The New Mexico
Breastfeeding
Task Force
R. C. Gorman
BREASTFEEDING LITERATURE
(From peer reviewed journals--links and commentary)
"Nowhere in clinical medicine is practice more in conflict with the published data than in maternal/infant care."  Marsha Walker, RN,  IBCLC
LOWER RESPIRATORY TRACT INFECTIONS

The evidence continues to mount that breastfeeding is protective against lower respiratory tract infection and hospitalization.  In a study of Alaska native children published in Pediatrics in February, 2002 Bulkow et al found that breastfeeding was associated with a lower risk of hospitalization  for Respiratory Syncitial Virus (RSV) infection. Household crowding and pre-existing serious medical conditions were associated with increased risk of hospitalization. The authors suggest that  encouraging breastfeeding and reducing household crowding, could reduce the risk of hospitalization attributable to RSV. (Medline abstract)
BREAST CANCER

The 1997 American Acadamy of Pediatrics Policy Statement on Breastfeeding and Human Milk cautiously suggests that breastfeeding may be protective against pre-menapausal breast cancer.  Now a study by the Collaborative Group on Hormonal Factors in Breast Cancer confirms that breastfeeding is protective against breast cancer regardless of menapausal  status.  This  study, which was published in Lancet on July 20, 2002  analysed 47 studies from 30 countries, and took into account more than 80% of the world-wide data on breastfeeding and breast cancer.
The study found that the the relative risk of breast cancer decreased by  4.3% for every 12 months of breastfeeding.  The much higher incidence of breast cancer in the developed world can be explained by the smaller number of births and the shorter duration of breastfeeding that is typical of women in  these countries.   If women in the developed world had the average number of births and lifetime duration of breastfeeding that has been prevalent in the developing world, the incidence of breast cancer could be reduced by more than half.  Breastfeeding could account for two thirds of this estimated reduction. (Medline abstract)                                     
COGNITIVE DEVELOPMENT

 A meta-analysis of 11 studies looking at cognitive development was published in the American Journal of Clinical Nutrition in 1999.  The authors, Anderson et al,  found that, after adjustment for appropriate key cofactors, breast-feeding was associated with significantly higher scores for cognitive development than was formula feeding (3.16 points). This finding was more marked for low birth weight infants (5.18 points). (Medline abstract).   More recently, in July, 2002, another  meta-analysis by Jain et al was published in Pediatrics.  These authors looked at 40 studies in the literature dating from 1929 to 2001, and found that 68% of them noted a favorable effect on intellegence.  However, only 2 met their methodological criteria, which included limitation to term infants. While both found differences favoring term breastfed babies, only one had statistical significance. (Medline abstract).  Of course, one can only conclude that more high quality studies are needed.

The saluatory effect of breastfeeding on small for gestational age (SGA) infants is more definite.  Rau et al writing in Acta Paediatrica in March 2002 found that small term babies who were breastfeed for 24 weeks had an 11 point IQ advantage over small babies who were breastfed for only 12 weeks when evaluated at age 5 years. (Medline abstract).

Finally, Mortensen et al writing in the Journal of the American Medical Association in June 2002 reported a positive correlation with the duration of  breastfeeding in infancy to intelligence in young adulthood.  Only one previous study has addressed this issue. The authors used the Wechsler Adult Intelligence Scale (WAIS) to evaluate a mixed sex sample, and the Borge Priens Prove (BPP) test to evaluate an all male sample.  The mean Full Scale WAIS IQs were 99.4, 101.7, 102.3, 106.0, and 104.0 respectively, for breastfeeding durations of less than 1 month, 2 to 3 months, 4 to 6 months, 7 to 9 months, and more than 9 months.  The corresponding mean scores on the BPP were 38.0, 39.2, 39.9, 40.1, and 40.  These differences were, of course, statistically significant and, like many breastfeeding studies regardless of endpoint, show a dose response relationship.(Medline abstract).

OBESITY

A number of studies have shown a favorable effect of breastfeeding on obesity.  For example, Von Kries and Koletzko reported on Pima Indians here in the Southwest in 2001 and found at age 3 a 17% incidence of obesity in never breastfed infants compared to less than 6% in infants breastfed for greater than 12 months. (Abstract not available).  Now in a very different population based study of 32,200 children in Scotland, Armstrong and Reilly report that breastfeeding in infancy reduced the risk of obesity by 30% at age 3. (Medline abstract).


TYPE 2 DIABETES

Early exposure to cow's milk has been implicated in the occurrence of type 1, insulin-dependent diabetes mellitus.  There are now studies which suggest that breastfeeding may also protect against type two diabetes particularly among North  American Native populations. (Medline abstract, Pettitt, D et al) (Medline abstract, Young TK et al).  While the epidemics of obesity and type 2 diabetes are associated, one can infer from Young et al  that breastfeeding may offer protection from type 2 diabetes which is  independent of its favorable effect on obesity.  Quoting other authors they say that  "a study of Australian 2 year olds found that those who were exclusively breastfed had lower plasma glucose levels and higher levels of of long-chain polyunsaturated fatty acids than those who were bottle fed.  Early changes in skeletal muscle membrane phospholipid fatty acid saturation have been postulated to play a role in the development of insulin resistance."


ANKYLOGLOSSIA (TOUNGUE-TIE) AND BREASTFEEDING

Ankyloglossia in the newborn is the subject of ongoing controversy among medical professionals regarding speech, feeding and mechanical problems.  The latter includes difficulties experienced by the breastfeeding dyad, specifically poor latch and nipple pain. The literature is somewhat sparse on this issue.  However, an engaging study looking at the efficacy of frenuloplasty has just been published in Pediatrics.  Ballard, Auer and Khoury evaluated 3036 infants with breastfeeding problems and found 123 infants with ankyloglossia.  Latch and nipple pain were quantitatively evaluated before and after the proceedure and significant improvement was noted in both endpoints.  Additionally, the article discribes the frenuloplasty proceedure which can be done without anesthesia in infants younger than 4 months, and should not require referral to a surgical specialist.  (Medline abstract).