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BACKGROUND Data from the NHANES indicate that BMI has increased in some subgroups of children and adolescents in the United States over the past 20 y; however, BMI is an indirect measure of body fatness. OBJECTIVES We assessed changes in DXA-derived measures of adiposity in a nationally representative population of US children and adolescents aged 8-19 y from 1999-2006 to 2011-2018. METHODS Using data from the NHANES, we compared the means and distributions of DXA-derived percentage body fat (%BF) and fat mass index (FMI; fat mass/height2 in kg/m2) between 1999-2006 (n = 10,231) and 2011-2018 (n = 6923) among males and females by age group, race and Hispanic origin, and BMI categories. Estimates were standardized by age and race and Hispanic origin. RESULTS From 1999-2006 to 2011-2018, mean %BF increased from 25.6% to 26.3% (change in %BF: 0.7%; 95% CI: 0.2%, 1.2%; P

Objective The purpose of this study was to investigate the association of sodium intake with obesity in US children and adolescents. Methods Cross-sectional data were analyzed for 9,026 children and adolescents in the National Health and Nutrition Examination Survey (NHANES) 2009-2016. Usual sodium intake was estimated from 24-hour dietary recalls using a measurement error model. Logistic regression was used to assess the association of sodium intake with overweight/obesity, obesity, and central obesity (waist to height ratio [WtHR] ≥ 0.5; waist circumferences (WC) ≥ age- and sex-specific 90th percentile). Results Mean (SE) sodium intake was 3,010 (9) and 3,404 (20) mg/d for children and adolescents, respectively. The adjusted odds ratio (AOR) comparing Q4 versus Q1 (87.5th vs. 12.5th percentile of sodium intake) among children was 1.98 (95% CI: 1.19-3.28) for overweight/obesity, 2.20 (1.30-3.73) for obesity, 2.10 (1.12-3.95) for WC ≥ 90th percentile, and 1.68 (0.95-2.97) for WtHR ≥ 0.5, adjusting for demographics, energy, and sugar-sweetened beverage intake. Among adolescents, AOR was 1.81 (0.98-3.37) for overweight/obesity, 1.71 (0.82-3.56) for obesity, 1.62 (0.71-3.66) for WC ≥ 90th percentile, and 1.73 (0.85-3.50) for WtHR ≥ 0.5. Conclusions Sodium intake was positively associated with overweight/obesity, obesity, and central obesity among US children independent of energy and SSB intake, but the association did not reach significance among adolescents.

BACKGROUND: The association between body mass index (BMI) and adiposity differs by race/ethnicity. OBJECTIVE: To examine differences in adiposity by race/Hispanic origin among US youth and explore how those differences relate to differences in BMI using the most recent national data, including non-Hispanic Asian youth. METHODS: Weight, height, and DXA-derived fat mass index (FMI) and percentage body fat (%BF) from 6923 youth 8-19y in the National Health and Nutrition Examination Survey (NHANES) 2011-2018 were examined. Age-adjusted mean BMI, FMI and %BF were reported. Sex-specific linear regression models predicting %BF and FMI were adjusted for age, BMI category and BMI category*race/Hispanic origin interaction. RESULTS: %BF was highest among Hispanic males (28.2%) and females (35.7%). %BF was lower among non-Hispanic Black (23.9%) compared with non-Hispanic White (26.0%) and non-Hispanic Asian (26.6%) males. There was no difference between non-Hispanic Black females (32.7%) and non-Hispanic White (33.2%) or non-Hispanic Asian (32.7%) females. FMI was higher among Hispanic youth compared with non-Hispanic White youth. Among youth with underweight/healthy weight, predicted %BF and FMI were lower among non-Hispanic Black males (−2.8%; −0.5) and females (−2.0%; −0.3), compared with non-Hispanic White youth, and higher among Hispanic males (0.9%; 0.2) and females (2.0%; 0.5), while %BF but not FMI was higher among non-Hispanic Asian males (1.3%) and females (1.4%). Among females with obesity, non-Hispanic Asian females had lower %BF (−2.3%) and FMI (−1.7) than non-Hispanic White females. CONCLUSIONS: Differences in %BF and FMI by race/Hispanic origin were not consistent by BMI category among U.S. youth in 2011-2018.

BMI z (BMIz) score based on the Centers for Disease Control and Prevention growth charts is widely used, but it is inaccurate above the 97th percentile. We explored the performance of alternative metrics based on the absolute distance or % distance of a child’s BMI from the median BMI for sex and age. We used longitudinal data from 5628 children who were first examined 3 years. The ICCs of the age-adjusted metrics were also higher compared with that of BMIz among children who were overweight or obese. Unlike BMIz, these alternative metrics do not have an upper limit and can be used for assessing BMI in all children, even those with very high BMIs. The age-adjusted % from median (on a log or linear scale) works well for all ages, while unadjusted % from median is better limited to older children or short follow-up periods.

Objective - This report calculates the prevalence of selected conditions by race and Hispanic origin among U.S. adults (aged 20 and over) during 2015-2018. Methods - Interview, physical examination, and laboratory data were used from the National Health and Nutrition Examination Survey. Conditions included asthma, chronic obstructive pulmonary disease, and heart disease based on self-report;and obesity, severe obesity, diabetes, chronic kidney disease, smoking, and hypertension based on physical measurements. Estimates accounted for survey design. Results - Seventy-six percent of adults and 86.4% (95% CI: 83.5-89.0) of non-Hispanic black adults had at least one condition. Obesity and diabetes were highest among non-Hispanic black (47.9% CI: 45.0-50.8;19.2% CI: 16.7-21.8, respectively) and Hispanic adults (45.7% CI: 42.9-48.6;21.3% CI: 19.0-23.7, respectively). Conclusions - Non-Hispanic black and Hispanic adults had a disproportionate burden of some conditions, including obesity and diabetes. Understanding populations at highest risk for severe coronavirus disease 2019-related illness could help inform prevention strategies.

Obesity is associated with serious health risks (1). Severe obesity further increases the risk of obesity-related complications, such as coronary heart disease and end-stage renal disease (2,3). From 1999-2000 through 2015-2016, a significantly increasing trend in obesity was observed (4). This report provides the most recent national data for 2017-2018 on obesity and severe obesity prevalence among adults by sex, age, and race and Hispanic origin. Trends from 1999-2000 through 2017-2018 for adults aged 20 and over are also presented.

Studies have suggested that obesity prevalence varies by income and educational level, although patterns might differ between high-income and low-income countries (1-3). Previous analyses of U.S. data have shown that the prevalence of obesity varied by income and education, but results were not consistent by sex and race/Hispanic origin (4). Using data from the National Health and Nutrition Examination Survey (NHANES), CDC analyzed obesity prevalence among adults (aged ≥20 years) by three levels of household income, based on percentage (≤130%, >130% to ≤350%, and >350%) of the federal poverty level (FPL) and individual education level (high school graduate or less, some college, and college graduate). During 2011-2014, the age-adjusted prevalence of obesity among adults was lower in the highest income group (31.2%) than the other groups (40.8% [>130% to ≤350%] and 39.0% [≤130%]). The age-adjusted prevalence of obesity among college graduates was lower (27.8%) than among those with some college (40.6%) and those who were high school graduates or less (40.0%). The patterns were not consistent across all sex and racial/Hispanic origin subgroups. Continued progress is needed to achieve the Healthy People 2020 targets of reducing age-adjusted obesity prevalence to

Differences by nativity status for cardiovascular disease (CVD) risk factors have been previously reported. Recent research has focused on understanding how other acculturation factors, such as length of residence, affect health behaviors and outcomes. This study examines the association between CVD risk factors and nativity/length of US residence. Using cross-sectional data from 15,965 adults in the 2011–2016 National Health and Nutrition Examination Surveys (analyzed in 2018), prevalence ratios and predicted marginals from logistic regression models are used to estimate associations of CVD risk factors (i.e., hypertension, hypercholesterolemia, diabetes, overweight/obesity and smoking) with nativity/length of residence (< 15 years, ≥15 years) in the US. In sex-, age-, education- and race and Hispanic origin- adjusted analyses, a higher percentage of US (50 states and District of Columbia) born adults (86.4%) had ≥1 CVD risk factor compared to non-US born residents in the US < 15 years (80.1%) but not ≥15 years (85.1%). Compared to US born counterparts, regardless of length of residence, hypertension overall and smoking among non-Hispanic white and Hispanic adults were lower among non-US born residents. Overweight/obesity overall and diabetes among Hispanic adults were lower among non-US born residents in the US < 15 years. In contrast, non-US born non-Hispanic Asian residents in the US < 15 years had higher prevalence of diabetes. Non-US born adults were less likely to have most CVD risk factors compared to US born adults regardless of length of residence, although, for smoking and diabetes this pattern differed by race and Hispanic origin.

Objective Although the Centers for Disease Control and Prevention (CDC) growth charts are widely used, BMI-for-age z-Scores (BMIz) are known to be uninformative above the 97th percentile. This study compared the relations of BMIz and other BMI metrics (%BMIp95, percent of 95th percentile, and ΔBMIp95, BMI minus 95th percentile) to circumferences, skinfolds, and fat mass. We were particularly interested in the differences among children with severe obesity (%BMIp95 ≥ 120). Methods Data was used from 30,003 2- to 19-year-olds who were examined from 1999-2000 through 2013-2014 in the National Health and Nutrition Examination Survey (NHANES). Results The theoretical maximum BMIz based on the growth charts varied by more than threefold across ages. The BMI metrics were strongly intercorrelated, but BMIz was less strongly related to the adiposity measures than were ΔBMIp95 and %BMIp95. Among children with severe obesity, circumferences and triceps skinfold showed almost no association with BMIz (r ≤ 0.10), whereas associations with %BMIp95 and ΔBMIp95 ranged from r = 0.32 to 0.79. Corresponding associations with fat mass ÷ height2 ranged from r = 0.40 (BMIz) to r =0.82 (%BMIp95) among 8- to 19-year-olds. Conclusions Among children with severe obesity, BMIz is only weakly associated with other measures of body fatness. Very high BMIs should be expressed relative to the CDC 95th percentile, particularly in studies that evaluate obesity interventions.

Objective Although the CDC growth charts are widely used, BMIz is known to be uninformative above the 97th percentile. We compared the relations of BMIz and other BMI metrics (%BMIp95, percent of 95th percentile, and ΔBMIp95, BMI minus 95th percentile) to circumferences, skinfolds and fat mass. We were particularly interested in the differences among children with severe obesity (%BMIp95 ≥ 120). Methods We used data from 30,003 2- to 19-year-olds who were examined from 1999-2000 through 2013-14 in NHANES. Results The theoretical maximum BMIz based on the growth charts varied by more than 3-fold across ages. The BMI metrics were strongly intercorrelated, but BMIz was less strongly related to the adiposity measures than were ΔBMIp95 and %BMIp95. Among children with severe obesity, circumferences and triceps skinfold showed almost no association with BMIz (r ≤ 0.10), whereas associations with %BMIp95 and ΔBMIp95 ranged from r=0.32 to 0.79. Corresponding associations with fat mass ÷ height2 ranged from r=0.40 (BMIz) to r=0.82 (%BMIp95) among 8- to 19-year-olds. Conclusions Among children with severe obesity, BMIz is only weakly associated with other measures of body fatness. Very high BMIs should be expressed relative to the CDC 95th percentile, particularly in studies that evaluate obesity interventions.

Background Although the prevalence of a body mass index [BMI (in kg/m2)] ≥30 has tripled among US adults since the 1960s, BMI is only moderately correlated with body fatness. Because skinfolds can more accurately estimate body fatness than can BMI, it is possible that skinfolds could be useful in monitoring secular trends in body fatness. Objective We examined whether there were similar secular trends for skinfolds (triceps and subscapular), BMI, and waist circumference between US adults. Design This study was an analysis of 45,754 adults who participated in the NHANES from 1988-1994 through 2009-2010. Approximately 19% of the subjects were missing ≥1 skinfold-thickness measurement. These missing values were imputed from other characteristics. Results Trends in mean levels and in the prevalence of high levels of the 4 body size measures were fairly similar between men, with mean levels increasing by ≥5% from 1988-1994 through 2009-2010. Slightly larger increases were seen in women for BMI and waist circumference (7-8%), but trends in skinfolds were markedly different. The mean triceps skinfold, for example, increased by 2 mm through 2003-2004, but subsequently decreased so that the mean in 2009-2010 did not differ from that in 1988-1994. Compared with obese women in 1988-1994, the mean BMI of obese women in 2009-2010 was 1 higher, but mean levels of both skinfolds were 5-10% lower. Conclusions Although there were fairly similar trends in levels of BMI, waist circumference, and skinfold thicknesses in men in the United States from 1988-1994 through 2009-2010, there were substantial differences in women. Our results indicate that it is unlikely that skinfold thicknesses could be used to monitor trends in obesity.

Objective Previous research has not investigated the role of prescription medication in sleep-obesity associations despite the fact that 56% of U.S. adults take at least one prescription medication. Methods Data from n = 16,622 adults in the National Health and Nutrition Examination Survey (2007-2012) were used to examine how the association between obesity and self-reported sleep duration varied by total number of prescription medications used in the past 30 days and by select classes of prescription medications including anxiolytics/sedatives/hypnotics, antidepressants, sleep aids, anticonvulsants, thyroid agents, and metabolic agents. Results Logistic regression analyses showed a significant inverse linear association of sleep duration and obesity, regardless of the total number of prescription medications individuals were taking. Each additional hour of sleep was associated with a 10% decrease in the odds of obesity. Results suggest that increased sleep duration is associated with lower odds of having obesity overall, even for long-duration sleepers (≥9 h), and this association does not differ for those taking antidepressants, thyroid agents, metabolic agents, and multiple prescription medications. Conclusions The relationship between sleep duration and obesity was similar among all prescription medication users and nonusers. The potential for a nonlinear association between sleep duration and obesity may be important to examine in some specific prescription medication classes.

This study uses NHANES data to assess trends in obesity and severe obesity stratified by race and Hispanic origin among US residents from 1999 to 2018.

Objective The aim of this study was to compare national estimates of self-reported and measured height and weight, BMI, and obesity prevalence among adults from US surveys. Methods Self-reported height and weight data came from the National Health and Nutrition Examination Survey (NHANES), the National Health Interview Survey, and the Behavioral Risk Factor Surveillance System for the years 1999 to 2016. Measured height and weight data were available from NHANES. BMI was calculated from height and weight; obesity was defined as BMI ≥ 30. Results In all three surveys, mean self-reported height was higher than mean measured height in NHANES for both men and women. Mean BMI from self-reported data was lower than mean BMI from measured data across all surveys. For women, mean self-reported weight, BMI, and obesity prevalence in the National Health Interview Survey and Behavioral Risk Factor Surveillance System were lower than self-report in NHANES. The distribution of BMI was narrower for self-reported than for measured data, leading to lower estimates of obesity prevalence. Conclusions Self-reported height, weight, BMI, and obesity prevalence were not identical across the three surveys, particularly for women. Patterns of misreporting of height and weight and their effects on BMI and obesity prevalence are complex.

Almost 40% of adults in the United States had obesity in 2015-2016 (1). Obesity is associated with a range of serious health risks (2). Individuals may have multiple motivations for trying to losing weight, including health and appearance reasons (3). This report describes the percentage of U.S. adults who tried to lose weight in the past year by sex, age, race and Hispanic origin, family income, and weight status, based on data collected in the National Health and Nutrition Examination Survey (NHANES) from 2013 -2016.

Background Both excessive sodium intake and obesity are risk factors for hypertension and cardiovascular disease. The association between sodium intake and obesity is unclear, with few studies assessing sodium intake using 24-h urine collection. Objectives Our objective was to assess the association between usual 24-h sodium excretion and measures of adiposity among US adults. Methods Cross-sectional data were analyzed from a sample of 730 nonpregnant participants aged 20-69 y who provided up to 2 complete 24-h urine specimens in the NHANES 2014 and had data on overweight or obesity [body mass index (kg/m2) ≥25] and central adiposity [waist circumference (WC): >88 cm for women, >102 cm for men]. Measurement error models were used to estimate usual sodium excretion, and multiple linear and logistic regression models were used to assess its associations with measures of adiposity, adjusting for sociodemographic, health, and dietary variables [i.e., energy intake or sugar-sweetened beverage (SSB) intake]. All analyses accounted for the complex survey sample design. Results Unadjusted mean ± SE usual sodium excretion was 3727 ± 43.5 mg/d and 3145 ± 55.0 mg/d among participants with and without overweight/obesity and 3653 ± 58.1 mg/d and 3443 ± 35.3 mg/d among participants with or without central adiposity, respectively. A 1000-mg/d higher sodium excretion was significantly associated with 3.8-units higher BMI (95% CI: 2.8, 4.8) and a 9.2-cm greater WC (95% CI: 6.9, 11.5 cm) adjusted for covariates. Compared with participants in the lowest quartile of sodium excretion, the adjusted prevalence ratios in the highest quartile were 1.93 (95% CI: 1.69, 2.20) for overweight/obesity and 2.07 (95% CI: 1.74, 2.46) for central adiposity. The associations also were significant when adjusting for SSBs, instead of energy, in models. Conclusions Higher usual sodium excretion is associated with overweight/obesity and central adiposity among US adults.

Importance Differences in obesity by sex, age group, race and Hispanic origin among US adults have been reported, but differences by urbanization level have been less studied. Objectives To provide estimates of obesity by demographic characteristics and urbanization level and to examine trends in obesity prevalence by urbanization level. Design, Setting, and Participants Serial cross-sectional analysis of measured height and weight among adults aged 20 years or older in the 2001-2016 National Health and Nutrition Examination Survey, a nationally representative survey of the civilian, noninstitutionalized US population. Exposures Sex, age group, race and Hispanic origin, education level, smoking status, and urbanization level as assessed by metropolitan statistical areas (MSAs; large: ≥1 million population). Main Outcomes and Measures Prevalence of obesity (body mass index [BMI] ≥30) and severe obesity (BMI ≥40) by subgroups in 2013-2016 and trends by urbanization level between 2001-2004 and 2013-2016. Results Complete data on weight, height, and urbanization level were available for 10 792 adults (mean age, 48 years; 51% female [weighted]). During 2013-2016, 38.9% (95% CI, 37.0% to 40.7%) of US adults had obesity and 7.6% (95% CI, 6.8% to 8.6%) had severe obesity. Men living in medium or small MSAs had a higher age-adjusted prevalence of obesity compared with men living in large MSAs (42.4% vs 31.8%, respectively; adjusted difference, 9.8 percentage points [95% CI, 5.1 to 14.5 percentage points]); however, the age-adjusted prevalence among men living in non-MSAs was not significantly different compared with men living in large MSAs (38.9% vs 31.8%, respectively; adjusted difference, 4.8 percentage points [95% CI, −2.9 to 12.6 percentage points]). The age-adjusted prevalence of obesity was higher among women living in medium or small MSAs compared with women living in large MSAs (42.5% vs 38.1%, respectively; adjusted difference, 4.3 percentage points [95% CI, 0.2 to 8.5 percentage points]) and among women living in non-MSAs compared with women living in large MSAs (47.2% vs 38.1%, respectively; adjusted difference, 4.7 percentage points [95% CI, 0.2 to 9.3 percentage points]). Similar patterns were seen for severe obesity except that the difference between men living in large MSAs compared with non-MSAs was significant. The age-adjusted prevalence of obesity and severe obesity also varied significantly by age group, race and Hispanic origin, and education level, and these patterns of variation were often different by sex. Between 2001-2004 and 2013-2016, the age-adjusted prevalence of obesity and severe obesity significantly increased among all adults at all urbanization levels. Conclusions and Relevance In this nationally representative survey of adults in the United States, the age-adjusted prevalence of obesity and severe obesity in 2013-2016 varied by level of urbanization, with significantly greater prevalence of obesity and severe obesity among adults living in nonmetropolitan statistical areas compared with adults living in large metropolitan statistical areas.

Importance Differences in childhood obesity by demographics and urbanization have been reported. Objective To present data on obesity and severe obesity among US youth by demographics and urbanization and to investigate trends by urbanization. Design, Setting, and Participants Measured weight and height among youth aged 2 to 19 years in the 2001-2016 National Health and Nutrition Examination Surveys, which are serial, cross-sectional, nationally representative surveys of the civilian, noninstitutionalized population. Exposures Sex, age, race and Hispanic origin, education of household head, and urbanization, as assessed by metropolitan statistical areas (MSAs; large: ≥ 1 million population). Main Outcomes and Measures Prevalence of obesity (body mass index [BMI] ≥95th percentile of US Centers for Disease Control and Prevention [CDC] growth charts) and severe obesity (BMI ≥120% of 95th percentile) by subgroups in 2013-2016 and trends by urbanization between 2001-2004 and 2013-2016. Results Complete data on weight, height, and urbanization were available for 6863 children and adolescents (mean age, 11 years; female, 49%). In 2013-2016, the prevalence among youth aged 2 to 19 years was 17.8% (95% CI, 16.1%-19.6%) for obesity and 5.8% (95% CI, 4.8%-6.9%) for severe obesity. Prevalence of obesity in large MSAs (17.1% [95% CI, 14.9%-19.5%]), medium or small MSAs (17.2% [95% CI, 14.5%-20.2%]) and non-MSAs (21.7% [95% CI, 16.1%-28.1%]) were not significantly different from each other (range of pairwise comparisons P = .09-.96). Severe obesity was significantly higher in non-MSAs (9.4% [95% CI, 5.7%-14.4%]) compared with large MSAs (5.1% [95% CI, 4.1%-6.2%]; P = .02). In adjusted analyses, obesity and severe obesity significantly increased with greater age and lower education of household head, and severe obesity increased with lower level of urbanization. Compared with non-Hispanic white youth, obesity and severe obesity prevalence were significantly higher among non-Hispanic black and Hispanic youth. Severe obesity, but not obesity, was significantly lower among non-Hispanic Asian youth than among non-Hispanic white youth. There were no significant linear or quadratic trends in obesity or severe obesity prevalence from 2001-2004 to 2013-2016 for any urbanization category ( P range = .07-.83). Conclusions and Relevance In 2013-2016, there were differences in the prevalence of obesity and severe obesity by age, race and Hispanic origin, and household education, and severe obesity was inversely associated with urbanization. Demographics were not related to the urbanization findings.

This study uses National Health and Nutrition Examination Survey data to characterize trends in obesity prevalence among US youth and adults between 2007-2008 and 2015-2016.

Obesity is associated with serious health risks. Monitoring obesity prevalence is relevant for public health programs that focus on reducing or preventing obesity. Between 2003–2004 and 2013–2014, there were no significant changes in childhood obesity prevalence, but adults showed an increasing trend. This report provides the most recent national estimates from 2015–2016 on obesity prevalence by sex, age, and race and Hispanic origin, and overall estimates from 1999–2000 through 2015–2016.

Objective To examine the associations among several body mass index (BMI) metrics ( z -scores, percent of the 95th percentile (%BMI p95 ) and BMI minus 95th percentile (ΔBMI p95 ) as calculated in the growth charts from the Centers for Disease Control and Prevention (CDC). It is known that the widely used BMI z -scores (BMIz) and percentiles calculated from the growth charts can differ substantially from those that directly observed in the data for BMIs above the 97th percentile ( z = 1.88). Study design Cross-sectional analyses of 8.7 million 2- to 4-year-old children who were examined from 2008 through 2011 in the CDC's Pediatric Nutrition Surveillance System. Results Because of the transformation used to calculate z -scores, the theoretical maximum BMIz varied by >3-fold across ages. This results in the conversion of very high BMIs into a narrow range of z -scores that varied by sex and age. Among children with severe obesity, levels of BMIz were only moderately correlated (r ~ 0.5) with %BMI p95 and ΔBMI p95 . Among these children with severe obesity, BMIz levels could differ by more than 1 SD among children who had very similar levels of BMI, %BMI p95 and ΔBMI p95 due to differences in age or sex. Conclusions The effective upper limit of BMIz values calculated from the CDC growth charts, which varies by sex and age, strongly influences the calculation of z -scores for children with severe obesity. Expressing these very high BMIs relative to the CDC 95th percentile, either as a difference or percentage, would be preferable to using BMI-for-age, particularly when assessing the effectiveness of interventions.

SummaryBackground Few studies have assessed how well body mass index (BMI), waist circumference (WC), or waist to height ratio (WtHR) perform in identifying cardio-metabolic risk among youth. Objective The objective of this study was to evaluate the utility of BMI and WC percentiles and WtHR to distinguish adolescents with and without cardio-metabolic risk. Methods A cross-sectional analysis of data from 6097 adolescents aged 10–13 years who participated in the HEALTHY study was conducted. Receiver operating characteristic curves determined the discriminatory ability of BMI and WC percentiles and WtHR. Results The discriminatory ability of BMI percentile was good (area under the curve [AUC] ≥ 0.80) for elevated insulin and clustering of ≥3 risk factors, with optimal cut-points of 96 and 95, respectively. BMI percentile performed poor to fair (AUC = 0.57–0.75) in identifying youth with the majority of individual risk factors examined (elevated glucose, total cholesterol, low-density lipoprotein, blood pressure, triglycerides and high-density lipoprotein). WC percentile and WtHR performed similarly to BMI percentile. Conclusions The current definition of obesity among US children performs well at identifying adolescents with elevated insulin and a clustering of ≥3 cardio-metabolic risk factors. Evidence does not support WC percentile or WtHR as superior screening tools compared with BMI percentile for identifying cardio-metabolic risk.

Objective: A recent, cross-sectional analysis of adults found that the hip circumference divided by height1.5 minus 18 (the body adiposity index, BAI) was strongly correlated (r = 0.79) with percent body fat determined by dual energy X-ray absorptiometry. The BAI was proposed as a more accurate index of body fatness than BMI. We examined whether BAI was more strongly related, than was BMI and waist circumference, to skinfold thicknesses and levels of various risk factors for coronary heart disease. Design and Methods: Cross-sectional analyses of adults (n = 14,263 for skinfold thickness; n=6291 for fasting lipid levels) in the National Health and Nutrition Examination Survey (NHANES) III, 1988-1994. Results: As compared with BMI and waist circumference, we found that BAI was less strongly associated with the skinfold sum and with risk factor levels. For example, correlations with the skinfold sum were r = 0.79 (BMI) vs. r = 0.70 (BAI) among men, and r = 0.86 (BMI) vs. r = 0.79 (BAI) among women; p < 0.001 for the difference between each pair of correlations. An overall index of the 7 risk factors was also more strongly associated with BMI and waist circumference than BAI in analyses stratified by sex, race-ethnicity and age. Multivariable analyses indicated that if BMI was known, BAI provided little additional information on risk factor levels. Conclusions: Based on the observed associations with risk factor levels and skinfold thicknesses, we conclude that BAI is unlikely to be a better index of adiposity than BMI.

Until quite recently, there has been a widespread belief in the popular media and scientific literature that the prevalence of childhood obesity is rapidly increasing. However, high quality evidence has emerged from several countries suggesting that the rise in the prevalence has slowed appreciably, or even plateaued. This review brings together such data from nine countries (Australia, China, England, France, Netherlands, New Zealand, Sweden, Switzerland and USA), with data from 467,294 children aged 2-19 years. The mean unweighted rate of change in prevalence of overweight and obesity was +0.00 (0.49)% per year across all age ×sex groups and all countries between 1995 and 2008. For overweight alone, the figure was +0.01 (0.56)%, and for obesity alone -0.01 (0.24)%. Rates of change differed by sex, age, socioeconomic status and ethnicity. While the prevalence of overweight and obesity appears to be stabilizing at different levels in different countries, it remains high, and a significant public health issue. Possible reasons for the apparent flattening are hypothesised. Refereed/Peer-reviewed

Terminology and measures used in studies of weight and adiposity in children can be complex and confusing. Differences arise in metrics, terminology, reference values, and reference levels. Most studies depend on body mass index (BMI) calculated from weight and height, rather than on more direct measures of body fatness. Definitions of overweight and obesity are generally statistical rather than risk-based and use a variety of different reference data sets for BMI. As a result, different definitions often do not give the same results. A basic problem is the lack of strong evidence for any one particular definition. Rather than formulate the question as being one of how to define obesity, it might be useful to consider what BMI cut-points best predict future health risks and how efficiently to screen for such risks. The answers may be different for different populations. In addition, rather than depending solely on BMI to make screening decisions, it is likely to be useful to also consider other factors, including not only race-ethnicity, sex and age, but also factors such as family history. Despite their limitations, BMI-based definitions of overweight and obesity provide working practical definitions that are valuable for general public health surveillance and screening.

Background: Body mass index (BMI), waist circumference (WC), and the waist-stature ratio (WSR) are considered to be possible proxies for adiposity. Objective: The objective was to investigate the relations between BMI, WC, WSR, and percentage body fat (measured by dual-energy X-ray absorptiometry) in adults in a large nationally representative US population sample from the National Health and Nutrition Examination Survey (NHANES). Design: BMI, WC, and WSR were compared with percentage body fat in a sample of 12,901 adults. Results: WC, WSR, and BMI were significantly more correlated with each other than with percentage body fat (P < 0.0001 for all sex-age groups). Percentage body fat tended to be significantly more correlated with WC than with BMI in men but significantly more correlated with BMI than with WC in women (P < 0.0001 except in the oldest age group). WSR tended to be slightly more correlated with percentage body fat than was WC. Percentile values of BMI, WC, and WSR are shown that correspond to percentiles of percentage body fat increments of 5 percentage points. More than 90% of the sample could be categorized to within one category of percentage body fat by each measure. Conclusions: BMI, WC, and WSR perform similarly as indicators of body fatness and are more closely related to each other than with percentage body fat. These variables may be an inaccurate measure of percentage body fat for an individual, but they correspond fairly well overall with percentage body fat within sex-age groups and distinguish categories of percentage body fat.

Obesity is associated with health risks (1,2). Monitoring the prevalence of obesity is relevant for public health programs that focus on reducing or preventing obesity. No significant changes were seen in either adult or childhood obesity prevalence in the United States between 2003-2004 and 2011-2012 (3). This report provides the most recent national data on obesity prevalence by sex, age, and race and Hispanic origin, using data for 2011- 2014. Overall prevalence estimates from 1999-2000 through 2013-2014 are also presented.

Studies in a variety of countries have shown increases in the prevalence of overweight among children in recent years. These increases have given rise to concern about children's health and well-being. The terminology used in these studies varies considerably. However, whatever the terminology used, such studies are generally based on weight [expressed as body mass index (BMI), a measure of weight for height, calculated as weight in kilograms divided by the square of height in meters] and not on body fatness per se. There are many different BMI references that can be used to define childhood overweight or obesity. Children are defined as overweight for population surveillance purposes using a variety of BMI cut points. BMI is a screening tool, not a diagnostic tool. Children with a BMI over these cut points do not necessarily have clinical complications or health risks related to overfatness. More in-depth assessment of individual children is required to ascertain health status. The definitions of overweight generally used are working definitions that are valuable for general public health surveillance, screening and similar purposes.

Objectives: The prevalence of childhood overweight in the United States has markedly increased over the last 30 years. We examined differences in the secular trends for BMI, weight, and height among white, black, and Mexican-American children. Research Methods and Procedures: Analyses were based on nationally representative data collected from 2 to 17 year olds in four examinations (1971–1974 through 1999–2002). Results: Overall, black children experienced much larger secular increases in BMI, weight, and height than did white children. For example, over the 30-year period, the prevalence of overweight increased ∼3-fold (4% to 13%) among 6- to 11-year-old white children but 5-fold (4% to 20%) among black children. In most sex-age groups, Mexican-American children experienced increases in BMI and overweight that were between those experienced by blacks and whites. Race/ethnicity differences were less marked among 2 to 5 year olds, and in this age group, white children experienced the largest increase in overweight (from 4% to 9%). In 1999–2002, the prevalence of extreme BMI levels (≥99th percentile) reached 6% to 7% among black girls and Mexican-American boys. Discussion: Because of the strong tracking of childhood BMI levels into adulthood, it is likely that the secular increases in childhood overweight will greatly increase the burden of adult disease. The further development of obesity interventions in different racial/ethnic groups should be emphasized.

The prevalence of overweight, as assessed by a high body mass index (kg/m), has greatly increased among children and adolescents over the last three decades. Because body mass index is a measure of excess weight rather than excess body fatness, it is important to understand the ability of a high level to identify children who truly have excess adiposity. This review covers the measurement and classification of overweight and obesity, the expression of body composition data, and the relation of body mass index to adiposity.Although adiposity has typically been expressed as percentage body fat, the use of the fat mass index (fat mass/height) and the fat-free mass index (fat-free mass/height) may provide more information. For example, body mass index differences among relatively thin children have been found to largely reflect differences in fat-free mass index, whereas differences among relatively heavy children are primarily due to differences in fat mass index. In addition, the ability of overweight to identify obese children is greatly influenced by the cutpoints selected for body mass index and adiposity. The use of inappropriate cutpoints, rather than the limitations of body mass index, may account for the frequently reported finding that many obese children are not overweight.The use of fat mass index and fat-free mass index in expressing body composition data allows one to easily assess the contribution of each to body mass index. If appropriate cutpoints are used, a high body mass index level is a moderately sensitive and a very specific indicator of excess adiposity among children.

Overweight and obesity have been increasing in many countries. Our objective is to describe the trends in overweight and obesity occurring in the Mexican-American population in the United States. Data on measured height and weight for Mexican Americans come from the following surveys: the Hispanic Health and Nutrition Examination Survey (HHANES, 1982-84), the Third National Health and Nutrition Examination Survey (NHANES III, 1988-94), and NHANES 1999-2002. In 1999-2002, 73% of Mexican-American adults were overweight and 33% were obese. Obesity increased between NHANES III and NHANES 1999-2002, from 24% to 27% for men and from 35% to 38% for women. Increases were also seen for children and adolescents. The Mexican-American population in the United States, both children and adults, is showing trends in overweight and obesity over time that are similar to those seen in other segments of the U.S. population and indeed in many countries.

INTRODUCTION: Cardiovascular disease remains an important cause of death in the U.S. where veterans of the U.S. Armed Forces represent a significant segment of the population. Limited national estimates of cardiovascular disease risk factors using physical measurements and reported veteran status in the U.S. civilian population have been reported. The purpose of this study was to compare the prevalence of cardiovascular disease risk factors among veteran and non-veteran men in the U.S. civilian population. METHODS: Using data from the 2009–2012 National Health and Nutrition Examination Surveys, 1,107 veteran and 3,972 non-veteran men were identified for this study (analyzed in 2014–2015). Differences in hypertension, dsylipidemia, diabetes, obesity, and smoking between veterans and non-veterans were compared using chi-square and t-tests. Predicted prevalence from multivariable logistic regression models adjusted for age, race/Hispanic origin, and poverty level were used to assess whether previous military service was associated with having a cardiovascular disease risk factor. RESULTS: Veteran men were older than non-veteran men (59.9 years vs 43.4 years) and were more likely to be non-Hispanic white (79.9% vs 65.7%). Adjusted predicted prevalence estimates show that veterans were more likely than non-veterans to be obese (42.6% vs 33.7%, p

Background Food insecurity can put children at greater risk of obesity because of altered food choices and nonuniform consumption patterns. Objective We examined the association between obesity and both child-level food insecurity and personal food insecurity in US children. Design Data from 9,701 participants in the National Health and Nutrition Examination Survey, 2001-2010, aged 2 to 11 years were analyzed. Child-level food insecurity was assessed with the US Department of Agriculture's Food Security Survey Module based on eight child-specific questions. Personal food insecurity was assessed with five additional questions. Obesity was defined, using physical measurements, as body mass index (calculated as kg/m 2 ) greater than or equal to the age- and sex-specific 95th percentile of the Centers for Disease Control and Prevention growth charts. Logistic regressions adjusted for sex, race/ethnic group, poverty level, and survey year were conducted to describe associations between obesity and food insecurity. Results Obesity was significantly associated with personal food insecurity for children aged 6 to 11 years (odds ratio=1.81; 95% CI 1.33 to 2.48), but not in children aged 2 to 5 years (odds ratio=0.88; 95% CI 0.51 to 1.51). Child-level food insecurity was not associated with obesity among 2- to 5-year-olds or 6- to 11-year-olds. Conclusions Personal food insecurity is associated with an increased risk of obesity only in children aged 6 to 11 years. Personal food-insecurity measures may give different results than aggregate food-insecurity measures in children.

Background: Several different sets of reference body mass index (BMI) values are available to define overweight in children. Objective: The objective of this study was to compare the prevalence of overweight in US children calculated with 3 sets of reference BMI values: the revised growth charts of the Centers for Disease Control and Prevention (CDC-US growth charts), international standards proposed by Cole et al, and values developed by Must et al. Design: Data for children and adolescents came from cross-sectional nationally representative US surveys: cycles II and III of the National Health Examination Survey (1963-1965 and 1966-1970) and the first, second, and third National Health and Nutrition Examination Surveys: NHANES I (1971-1974), II (1976-1980), and III (1988-1994). The reference values of Cole et al equivalent to a BMI of 25 were compared with the 85th percentiles from the other 2 methods; the values equivalent to a BMI of 30 were compared with the 95th percentiles. Results: The 3 methods gave similar but not identical results. The reference values of Cole et al gave lower estimates than did the CDC-US growth charts for young children but higher estimates for older children. The reference values of Must et al gave much higher prevalences for younger girls than did the other 2 methods. Conclusions: Differences between methods were related to differences in data sets, smoothing methods, and theoretical approaches. All 3 methods are based on statistical criteria and incorporate arbitrary assumptions. These methods should be used cautiously, with awareness of the possible limitations.

Data from the National Health and Nutrition Examination Survey, 2011-2012. More than one-third (34.9%) of adults were obese in 2011-2012. In 2011-2012, the prevalence of obesity was higher among middle-aged adults (39.5%) than among younger (30.3%) or older (35.4%) adults. The overall prevalence of obesity did not differ between men and women in 2011-2012. Among non-Hispanic black adults, however, 56.6% of women were obese compared with 37.1% of men. In 2011-2012, the prevalence of obesity was higher among non-Hispanic black (47.8%), Hispanic (42.5%), and non-Hispanic white (32.6%) adults than among non-Hispanic Asian adults (10.8%). The prevalence of obesity among adults did not change between 2009-2010 and 2011-2012.

Between 1999-2000 and 2009-2010, the prevalence of obesity increased among boys, but not among girls. There was no change however, in the prevalence of obesity between 2007-2008 and 2009-2010 for either boys or girls (1). It is unclear if the changes in the prevalence of obesity were associated with corresponding changes in energy and macronutrient intakes in children and adolescents during this time frame. An earlier publication reported trends in energy and macronutrient intake in adults between 1999 and 2008 (2). The objective of this report is to present trends in energy and macronutrient intakes among U.S. children and adolescents aged 2–19 years between 1999 and 2010. These results are presented by sex, age group, and race and ethnicity.

OBJECTIVES To describe the percentage of children who met physical activity and screen-time recommendations and to examine demographic differences. Recommendations for school-aged children include 60 minutes of daily moderate-to-vigorous physical activity and no more than 2 hours per day of screen-time viewing. DESIGN Cross-sectional study. SETTING Data from the 2009-2010 National Health and Nutrition Examination Survey, a representative sample of the US population. PARTICIPANTS Analysis included 1218 children 6 to 11 years of age. MAIN EXPOSURES Age, race/ethnicity, sex, income, family structure, and obesity status. MAIN OUTCOME MEASURES Proxy-reported adherence to physical activity and screen-time recommendations, separately and concurrently. RESULTS Based on proxy reports, overall, 70% of children met physical activity recommendations, and 54% met screen-time viewing recommendations. Although Hispanics were less likely to meet physical activity recommendations (adjusted odds ratio [aOR], 0.60 [95% CI, 0.38-0.95]), they were more likely to meet screen-time recommendations compared with non-Hispanic whites (aOR, 1.69 [95% CI, 1.18-2.43]). Only 38% met both recommendations concurrently. Age (9-11 years vs 6-8 years: aOR, 0.57 [95% CI, 0.38-0.85]) and obesity (aOR, 0.53 [95% CI, 0.38-0.73]) were inversely associated with concurrent adherence to both recommendations. CONCLUSIONS Fewer than 4 in 10 children met both physical activity and screen-time recommendations concurrently. The prevalence of sedentary behavior was higher in older children. Low levels of screen-time viewing may not necessarily predict higher levels of physical activity.

Importance Between 1980 and 2000, the prevalence of obesity increased significantly among adult men and women in the United States; further significant increases were observed through 2003-2004 for men but not women. Subsequent comparisons of data from 2003-2004 with data through 2011-2012 showed no significant increases for men or women. Objective To examine obesity prevalence for 2013-2014 and trends over the decade from 2005 through 2014 adjusting for sex, age, race/Hispanic origin, smoking status, and education. Design, Setting, and Participants Analysis of data obtained from the National Health and Nutrition Examination Survey (NHANES), a cross-sectional, nationally representative health examination survey of the US civilian noninstitutionalized population that includes measured weight and height. Exposures Survey period. Main Outcomes and Measures Prevalence of obesity (body mass index ≥30) and class 3 obesity (body mass index ≥40). Results This report is based on data from 2638 adult men (mean age, 46.8 years) and 2817 women (mean age, 48.4 years) from the most recent 2 years (2013-2014) of NHANES and data from 21 013 participants in previous NHANES surveys from 2005 through 2012. For the years 2013-2014, the overall age-adjusted prevalence of obesity was 37.7% (95% CI, 35.8%-39.7%); among men, it was 35.0% (95% CI, 32.8%-37.3%); and among women, it was 40.4% (95% CI, 37.6%-43.3%). The corresponding prevalence of class 3 obesity overall was 7.7% (95% CI, 6.2%-9.3%); among men, it was 5.5% (95% CI, 4.0%-7.2%); and among women, it was 9.9% (95% CI, 7.5%-12.3%). Analyses of changes over the decade from 2005 through 2014, adjusted for age, race/Hispanic origin, smoking status, and education, showed significant increasing linear trends among women for overall obesity ( P = .004) and for class 3 obesity ( P = .01) but not among men ( P = .30 for overall obesity; P = .14 for class 3 obesity). Conclusions and Relevance In this nationally representative survey of adults in the United States, the age-adjusted prevalence of obesity in 2013-2014 was 35.0% among men and 40.4% among women. The corresponding values for class 3 obesity were 5.5% for men and 9.9% for women. For women, the prevalence of overall obesity and of class 3 obesity showed significant linear trends for increase between 2005 and 2014; there were no significant trends for men. Other studies are needed to determine the reasons for these trends.

By 2050, the number of U.S. older adults, defined as persons aged 65 and over, is expected to more than double, rising from 40.2 million to 88.5 million (1). Both aging and obesity contribute to increased health care service use (2,3). Consequently, an increase in the proportion of older adults who are obese may compound health care spending. Given the demographic changes forecasted and the potential health care costs of obesity, it is important to track the prevalence of obesity among older adults (2,3). This report presents the most recent national estimates of obesity in older adults, by sex, age, race and ethnicity, and educational attainment, and examines changes in the prevalence of obesity between 1999 and 2010.

The most recent national data on obesity prevalence among U.S. adults, adolescents, and children show that more than one-third of adults and almost 17% of children and adolescents were obese in 2009–2010. Differences in prevalence between men and women diminished between 1999–2000 and 2009–2010, with the prevalence of obesity among men reaching the same level as that among women. Age differences in obesity prevalence varied between men and women. The prevalence of obesity was higher among older women compared with younger women, but there was no difference by age in obesity prevalence among men. Among children and adolescents, the prevalence of obesity was higher among adolescents than among preschool-aged children. There has been no change in obesity prevalence in recent years; however, over the last decade there has been a significant increase in obesity prevalence among men and boys but not among women and girls overall. The Healthy People 2010 goals of 15% obesity among adults and 5% obesity among children were not met (6).

A recent, cross-sectional analysis of adults found that the hip circumference divided by height(1.5) minus 18 (the body adiposity index, BAI) was strongly correlated (r = 0.79) with percent body fat determined by dual energy X-ray absorptiometry. The BAI was proposed as a more accurate index of body fatness than BMI. We examined whether BAI was more strongly related, than was BMI and waist circumference, to skinfold thicknesses and levels of various risk factors for coronary heart disease.Cross-sectional analyses of adults (n = 14,263 for skinfold thickness; n=6291 for fasting lipid levels) in the National Health and Nutrition Examination Survey (NHANES) III, 1988-1994.As compared with BMI and waist circumference, we found that BAI was less strongly associated with the skinfold sum and with risk factor levels. For example, correlations with the skinfold sum were r = 0.79 (BMI) vs. r = 0.70 (BAI) among men, and r = 0.86 (BMI) vs. r = 0.79 (BAI) among women; p0.001 for the difference between each pair of correlations. An overall index of the 7 risk factors was also more strongly associated with BMI and waist circumference than BAI in analyses stratified by sex, race-ethnicity and age. Multivariable analyses indicated that if BMI was known, BAI provided little additional information on risk factor levels.Based on the observed associations with risk factor levels and skinfold thicknesses, we conclude that BAI is unlikely to be a better index of adiposity than BMI.

Background: BMI is one factor that is used to determine a child’s eligibility for lipid screening and treatment. BMI, which is an indirect measure of body fat, may inadequately represent the biological effect of body fat percentage on lipid concentrations. Objective: We examined the relation between directly measured body fat percentage and lipid concentrations in a representative sample of US youths. Design: Data from 7821 participants aged 8–19 y from the 1999– 2004 NHANES were analyzed. Body fat percentage was measured by dual-energy X-ray absorptiometry. Total and HDL-cholesterol concentrations were measured in serum. Serum triglyceride and LDL-cholesterol concentrations were measured in a subsample of 2661 fasting NHANES participants aged 12–19 y. Prevalences of adverse total cholesterol (.200 mg/dL), LDL cholesterol (.130 mg/dL), triglycerides (.150 mg/dL), and HDL cholesterol (,35 mg/dL) were measured. Results: Approximately 10.0% [60.7% (SE)] of participants had high total cholesterol, 7.0 6 0.4% of participants had low HDL cholesterol, 9.7 6 1.0% of participants had high triglycerides, and 7.6 6 0.7% of participants had high LDL cholesterol. Prevalence of adverse total cholesterol, HDL cholesterol, triglycerides, and LDL cholesterol in US youths with high adiposity (greater than or equal to the age- and sex-specific 75th percentile of body fat percentage) was significantly greater (P , 0.01) than for participants without high adiposity. In multiple linear regressions adjusted for age, survey period, and race-ethnicity, the variance in lipid concentrations explained by body fat percentage was 2–20% (P , 0.001). Conclusion: Adverse lipid concentrations and high adiposity are significantly associated in youths. Am J Clin Nutr 2011;94:877–83.

We sought to describe differences between normal weight, overweight, and obese adults in use of specific prescription medication classes.Cross-sectional analysis of prescription medication use among 9789 adults in the National Health and Nutrition Examination Survey, a nationally representative sample of the United States.In 2005-2008, 56.4% (95% confidence interval [CI], 54.6-58.3) of adults used 1+ prescription medication. Approximately one-quarter of adults used a hypertension medication (26.1%; 95% CI, 24.5%-27.8%). The use of hypertension medications increased with increasing weight status (normal weight: 17.2%; 95% CI, 15.6%-18.8%; overweight: 24.5%, 95% CI, 22.6%-26.4%; and obese: 35.1%, 95% CI, 32.8%-37.4%). Similarly, lipid-lowering, analgesic, antidepressant, proton pump inhibitors, thyroid, diabetes, and bronchodilator medication use was greater among obese compared with normal weight adults (each p.01). Among adults 65+ years, 72% (95% CI, 68.2%-75.8%) of men and 67.7% (95% CI, 64.3%-71.2%) of women used a hypertension medication and a majority of men (51.2%, 95% CI, 48.4%-54%) and 40.3% (95% CI, 36.8%-43.8%) of women used lipid lowering medications; the use of both was greater among obese adults compared to normal weight adults (both p.01).Obese adults in the United States use several prescription medication classes more frequently, than normal weight adults, including hypertension, lipid-lowering, and diabetes medications.

Obesity is a public health challenge throughout the world. Ongoing monitoring of trends in obesity is important to assess interventions aimed at preventing or reducing the burden of obesity. Since the 1960s, measured height and weight have been collected in the United States as part of the National Health and Nutrition Examination Survey (NHANES). In Canada, data on measured height and weight have been collected from nationally representative samples of the population less regularly. This changed in 2007 with the launch of the Canadian Health Measures Survey (CHMS), the scope and purpose of which are similar to those of NHANES. The objective of this report is to compare estimates of the prevalence of obesity between Canadian and American adults.

Data from the National Health and Nutrition Examination Survey, 2005-2008. Among men, obesity prevalence is generally similar at all income levels, however, among non-Hispanic black and Mexican-American men those with higher income are more likely to be obese than those with low income. Higher income women are less likely to be obese than low income women, but most obese women are not low income. There is no significant trend between obesity and education among men. Among women, however, there is a trend, those with college degrees are less likely to be obese compared with less educated women. Between 1988-1994 and 2007-2008 the prevalence of obesity increased in adults at all income and education levels.

Published reports based on different definitions indicate that in Canada, Mexico and the United States childhood overweight and obesity have increased dramatically since 1980, with the US leading the way. The prevalence of overweight, using the International Obesity Task Force (IOTF) definitions (Cole et al. 2000) in 7–13 year old girls doubled in Canada between 1981 and 1996 and tripled in boys (Tremblay et al. 2002). In 2004 in Canada, 26% of children and adolescents aged 2–17 were overweight or obese and 8% were obese (Shields 2006). Among children under 5 years of age in Mexico, overweight prevalence (z-score of weight-for-height above +2 of World Health Organization/National Center for Health Statistics/Centers for Disease Control and Prevention (WHO/NCHS/CDC) references (Dibley et al. 1987)) increased from 4.2 to 5.3% between 1988 and 1999 (Rivera et al. 2002). In the US, between 1980 and 2006 the prevalence of high body mass index (BMI ≥95th percentile of the sex specific 2000 CDC growth charts) increased from 6 to 16% among children and teens 2 through 19 years of age (Ogden et al. 2002, 2003, 2007, 2008).

A variety of different terms, metrics, and cut-off values have been used to describe and assess overweight and obesity in children. Body mass index (BMI) calculated as weight in kilograms divided by height in meters squared can be used to express weight adjusted for height. In order to account for variability by sex and age, BMI in children is compared to sex- and age-specific reference values. In the United States, the Centers for Disease Control and Prevention (CDC) 2000 growth charts serve as reference values. The terminology used for high BMI-for-age in children in the United States to date has been based on the recommendation of an expert committee convened by federal agencies. This committee recommended the use of BMI and defined overweight as a BMI-forage at or above the 95th percentile of a specified reference population and the designation of "at risk for overweight" for BMI values between the 85th and the 95th percentiles of BMI for age. More recently, although the cut-off values and the interpretation have not changed, changes in terminology were proposed. An American Medical Association expert committee report retained the two cut-off values of the 85th and 95th percentiles of BMI-for-age but used different terminology, referring to BMI-for-age from the 85th up to the 95th percentile as "overweight" and to BMI-for-age at or above the 95th percentile as "obesity." The National Center for Health Statistics (NCHS) and other CDC publications will continue to include prevalence estimates at the 85th and 95th percentiles as before but will change the terminology to use the term "overweight" for a BMI-for-age between the 85th and 95th percentile (formerly called "at risk for overweight") and the term "obesity" for a BMI-for-age at or above the 95th percentile (formerly called "overweight").