Obesity Reviews

Background Dissatisfaction with body weight and the use of unhealthy weight reduction practices have been reported among adolescents. Objective The aim of the present study was to examine the severity of dieting and its association with obesity, body satisfaction and psychological problems in female adolescents. Subjects A representative sample of 800 girls aged 14-19 years were approached during the period October to December 2004 and 566 girls gave consent and participated in the study, thus giving a response rate of 70.8%. Methods Self-reports were obtained from 566 teenage girls using the Adolescent Dieting Scale (ADS) and the Self-Reporting Questionnaire (SRQ-20) for psychopathology. Results The prevalence of overweight and obesity for female adolescents were 13.4% vs 1.8%;-; 39.9% were intermediate dieters, and 8.3% were extreme dieters. Dieting was not associated with age but was significantly associated with body mass index (BMI) (p=0.045). Extreme dieting was strongly associated with peer perception of respondent's figure (p< 0.001) and self perception of figure (p=0.016). Additionally, in adult Qatari population overweight and obesity for males were (34.4% vs 34.6%) and for females were (33.0% vs 45.3%). This is significantly higher than adolescent girls. (p< 0.01). The SRQ score was significantly highest in the extreme dieters group (p=0.005). The extreme dieters get most of their education (or information?) about dieting from school(14.0%) and TV(43.6%). Conclusion The present study revealed strong evidence for the association between frequent dieting and overweight, body image dissatisfaction and psychological problems among adolescent females.

Now that analysis of the organization of the human genome sequence is reaching completion, studies of the finely tuned chromatin epigenetic networks, DNA methylation and histone modifications, are required to determine how the same DNA sequence generates different cells, lineages and organs, i.e. the phenotype. Maternal nutrition, behaviour and metabolic disturbances as well as other environmental factors have been shown to have major effects on these epigenetic processes, potentially affecting the predisposition of offspring to obesity and related adult disorders. The March 2006 Stock Conference considered the latest evidence from studies in the field of obesity and other related areas that elucidate mechanisms by which the environment can modify gene expression and the resulting individual phenotype. Presentations included evaluation of the molecular basis of epigenetic memory and the nature of relevant sequence targets, windows of susceptibility, and maternal dietary and behavioural factors that determine epigenetic changes. Imprinted genes, age and tissue-related exposures, transgenerational and potential interventions were also discussed. In summary, it is clear that epigenetic alterations can no longer be ignored in evaluations of the causes of obesity and its associated disorders. There is a need for systematic large-scale epigenetic studies of obesity, employing appropriate strategies and techniques and appropriately chosen environmental factors in critical spatio-temporal windows.

Keywords:Adolescents;children;obesity;overweight;policy;WHO

This paper is a systematic review of research data on associations between physical activity and weight gain, with or without prior weight reduction. The selected studies were restricted to Caucasian (white) adults. Most studies with data on physical activity collected at follow-up, found an inverse association between physical activity and long-term weight gain. This finding was present in studies both with and without prior weight reduction. Prospective studies with physical activity measured at baseline, and randomized weight reduction interventions, gave inconsistent results regarding the effects of increased physical activity on weight change. The weighted mean weight regain in randomized studies with or without exercise training was 0.28 and 0.33 kg/month, respectively. Based on observational studies, it seemed that an actual increase in energy expenditure of physical activity of approximately 6300-8400 kJ/week (1500-2000 kcal/week) is associated with improved weight maintenance. This is more than was prescribed in most randomized trials, and certainly more than the participants actually achieved. Adherence to a prescribed exercise programme remains a big challenge. Before new methods to improve exercise adherence are found, the role of prescribed physical activity in prevention of weight gain remains modest.

The search for effective ways of dealing with obesity has centred on biological research and clinical management. However, obesity needs to be conceptualized more broadly if the modern pandemic is to be arrested. The epidemiological triad (hosts, agent/vectors and environments) has served us well in dealing with epidemics in the past, and may be worth re-evaluating to this end. Education, behaviour change and clinical practices deal predominantly with the host, although multidisciplinary practices such as shared-care might also be expected to impact on other corners of the triad. Technology deals best with the agent of obesity (energy imbalance) and it's vectors (excessive energy intake and/or inadequate energy expenditure), and policy and social change are needed to cope with the environment. The value of a broad model like this, rather than specific isolated approaches, is that the key players such as legislators, health professionals, governments and industry can see their roles in attenuating and eventually reversing the epidemic. It also highlights the need to intervene at all levels in obesity control and reduces the relevance of arguments about nature vs. nurture.

The immunological processes involved in the collaborative defence of organisms are affected by nutritional status. Thus, a positive chronic imbalance between energy intake and expenditure leads to situations of obesity, which may influence unspecific and specific immune responses mediated by humoral and cell mediated mechanisms. Furthermore, several lines of evidence have supported a link between adipose tissue and immunocompetent cells. This interaction is illustrated in obesity, where excess adiposity and impaired immune function have been described in both humans and genetically obese rodents. However, limited and often controversial information exist comparing immunity in obese and non-obese subjects as well as about the cellular and molecular mechanisms implicated. In general terms, clinical and epidemiological data support the evidence that the incidence and severity of specific types of infectious illnesses are higher in obese persons as compared to lean individuals together with the occurrence of poor antibody responses to antigens in overweight subjects. Leptin might play a key role in linking nutritional status with T-cell function. The complexities and heterogeneity of the host defences concerning the immune response in different nutritional circumstances affecting the energy balance require an integral study of the immunocompetent cells, their subsets and products as well as specific and unspecific inducer/regulator systems. In this context, more research is needed to clarify the clinical implications of the alterations induced by obesity on the immune function.

Recent research has provided evidence that bariatric surgery maximizes long-term weight loss in patients with severe obesity. However, a substantial number of patients experience poor weight loss outcome and weight regain over time. Post-operative behavioural management may facilitate long-term weight control in bariatric surgery population. The objective of this systematic review and meta-analysis was to determine the effects of post-operative behavioural management on weight loss following bariatric surgery. Eligible articles were systematically searched in electronic databases. Among the 414 citations, five randomized controlled trials, two prospective and eight retrospective cohort trials analysing behavioural lifestyle interventions and support groups fulfilled the inclusion criteria. The main finding is that behavioural management had a positive effect on weight loss following surgery. In 13 studies, patients receiving behavioural management had greater weight loss than patients receiving usual care or no treatment. A meta-analysis of five randomized controlled trials suggests greater weight loss in patients with behavioural lifestyle interventions compared with control groups. Post-operative behavioural management has the potential to facilitate optimal weight loss following bariatric surgery, but conclusions were limited by the small and heterogeneous samples of studies. A more rigorous empirical evaluation on its clinical significance is warranted to improve effectiveness of bariatric surgery.

The adipocytokines are biologically active polypeptides that are produced either exclusively or substantially by the adipocytes, and act by endocrine, paracrine, and autocrine mechanisms. Most have been associated with obesity, hyperinsulinaemia, type 2 diabetes, and chronic vascular disease; in addition, six adipocytokines--vascular endothelial growth factor, hepatocyte growth factor, leptin, tumour necrosis factor-alpha, heparin-binding epidermal growth factor-like growth factor, and interleukin-6--promote angiogenesis while one, adiponectin, is inhibitory. Obesity and insulin resistance have both been identified as risk factors for breast cancer and are associated with late-stage disease and poor prognosis. Angiogenesis is essential for breast cancer development and progression, and so it is plausible that obesity-related increases in adipocytokine production and a reduction in adiponectin may adversely affect breast cancer outcome by their angiogenesis-related activities. There is also experimental evidence that some adipocytokines can act directly on breast cancer cells to stimulate their proliferation and invasive capacity. Thus, adipocytokines may provide a biological mechanism by which obesity and insulin resistance are causally associated with breast cancer risk and poor prognosis. Both experimental and clinical studies are needed to develop this concept, and particularly in oestrogen-independent breast cancers where preventive and therapeutic options are limited.

The specific effect of central rather than general obesity on breast cancer risk is not clear. This review examines the relationship between waist and waist-hip ratio (WHR) and risk of breast cancer in pre- and post-menopausal women using all available cohort and case-control data. The databases of the Cochrane Library, Medline, Cancer Lit and Embase were searched until October 2002. Relevant cohort and case-control studies with separate analyses in pre- and/or post-menopausal women were included. Random effects meta-analyses were carried out, subgrouped by pre- or post-menopausal status and cohort or case-control design. Sensitivity analyses were also performed. Five cohort studies with 72,1705 person years of observation (453 pre-menopausal and 2684 post-menopausal cases), and three case-control studies comprising 276 pre-menopausal cases with 758 pre-menopausal controls and 390 post-menopausal cases with 1071 post-menopausal controls were included. Pooled results from cohort studies using the most adjusted data [but without adjustment for weight or body mass index (BMI)] suggest a 39% lower risk of breast cancer in post-menopausal women with the smallest waist (compared with the largest) and a 24% lower risk in women with the smallest WHR. In pre-menopausal women, however, pooled results suggest that measurement of waist or WHR have little effect on risk of breast cancer. Adjustment for BMI abolished the relationship between waist or WHR and risk of post-menopausal breast cancer, but introduced such a relationship amongst pre-menopausal women. The relationship between a smaller measurement of waist or WHR and lower risk of post-menopausal breast cancer appears to result from the associated correlation with BMI. Amongst pre-menopausal women, central (not general) obesity may be specifically associated with an increased risk of breast cancer.

In the present study we explore the association between the ponderal index (PI) at birth and the metabolic syndrome (MetS) in middle-aged population in China. A total of 975 men and women aged 41-52 years with detailed birth records were followed up and recruited for clinic examinations, involving anthropometry and measurements of blood pressure, fasting plasma glucose, serum lipid profile. The MetS was diagnosed according to the National Cholesterol Education Program (Adult Treatment Panel III) definition. Multivariate logistic regression analysis estimated the effect of PI on MetS and the interaction between PI at birth and adult body mass index (BMI). The average prevalence of MetS was 19.3%, with rates of 23.7%, 22.9%, 16.9% and 16.5% in those who at birth were <25th percentile, the 25th-50th percentile, the 50th-75th percentile and >75th percentile PI respectively, with a significant decreasing trend (x(2) (for trend) = 5.661, P = 0.017). Logistic regression analysis showed that 25.7% of the occurrence of MetS was attributable to PI at birth and adult BMI both acting independently and synergistically. In summary thinness at birth predicts the later occurrence of MetS, as well as modifying the association between later BMI and MetS. Overweight later in life was most deleterious for those with growth retardation at birth.

Previously, a single nucleotide polymorphism (SNP), rs9939609, in the FTO gene showed a much stronger association with all-cause mortality than expected from its association with body mass index (BMI), body fat mass index (FMI) and waist circumference (WC). This finding implies that the SNP has strong pleiotropic effects on adiposity and adiposity-independent pathological pathways that leads to increased mortality. To investigate this further, we conducted a meta-analysis of similar data from 34 longitudinal studies including 169,551 adult Caucasians among whom 27,100 died during follow-up. Linear regression showed that the minor allele of the FTO SNP was associated with greater BMI (n = 169,551; 0.32 kg m(-2) ; 95% CI 0.28-0.32, P < 1 × 10(-32) ), WC (n = 152,631; 0.76 cm; 0.68-0.84, P < 1 × 10(-32) ) and FMI (n = 48,192; 0.17 kg m(-2) ; 0.13-0.22, P = 1.0 × 10(-13) ). Cox proportional hazard regression analyses for mortality showed that the hazards ratio (HR) for the minor allele of the FTO SNPs was 1.02 (1.00-1.04, P = 0.097), but the apparent excess risk was eliminated after adjustment for BMI and WC (HR: 1.00; 0.98-1.03, P = 0.662) and for FMI (HR: 1.00; 0.96-1.04, P = 0.932). In conclusion, this study does not support that the FTO SNP is associated with all-cause mortality independently of the adiposity phenotypes. © 2015 World Obesity.

The current global epidemic of obesity is fuelled by a constant, unidirectional adverse effect on energy balance that exceeds the adaptive capacity of the system. The individual response to this environmental pressure is under the control of a variety of genes, which not only interacts with environmental factors but also with one another. Since the discovery that adipocytes may produce and secrete hormones, the adipose tissue has taken on increasing importance in the regulation of energy balance. Indeed, the pathogenesis of obesity, once regarded as so obvious and simple, is becoming one of the most complex in medical practice. From a clinical perspective, obesity is associated with a remarkably broad spectrum of health complications and, over the years, obesity-related mortality has consistently increased. From a theoretical viewpoint, the growing complexity of factors affecting the liability to obesity, the inconsistency of scientific results, the lack of consensus among scientists, and so forth, obstruct our efforts to unravel the aetiology of obesity. Is the field of obesity research merely a striving after wind, and nothing more?

The objective of the study was to estimate the prevalence of overweight and obesity in children and adolescents in the Basque Country, Spain. It consisted of an analysis of baseline data of the Nutrition Survey, a cross-sectional study, carried out in 2004-2005. The study population comprised child and adolescent living in the Basque Country. The analysis was carried out in a representative random sample of 1178 people aged 4-18 years. Anthropometric examinations were undertaken by trained observers using standardized methods and included measurements of weight and height. Subjects were classified into different body mass index categories, according to the International Obesity Task Force guidelines. A 5.4% of the population studied was obese; 6% of males and 4.7% of females, the highest in the 11-14 age group in boys (7.2%) and in the 4-6 age group in girls (12.5%). Overweight (22.9%) was slightly higher in girls. The highest prevalence of excess weight (overweight+obesity) was observed in girls aged 4-6 years (38.4%), decreasing with age. Subjects in the 15-18 age group rated 16.6%. Boys evidenced a higher excess weight rate in the 11-14 (32.9%) and 7-10 (32%) age groups; the lowest rate was found in the 4-6 age group. Prevalence of obesity was higher in the less privileged socio-economic strata (6.9% vs. 5.2%), for both boys and girls. However, this trend was observed only in girls for overweight (25.9% vs. 21.8%). This study shows a high prevalence of obesity and overweight in the studied population and similar to other European countries and regions.

This systematic review assesses weight loss interventions in young adults (18-25 years), who are vulnerable to weight gain. This age group experience critical life course points (leaving home for higher studies or job, pregnancy, cohabitation) and develop/establish lifestyle and behavioural patterns making this an opportune intervention period. Medline, Embase, Cinahl, PsychINFO and Cochrane Library were searched (1980 to March 2008). All trials and cohort studies with control groups that assessed weight loss interventions in this specific age group were included finally identifying 14 studies. Before and after comparison of behavioural/motivational interventions (-2.40 kg; 95% CI -5.4 to 0.6) and combination interventions (-2.96; 95% CI -4.4 to -1.5) consistently showed weight loss. Behavioural/motivational interventions increased self-efficacy, the desire to control weight, boosted self-esteem, and increased satisfaction with body areas and appearance. Interventions also showed improvements in HDL cholesterol, insulin, glucose and maximum oxygen uptake. However, recruitment to participation in interventions was a barrier for this age group with small sample sizes and short-term interventions. There may be gender differences in preference to participation in certain type of interventions. Further research to understand attitudes towards healthy lifestyle and preferences of interventions is needed to develop suitable interventions for this vulnerable age group.

Australia is a large country approximately equal in area to mainland United States. The relatively small population of around 20 million are composed primarily of Caucasians. Extensive immigration from many different countries has made Australia one of the most culturally diverse populations in the world. Indigenous Australians make up only 2.4% of the total population. Australia has a prosperous Western-style capitalist economy, and spends approximately 830 million dollars on the direct health care costs of obesity. For Australians, it is now more common to have a weight problem, with overweight affecting 48% of men and 30% of women and obesity affecting a further 19% of men and 22% of women. This paper reports on recent epidemiological studies documenting the extent of overweight and obesity in adults and children in Australia.

The aim of the study was to develop waist circumference (WC) percentiles in Polish children and youth and to compare these with the results obtained in other countries. The study comprised a random group of 5663 Polish children aged 7-18 years. Smoothed WC percentile curves were computed using the LMS method. The curves displaying the values of the 50th (WC(50)) and the 90th (WC(90)) percentile were then compared with the results of similar studies carried out in children from the UK, Spain, Germany, Turkey, Cyprus, Canada and the USA. WC increased with age in both boys and girls and in all observed age periods the boys were seen to dominate. For 18-year-old Polish boys and girls the values of WC(90) were 86.5 and 78.2, respectively, and were lower than the current criteria developed by the International Diabetes Federation. Both WC(50) and WC(90) were higher in Polish boys and girls compared with their counterparts in the UK, Turkey and Canada and significantly lower than in children from the USA, Cyprus and Spain. The percentile curves for Polish children and youth, which were developed here for the first time, are base curves that can be applied in analysing trends as well as making comparisons with results of similar studies performed in other countries.

MEDLINE surveys were carried out and reference lists were cross-checked to identify publications on long-term outcome for dietary treatment of obesity. 898 papers were identified, 17 fulfilled our planned criteria for inclusion (dietary treatment; adults; follow-up period > or = 3 years; follow-up rate > or = 50% of original study group; information on one of the success criteria: maintenance of all weight initially lost (or further weight reduction) or maintenance of at least nine to 11 kg of initial weight loss; obesity complications of the patient group not over-represented; English, German or Scandinavian languages). The 17 included publications (here of three publications on randomized clinical trials with control group relevant for this review) reported on 21 study groups, comprising 3030 patients. Of these 2131 (70%) were followed-up for 3-14 years (median 5 years). Mean initial weight loss ranged from four to 28 kg (median 11 kg). Overall, 15% (median, range 0-49%) of followed-up patients fulfilled one of the criteria for success. Overall, success rates seemed stable for up to 14 years of observation. Diet combined with group therapy lead to better long-term success rates (median 27%) than did diet alone (median 15%) or diet combined with behaviour modification (median 14%). Active follow-up was generally associated with better success rates than was passive follow-up (19% vs. 10%). Conventional diet seemed to be most efficacious in addition with group therapy, whereas VLCD apparently was most efficacious if combined with behaviour modification and active follow-up. The literature on long-term follow-up of dietary treatment of obesity, although limited and inhomogeneous, points to an overall median success rate of 15% and a possible adjuvant effect of group therapy, behaviour modification and active follow-up.

This study uses unique official data to document nutritional changes in the 1949-1992 period. In 1949, widespread famine, high mortality and low life expectancy dominated. Economic progress was uneven; however, the longer term food supply changed greatly, and hunger was conquered. Diet composition shifted greatly over this period. Cereal consumption, already high, increased from 541.2 g d(-1) (70.0% coarse grains) in 1952 to 645.9 g d(-1) (15.9% coarse grains) in 1992. Consumption of animal-source foods, half of which were pork and pork products, tripled from 30.0 to 103.0 g d(-1) . The proportion of energy intake from fat tripled from 7.6% to 22.5%, and that from carbohydrates decreased from 83.0% to 65.8% over the same period. Physical activity was high in all domains, but shifts were beginning to occur (e.g. the initial mechanization of work and the expansion of biking). Nutritional improvement was uneven, including increased undernutrition in the 1959-1962 period and a remarkable rebound and continued improvement thereafter. Overweight emerged only after 1982. Shifts in diet, activity and body composition in 1949-1992 set the stage for major shifts in nutrition in the subsequent decades.

This paper examines trends in obesity rates and education-related absolute and relative inequalities in obesity over the last 40 years in France. Data are drawn from the French Decennial Health Surveys of 1970, 1980, 1991 and 2003. The difference in obesity rates between the least- and most-educated, the Slope Index of Inequality, is used to estimate absolute inequalities in obesity. The ratio of the corresponding rates, the Relative Index of Inequality, reveals the relative inequalities in obesity. Obesity rates were similar in men and women, but educational inequalities were greater in women. Obesity rates were similar over the first three surveys but increased for all in the 2003 survey. This increase was accompanied by increases in absolute inequalities in men (P = 0.04) from a Slope Index of Inequality of 4.80% (95% confidence interval [CI] = 2.27, 7.32) to 8.64% (95% CI = 5.97, 11.32) and women (P = 0.004) from 8.90% (95% CI = 6.18, 11.63) to 14.57% (95% CI = 11.83, 17.32). Relative inequalities in obesity remained stable over the 40 years. Recent increase in obesity rates in France is accompanied by increases in absolute education-related inequalities, while relative inequalities have remained stable; this suggests that obesity rates have increased at a much faster rate in the low-education groups.

The aim of this study was to describe the 20-year changes in body mass index (BMI; kgm(-2)) and the prevalence of overweight in Japanese adults. Cross-sectional annual nationwide surveys (National Nutrition Survey, Japan) were carried out with a large probability sample of the Japanese population. Data sets of the 1976-95 surveys, comprising 91983 men and 120822 women (> or =20 years of age), were used. The analyses were carried out in age and gender groups, and by residential area according to the size of the municipality (metropolitan areas, cities and small towns). The mean BMI increaseed in men with an increment of +0.44 kg m(-2) 10 years(-1) and slightly decreased in women, by -0.09 kg m(-2) 10 years(-1), after adjustment for age. A decreasing trend of mean BMI was most significant in the female 20-29 years age-group (-0.38 kg m(-2) 10 years(-1)), in contrast to an increasing trend observed in elderly women (60-69 and 70+ years age-groups). The prevalence of preobese (BMI: 25-29.9kg m(-2)) and obese (BMI > or = 30 kg m(-2)) men increased from 14.5% and 0.8%, respectively, in the time-period 1976-80 to 20.5% and 2.01% during 1991-95. The increasing trend was most evident in the youngest age-group (20-29 years) and in those from small towns. The overall prevalence of preobese and obese women did not change during the 20-year study period. The prevalence in younger women decreased, this trend being more prominent in metropolitan areas. Although the prevalence of overweight (BMI > or =25 kg m(-2)) in Japanese men and elderly women has increased in the last 20 years, the mean BMI in younger women, especially those in metropolitan areas, has decreased. A population approach to control obesity and prevent obesity-associated diseases should be mainly focused on men and women older than 40 years of age.

The purposes of this study were to: (i) provide contemporary estimates of the prevalence of abdominal obesity, as assessed by waist circumference (WC), in Canadian adolescents and adults; (ii) provide estimates of the prevalence of abdominal obesity within normal weight, overweight and obese body mass index categories and (iii) examine secular changes in abdominal obesity. Data were based on three national health surveys conducted in 1981, 1988 and 2007-2009. WC was measured at the mid-point between the last rib and iliac crest in all three surveys. The prevalence of Canadians with abdominal obesity increased with age and was higher in females than in males. In 12- to 19-year-old adolescents, the estimated prevalence of abdominal obesity was 1.8% in 1981, 2.4% in 1988 and 12.8% in 2007-2009. The corresponding values for 20- to 69-year-old adults were 11.4%, 14.2% and 35.6%. Between 1981 and 2007-2009, mean WC values increased by 4.2 cm in adolescent males, 6.7 cm in adolescent females, 6.5 cm in men and 10.6 cm in women. Within the 2007-2009 survey, 2.6% of normal weight adults had abdominal obesity, 35.3% of overweight adults had abdominal obesity and 93.0% of obese adults had abdominal obesity.

The epidemic of obesity as measured by body mass index (BMI) maybe plateauing. However, studies using skin-fold and waist circumference measurements suggest that BMI may underestimate changes in fatness in children. In this study we examine changes in waist circumference and waist-to-height ratio (WHtR) in Australian children between 1985 and 2007, by undertaking secondary data analysis of three national data sets. The mean waist circumference z-score for boys increased from -0.02 (95% CI -0.05 to 0.01) in 1985, to 0.33 (0.26 to 0.40) in 1995 and 0.41 (0.35 to 0.47) in 2007 and was greater (P<0.001) than the increase in BMI z-score. The increase in mean waist circumference z-score for girls was greater (P<0.001) than boys and increased from -0.02 (0.05 to 0.01) in 1985, to 0.33 (0.26 to 0.41) in 1995 and to 0.57 (0.51 to 0.63) in 2007. The number of children with a WHtR ≥ 0.5 increased from 8.6% in 1985, to 13.6% in 1995 and 18.3% in 2007. Between 1985 and 2007 central adiposity increased at a faster rate than total adiposity, particularly in girls. The secular increase in waist circumference and WHtR is concerning as measures of central adiposity are associated with metabolic and cardiovascular risk.

This paper describes the nationwide prevalence of childhood overweight/obesity in Chinese urban population. Data sets of boys and girls aged 7-18 yrs were collected from the series of Chinese national surveillance on students' constitution and health between 1985 and 2000 were divided into five socioeconomic groups, while WGOC BMI-reference was used as definitions of overweight and obesity. In 2000, the prevalence of childhood obesity/overweight in the coastal big cities, followed by that of the coastal middle/small cities, had reached the average level of the developed countries. The prevalence of obesity was low in most of the inland cities at an early stage of epidemic overweight. The epidemic manifested a gradient distribution in groups, which was closely related to socioeconomic status of the populations. A dramatic and steady increasing trend was witnessed among all sex-age subgroups in these urban groups, and the increments in obesity/overweight are exceptionally high in recent 5 years, and the prospect of epidemic obesity in China is in no way optimistic. Preventive program should be focused on the improvement of the balance between caloric intake and energy expenditure, and interventions aimed at changing children's life styles.

This article describes a bibliometric review of the publications on obesity research in PubMed over the last 20 years. We used Medline via the PubMed online service of the US National Library of Medicine from 1988 to 2007. The search strategy was: ([obesity] in MesH). A total of 58,325 references were retrieved, 25.5% in 1988-1997, and 74.5% in 1998-2007. The growth in the number of publications showed an exponential increase. The references were published in 3613 different journals, with 20 journals contributing 25% of obesity literature. The two journals contributing most were the International Journal of Obesity (5.1%), Obesity-Obesity Research (2.9%). North America and Europe were the most productive world areas with 44.1% and 37.9% of the literature, respectively. The US was the predominant country in number of publications, followed by the United Kingdom, Japan and Italy. The ranking of production changed when the number of publications was normalized by population, gross domestic product and obesity prevalence by countries. The great increase of publications on obesity during the period 1988-2007 was particularly evident in the second decade of the period which is concordant with the worldwide obesity epidemic. USA and Europe were leaders in the production of scientific articles on obesity.

The China Health and Nutrition Survey (CHNS) began in 1989 with the goal of creating a multilevel method of data collection from individuals and households and their communities to understand how the wide-ranging social and economic changes in China affect a wide array of nutrition and health-related outcomes. Initiated with a partial sample in 1989, the full survey runs from 1991 to 2011, and this issue documents the CHNS history. The CHNS cohort includes new household formation and replacement communities and households; all household members are studied. Furthermore, in-depth community data are collected. The sample began with eight provinces and added a ninth, Heilongjiang, in 1997 and three autonomous cities, Beijing, Shanghai, and Chongqing, in 2011. The in-depth community contextual measures have allowed us to create a unique measure of urbanicity that captures major dimensions of modernization across all 288 communities currently in the CHNS sample. The standardized, validated urbanicity measure captures the changes in 12 dimensions: population density; economic activity; traditional markets; modern markets; transportation infrastructure; sanitation; communications; housing; education; diversity; health infrastructure; and social services. Each is based on numerous measures applicable to each dimension. They are used jointly and separately in hundreds of studies.

China's food consumption patterns and eating and cooking behaviours changed dramatically between 1991 and 2011. Macronutrient composition has shifted towards fats, and protein and sodium intakes remain high and potassium intake low. The rapid decline in intake of coarse grains and, later, of refined grains and increases in intake of edible oils and animal-source foods accompanied by major eating and cooking behaviour shifts are leading to what might be characterized as an unhealthy Western type of diet, often based on traditional recipes with major additions and changes. The most popular animal-source food is pork, and consumption of poultry and eggs is increasing. The changes in cooking and eating styles include a decrease in the proportion of food steamed, baked, or boiled, and an increase in snacking and eating away from home. Prior to the last decade, there was essentially no snacking in China except for hot water or green tea. Most recently, the intake of foods high in added sugar has increased. The dietary shifts are affected greatly by the country's urbanization. The future, as exemplified by the diet of the three mega cities, promises major growth in consumption of processed foods and beverages.