The relationship between breastfeeding and weight status in a national sample of Australian children and adolescents.
Subject: Children (Physiological aspects)
Breast feeding (Health aspects)
Obesity in children (Risk factors)
Teenagers (Physiological aspects)
Youth (Physiological aspects)
Body weight
Author: Dickson, Emily
Pub Date: 11/01/2012
Publication: Name: Breastfeeding Review Publisher: Australian Breastfeeding Association Audience: Academic Format: Magazine/Journal Subject: Health Copyright: COPYRIGHT 2012 Australian Breastfeeding Association ISSN: 0729-2759
Issue: Date: Nov, 2012 Source Volume: 20 Source Issue: 3
Topic: Event Code: 310 Science & research
Product: Product Code: E121920 Children; E121930 Youth
Geographic: Geographic Scope: Australia Geographic Code: 8AUST Australia
Accession Number: 310739995
Full Text: The relationship between breastfeeding and weight status in a national sample of Australian children and adolescents Scott JA, Ng SY, Cobiac L 2012, BMC Public Health 12: 107.

The number of overweight and obese children has increased rapidly globally since the mid-1980s. Research has consistently shown that breastfeeding is protective against being overweight or obese in later life with studies concluding that breastfed children were 22% less likely to be considered as overweight or obese than individuals who had not been breastfed. In Australia, 22% of boys and 25% of girls aged 2 to 16 years were reported as being overweight or obese in 2007 but there has been little research investigating the association between breastfeeding and being overweight or obese in Australian children and adolescents.

In this study, data from the 2007 Australian National Children's Nutrition and Physical Activity Survey (NCNPAS) was analysed using multivariate logistic regression analysis to identify any association between weight status and breastfeeding duration. The final sample involved 2066 children aged 9 to 16 for whom there was complete data on daily energy intake, physical activity, total screen time, hours of sleep, height, weight, birth weight, breastfeeding duration, and sociodemographics. The mother's recall of breastfeeding duration was categorised as: no breastfeeding, < 2 months, 2-< 4 months, 4-< 6 months, and [greater than or equal to] 6 months. It was not possible to distinguish partial breastfeeding from exclusive breastfeeding.

Results indicated that the majority of the children (92.4%) had been breastfed, 57.4% for over 6 months and that most (69.6%) were in the healthy weight range for their age, while 18.7% were overweight and 6.4% were obese. More than half of the mothers (57 4%) had completed 12 or more years of schooling, 78.1% of the children met the National Physical Activity Guidelines of 60 minutes or more of moderate-to-vigorous physical activity per day but failed (83. 1%) to meet the screen guidelines of less than 2 hours of screen time. After adjusting the results for maternal characteristics (age, education, and ethnicity) and children's age, gender, mean energy intake, level of moderate and vigorous physical activity, screen time and sleep duration, it was found that those children who had been breastfed for over 6 months were 36% less likely to be overweight (adjusted OR 0.64, 95% CI 0.44-0.91) and 49% less likely to be obese (adjusted OR 0.51, 95% CI 0.29-0.90), compared with children who were never breastfed This was a dose-related effect, the shorter the duration of any breastfeeding, the higher the risk of being overweight or obese.

The researchers suggested three possible mechanisms to explain this dose-related effect. It could be a phantom relationship, caused by an unidentified confounding factor which has not been controlled for. Breastfed children may maintain better appetite control; they may recognise satiety signals more effectively than bottle-fed babies who are usually fed to a schedule and often made to finish a bottle even though they may no longer be hungry. A third plausible mechanism is that there may be long-term metabolic consequences caused by the different composition of artificial baby milk compared with breastmilk.

The limitations of the study are that breastfeeding duration was determined by maternal recall of an event 9 to 16 years previous. Maternal characteristics which are associated with childhood obesity, such as maternal BMI, or with breastfeeding duration, such as smoking during pregnancy, could not be adjusted for, because this information was not collected. It was also not possible to measure or adjust for exclusivity of breastfeeding. Despite these limitations, the findings of this Australian study were consistent with those of previous analyses showing that no or short breastfeeding is associated with an increased risk of being overweight or obese in later life. ED

ED Emily Dickson BA, LTCL TEFSL, Gr Cert Hlth St
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