Obesity rates remain high, but stable in the U.S

More than a third of U.S. adults and 17 percent of kids and teens are obese, rates that haven’t changed much in a decade, researchers say.

Only preschool-age children show signs of a turnaround, with their obesity rates nearly halved in the same period, according to a new federal study published in the Journal of the American Medical Association.

“The rapid increase in obesity we saw in the ‘80s and ‘90s has definitely slowed,” epidemiologist Cynthia Ogden told Reuters Health. “There’s some glimmer of hope in the new data in relation to the 2 to 5 year olds.”

Ogden, a branch chief at the National Center for Health Statistics in Rockville, Maryland, a division of the Centers for Disease Control and Prevention (CDC), is lead author of the new study.

Obesity rates among 2 to 5 year old Americans dropped from 13.9 percent to 8.4 percent between 2003 and 2012, her team reports.

Not all the news on the national state of weight was positive, however.

In the U.S.:

  68.8% of adults are overweight or obese; 35.7% are obese.
  31.8% of children and adolescents are overweight or obese; 16.9% are obese.
  30.4% of low-income preschoolers are overweight or obese.
  Disparities exist based on race-ethnicity, gender, age, geographic region, and socioeconomic status.

Obesity rates remain high, but stable in the U.S Though the overall obesity rate across all U.S. age groups has been stable since 2003, women 60 years and older have been growing fatter. Their rate of obesity rose from 31.5 percent to 38 percent over nine years, the study found.

Ogden and her colleagues used the annual National Health and Nutrition Examination Surveys to examine obesity trends in representative samples of Americans between the 2003 - 2004 survey year and 2011 - 2012.

The 5.5 percentage point drop in the obesity rate among 2 to 5 year olds mirrored decreases found among preschoolers in previous studies, the authors write.

A report published last year, for example, found that after doubling over 30 years, the obesity rate among low-income preschool children fell in 19 U.S. states and territories (see Reuters story of August 6, 2013 here: reut.rs/OuyauP).

Nonetheless, more than two-thirds of American adults and nearly one-third of youth aged 2 to 19 years old fell into the overweight or obese categories in 2011 - 2012.

For adults, body mass index (BMI) - a measure of weight relative to height - defines obesity. A BMI above 25 is considered overweight, and BMI over 29.5, which is equivalent to a 5-foot, 4-inch adult weighing 174 pounds, is considered obese.

Obesity rates have more than doubled in adults and children since the 1970’s (National Center for Health Statistics, 2009). While recent estimates suggest that the overall rates of obesity have plateaued or even declined, obesity is widespread and continues to be a leading public health problem in the U.S. (Flegal et al., 2012; Ogden et al., 2012; Robert Wood Johnson Foundation, 2012; Wen et al., 2012). Plus, substantial disparities exist based on demographics (e.g., race-ethnicity, gender), geographic region, and socioeconomic status (SES). See the section on the Relationship Between Poverty and Overweight or Obesity for more information on SES disparities.

For children, BMI calculations also factor-in the weights of other kids in the same age group.

Obesity rates remain high, but stable in the U.S The report does not discuss reasons for the drop in preschool obesity or the rising obesity among older women.

“There’s been a lot of attention in this country on obesity, but we’ve really focused on childhood obesity,” Lieutenant Commander Ashleigh May told Reuters Health.

“We’re on the right track it appears with young children, but we still have a lot of work to do,” said May, an epidemiologist in the CDC’s Obesity Prevention and Control branch in Atlanta, Georgia, who was not involved in the study.

Childhood Overweight and Obesity in the U.S.

About a quarter of 2-5 year olds and one-third of school-age children (including adolescents) are overweight or obese in the U.S. (Ogden et al., 2012). About 30 percent of low-income preschoolers are overweight or obese (Centers for Disease Control and Prevention, 2011).  Overweight and obesity rates tend to be higher and have increased more rapidly over time among African-American and Hispanic children than Caucasian children (Freedman et al., 2006; Ogden et al., 2012). The prevalence is also higher among children living in the Southern region of the U.S. (e.g., Mississippi, Tennessee, Kentucky) (Singh et al., 2008).

Racial-Ethnic Disparities
Based on recent national figures, 25.6 percent of White girls are overweight or obese compared to 41.3 percent of Black and 38.6 percent of Hispanic girls (Ogden et al., 2012). About 40 percent of Hispanic boys are overweight or obese, compared to 36.9 percent and 30.1 percent of Black and White boys, respectively (Ogden et al., 2012). Rates are the highest, and very alarming, for 12-19 year old Hispanic boys (42.9 percent are overweight or obese) and 12-19 year old Black girls (45.1 percent are overweight or obese) (Ogden et al., 2012).

While little national data are available on Native American children, several studies have found substantially higher obesity rates compared to the national average and other racial-ethnic groups (Gordon & Oddo, 2012; Smith et al., 2009; Zephier et al., 2006). For example, obesity rates are twice as high for Native American preschoolers than for White or Asian preschoolers (Anderson & Whitaker, 2009). In addition, while obesity risk tends to rise among adult immigrants as they become more acculturated to the American diet and health behaviors (Singh et al., 2011), there is evidence that children of the least acculturated immigrants have a greater risk of obesity than children of natives or settled immigrants, especially among boys, Whites, and Hispanics (Van Hook et al., 2009).

Contributors to the downward trend among young children may include increases in breastfeeding, decreases in sugar consumption, a national program promoting exercise and another that now gives low-income children more fruits and vegetables, May said.

Dr. David Ludwig, a pediatrics and nutrition researcher at the Harvard School of Public Health in Boston, read the report as a sign of a possible tiny step forward in the fight against obesity.

“The key finding is that obesity prevalence throughout the U.S. population has not changed in the last decade and remains at historic highs,” Ludwig told Reuters Health in an email.

He also cautioned that the decline in obesity rates among preschool kids could result from chance.

“Nevertheless, if real, the lower prevalence among young children would be an encouraging sign that national pediatric obesity prevention efforts - though still grossly inadequate - may be having some impact,” he said.

Michael Jacobson, executive director of the Center for Science in the Public Interest, told Reuters Health he sees the report as a sign the obesity epidemic may have peaked.

Gains against obesity in preschool children may be attributable to a decline in soda consumption and to adding fruit and vegetables to the federal nutrition program for low-income children, he said.

But Jacobson, who was not involved in the study, pointed out longstanding disparities among ethnic groups that it reveals. A stunning 82 percent of African-American women and 77 percent of Hispanic women were overweight or obese, compared to 63 percent of white women, in 2011-2012, the report finds.

“That’s a real health crisis,” Jacobson said. “These numbers are crying out for some real action.”

SOURCE: Journal of the American Medical Association, online February 25, 2014.


Prevalence of Childhood and Adult Obesity in the United States, 2011-2012

Main Outcomes and Measures
  In infants and toddlers from birth to 2 years, high weight for recumbent length was defined as weight for length at or above the 95th percentile of the sex-specific Centers for Disease Control and Prevention (CDC) growth charts. In children and adolescents aged 2 to 19 years, obesity was defined as a body mass index (BMI) at or above the 95th percentile of the sex-specific CDC BMI-for-age growth charts. In adults, obesity was defined as a BMI greater than or equal to 30. Analyses of trends in high weight for recumbent length or obesity prevalence were conducted overall and separately by age across 5 periods (2003-2004, 2005-2006, 2007-2008, 2009-2010, and 2011-2012).

Results  In 2011-2012, 8.1% (95% CI, 5.8%-11.1%) of infants and toddlers had high weight for recumbent length, and 16.9% (95% CI, 14.9%-19.2%) of 2- to 19-year-olds and 34.9% (95% CI, 32.0%-37.9%) of adults (age-adjusted) aged 20 years or older were obese. Overall, there was no significant change from 2003-2004 through 2011-2012 in high weight for recumbent length among infants and toddlers, obesity in 2- to 19-year-olds, or obesity in adults. Tests for an interaction between survey period and age found an interaction in children (P = .03) and women (P = .02). There was a significant decrease in obesity among 2- to 5-year-old children (from 13.9% to 8.4%; P = .03) and a significant increase in obesity among women aged 60 years and older (from 31.5% to 38.1%; P = .006).

Conclusions and Relevance  Overall, there have been no significant changes in obesity prevalence in youth or adults between 2003-2004 and 2011-2012. Obesity prevalence remains high and thus it is important to continue surveillance.
Cynthia L. Ogden, PhD; Margaret D. Carroll, MSPH; Brian K. Kit, MD, MPH; Katherine M. Flegal, PhD

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