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Breastfeeding and later developmental outcome
The following tables summarize the results of two studies
of the effect of breastfeeding on children's test scores
at the ages of 5, 7, 9 and 15 to 17 years.
Fergusson et. al. (
Fergusson, 1982
) studied 950 New Zealand
children who had taken the Stanford-Binet (SB) test at 5 years of
age and the Weschler Intelligence Scale for Children - Revised (WISC-R)
at the age of 7 years.
| Breast Fed |
SB at 5 years |
WISC-R at 7 years |
| not |
98.5 |
98.8 |
| < 4 months |
101.1 |
100.7 |
| > 4 months |
100.9 |
101.1 |
|
p < 0.001 |
p < 0.01 |
Horwood and Fergusson (
Horwood, 1998
) reported results on
the effect of breastfeeding on test scores at age 9 and academic
achievment by the age of 15 to 17 years.
Their study of 1025 New Zealand children
used the WISC-R test and a simple count of the
number of subjects in which students received certificates of school completion
(SC).
| Breast Fed |
WISC-R at 9 years |
SC at 15-17 years |
| not |
98.9 |
3.05 |
| < 4 months |
99.8 |
3.22 |
| 4 to 7 months |
100.6 |
3.40 |
| > 8 months |
101.4 |
3.57 |
|
p < 0.005 |
p < 0.005 |
Definitions:
| SB: |
Stanford-Binet test. |
| WISC-R: |
Weschler Intelligence Scale forChildren - Revised.
|
| SC: |
Number of subjects in which students received certificates of
school completion. |
Kramer and coauthors evaluated the cognitive development of
over 13,000 of 17,046 breastfed infants in the PROBIT study at 6.5
years of age. Breastfed infants randomized to the experimental group
of breastfeeding promotion had 43% of infants being exclusively
breastfed at 3 months of age compared to 6% in the control group.
They used teacher reports and the Weschler Abbreviated Scales of
Intelligence for evaluation. Teacher academic ratings were
significantly higher in reading and writing in the experimental group.
Mean scores on the Weschler (in table below) were higher in all domains
(
Kramer, 2008
).
| Group |
Weschler Abbreviated Scales |
Verbal IQ
N=13,828 |
Performance IQ
N=13,836 |
Full IQ
N=13,824 |
| Experimental |
108.7 |
108.6 |
109.7 |
| Control |
98.7 |
104.8 |
101.9 |
| Adjusted Differences (95% C.I.) |
+7.5 (0.8-14.3) |
+2.9 (-3.3-9.1) |
+5.9 (-1.0-12.8) |
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