal‐weight women and an even greater proportion of overweight women exceed these guidelines, which increases postpartum weight retention and may contribute to the development of obesity OBJECTIVE: To determine whether a stepped care, behavioral intervention will decrease the percentage of women who gain more than the IOM recommendation DESIGN: Randomized controlled trial comparing a stepped-care behavioral intervention with usual care Women (n=120) who had a BMI>198, age>18 and <20 weeks gestation were recruited from a hospital-based clinic serving low-income women and randomized by race and BMI category to the intervention or control group The intervention group received education about weight gain, healthy eating, and exercise and individual graphs of their weight gain Those exceeding weight gain goals were given more intensive intervention Women were followed through pregnancy to their first postpartum clinic visit The main outcome measure was weight gain during pregnancy categorized as above the IOM recommendations vs below or within the IOM recommendations RESULTS: The intervention significantly decreased the percentage of normal-weight women who exceeded the IOM recommendations (33 vs 58%, P<005) There was a non-significant (P=009) effect in the opposite direction among overweight women (59% of intervention and 32% of control gained more than recommended) Postpartum weight retention was strongly related to weight gain during pregnancy (r=089) CONCLUSIONS: The intervention reduced excessive weight gain during pregnancy among normal weight women
475 citations
TL;DR: Omentectomy, when performed together with AGB, has significant positive and long-term effects on the glucose and insulin metabolic profiles in obese subjects.
Abstract: AIM: To determine whether visceral fat reduction in connection with bariatric surgery could improve weight loss and metabolic profile of obese subjects. PATIENTS AND METHODS: In a one-center, randomized and controlled pilot trial we assigned 50 subjects with severe obesity (body mass index >35 kg/m2) to either adjustable gastric banding (AGB) alone (11 men and 14 women), or AGB plus surgical removal of the total greater omentum (11 men and 14 women). The patients were followed at regular intervals for 2 y and examined at 0 and 24 months with respect to body composition and metabolic profile. RESULTS: No significant differences between control and omentectomized patients were observed at baseline. The removed greater omentum constituted 0.8±0.4% (mean±s.d.) of total body fat. At 2 y follow-up there was an expected decrease in body weight and an improvement in metabolic profile in both groups. Although omentectomized subjects tended to lose more weight than control subjects the difference was not statistically significant and changes in waist-to-hip ratio and saggital diameter did not differ between groups. However, the improvements in oral glucose tolerance, insulin sensitivity and fasting plasma glucose and insulin were 2–3 times greater in omentectomized as compared to control subjects (P from 0.009 to 0.04), which was statistically independent of the loss in body mass index. No differences in blood lipids between the groups were recorded. No adverse effects related to omentectomy were observed. CONCLUSIONS: Omentectomy, when performed together with AGB, has significant positive and long-term effects on the glucose and insulin metabolic profiles in obese subjects.
TL;DR: If causal, preventing child abuse may modestly decrease adult obesity, and treatment of obese adults abused as children may benefit from identification of mechanisms that lead to maintenance of adult obesity.
Abstract: BACKGROUND: Little is known about childhood factors and adult obesity. A previous study found a strong association between childhood neglect and obesity in young adults. OBJECTIVE: To estimate associations between self-reported abuse in childhood (sexual, verbal, fear of physical abuse and physical) adult body weight, and risk of obesity. DESIGN: Retrospective cohort study with surveys during 1995–1997. PATIENTS: A total of 13 177 members of California health maintenance organization aged 19–92 y. MEASUREMENTS: Body weight measured during clinical examination, followed by mailed survey to recall experiences during first 18 y of life. Estimates adjusted for adult demographic factors and health practices, and characteristics of the childhood household. RESULTS: Some 66% of participants reported one or more type of abuse. Physical abuse and verbal abuse were most strongly associated with body weight and obesity. Compared with no physical abuse (55%), being ‘often hit and injured’ (2.5%) had a 4.0 kg (95% confidence interval: 2.4–5.6 kg) higher weight and a 1.4 (1.2–1.6) relative risk (RR) of body mass index (BMI)≥30. Compared with no verbal abuse (53%), being ‘often verbally abused’ (9.5%) had an RR of 1.9 (1.3–2.7) for BMI≥40. The abuse associations were not mutually independent, however, because the abuse types strongly co-occurred. Obesity risk increased with number and severity of each type of abuse. The population attributable fraction for ‘any mention’ of abuse (67%) was 8% (3.4–12.3%) for BMI≥30 and 17.3% (−1.0–32.4%) for BMI≥40. CONCLUSIONS: Abuse in childhood is associated with adult obesity. If causal, preventing child abuse may modestly decrease adult obesity. Treatment of obese adults abused as children may benefit from identification of mechanisms that lead to maintenance of adult obesity.
TL;DR: The findings support the current opinion that, although the nature of obesity-related health risks is similar in all populations, the specific level of risk associated with a given level of obesity may be different depending on gender, race and socioeconomic condition.
Abstract: OBJECTIVE: To examine the obesity-related chronic diseases in the US adult population according to gender, race and socioeconomic status. METHODS: Data from the 1994-1996 Continuing Survey of Food Intakes by Individuals (1994-1996 CSFII) conducted by the US Department of Agriculture/Agricultural Research Service (USDA/ARS) were used in the analysis. Relevant data included self-reported weight and height, self-reported physician-diagnosed diabetes mellitus, hypertension, heart disease and high serum cholesterol. Analysis was conducted according to gender, race, income level and education level. RESULTS: There was a graded increase in diabetes, hypertension and high serum cholesterol with increasing body weight in nearly all gender, racial and socioeconomic groups. Among the obese individuals, the prevalence of hypertension was higher in black subjects and the prevalence of diabetes, hypertension and heart disease was higher in individuals with lower education compared to their counterparts. The odds of having diabetes, hypertension, heart disease and high serum cholesterol increased with increasing body weight after adjusting for age, gender, race, income, education and smoking. CONCLUSION: Although cross-sectional in nature, our results suggest that the disease burden associated with obesity in the population may be substantial. This burden increases with increasing severity of obesity. Our findings support the current opinion that, although the nature of obesity-related health risks is similar in all populations, the specific level of risk associated with a given level of obesity may be different depending on gender, race and socioeconomic condition.
TL;DR: In this article, the authors identified and investigated obstacles to the initiation of insulin therapy in Type 2 diabetes patients, such as patients' fear of disease progression and needle anxiety; mutual concerns about hypoglycaemia and weight gain; and health professionals' use of insulin as a threat to encourage compliance with earlier therapies.
Abstract: Insulin therapy has proven benefits in Type 2 diabetes patients when combination therapy has failed. However, there is some reluctance by both patients and healthcare professionals to initiate insulin therapy. This reluctance has been termed 'psychological insulin resistance'. Barriers to the initiation of insulin therapy include patients' fear of disease progression and needle anxiety; mutual concerns about hypoglycaemia and weight gain; and health professionals' use of insulin as a threat to encourage compliance with earlier therapies. It is essential that these obstacles are identified and investigated as a means of overcoming these impediments to recommended levels of glycaemic control, an initiative being pursued by the DAWN study. Where concerns are tangible, such as fear of hypoglycaemia, therapeutic solutions can be pursued. Overcoming psychological barriers relies more on innovative management techniques. Improving insulin delivery to meet these needs, coupled with enhanced healthcare services, can address psychological insulin resistance and contribute to the maintenance of good metabolic control.
TL;DR: W waist-to-height ratio (WHtR) in women was found to have the largest areas under the ROC curve, which supported the hypothesis that the cut-off values using BMI and WC to define obesity should be much lower in Taiwan than in Western countries.
Abstract: BACKGROUND: The increased health risks associated with obesity have been found to occur in Asians at lower body mass indices (BMIs). To determine the optimal cut-off values for overweight or obesity in Taiwan, we examined the relationships between four anthropometric indices and cardiovascular risk factors. METHODS: The data were collected from four health-screening centers from 1998 to 2000 in Taiwan. Included were 55 563 subjects (26 359 men and 29 204 women, mean age=37.3±10.9 and 37.0±11.1 y, respectively). None had known major systemic diseases or were taking medication. Individual body weight, height, waist circumference (WC), and a series of tests related to cardiovascular risk (blood pressure, fasting plasma glucose, triglycerides, total cholesterol, low- and high-density lipoprotein cholesterol) were assessed and their relationships were examined. Receiver operating characteristic (ROC) analysis was used to find out the optimal cut-off values of various anthropometric indices to predict hypertension, diabetes mellitus and dyslipidemia. RESULTS: Of the four anthropometric indices we studied, waist-to-height ratio (WHtR) in women was found to have the largest areas under the ROC curve (women=0.755, 95% CI 0.748–0.763) relative to at least one risk factor (ie hypertension or diabetes or dyslipidemia). The optimal cut-off values for overweight or obesity from our study in men and women showed that BMIs of 23.6 and 22.1 kg/m2, WCs of 80.5 and 71.5 cm, waist-to-hip ratios (WHpR) of 0.85 and 0.76, and WHtR of 0.48 and 0.45, respectively, may be more appropriate in Taiwan. CONCLUSIONS: WHtR may be a better indicator for screening overweight- or obesity-related CVD risk factors than the other three indexes (BMI, WC and WHpR) in Taiwan. Our study also supported the hypothesis that the cut-off values using BMI and WC to define obesity should be much lower in Taiwan than in Western countries.
TL;DR: It is concluded that obesity in the absence of smoking, diabetes mellitus, hyperlipidaemia, renal or liver disease causes lipid peroxidation and decreased activities of cytoprotective enzymes, and should therefore receive the same attention as obesity with complications.
Abstract: OBJECTIVE: Obesity, defined as a body mass index (BMI) greater than 30 kg/m2, is now recognised as a risk factor for diabetes mellitus, hyperlipidaemia, colon cancer, sudden death and other cardiovascular diseases. In this study, it is hypothesized that obesity is an independent risk factor for lipid peroxidation and decreased activities of cytoprotective enzymes in humans. SUBJECTS: Fifty normal healthy subjects with healthy BMI (19–25 kg/m2) and 250 subjects with different grades of obesity (30–50 kg/m2) with no history of smoking or biochemical evidence of diabetes mellitus, hypertension, hyperlipidaemia, renal or liver disease or cancer. MEASUREMENTS: To test this hypothesis, we assessed lipid peroxidation and cytoprotection by measuring the concentrations of plasma malondialdehyde (P-MDA) and the activities of erythrocyte copper zinc-superoxide dismutase (CuZn-SOD) and glutathione peroxidase (GPX). RESULTS: The concentration of P-MDA was significantly lower (P<0.001) in subjects with healthy BMI (2.53±0.04 µmol/l) than in those with BMI above 40 kg/m2 (4.75+0.05 µmol/l). Furthermore, there was a significantly positive association (r=0.342, P=0.013) between BMI and P-MDA. On the other hand, subjects with healthy BMI had significantly higher (P<0.001) erythrocyte CUZn-SOD (1464±23 units/g Hb) and GPX (98.4±3.3 units/g Hb) than those with BMI above 40 kg/m2 (1005±26 units/g Hb) and (84.3±6.7 units/g Hb) respectively. Furthermore, erythrocyte CuZn-SOD and GPX activities were negatively associated with BMI (r=−0.566, P=0.005 and r=−0.436, P=0.018) respectively. CONCLUSION: It is concluded from these results that obesity in the absence of smoking, diabetes mellitus, hyperlipidaemia, renal or liver disease causes lipid peroxidation and decreased activities of cytoprotective enzymes, and should therefore receive the same attention as obesity with complications.
TL;DR: Not only does the level of obesity affect HRQL, the impact of overweight and obesity also differs by age and sex, and in younger men and women the analysis indicated a clearer negative association between Obesity and physical health than between obesity and mental health.
Abstract: OBJECTIVE: To investigate the impact of overweight and obesity on health-related quality-of-life (HRQL) in the general population in western Sweden. DESIGN: Cross-sectional survey. SUBJECTS: A total of 5633 men and women aged 16–64 y born in Sweden. MAIN OUTCOME MEASURES: Scale and summary component scores of the SF-36 Health Survey. RESULTS: Obese men aged 16–34 y rated their HRQL lower than normal-weight men did on all four physical health scales of the SF-36 and on two of the four mental health scales. Obese women in the same age group rated their health worse than normal-weight women on three of the physical health scales. Thus, in younger men and women the analysis indicated a clearer negative association between obesity and physical health than between obesity and mental health. Obese women aged 35–64 y rated their health worse on all scales than normal-weight women did, while obese men in this age group rated their health worse on only two SF-36 subscales—physical functioning and general health perception. The massively obese men and women suffered from a poor level of HRQL. CONCLUSION: Not only does the level of obesity affect HRQL, the impact of overweight and obesity also differs by age and sex. The importance of aspects of both physical and mental health should be fully recognised.
TL;DR: The effect of sleep duration on obesity in children reflects a higher body fat composition and appears to be independent of other risk factors for childhood obesity.
Abstract: Objective: To assess the relationship between sleep duration and adiposity in 5- and 6-y-old Bavarian children. Design: Cross-sectional study. Subjects: A total of 6862 German children aged 5–6 y participating in the obligatory health examination in Bavaria, southern Germany. Measurements: Routine data were collected on the height and weight of children at the time of school entry in six public health offices in 1999 and in another two in 2000. Body fat mass was estimated by BIA performed in three of those offices. An extensive questionnaire was given to all children's parents in order to assess risk factors for overweight and obesity. The main outcome measures were overweight, defined by a body mass index (BMI) above the 90th centile and obesity, defined by a BMI above the 97th centile for the German children in Bavaria. Excessive body fat was defined as fat mass above the 90th centile for all German children seen in this survey. The main exposure was usual sleeping hours on week days. Results: The prevalence of obesity decreased by duration of sleep: ≤10 h, 5.4% (95% CI 4.1–7.0), 10.5–11.0 h, 2.8% (95% CI 2.3–3.3), and ≥11.5 h, 2.1% (95% CI 1.5–2.9). Similar relations were found with the prevalence of overweight and excessive body fat. These effects could not be explained by confounding due to a wide range of constitutional, sociodemographic and lifestyle factors. The adjusted odds ratio for obesity were: for sleeping 10.5–11.0 h, 0.52 (95% CI 0.34–0.78) and 0.46 (95% CI 0.28–0.75) for sleeping 11.5 h. Conclusion: The effect of sleep duration on obesity in children reflects a higher body fat composition and appears to be independent of other risk factors for childhood obesity.
TL;DR: In this paper, the authors investigated the visceral fat distribution in patients with schizophrenia using CT scans and anthropometry and found increased intra-abdominal fat which may provide one explanation for why they die prematurely.
Abstract: OBJECTIVE: To investigate visceral fat distribution in patients with schizophrenia. DESIGN: Cross sectional study using CT scanning in patients with drug-naive and drug-free schizophrenia. SUBJECTS: Fifteen (13 men and two women) subjects with schizophrenia (mean age 33.7 y; mean body mass index (BMI)=26.7 kg/m2), and 15 age- and sex-matched controls (mean age 30.5 y; mean BMI=22.8 kg/2). MEASUREMENTS: Various fatness and fat distribution parameters (by CT scanning and anthropometry) and 16:00 h plasma cortisol. RESULTS: In comparison to controls, patients with schizophrenia had central obesity and had significantly higher levels of plasma cortisol. Furthermore, previous neuroleptic exposure did not appear to influence these findings as both drug-naive and drug-free patients had equally high levels of visceral fat deposition. CONCLUSION: Central obesity is a well recognized risk factor in developing certain general medical conditions. This study shows that patients with schizophrenia have increased intra-abdominal fat which may provide one explanation for why they die prematurely.
TL;DR: National health policymakers must take action to deal with the obesity problem, and prevention should be the primary target, but it is also important to develop strategies to treat those already affected with obesity.
Abstract: The prevalence of obesity is increasing globally, with nearly half a billion of the world's population now considered to be overweight or obese. The obesity epidemic is related both to dietary factors and to an increasingly sedentary lifestyle. Obesity has significant co-morbidities and these are associated with substantial health care and social costs. Of particular concern is the fact that obesity is increasing among children and adolescents. National health policymakers must take action to deal with the obesity problem. Prevention should be the primary target, but it is also important to develop strategies to treat those already affected with obesity.
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TL;DR: In this review, several lines of evidence are presented to illustrate why dietary fat does affect obesity development, and there are four factors which support a link between dietary fat and obesity development.
Abstract: The prevalence of obesity is increasing worldwide, which indicates that the primary cause of obesity lies in environmental and behavioural changes rather than in genetic modifications. Among the environmental influences, the percentage of fat energy of the everyday diet and the lack of physical activity are two important factors, which contribute to explain the rising prevalence of obesity. In this review, several lines of evidence are presented to illustrate why dietary fat does affect obesity development. There are four factors which support a link between dietary fat and obesity development:The thermic effect of nutrients, expressed as percentage of their energy content, is 2-3% for lipids, 6-8% for carbohydrates and 25-30% for proteins. This means that the efficiency of nutrient utilization (calculated as 100%-the thermic effect of the nutrient) is higher for fat than for carbohydrate or protein.Postingestive fuel selection favours the oxidation of dietary proteins and carbohydrates, whereas dietary fats are preferentially stored as triacylglycerol in adipose tissue. Alcohol, by inhibiting lipid oxidation, indirectly favours the storage of dietary fats.High-fat diet promotes excessive energy intake by passive overconsumption; the fat-induced appetite control signals are too weak or too delayed to prevent excessive energy intake from a fatty meal. The only proof that dietary fats contribute to weight gain is to test the long-term effect of ad libitum low-fat diets. Most studies on low-fat diets show that they induce a modest weight loss in obese individuals, but their long-term effect from a public health perspective is limited, probably due to a low compliance to the dietary advice.
TL;DR: Findings suggest a stable linear relation of adiposity with BP, independent of age and body fat distribution, across developed and developing countries.
Abstract: BACKGROUND: Obesity is increasing worldwide because developing countries are adopting Western high-fat foods and sedentary lifestyles. In parallel, in many of them, hypertension is rising more rapidly, particularly with age, than in Western countries. OBJECTIVE: To assess the relationship between adiposity and blood pressure (BP) in a developing country with high average BP (The Seychelles, Indian Ocean, population mainly of African origin) in comparison to a developed country with low average BP (Switzerland, population mainly of Caucasian origin). DESIGN: Cross-sectional health examination surveys based on population random samples. SETTING: The main Seychelles island (Mahe) and two Swiss regions (Vaud-Fribourg and Ticino). SUBJECTS: Three thousand one hundred and sixteen adults (age range 35–64) untreated for hypertension. MEASUREMENTS: Body mass index (BMI), waist circumference (WC), waist-to-hip ratio (WHR), systolic and diastolic blood pressure (SBP and DBP, mean of two measures). METHODS: Scatterplot smoothing techniques and gender-specific linear regression models. RESULTS: On average, SBP and DBP were found to increase linearly over the whole variation range of BMI, WHR and WC. A modest, but statistically significant linear association was found between each indicator of adiposity and BP levels in separate regression models controlling for age. The regression coefficients were not significantly different between the Seychelles and the two Swiss regions, but were generally higher in women than in men. For the latter, a gain of 1.7 kg/m2 in BMI, of 4.5 cm in WC or of 3.4% in WHR corresponded to an elevation of 1 mmHg in SBP. For women, corresponding figures were 1.25 kg/m2, 2.5 cm and 1.8% respectively. Regression coefficients for age reflected a higher effect of this variable on both SBP and DBP in the Seychelles than in Switzerland. CONCLUSION: These findings suggest a stable linear relation of adiposity with BP, independent of age and body fat distribution, across developed and developing countries. The more rapid increase of BP with age observed in the latter countries are likely to reflect higher genetic susceptibility and/or higher cumulative exposure to another risk factor than adiposity.
TL;DR: Obesity, diabetes and hypertension prevalence is higher in urban compared to rural dwellers in the populations studied, and physical inactivity is associated with these diseases, although not always significant in women.
Abstract: Objectives: To evaluate and compare physical activity patterns of urban and rural dwellers in Cameroon, and study their relationship with obesity, diabetes and hypertension Methods: We studied 2465 subjects aged ≥15 y, recruited on the basis of a random sampling of households, of whom 1183 were urban dwellers from Yaounde, the capital city of Cameroon and 1282 rural subjects from Bafut, a village of western Cameroon They all had an interviewer-administered questionnaire for the assessment of their physical activity and anthropometric measurements, blood pressure and fasting blood glucose determination The procedure was satisfactorily completed in 2325 (943%) subjects Prevalences were age-adjusted and subjects compared according to their region, sex and age group Results: Obesity was diagnosed in 171 and 30% urban and rural women, respectively (P<0001), and in 54 vs 12% urban and rural men, respectively (P<0001) The prevalence of hypertension was significantly higher in urban vs rural dwellers (114 vs 66% and 176 vs 91% in women and men, respectively; P<0001) Diabetes was more prevalent in urban compared to rural women (P<005), but not men Urban subjects were characterized by lower physical activity (P<0001), light occupation, high prevalence of multiple occupations, and reduced walking and cycling time compared to rural subjects Univariate analysis showed significant associations between both physical inactivity and obesity and high blood pressure The relationship of physical inactivity with hypertension and obesity were independent in both urban and rural men, but not in women Body mass index, blood pressure and glycaemia were higher in the first compared with the fourth quartiles of energy expenditure Conclusion: Obesity, diabetes and hypertension prevalence is higher in urban compared to rural dwellers in the populations studied Physical activity is significantly lower and differs in pattern in urban subjects compared to rural Physical inactivity is associated with these diseases, although not always significant in women
TL;DR: This article provides the first comprehensive meta-analysis of randomized clinical trials of medications for obesity, and no drug, or class of drugs, demonstrated clear superiority as an obesity medication.
Abstract: AIM: This article provides the first comprehensive meta-analysis of randomized clinical trials of medications for obesity. METHOD: Based on stringent inclusionary criteria, a total of 108 studies were included in the final database. Outcomes are presented for comparisons of single and combination drugs to placebo and for comparisons of medications to one another. RESULT: Overall, the medications studied produced medium effect sizes. Four drugs produced large effect sizes (ie d>0.80; amphetamine, benzphetamine, fenfluramine and sibutramine). The placebo-subtracted weight losses for single drugs vs placebo included in the meta-analysis never exceeded 4.0 kg. No drug, or class of drugs, demonstrated clear superiority as an obesity medication. Effects of methodological factors are also presented along with suggestions for future research.
TL;DR: The indices FFM/ HT2 and FM/HT2 are appropriate for many purposes, and have the advantage of expressing both aspects of body composition in common units, however, in some scenarios a more sophisticated approach is required for evaluating body fatness.
Abstract: Objective: To explore the relationships between height and (a) fat-free mass (FFM) and (b) fat mass (FM) in children in order to determine the optimum means of adjusting body composition for height. Design: Cross-sectional study. Subjects: Sixty-nine children aged 8 y. Measurements and Methods: Weight and height (HT) were measured, and total body water by deuterium dilution for estimation of fat-free mass and fat mass. The indices FFM/HT2 and FM/HT2 were calculated, as were the indices FFM/HTp and FM/HTp where P was selected in order to eliminate the correlation of these indices with height. Results: FFM was optimally adjusted for height by calculating FFM/HT2. FM was optimally adjusted by calculating FM/HT6. However, height accounted for <8% of the variation in FM/HT2, indicating that the bias of this simpler index is small. Conclusions: Different adjustments of FFM and FM for height are possible, depending on the study design. The indices FFM/HT2 and FM/HT2 are appropriate for many purposes, and have the advantage of expressing both aspects of body composition in common units. However, in some scenarios a more sophisticated approach is required for evaluating body fatness.
TL;DR: Whether the dual-energy X-ray absorptiometry (DXA) method, possibly combined with anthropometry, offers a good alternative to CT for the prediction of visceral fat in the elderly is investigated.
Abstract: Introduction: Effective methods for assessing visceral fat are important to investigate the role of visceral fat for the increased health risks in obesity. Techniques for direct measurement of soft tissue composition such as CT or MRI are expensive, time-consuming or require a relatively high radiation dose. Simple anthropometric methods, such as waist-to-hip ratio, waist circumference or sagittal diameter are widely used. However, these methods cannot differentiate between visceral and subcutaneous fat and are less accurate. The aim of the present study is to investigate whether the dual-energy X-ray absorptiometry (DXA) method, possibly combined with anthropometry, offers a good alternative to CT for the prediction of visceral fat in the elderly. Methods: Subjects were participants in the Health ABC-study, a cohort study of black and white men and women aged 70–79, investigating the effect of weight-related health conditions on disablement. Total body fat and trunk fat were measured by DXA using a Hologic QDR 1500. A 10 mm CT scan at the L4–L5 level was acquired to measure visceral fat and total abdominal fat. Weight, height, sagittal diameter and waist circumference were measured using standard methods. Fat in a manually defined DXA subregion (4 cm slice at the top of iliac crest) at the abdomen was calculated in a sub-group of participants (n=150; 50% male; 45.3% Afro-American/54.7% Caucasian, age 70–79 y). This subregion, the standard trunk region and total fat were used as indicators of visceral fat. Results: Total abdominal fat by DXA (subregion) was strongly correlated with total abdominal fat by CT (r ranging from 0.87 in white men to 0.98 in black women). The DXA subregion underestimated total abdominal fat by 10% compared to the CT slice. The underestimation by DXA was seen especially in people with less abdominal fat. The association of visceral fat by CT with the DXA subregion (r=0.66, 0.78, 0.79 and 0.65 for white and black men and women, respectively) was comparable with the association of the CT measure with the sagittal diameter (r=0.74, 0.70, 0.84 and 0.68). Combining DXA measurements with anthropometry gave only limited improvement for the prediction of visceral fat by CT compared to univariate models (maximal increase of r2 4%). Conclusion: DXA is a good alternative to CT for predicting total abdominal fat in an elderly population. For the prediction of visceral fat the sagittal diameter, which has a practical advantage compared to DXA, is just as effective.
TL;DR: Overweight and obesity increased remarkably among Finnish adolescents from 1977 to 1999, with changes concentrated at the upper end of the BMI distribution, suggesting that factors behind this development have influenced only a part of the adolescent population.
Abstract: OBJECTIVE: To study the trends in overweight and obesity among Finnish adolescents in 1977–1999. DESIGN: Mailed surveys every other year. SUBJECTS: Nationally representative samples of 12, 14, 16 and 18-y-olds (n=64 147, response rate 78.9%). METHODS: Overweight and obesity were measured by body mass index (BMI) and relative weight (RW) based on self-reported height and weight. BMI ≥the 85th percentile cut-off point for BMI in each age- and sex-specific group in the entire data set was considered as overweight, and BMI ≥95th percentile cut-off point as obesity. RW ≥110% and ≥120%, calculated as the individual's weight divided by the mean weight in each age- and sex-specific height percentile group in the entire data set, were considered as overweight and obesity, respectively. The trends in overweight and obesity are described by the change in the 85th and 95th percentile cut-off points of BMI over time. The prevalence of overweight and obesity is also reported using BMI reference values recommended for international comparisons. Because of the similarity of the BMI and the RW criteria in classifying adolescents as overweight and obese, only results based on BMI are presented. RESULTS: Overweight and obesity increased linearly in all sex and age groups from 1977 to 1999. Depending on the age group, the average increase in the 85th percentile cut-off point of the BMI per 10 y was 0.6–1.1 kg/m2 in boys and 0.3–0.7 kg/m2 in girls. The 95th percentile cut-off point of the BMI for boys and girls increased by 1.1–1.6 kg/m2 and by 0.6–1.0 kg/m2 per 10 y, respectively. In boys, the increase in overweight and obesity was largest in the two youngest age groups. In girls, the increase in overweight was largest in the oldest age group, and that of obesity both in the 14 and 18-y-olds. Overweight and obesity increased more in boys than in girls in all age groups except in the 18-y-olds among whom the increase was similar in both sexes. Examination of the entire BMI distribution showed that there was little or no change over time at the lower (5th, 15th) and middle (50th) percentiles, but increasing differences at the upper end of the distribution, the increases in the 95th percentile being even more marked than those in the 85th percentile curves. According to international reference values, the age-standardized prevalence of overweight increased in boys from 7.2 to 16.7%, and in girls from 4.0 to 9.8%, between 1977 and 1999. The prevalence of obesity in boys was 1.1% in 1977 and 2.7% in 1999, and in girls 0.4 and 1.4%, respectively. CONCLUSION: Overweight and obesity increased remarkably among Finnish adolescents from 1977 to 1999. The changes concentrated at the upper end of the BMI distribution, suggesting that factors behind this development have influenced only a part of the adolescent population.
TL;DR: The present study revealed an increasing prevalence of overweight in comparison with previous French data and a trend for increase prevalence of thinness.
Abstract: OBJECTIVE: To assess the frequency of different grades of nutritional status (obesity, overweight and thinness) in French children aged 7–9 y using four current definitions based on body mass index (BMI). METHODS: Data were collected in 2000 in a randomly selected sample of French children following the protocol recommended by the European Childhood Obesity Group (ECOG). After computing the BMI (weight/height squared), four references were used to define grades of nutritional status: (1) the French references to define thinness and overweight (3rd and 97th percentiles respectively); (2) the Must et al references to define thinness, overweight and obesity (5th, 85th and 95th percentiles respectively); (3) the International Obesity Task Force cut-offs to define overweight and obesity; and (4) the Center for Disease Control 2000 references to define thinness, overweight and obesity (5th, 85th and 95th percentiles respectively). RESULTS: Age and gender standardized frequencies were estimated in 1582 children. According to the French, Must et al, IOTF and CDC references, overweight (including obesity) affected 16.3, 23.9, 18.1 and 20.6% of children, respectively; obesity affected 9.3, 3.8 and 6.4% of children according to the Must, IOTF and CDC references, respectively. Thinness was present in 3.9, 6.0 and 6.0% of children according to the French, Must and CDC references. Whatever the definition, little difference was observed between sexes. Through age classes, as a rule, overweight and obesity tended to decrease while thinness tended to increase. CONCLUSION: The present study revealed an increasing prevalence of overweight in comparison with previous French data and a trend for increasing prevalence of thinness. The IOTF-based prevalence of overweight (including obesity) in 2000 in France was similar with the prevalence recorded in the late 1980s in the USA and the prevalence of obesity in 2000 in France was similar to the prevalence of obesity in the late 1970s in the USA. Data in France are comparable to those reported in other studies conducted in Western Europe. This study provides baseline information for analysis of time trends and for geographical comparisons.
TL;DR: Findings of widespread weight gain, particularly among those already overweight, suggest that early adulthood, which is a time of significant life changes for many women, may be an important time for implementing strategies to promote maintenance of healthy weight.
Abstract: OBJECTIVE: To investigate the prevalence and predictors of weight maintenance over time in a large sample of young Australian women. DESIGN: This population study examined baseline and 4y follow-up data from the cohort of young women participating in the Australian Longitudinal Study on Women's Health. SUBJECTS: A total of 8726 young women aged 18 - 23y at baseline. MEASURES: Height, weight and body mass index (BMI); physical activity; time spent sitting; selected eating behaviours (eg dieting, disordered eating, takeaway food consumption); cigarette smoking, alcohol consumption; parity; and socio-demographic characteristics. RESULTS: Only 44% of the women reported their BMI at follow-up to be within 5% of their baseline BMI (maintainers); 41% had gained weight and 15% had lost weight. Weight maintainers were more likely to be in managerial or professional occupations; to have never married; to be currently studying; and not to be mothers. Controlling for sociodemographic factors, weight maintainers were more likely to be in a healthy weight range at baseline, and to report that they spent less time sitting, and consumed less takeaway food, than women who gained weight. CONCLUSIONS: Fewer than half the young women in this community sample maintained their weight over this 4y period in their early twenties. Findings of widespread weight gain, particularly among those already overweight, suggest that early adulthood, which is a time of significant life changes for many women, may be an important time for implementing strategies to promote maintenance of healthy weight. Strategies which encourage decreased sitting time and less takeaway food consumption may be effective for encouraging weight maintenance at this life stage.
TL;DR: The present review discusses general mechanisms of reduced NO bioavailability including factors determining production of both NO and reactive oxygen species and the potential factors responsible for endothelial dysfunction in obesity and possible therapeutic interventions targetted at thses abnormalities.
Abstract: It is now well established that obesity is an independent risk factor for the development of coronary artery atherosclerosis. The maintenance of vascular homeostasis is critically dependent on the continued integrity of vascular endothelial cell function. A key early event in the development of atherosclerosis is thought to be endothelial cell dysfunction. A primary feature of endothelial cell dysfunction is the reduced bioavailability of the signalling molecule nitric oxide (NO), which has important anti atherogenic properties. Recent studies have produced persuasive evidence showing the presence of endothelial dysfunction in obese humans NO bioavailability is dependent on the balance between its production by a family of enzymes, the nitric oxide synthases, and its reaction with reactive oxygen species. The endothelial isoform (eNOS) is responsible for a significant amount of the NO produced in the vascular wall. NO production can be modulated in both physiological and pathophysiological settings, by regulation of the activity of eNOS at a transcriptional and post-transcriptional level, by substrate and co-factor provision and through calcium dependent and independent signalling pathways. The present review discusses general mechanisms of reduced NO bioavailability including factors determining production of both NO and reactive oxygen species. We then focus on the potential factors responsible for endothelial dysfunction in obesity and possible therapeutic interventions targetted at thses abnormalities.