Breastfeeding and Health

Breast Cancer Risk Cut by Almost Half in At-Risk Women who Breastfeed

Journal of the National Cancer Institute, 
Vol. 96, No. 14, 1094-1098, July 21, 2004
 
DOI: 10.1093/jnci/djh211

Breast-feeding and the Risk of Breast Cancer in BRCA1 and BRCA2 Mutation Carriers 
H. Jernström, J. Lubinski, H. T. Lynch, P. Ghadirian, S. Neuhausen, C. Isaacs, B. L. Weber, D. Horsman, B. Rosen, W. D. Foulkes, E. Friedman, R. Gershoni-Baruch, P. Ainsworth, M. Daly, J. Garber, H. Olsson, P. Sun, S. A. Narod


Methods:

We conducted a case—control study of women with deleterious mutations in either the BRCA1 or the BRCA2 gene. Study participants, drawn from an international cohort, were matched on the basis of BRCA mutation (BRCA1 [n = 685] or BRCA2 [n = 280]), year of birth (± years), and country of residence. The study involved 965 case subjects diagnosed with breast cancer and 965 control subjects who had no history of breast or ovarian cancer. Information on pregnancies and breast-feeding practices was derived from a questionnaire administered to the women during the course of genetic counseling. Conditional logistic regression analyses were used to estimate odds ratios (ORs) for the risk of breast cancer. All statistical tests were two-sided.


Results:

Among women with BRCA1 mutations, the mean total duration of breast-feeding was statistically significantly shorter for case subjects than for control subjects (6.0 versus 8.7 months, respectively; mean difference = 2.7 months, 95% confidence interval [CI] = 1.4 to 4.0; P<.001). The total duration of breast-feeding was associated with a reduced risk of breast cancer (for each month of breast-feeding, OR = 0.98, 95% CI = 0.97 to 0.99; Ptrend<.001). Women with BRCA1 mutations who breast-fed for more than 1 year were less likely to have breast cancer than those who never breast-fed (OR = 0.55, 95% CI = 0.38 to 0.80; P = .001), although no such association was seen for BRCA2 (OR = 0.95, 95% CI = 0.56 to 1.59; P = .83).


Conclusions:

Women with deleterious BRCA1 mutations who breast-fed for a cumulative total of more than 1 year had a statistically significantly reduced risk of breast cancer.

Breastfeeding and the Risk of Postneonatal Death in the United States

PEDIATRICS Vol. 113 No. 5 May 2004, pp. e435-e439

pediatrics.aappublications.org

ABSTRACT:

Objective

Breastfed infants in the United States have lower rates of morbidity, especially from infectious disease, but there are few contemporary studies in the developed world of the effect of breastfeeding on postneonatal mortality. We evaluated the effect of breastfeeding on postneonatal mortality in United States using 1988 National Maternal and Infant Health Survey (NMIHS) data.

Methods

Nationally representative samples of 1204 infants who died between 28 days and 1 year from causes other than congenital anomaly or malignant tumor (cases of postneonatal death) and 7740 children who were still alive at 1 year (controls) were included. We calculated overall and cause-specific odds ratios for ever/never breastfeeding among all children, conducted race and birth weight-specific analyses, and looked for duration-response effects.

Results

Overall, children who were ever breastfed had 0.79 (95% confidence interval [CI]: 0.67-0.93) times the risk of never breastfed children for dying in the postneonatal period. Longer breastfeeding was associated with lower risk. Odds ratios by cause of death varied from 0.59 (95% CI: 0.38-0.94) for injuries to 0.84 (95% CI: 0.67-1.05) for sudden infant death syndrome.

Conclusions

Breastfeeding is associated with a reduction in risk for postneonatal death. This large data set allowed robust estimates and control of confounding, but the effects of breast milk and breastfeeding cannot be separated completely from other characteristics of the mother and child. Assuming causality, however, promoting breastfeeding has the potential to save or delay ~720 postneonatal deaths in the United States each year.


Aimin Chen, MD, PhD and Walter J. Rogan, MD

From the Epidemiology Branch, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina

See the full article on pediatrics.aappublications.org.

Breastfeeding a potent painkiller for infants: study

April 2, 2002 - Reuters

CHICAGO - Breastfeeding eases a baby’s discomfort during a painful needle stick procedure and might work as a potent painkiller during potentially traumatizing experiences such as circumcision, researchers said yesterday.

Infants who were held and breastfed while undergoing a painful heel lance, a routine hospital procedure used to obtain a blood sample, cried and grimaced less and their heartbeats remained calmer than infants who were not breastfed, a University of Chicago study said.

"Breastfeeding is a potent analgesic intervention in newborns during a standard blood collection," study author Larry Gray of the University of Chicago wrote in this month’s issue of the journal Pediatrics.

Previous animal studies have shown tastes and flavours in breastmilk can block pain signals in the spinal cord, and suckling can have a calming effect. The researchers said infants' physical contact with their mothers likely also kept them calmer.

There is a debate about whether babies retain memories of single, intensely painful experiences such as circumcision, but some circumcised infants do manifest exaggerated reactions to a needle stick months later.

"The claim can no longer be made that newborn pain is for the moment only," Gray wrote.

In another study in the same journal on the subject of breastfeeding, researchers at the University of New Hampshire in Durham examined the hypothesis that a mother who exercises might produce less appetizing breastmilk.

A previous study found lactic acid levels in breastmilk 30 minutes after a strenuous treadmill test were high enough to deter some babies from drinking it.

In the latest study, researchers waited an hour after exercise before obtaining expressed breastmilk, and also compared milk produced after moderate exercise.

Strenuous exercise did raise the level of lactic acid in the mothers' breastmilk, but their babies showed no sign of rejecting the milk, researcher Timothy Quinn wrote. Moderate exercise did not produce higher lactic acid levels.

HIV positive mothers in developing countries advised to breastfeed for 6 months and then abruptly wean.

Breastfeeding best for infant, HIV mothers in Africa told

By STEPHANIE NOLEN

Research shows health benefits for the newborn outweigh the risks of transmitting disease through milk, STEPHANIE NOLEN writes

Globe and Mail Update 
Tuesday, January 6, 2004

HARARE -- On health-clinic walls across Africa, the posters have shouted the same cheery message for years now: "Breast is best!"

Breastfeeding passes on crucial antibodies to babies, protects them against allergies, promotes their cognitive development and is much safer than formula that must be mixed with possibly contaminated water.

But then came AIDS. Ninety per cent of people with HIV in Africa don't know they have it and many women first learn they carry the virus when they're already pregnant and are tested at a prenatal clinic.

Half of the children with HIV in sub-Saharan Africa today were infected with the disease through breast milk from their HIV-positive mothers.

Doctors in North America first discovered that a woman with the virus could pass it on in breast milk in 1985. Soon, Western women with HIV were being strongly advised not to breastfeed.

But in Africa, it’s the poorest women -- those least able to afford formula or have access to clean water with which to mix it -- that are statistically the most likely to be infected with HIV.

"You can't just say, ’don't breastfeed.' That’s a death sentence for many babies. Fine, they won't get HIV, but they will die of diarrhea," said Jean Humphrey, who heads Zvitambo, a research project funded in part by Canada that examines HIV and breastfeeding in Zimbabwe.

The issue soon pitted Western scientists against doctors in sub-Saharan Africa. From the West came pressure on the World Health Organization to adopt the policy that HIV-positive women should not breastfeed; from doctors in Africa and elsewhere in the Third World came the reply: So then what?

"It’s a real dilemma, and I’m not pretending it’s easy to solve, but what I resent is the old colonial attitude, 'Look, the U.S. does it and Canada does it, so why don't we do it?' " said Hoosen Coovadia, professor of HIV/AIDS research at the Nelson Mandela School of Medicine at the University of KwaZulu-Natal. "This is a huge cultural question."

African researchers, including Prof. Coovadia, assessed the relative risks of transmitting HIV versus diarrhea, and decided the way forward might be better breastfeeding.

The early results are surprising. They suggest the best thing a mother with HIV can do for her baby is to breastfeed, all the time. "Unicef didn't believe us when we told them the results [of the first studies]," Dr. Coovadia said. "Now, they’ve stopped subsidizing formula."

While the researchers are still puzzling over exactly why this is, they have found that breast milk really is best. Anything else given to an infant -- water, bits of porridge or cooking oil (given in this region to combat constipation) irritate the lining of the gut, increasing the possibility that the baby’s body will absorb the HIV virus. So researchers are now proposing that women practise "exclusive breastfeeding and abrupt weaning." That is, nothing at all except breast milk for six months, and then an abrupt cutoff.

Six months is the current best guess at an optimal length of time that allows babies to get the most important benefits of breast milk while trying to minimize the length of exposure to the virus.

But safer breastfeeding is not as easy as a quick conversation at the clinic. If women are being encouraged to wean abruptly at six months, they must receive intense support from counsellors and their community as it can be deeply traumatic for both mothers and their infants, explained Katherine Semrau, project co-ordinator for the Zambia Exclusive Breastfeeding Study run at a Lusaka clinic. Mothers can end up with breast diseases such as mastitis, and anguished babies can become malnourished.

Mothers also need to be taught the safest possible techniques for breastfeeding to reduce the risk of problems such as cracked nipples, which will increase the possibility of blood being passed to the baby along with breast milk.

Dr. Humphrey said her team has also realized the importance of looking at issues of consent since many rural Zimbabwean women don't make the decisions about child-rearing. Rather, they must follow instructions from their partners or mothers-in-law.

Dr. Coovadia believes that if women with HIV choose to breastfeed and are shown the safest way to do it, and follow the guidelines, their risk of transmission to their babies may be as low as 6 per cent. "Safer breastfeeding is now the only real choice," Dr. Humphrey said.