[Research article] Breastfeeding and Overweight Kids

PEDIATRICS Vol. 113 No. 2 February 2004, pp. e81-e86


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ELECTRONIC ARTICLE

Does Breastfeeding Protect Against Pediatric Overweight? Analysis of
Longitudinal Data From the Centers for Disease Control and Prevention
Pediatric Nutrition Surveillance System
Laurence M. Grummer-Strawn, PhD and Zuguo Mei, MD

From the Maternal and Child Nutrition Branch, Division of Nutrition and
Physical Activity, National Center for Chronic Disease Prevention and Health
Promotion, Centers for Disease Control and Prevention, Atlanta, Georgia

Objective. To examine whether increasing duration of breastfeeding is
associated with a lower risk of overweight in a low-income population of
4-year-olds in the United States.

Methods. Visit data were linked to determine prospectively the duration of
breastfeeding (up to 2 years of age) and weight status at 4 years of age.
Overweight among 4-year-old children was defined as a body mass index
(BMI)-for-age at or above the 95th percentile based on the 2000 Centers for
Disease Control and Prevention growth charts. Logistic regression was
performed, controlling for gender, race/ethnicity, and birth weight. In a
subset of states, links to maternal pregnancy records also permitted
regression analysis controlling for mother's age, education, prepregnancy
BMI, weight gain during pregnancy, and postpartum smoking. Data from the
Pediatric Nutrition Surveillance System, which extracts breastfeeding,
height, and weight data from child visits to public health programs, were
analyzed. In 7 states, data were linked to Pregnancy Nutrition Surveillance
System data. A total of 177 304 children up to 60 months of age were
included in our final pediatric-only analysis, and 12 587 were included in
the pregnancy-pediatric linked analysis.

Results. The duration of breastfeeding showed a dose-response, protective
relationship with the risk of overweight only among non-Hispanic whites; no
significant association was found among non-Hispanic blacks or Hispanics.
Among non-Hispanic whites, the adjusted odds ratio of overweight by
breastfeeding for 6 to 12 months versus never breastfeeding was 0.70 (95%
confidence interval: 0.50-0.99) and for 12 months versus never was 0.49
(95% confidence interval: 0.25-0.95). Breastfeeding for any duration was
also protective against underweight (BMI-for-age below the 5th percentile).

Conclusion. Prolonged breastfeeding is associated with a reduced risk of
overweight among non-Hispanic white children. Breastfeeding longer than 6
months provides health benefits to children well beyond the period of
breastfeeding.

Robin T. wrote:

PEDIATRICS Vol. 113 No. 2 February 2004, pp. e81-e86

[...]

Conclusion. Prolonged breastfeeding is associated with a reduced risk of
overweight among non-Hispanic white children. Breastfeeding longer than 6
months provides health benefits to children well beyond the period of
breastfeeding.

It's somewhat surprising that they should have found differences
among ethnic groups. I'd be really surprised if the differences
had biological foundations. I wonder if there would be a way to
design a study that also controlled for other feeding practices/
if studies have looked into differences across ethnic and socio-economic
groups in the way children are fed outside of bf/ff (understanding
of course that it's all averages ... individuals in any one group
don't necessarily follow the group norms). Likewise I guess that
TV and overall activity levels would be relevant factors.

--
Emily
mom to Toby 5/1/02
#2 EDD 7/19/04

Results. The duration of breastfeeding showed a dose-response, protective
relationship with the risk of overweight only among non-Hispanic whites; no
significant association was found among non-Hispanic blacks or Hispanics.
Among non-Hispanic whites, the adjusted odds ratio of overweight by
breastfeeding for 6 to 12 months versus never breastfeeding was 0.70 (95%
confidence interval: 0.50-0.99) and for 12 months versus never was 0.49
(95% confidence interval: 0.25-0.95). Breastfeeding for any duration was
also protective against underweight (BMI-for-age below the 5th percentile).

Interesting. I am very pro-breastfeeding and know it does lots of
good things for kids. Nonetheless, I suspect that once really good
studies are done they won't be able to show that it prevents
overweight. The confidence intervals even for white children barely
reach statistical significance (if a confidence interval includes 1.0,
it means the finding is not significant). It doesn't make much
biological sense that this would vary between races. And most
importantly, these types of studies can't really control for all the
confounding factors that differentiate moms who breastfeed from moms
who formula feed.

Kate
and the Bug, 8 months

Emily wrote in message news:4c9Zb.14820$Xp.77529@attbi_s54...
Robin T. wrote:

PEDIATRICS Vol. 113 No. 2 February 2004, pp. e81-e86

[...]

Conclusion. Prolonged breastfeeding is associated with a reduced risk of
overweight among non-Hispanic white children. Breastfeeding longer than 6
months provides health benefits to children well beyond the period of
breastfeeding.

It's somewhat surprising that they should have found differences
among ethnic groups. I'd be really surprised if the differences
had biological foundations. I wonder if there would be a way to
design a study that also controlled for other feeding practices/
if studies have looked into differences across ethnic and socio-economic
groups in the way children are fed outside of bf/ff (understanding
of course that it's all averages ... individuals in any one group
don't necessarily follow the group norms). Likewise I guess that
TV and overall activity levels would be relevant factors.

I don't think it's that surprising. I've read that hispanic and
black adults have higher occurences of metabolic syndrome (insulin
resistance, upper body obesity, dislipidemia, etc.), so perhaps their
children do too despite being breastfed. Metabolic syndrome tends to
produce infertile females (PCOS) if there is sufficient amounts of
food available to induce obesity, and I think Europeans have had
larger food stores for longer than blacks and hispanics, and so have
evolved to have fewer people with metaboic syndrome.

KC

KC wrote:

I don't think it's that surprising. I've read that hispanic and
black adults have higher occurences of metabolic syndrome (insulin
resistance, upper body obesity, dislipidemia, etc.), so perhaps their
children do too despite being breastfed. Metabolic syndrome tends to
produce infertile females (PCOS) if there is sufficient amounts of
food available to induce obesity, and I think Europeans have had
larger food stores for longer than blacks and hispanics, and so have
evolved to have fewer people with metaboic syndrome.

KC

But is that biological or culturally mediated? I keep reading
in other contexts that there is no biological foundation for
the concept of race. (Which isn't the same thing as saying that
certain genetic issues aren't more common in some populations
than others, I suppose.)

--
Emily
mom to Toby 5/1/02
#2 EDD 7/19/04