Official data indicate that around 42% of US adults aged 20 are obese — including 9% with severe obesity — and another 31% are overweight, writes MedicalBrief.
Data from the 2017–2018 National Health and Nutrition Examination Survey (NHANES), using measured heights and weights, indicate that an estimated 42.5% of US adults aged 20 and over are obese – including 9% with severe obesity – and another 31.1% are overweight. When the results were stratified by age, adults 40-59 saw the highest rates of obesity, with 45% of this age group with a Body Mass Index (BMI) of 30 or higher. Middle-aged men had the highest prevalence of obesity, at 46%. Non-Hispanic Asian Americans had the lowest rates of obesity, with only 18% and 17% of Asian men and women having a BMI over 30 in the most recent survey period. Mexican American adults had some of the highest rates, with 51% of men and 50% of women with obesity. Similarly, 41% of non-Hispanic Black men had obesity, as did 57% of Black adult women.
The current prevalence of obesity in the U.S. is in stark contrast to what the nation looked like several decades ago, writes MedPage in its analysis. In national data from the survey period of 1960-1962, only about 13.4% of adults had obesity and less than 1% had severe obesity. And during that same survey period, about 31.5% of American adults were considered overweight.
From the early 1960s to today, however, the rates of obesity steadily increased each decade, doubling from 15% in 1976-1980 to 30.9% in 1999-2000. But since the turn of the century, the rise in obesity rates seemed to slow down a bit despite still increasing. For example, the only times that obesity rates actually fell in the past 60 years was in 2007-2008 and again in 2011-2012.
Regarding children, the researchers found that 19.3% of Americans ages 2-19 had obesity, defined as a BMI at or above the 95th percentile on the growth chart. This included about 6.1% of kids who were identified as having severe obesity, measured as a BMI at or above 120% of the 95th percentile.
In addition to this, another 16.1% of U.S. children were overweight during the 2017-2018 survey period, defined as at or above the 85th percentile on the sex-specific BMI-for-age growth chart. At this time, the rates of obesity were highest among teens: 21% of those ages 12-19 had obesity, with the rates for teen boys slightly higher than for teen girls (23% vs 20%).
Similar to in adults, the obesity rates followed similar ethnic patterns among kids. As for boys, the highest rates of obesity were seen among those of Mexican American (29%) and Hispanic (28%) descent, whereas for girls, the highest rates of obesity were among Black (29%) and Mexican American (25%) children and adolescents.
Again similar to the situation in adults, obesity in American kids followed a trajectory over the past several decades. In the 1971-1974 survey period, only 5% of U.S. kids had obesity, with only 1% of this subset having severe obesity; only 10% of kids were then overweight.
2017–2018 National Health and Nutrition Examination Survey (NHANES) Summary
Results from the 2017–2018 National Health and Nutrition Examination Survey (NHANES), using measured heights and weights, indicate that an estimated 42.5% of U.S. adults aged 20 and over have obesity, including 9.0% with severe obesity, and another 31.1% are overweight.
Body mass index (BMI), expressed as weight in kilograms divided by height in meters squared (kg/m2), is used commonly to classify overweight (BMI 25.0–29.9), obesity (BMI at or above 30.0), and severe obesity (BMI at or above 40.0).
Age-adjusted trends in overweight, obesity, and severe obesity prevalence from 1960–1962 through 2017–2018 are shown in Table 1. Because surveys before 1988 did not include persons over age 74, Table 1 shows the prevalence for adults aged 20 and over since 1988, and for adults aged 20–74 for all survey periods dating back to 1960. The age-adjusted sex-specific trends of overweight, obesity, and severe obesity among adults aged 20–74 from 1960–1962 through 2017–2018 are shown in the Figure. Table 2 contains the prevalence of obesity by age for men and women since 1988–1994, and Table 3 contains the age-adjusted prevalence of obesity by race and Hispanic origin for men and women since 1988–1994.
The prevalence of obesity as measured by BMI among non-Hispanic Asian adults is consistently lower than that reported for non-Hispanic white, non-Hispanic black, and Hispanic adults. Although BMI is widely used as a measure of body fat, at a given BMI level, body fat may vary by sex, age, and race and Hispanic origin. In particular, research suggests that health risks may begin at a lower BMI among Asian persons compared with others (1,2).
NHANES, conducted by the National Center for Health Statistics, is a stratified, multistage probability sample of the civilian non-institutionalized population of the United States. The survey began oversampling non-Hispanic Asian persons in 2011–2012 and the total Hispanic population in 2007–2008. Beginning in 2007–2008, Mexican-American persons were no longer oversampled but are included in the oversampled total Hispanic population.
A household interview and a physical examination are conducted for each survey participant. During the physical examination, conducted in a mobile examination center, height and weight are measured as part of a comprehensive set of body measurements. These measurements are taken by trained health technicians, using standardized measuring procedures and equipment. Observations for pregnant women and for persons missing a valid height or weight measurement are not included in the data analysis.
Body mass index (BMI), expressed as weight in kilograms divided by height in metres squared (kg/m2), is used commonly to classify obesity among adults, and also is recommended for use with children and adolescents. Cutoff criteria are based on the sex-specific BMI-for-age 2000 CDC Growth Charts for the United States. Based on recommendations from expert committees, children and adolescents with BMI values at or above the 95th percentile of the growth charts are categorized as having obesity. Severe obesity is BMI at or above 120% of the 95th percentile.
Estimates of the prevalence of childhood obesity during the 1960s are available for certain age groups. Table 2 shows the prevalence of obesity among children and adolescents aged 2–5, 6–11, and 12–19 years since 1963–1965, by sex and age. The Figure shows trends in obesity by age.
Although BMI is widely used as a measure of body fat, at a given BMI level, body fat may vary by sex, age, and race and Hispanic origin. In particular, research suggests that health risks may begin at a lower BMI among Asian persons compared with others .
NHANES, conducted by the National Center for Health Statistics, is a stratified, multistage probability sample of the civilian non-institutionalized population of the United States. A household interview and a physical examination are conducted for each survey participant. During the physical examination, conducted in a mobile examination center, height and weight are measured as part of a more comprehensive set of body measurements. These measurements are taken by trained health technicians, using standardized measuring procedures and equipment.
Observations for persons missing a valid height or weight measurement and for pregnant females are not included in the data analysis.
[link url="https://www.medpagetoday.com/primarycare/obesity/90142"]Full MedPageToday report (registration required)[/link]
[link url="https://www.cdc.gov/nchs/data/hestat/obesity-child-17-18/obesity-child.htm"]Full NHANES report[/link]