Breastfeeding And Growth

According to a study of the relationship between nutritional status, growth and mortality risk in a sample ofmore than 5000 children aged 0-5 years, conducted in the Niakhar study area from 1983 to 1985, breastfed children had significantly lower height-for-age and weight-for-height than weaned children from 18 to 36 months of age.7 Traditional midwives, field workers and mothers of underfives in the area consistently stated that this association between malnutrition and breastfeeding did not surprise them, but that it was due to later weaning ofmalnourished children (K. Simondon, unpublished observations). In order to test this statement, a retrospective analysis of factors associated with age at weaning was conducted in a sample of 4515 children, who were born from 1989 to 1995 and had attended vaccination sessions from 1990 to 1996.26 Duration of breastfeeding was analyzed using Cox's proportional hazards models, because about 20% ofthe sample was right-censored, i.e. date of weaning was not available either because the child had died or out-migrated before weaning or because the child was still breastfed when follow-up was stopped. Median duration of breastfeeding was 23.7 months and half of the children were weaned between the ages of21.7 and 25.9 months. Main factors related to duration of breastfeeding were maternal age and parity (greater values were associated with longer durations), height (greater values were associated with shorter durations), education and occupation (if any: shorter durations), and season (longer durations for children born at the end of the rainy season and shortest durations for those born at the onset of the rainy season). The child's height-for-age and weight-for-height at the time of the last vaccination (at 9-10 months of age) were both very significantly associated with age at weaning. Infants with a height-for-age below -2 z-scores at 9-10 months of age were weaned 2.3 months later on average than children with a z-score above 0 (25.0 vs. 22.7 months), while differences were somewhat smaller for weight-for-height (24.2 vs. 23.2 months). These differences remained very significant when all variables linked to duration of breastfeeding were entered into a multivariate Cox model. Although these differences in median duration ofbreastfeeding seemed quite modest, great differences in prevalence of malnutrition existed during late infancy when four groups ofincreasing age ofweaning were compared (Table 1).

Since the high levels of stunting and wasting among children weaned late existed already during infancy, at an age at which all children were still breastfed, prolonged breastfeeding could not be the reason of their poor nutritional status. Our study thus proved that prolonged breastfeeding not necessarily impairs growth, even in communities where breastfed children are more malnourished.

Table 1. Prevalence of stunting and wasting at 9-10 months of age with 95% confidence intervals (CI), by duration of breastfeeding

Table 1. Prevalence of stunting and wasting at 9-10 months of age with 95% confidence intervals (CI), by duration of breastfeeding

Age at weaning (months)

Stunting (%)

95% CI

Wasting (%)

95% CI

<18

6.4

2.4 - 10.3

7.7

3.4 - 12.0

18-23.9

9.5

8.1 - 10.8

9.2

7.8 - 10.6

24-30

1 7.6

15.6 - 19.6

11.9

10.2 - 13.6

>30

26.6

18.7-34.5

14.5

From26

However, since no indicator of economic status was available in the database, these results did not prove that mothers consciously prolonged breastfeeding in response to a poor nutritional status of their child. It was still possible that richer mothers per se had less malnourished children and breastfed for shorter durations. Furthermore, the existence ofother, unknown confounding factors could not be excluded.

Published studies on the relationship between breastfeeding and growth have given conflicting results. Marquis et al found that breastfeeding was associated with faster growth in length (from 12 to 15 months)27 The dependent variable was intensity of breastfeeding, measured as the mean number offeeds per day (from 0-15.3). Thirty-one children were weaned by 12 months and 15 more were weaned during the interval, within the sample of 107. Second, part of the initial sample (27 out of 134 children) was excluded from the analysis because these children with a high diarrheal incidence and low dietary intake from non-breast milk foods were at significantly lower risk of weaning and thus showed evidence of reverse causality, as described above. Since the relationship between breastfeeding intensity and linear growth was negative for these children, no significant relationship between breastfeeding intensity and linear growth existed before their exclusion.22 Even after their exclusion from the analysis, the main effect ofbreastfeeding intensity on linear growth was not significant in a multiple linear regression analysis. However, the interaction between breastfeeding intensity and intake of animal-product foods was significant, which meant that breastfeeding intensity was positively associated with linear growth for children with low intake of animal products only. Growth in weight was not analyzed in this study.

A prospective, community-based study of 1 116 children from periurban Guinea-Bissau used random effect models to assess the effect ofweaning on weight or length, while adjusting for previous weight or length, age, sex, season and previous diarrheal prevalence.28 Weaning was associated with a significant, relative decrease in weight but not in length. The negative effect was strongest during infancy, but remained significant during the second year of life.

A prospective study of the effects of vitamin A supplementation on health and survival in Sudan was used to assess the relationship between breastfeeding and growth in length and weight in a sample of 28,753 children.23From12 to 24 months of age, breastfed children had 2 cm lower length increments and 50-100 g lower weight increments, compared to weaned children. These differences remained in all subgroups when the sample was stratified by economic level and maternal literacy. However, as stated by the authors themselves, it was difficult to exclude the possibility of additional confounding.

New Mothers Guide to Breast Feeding

New Mothers Guide to Breast Feeding

For many years, scientists have been playing out the ingredients that make breast milk the perfect food for babies. They've discovered to day over 200 close compounds to fight infection, help the immune system mature, aid in digestion, and support brain growth - nature made properties that science simply cannot copy. The important long term benefits of breast feeding include reduced risk of asthma, allergies, obesity, and some forms of childhood cancer. The more that scientists continue to learn, the better breast milk looks.

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