One third of US babies are obese or at risk for obesity, said researchers who monitored around 8,000 babies from 9 months to 2 years and also found that those were obese at 9 months had the highest risk of being obese at 2 years.

Dr Brian G. Moss, from the School of Social Work, Wayne State University in Detroit, Michigan, and Dr William H. Yeaton, from the Institute for Social Research at the University of Michigan in Ann Arbor, published their analysis of children’s early weight trajectories from the Early Childhood Longitudinal Study-Birth Cohort (ECLS-B) in the January/February 2011 issue of the American Journal of Health Promotion, which is available online.

The ECLS-B draws from a nationally representative sample of American children born in the year 2001 and with diverse socioeconomic and racial/ethnic backgrounds.

The ECLS-B is one of the first to monitor the weight of a nationally representative sample of very young children.

For their study, Moss and Yeaton used ECLS-B early weight trajectories and related demographic characteristics of babies who were weighed when they were 9 months old (8,900 babies) and then again when they were 2 years old (7,500 babies).

They assessed whether the babies were of normal weight, at risk, or obese at 9 months, how this changed when they were 2 years old, and using statistical tools, examined whether the weight persistence, loss, or gain was linked to demographic characteristics (eg the child’s sex, race/ethnicity, geographic region, socioeconomic status, community locale).

As there is no accepted standard of obesity for young children, the researchers put a child in the obese category if his or her weight was above the 95th percentile on standard growth charts.

Children in the 85th to 95th percentile were considered at risk for obesity.

When they analysed the results they found that:

  • About one third (31.9%) of the babies were at risk for obesity or obese at 9 months.
  • The figure was slightly higher at 2 years (34.3% obese or at risk).
  • 17% of the babies were obese at 9 months, rising to 20% at 2 years.
  • The babies who were obese at 9 months had the highest risk of being obese at 2 years.
  • 44% of the babies who were obese at 9 months remained obese at 2 years.
  • Some babies were at greater risk for obesity (eg Hispanics, and those from low income families).
  • Others were at lower risk (eg females and Asian/Pacific Islanders).
  • 40% of 2-year-olds from the lowest income homes were at risk or obese compared to 27% of those from the highest income homes.

Moss and Yeaton concluded that:

“Between age 9 months and age 2 years, US children consistently moved toward less desirable weight status.”

They suggested that since “obesity risk was not uniform across demographic subgroups … health policy might focus on those children at greatest risk”.

Moss told WebMD that:

“We are certainly not saying that overweight babies are doomed to be obese adults.”

However, he said they did find evidence that being overweight at 9 months puts you on track for being overweight or obese later on in childhood.

There is also no suggestion here that babies should go on diets.

You should never deny the breast or the bottle while your baby is being exclusively breast or bottle fed, said childhood obesity expert Dr Joyce Lee, from the University of Michigan at Ann Arbor.

But when babies get onto solid food, that’s when you have to be careful about food choices, she urged.

Lee told WebMD that the age at which children are introduced to junk food is getting younger.

“I know of 9-month-olds who eat French fries,” she said.

You can make a big difference to your children’s weight by keeping them off junk foods for as long as possible and making sure you give them plenty of fruits and vegetables, said Lee, who is an an assistant professor in pediatric endocrinology.

“Young Children’s Weight Trajectories and Associated Risk Factors: Results From the Early Childhood Longitudinal Study-Birth Cohort.”
Brian G. Moss and William H. Yeaton.
American Journal of Health Promotion: January/February 2011, Vol. 25, No. 3, pp. 190-198.
DOI: 10.4278/ajhp.090123-QUAN-29

Additional source: Salynn Boyles (31-Dec-2010), “Baby Fat May Predict Early Obesity”, WebMD Health News.

Written by: Catharine Paddock, PhD