May 5, 2011 -- Kids who regularly use a bottle at age 2 are more likely to be obese by the time they’re ready for kindergarten than those who switch to cups at younger ages, a study shows.
Current guidelines, which were written to help prevent tooth decay, recommend that babies stop bottle feeding around their first birthday.
But many parents don’t appear to be following that advice.
The study, which has tracked nearly 6,750 children across the U.S. from the time they were born in 2001, found that nearly one in four toddlers was still a regular bottle user at age 2.
Researchers found that, compared to those who were weaned off a bottle earlier, 24-month-olds who were drinking from a bottle were about 30% more likely to be obese by age 5 1/2. That’s after adjusting for a host of things thought to influence the risk of obesity, such as mom’s body weight, breastfeeding, the family’s income level, and time spent watching TV or computer screens.
“This is an important study because it identifies a clear risk factor for childhood obesity,” says Karen Bonuck, PhD, a professor in the department of family and social medicine at Albert Einstein College of Medicine in New York.
Bonuck, who reviewed the study for WebMD, is studying how weaning toddlers off bottles may affect the total number of daily calories they get. She was not involved in the current research.
Though it’s not entirely clear how bottles may be causing obesity, researchers have some theories.
“At older ages, the bottle is probably used for comfort or convenience, rather than nourishment,” says study researcher Rachel A. Gooze, MPH, a doctoral student in public health at Temple University in Philadelphia.
Gooze says by age 2 many kids are having meals and snacks at the family table. Calories they get from a bottle that’s tucked into a car seat or into bed at night are likely to be extra.
“If we think of a 2-year-old girl of average size who’s put to bed with an 8-ounce bottle of whole milk, she’d receive about 12% of her daily caloric needs from that bottle,” Gooze says.
If she has eaten well that day, those calories may be in excess, Gooze says.
Weight Gain After Bottle-Feeding
For the study, which is published in the Journal of Pediatrics, researchers analyzed data collected in the Department of Education’s Early Childhood Longitudinal Study, Birth Cohort.
Children were included in the study at birth and assessed at 9 months, 24 months, 4 1/2 years, and 5 1/2 years.
Parents were asked, at the 24-month interview, if the child primarily drank from a bottle, a sippy cup, or a regular cup. They were also asked whether they usually put the child to bed with a bottle. If the answer to either question was yes, the child was considered to be a regular bottle user.