Breastfeeding,
why...
Hop
LT, Gross R, Giay T, Sastroamidjojo S, Schultink W, Lang
NT. Premature complementary feeding is associated with
poorer growth of Vietnamese children. J Nutr 2000;130:2683-90
Four cohorts
of newborn children, consisting of 90 infants born in 1981,
90 in 1982, 60 in 1983 and 60 in 1984, were studied to investigate
the association between premature initiation of complementary
feeding and physical growth. The weights and heights of
children were measured monthly up to 1 year, then every
3 months for year 2 and 3, and once every 6 months in year
4. Information on feeding practices and diseases of the
children was obtained by interviewing the mothers at each
home visit. All but three children (98.6%) were breastfed.
Although 87% of the mothers breastfed their children for
at least 1 year, only 3.3% of the infants were breastfed
exclusively at the age of 4 months. Partially breastfed
and weaned infants gained weight more slowly than those
exclusively or predomi-nantly breastfed. From 1 to 3 months,
exclusively breastfed infants grew more quickly in both
weight and length, followed by predominantly breastfed infants.
From 3 to 6 months, exclusively breastfed infants gained
more weight compared with the other groups. In the older
period (6-12 months), exclusively and predominantly breastfed
infants grew in length more quickly than partially breastfed
and weaned groups. However, there was no difference in weight
gain among groups. Morbidity from diarrhoea and acute respiratory
infections was significantly lower for the 3 or more months
exclusively breastfed group. These results show a long-term
deterioration of physical growth in infants who received
premature complementary feeding and confirm the importance
of exclusive breastfeeding for at least 3 months.
Coutsoudis
A, Pillay K, Kuhn L, Spooner E, Tsai WY, Coovadia HM; South
African Vitamin A Study Group. Method of feeding and
transmission of HIV-1 from mothers to children by 15 months
of age: prospective cohort study from Durban, South Africa.
AIDS 2001;15:379-87
This paper represents
the follow-up to 15 months of the study published by the
same authors in 1999 (Lancet 1999;354:471-6), when the infants
had been observed up to age 3 months. A total of 551 HIV-infected
pregnant women had been enrolled in a randomized trial of
vitamin A. Women self-selected to breastfeed or formula
feed after being counselled. Breastfeeders were encouraged
to practice exclusive breastfeeding for 3-6 months. The
probability of HIV was compared in three groups: 157 formula-fed
(never breastfed); 118 exclusively breastfed for 3 months
or more; and 276 mixed-fed. The three feeding groups did
not differ in any risk factors for transmission, and the
probability of detecting HIV at birth was similar. The probabilities
of HIV detection remained similar among never and exclusive
breastfeeders up to 6 months (19.4%), whereas the probability
among mixed breastfeeders soon surpassed both groups, reaching
26.1%. By 15 months, the cumulative probability of HIV infection
remained lower among those who exclusively breastfed for
3 months or more than among other feeding patterns (24.7%
vs 35.9%). The authors conclude that infants exclusively
breastfed for 3 months or more had no excess risk of HIV
infection over 6 months than those never breastfed. These
findings, if confirmed elsewhere, can influence public health
policies on feeding choices available to HIV-infected mothers
in developing countries.
Williams
C, Birch EE, Emmett PM, Northstone K. Stereoacuity at
age 3.5 y in children born full-term is associated with
prenatal and postnatal dietary factors: a report from a
population-based cohort study. Am J Clin Nutr 2001;73:316-22
Observational
studies suggested that breastfeeding benefits the visual
development of preterm children, which has been attributed
to the presence of docosahexaenoic acid (DHA) in breastmilk.
Randomized studies showed that preterm children require
a dietary supply of DHA in the first few weeks of life for
optimal visual development, but it is unclear whether full-term
children experience similar benefits from breastmilk or
DHA supplements. The objective of this study was to compare
visual acuity at age 3.5 years in healthy, full-term children
who were breastfed and in similar children who had not been
breastfed after adjustment for socioeconomic status and
maternal diet. The results show that children who had been
breastfed for 4 months were 2.77 times more likely to achieve
high-grade stereoscopic vision than were children who had
not been breastfed. Children whose mothers ate oily fish
during pregnancy were also 1.57 times more likely to achieve
high-grade stereoscopic vision than were children whose
mothers did not eat oily fish. The authors suggest that
for full-term infants, breastfeeding is associated with
enhanced stereoscopic vision at age 3.5 years, as is a maternal
DHA-rich antenatal diet, irrespective of later infant feeding
practice.
Horwood
LJ, Darlow BA, Mogridge N. Breast milk feeding and cognitive
ability at 7-8 years. Arch Dis Child Fetal Neonatal
Ed 2001;84:F23-7.
280 survivors
from a national birth cohort of 413 New Zealand very low
birthweight infants born in 1986 were assessed at age 7-8
years on measures of verbal and performance intelligence
quotient (IQ). At the same time mothers were questioned
as to whether they had elected to provide expressed breastmilk
at birth and the total duration of breastmilk feeding. Some
73% of mothers provided expressed breastmilk and 37% breastfed
for four months or longer. Increasing duration of breastmilk
feeding was associated with increases in both verbal IQ
and performance IQ: children breastfed for eight months
or longer had mean verbal IQ scores that were 10.2 points
higher and performance IQ scores that were 6.2 points higher
than children who did not receive breastmilk. These differences
were substantially reduced after control for selection factors
associated with receipt of breastmilk. Nevertheless, even
after control for confounding factors, there remained a
significant association between duration of breastmilk feeding
and verbal IQ. These findings add to a growing body of evidence
to suggest that breastmilk feeding may have small long-term
benefits for child cognitive development.
Wright
AL, Holberg CJ, Taussig LM, Martinez FD. Factors influencing
the relation of infant feeding to asthma and recurrent wheeze
in childhood. Thorax 2001;56:192-7
Is the relation
between breastfeeding and childhood asthma altered by the
presence of maternal asthma? Healthy non-selected newborn
infants (n=1246) were enrolled at birth to investigate this
hypothesis. Asthma was defined as a physician diagnosis
of asthma plus asthma symptoms reported on at least 2 questionnaires
at 6, 9, 11 or 13 years. Recurrent wheeze (4 or more episodes
in the past year) was reported by questionnaire at seven
ages in the first 13 years of life. Duration of exclusive
breastfeeding was based on prospective physician reports
or parental questionnaires completed at 18 months. Atopy
(a skin manifestation of allergy, considered part of asthma
syndrome) was assessed by skin test responses at the age
of 6 years. The relationship between breastfeeding, asthma,
and wheeze differed with the presence or absence of maternal
asthma and atopy in the child. Children with asthmatic mothers
were almost 9 times more likely to have asthma if they had
been exclusively breastfed. This relationship was only evident
for atopic children. In contrast, the relation between recurrent
wheeze and breastfeeding was age dependent. In the first
2 years of life, exclusive breastfeeding was associated
with about 50% lower rates of recurrent wheeze, regardless
of the presence or absence of maternal asthma or atopy in
the child.
Romieu
I, Werneck G, Ruiz Velasco S, White M, Hernandez M. Breastfeeding
and asthma among Brazilian children. J Asthma 2000;37:575-83
The authors
examined the association of breastfeeding and the presence
of chronic respiratory symptoms among 5,182 Brazilian schoolchildren
7-14 years of age. The prevalence of medically diagnosed
asthma and current wheeze were respectively 4.6% and 11.9%.
90% of the mothers had breastfed their child. Differently
from the previous study (Wright et al.) no exclusive breasfeeding
was reported. Children who had not been breastfed were more
likely to have a medical diagnosis of asthma, experience
current wheeze, and wheeze after exercise, than children
who had been breastfed for more than 6 months. This effect
was only present among children with no family history of
asthma. The low prevalence of asthma and wheeze observed
in this population may be partly related to the high level
of breastfeeding.
Bener
A, Denic S, Galadari S. Longer breastfeeding and protection
against childhood leukaemia and lymphomas. Eur J
Cancer 2001;37:234-8
The authors
investigated the role of breastfeeding in protecting against
childhood acute leukaemia and lymphomas in a case-control
study comprising 117 patients, aged 2-14 years, with acute
lymphocytic leukaemia, Hodgkin's and non-Hodgkin's lymphoma,
as well as 117 controls matched for age, sex and ethnicity.
The median duration of breastfeeding among patients was
significantly shorter than among controls: 7 (range 0-23)
and 10 (range 0-20) months, respectively. Breastfeeding
of 0-6 months' duration, when compared with feeding of longer
than 6 months, was associated with increased risk for acute
leukaemia and Hodgkin's and non-Hodgkin's lymphomas (2.47,
3.75, and 4.06 times, respectively). In multivariate analysis,
breastfeeding duration continues to be an independent predictor
of lymphoid malignancies. In conclusion, breastfeeding lasting
longer than 6 months may protect against childhood acute
leukaemia and lymphomas.
Jones
G, Riley M, Dwyer T. Breastfeeding in early life and
bone mass in prepubertal children: a longitudinal study.
Osteoporos Int 2000;11:146-52
The aim of this
study was to determine whether breastfeeding in early life
is associated with bone mass in 330 8-year-old male and
female children from Southern Tasmania, representing 47%
of those who originally took part in a birth cohort study
of risk factors for Sudden Infant Death Syndrome (Lancet
1991;337:1244-7; N Engl J Med 1993;329:377-82; JAMA 1995;273:783-9).
Breastfeeding intention and habit were assessed in both
1988 and 1996. Bone mineral density was measured by X-ray
densitometry. Children who were breastfed had higher bone
mineral density at the femoral neck, lumbar spine and total
body compared with those who were bottle-fed. This association
with breastfeeding was present in children born at term
but not those born preterm, and remained significant after
adjustment for size, lifestyle factors and socioeconomic
factors. Breastfeeding for less than 3 months was not associated
with increased bone mass at any site. In conclusion, this
study has demonstrated a beneficial association between
breastfeeding in early life and bone mass in 8-year-old
children born at term, particularly those breastfed for
3 months or longer, which appears biological. If this association
is confirmed in other populations and persists until the
attainment of peak bone mass, then the implication would
be that osteoporosis prevention programmes need to start
very early in life.
Leeson
CP, Kattenhorn M, Deanfield JE, Lucas A. Duration of
breast feeding and arterial distensibility in early adult
life: population based study. BMJ 2001;322:643-7
This study tested
the hypothesis that duration of breastfeeding is related
to changes in vascular function relevant to the development
of cardiovascular disease. Participants were 331 adults
(171 women, 160 men) aged between 20 and 28 years, born
in Cambridge Maternity Hospital, UK. The distensibility
of the brachial artery was measured against type and duration
of infant feeding determined by a retrospective questionnaire.
The results showed that the longer the period of breastfeeding
the less distensible the artery wall was in early adult
life. The vascular changes observed were not explained by
alterations in plasma cholesterol concentration in adult
life. Participants, however, were self-selected and there
might have been other infant feeding factors associated
with the outcome that were not detected by the retrospective
questionnaire. In addition, there is no evidence of an association
between distensibility of the brachial artery and subsequent
development of cardiovascular disease. To conclude, the
possible causal relationship between breastfeeding in infancy
and increased risk of cardiovascular disease is not demonstrated
and these data should not alter current recommendations
in favour of breastfeeding.
Singhal
A, Cole TJ, Lucas A. Early nutrition in preterm infants
and later blood pressure: two cohorts after randomised trials.
Lancet 2001;357:413-9
The research
group that published the previous article reported also
the follow up to 13-16 years of a cohort of 926 children
who were born prematurely and had participated at birth
in two parallel randomised trials in five neonatal units
in the UK. The same children had been studied before for
other outcomes (Arch Dis Child 1984;59:722-30; BMJ 1990;300:837-40;
Lancet 1992;339:261-4; BMJ 1998;317:1481-7). The mean arterial
blood pressure at age 13-16 years was lower in the 66 children
assigned banked breastmilk (alone or in addition to mother's
milk) than in the 64 assigned preterm formula (81.9 vs 86.1
mm Hg). No differences were found in the term formula (n=44)
vs preterm formula (n=42) comparison. The children followed
up at age 13-16 years were similar to those not followed
up in terms of social class and anthropometry at birth.
Breastmilk consumption was associated with lower later blood
pressure, a protective factor for cardiovascular disease.
The data provide experimental evidence of programming of
a cardiovascular risk factor by early diet and further support
the long-term beneficial effects of breastmilk.
Zheng
T, Duan L, Liu Y, Zhang B, Wang Y, Chen Y, Zhang Y, Owens
PH. Lactation reduces breast cancer risk in Shandong
Province, China. Am J Epidemiol 2000;152:1129-35
The authors conducted
a hospital-based case-control study in Shandong Province,
China, in 1997-1999. A total of 404 cases and an equal number
of controls were included. Detailed information regarding
lactation, menstruation, and reproduction was collected
through in-person interviews. The authors found a significant
inverse association between duration of lactation and breast
cancer risk. For women who breastfed for more than 24 months
per child, the risk was about 50% lower when compared with
those who breastfed for 1-6 months per child. A significantly
reduced risk of breast cancer was also found for those whose
lifetime duration of lactation totaled 73-108 months and
for those who breastfed for 109 or more months. Further
stratification by menopausal status resulted in the same
conclusion. These data suggest that prolonged lactation
reduces breast cancer risk.
Chang-Claude
J, Eby N, Kiechle M, Bastert G, Becher H. Breastfeeding
and breast cancer risk by age 50 among women in Germany.
Cancer Causes Control 2000;11:687-95
The authors report
the results of a population-based case control family study
of breast cancer among women diagnosed by the age of 50,
conducted in two geographic areas in Germany, to evaluate
the effect of breastfeeding on risk of breast cancer. Among
parous women (553 cases, 1,094 age-matched controls), having
ever breastfed a child for at least 1 month did not confer
protection. However, risk of breast cancer significantly
decreased with increasing duration of breastfeeding and
the estimated risk was 40% lower for 13-24 months of cumulative
breastfeeding and 50% lower for 25 months or more. These
results support a protective role of prolonged breastfeeding
against the development of breast cancer in predominantly
premenopausal women.
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