Breast-feeding may lower blood pressure in childhood

www.reuters.com, Health eLine, 3/1/04
Breast-feeding may lower blood pressure in childhood

Last Updated: 2004-03-01 16:43:42 -0400 (Reuters Health)

NEW YORK (Reuters Health) - It has been reported that individuals who
were breast-fed during infancy appear to have decreased risk of death
from heart disease. Now, new research suggests that this may be due to
blood pressure-lowering effects of breast-feeding.

"The wider promotion of breast-feeding is a potential component of the
public health strategy to reduce population levels of blood pressure,"
the researchers suggest in the current issue of Circulation: Journal of
the American Heart Association.

The findings are based on a study of 4,763 non-twin, full-term infants
who had their blood pressures determined at 7.5 years of age.
Questionnaires were also sent to the mothers to assess breast-feeding
during infancy.

Dr. Richard M. Martin, from the University of Bristol in the UK, and
colleagues found that breast-fed children had systolic blood
pressure--the top number of the blood pressure reading--1.2 mm Hg lower
than those of children who were not breast-fed. The corresponding
decrease for diastolic pressure--the lower number of the blood pressure
reading--was 0.9 mm Hg

After Martin's group took into consideration various demographic factors
that could contribute to the development of high blood pressure, the
effects of breast-feeding were lessened, although still statistically
significant.

The findings did not differ between infants who were breast-fed only and
those who received a combination of breast milk and formula, the authors
note. However, the duration of breast-feeding did have an effect; for
each three-month period of feeding, the systolic pressure fell by 0.2 mm
Hg.

Although breast-feeding was only linked to a small reduction in blood
pressure, this could still have a strong impact on heart disease
mortality, Martin said in a statement.

"A one-percent reduction in population systolic blood pressure levels is
associated with about a 1.5-percent reduction in all-cause mortality,
equivalent to a lessening in premature death of about 8000 to 2000
deaths per year in the United States and the United Kingdom,
respectively," he added.

SOURCE: Circulation, March 1, 2004.

"JG" wrote in message ...
www.reuters.com, Health eLine, 3/1/04
Breast-feeding may lower blood pressure in childhood

Last Updated: 2004-03-01 16:43:42 -0400 (Reuters Health)

NEW YORK (Reuters Health) - It has been reported that individuals who
were breast-fed during infancy appear to have decreased risk of death
from heart disease. Now, new research suggests that this may be due to
blood pressure-lowering effects of breast-feeding.

"The wider promotion of breast-feeding is a potential component of the
public health strategy to reduce population levels of blood pressure,"
the researchers suggest in the current issue of Circulation: Journal of
the American Heart Association.

The findings are based on a study of 4,763 non-twin, full-term infants
who had their blood pressures determined at 7.5 years of age.
Questionnaires were also sent to the mothers to assess breast-feeding
during infancy.

Dr. Richard M. Martin, from the University of Bristol in the UK, and
colleagues found that breast-fed children had systolic blood
pressure--the top number of the blood pressure reading--1.2 mm Hg lower
than those of children who were not breast-fed. The corresponding
decrease for diastolic pressure--the lower number of the blood pressure
reading--was 0.9 mm Hg

After Martin's group took into consideration various demographic factors
that could contribute to the development of high blood pressure, the
effects of breast-feeding were lessened, although still statistically
significant.

The findings did not differ between infants who were breast-fed only and
those who received a combination of breast milk and formula, the authors
note. However, the duration of breast-feeding did have an effect; for
each three-month period of feeding, the systolic pressure fell by 0.2 mm
Hg.

Although breast-feeding was only linked to a small reduction in blood
pressure, this could still have a strong impact on heart disease
mortality, Martin said in a statement.

"A one-percent reduction in population systolic blood pressure levels is
associated with about a 1.5-percent reduction in all-cause mortality,
equivalent to a lessening in premature death of about 8000 to 2000
deaths per year in the United States and the United Kingdom,
respectively," he added.

SOURCE: Circulation, March 1, 2004.


Not to belabor a point - but another example of the lay press not
quite getting it right.

First, its Circulation, March 2, not March 1.

Here's an interesting piece of data -

"Breast feeding was inversely associated with maternal and child BMI."

In case you missed the implication - the non-breastfead kids - you
know, the ones with the higher BP - where chunkier than those with
lower BP (the breastfed group). Oh, and the breastfed cohort was
taller (even if the text says the opposite, the table is correct) and
had a lower resting pulse rate. These results have p values that are
in the .01 to .0001 range.

The regression equation appears to be a purposeful forward stepwise
with BF/NBF as the first variable. The child BMI adds significant
explanatory power over and above the BF/BFN - this to me suggests that
the BF/BNF variable isn't the best predictor of outcome, in spite of
the non-significant interaction term.

I think, in reading the study report itself, that the effect (about
1mmHg) and all the confounders, the conclusions in the news report are
hardly accurate.

"Now, new research suggests that this [long-term mortality benefit of
lowered BP] may be due to blood pressure-lowering effects of
breast-feeding."

This is bull.

The authors, in the study, are VERY clear in their conclusions that
there is NO causality evidence. They are VERY clear that the
assumption of causality is an assumption and is NOT supported by the
data.

They are also very very clear that though their experience and the
literature appears to suggest that lower BP in kids translates to a
long term lower BP in adults, these data hardly have this power.

The authors provide a scenario of hypotheses based on a series of
assumptions that suggest that there MAY be a link between breast
feeding and some long term mortality benefit. Reuters says something a
bit different.

In fact, Reuters uses the UNADJUSTED parameter estimates in their
report - not the appropriate adjusted results of 0.8 and 0.6 (with
some ratehr big confidence intervals, btw). It's not like these
numbers weren't CLEARLY spelled out in the ABSTRACT - they didn't even
need to read the article to get this information.

And if this type of journalistic sloppiness isn't problematic for you,
you aren't much of a critical thinker.

js