Infant weight and height are faithfully charted at each pediatrician's visit to make sure the child is growing properly. But nowadays doctors are more likely to see babies who are growing too fast rather than ones lagging behind. A new study shows that rapid growth on these charts foretells obesity in childhood.
Researchers looked at the weight-for-length charts that show how a baby's weight compares to that of other babies of the same length. For example, babies on the 5th percentile growth line have a weight that puts them among the smallest 5% of all babies their length. Doctors mostly want to see that a child is following his or her growth curve over time and not falling off or jumping up. The major percentile lines are the 5th, 10th, 25th, 50th, 75th, 90th and 95th.
The study, which tracked more than 44,000 babies, found that those who rose two or more major percentiles -- for example, going from 50% to 90% at some point -- before age 2 were twice as likely to be obese at age 5 and 75% more likely to be obese at age 10.
Babies who jumped two or more percentiles before six months of age had the highest risk of obesity at age 10 as well as babies who were already in a high percentile at their first visit. For example a 6-month-old baby who started at the 75th percentile who jumped two or more percentiles in the next six months had an obesity prevalence of almost 30% at age 5. Babies who started at less than the 25th percentile and jumped two or more percentiles had an obesity prevalence at age 5 of about 7%.