Sowing the seeds of the obesity epidemic in babyhood

The growth charts pediatricians use at well-baby visits can predict a baby's risk for obesity later in life, finds a population-based study from Children's Hospital Boston, Harvard Medical School and Harvard Pilgrim Healthcare.

The study, funded by the Centers for Disease Control and Prevention, tracked more than 44,000 babies and found that those who rose two or more major percentiles in weight-for-length on their growth charts at any time before age 2 doubled their odds of obesity at age 5 and were nearly twice as likely to be obese at age 10. (Weight-for-length percentiles show how a baby's weight compares to that of other babies of the same length.)

The study further found the highest prevalence of later obesity among babies who rose two or more weight-for-length percentiles before 6 months of age, or who were already in a high percentile at their first visit. The report appears in the November Archives of Pediatrics and Adolescent Medicine.

The findings provide specific guidance to help pediatricians recognize when a baby is at true risk of becoming obese later in childhood, which may help stem the obesity epidemic in its earliest stages, says study leader Elsie Taveras, MD, MPH, co-director of the One Step Ahead clinic, a pediatric overweight prevention program at Children's Hospital Boston. Specifically, the study suggests assessing how many weight-for-length percentiles a child crosses during the first two years, and especially in the first 6 months.

"We shouldn't neglect these early gains and think that it's just baby fat, and that these children are going to grow out of it," says Taveras, also co-director of the Obesity Prevention Program at Harvard Medical School and Harvard Pilgrim Health Care Institute. "Crossing two or more percentiles in weight-for-length should trigger a discussion between parents and their pediatric providers of what's contributing to the rapid gains. Infants are different than adults, and we wouldn't put infants on a diet, but we can detect some possible early risk factors that could be targets for counseling. "

Taveras and colleagues analyzed weight and height data from 44,622 babies making well-child visits at Harvard Vanguard Medical Associates/Atrius Health in eastern Massachusetts from 1980 through 2008, tracking the children until age 5 or 10.

In general, they observed:

Of all babies tracked, 11.6 percent were obese at the age of 5, and 16.1 percent at age 10. (Obesity was defined as a body mass index at or above the 95th percentile for age and sex.) Babies who were overweight anytime during the first 2 years of life were more likely to be obese at age 5 or age 10. Increases in weight-for-length were common: 43 percent of the infants rose 2 or more weight-for-length percentiles during their first 6 months, and 64 percent had such rises during their first 24 months.