No significant associations between breastfeeding practices and overweight in 8‐year‐old children

Abstract

Aim The aim was to examine if breastfeeding practices were associated with body mass index (BMI) and risk of overweight or obesity in third grade (8 years) of elementary school. Methods In a regional cohort, we related BMI z‐scores and presence of overweight or obesity at 8 years of age with ever being breastfed and with duration of exclusive and partial breastfeeding after adjusting for potential confounders. Parents completed questionnaires on breastfeeding and sociodemographic and lifestyle factors at school entry, and public health nurses measured height and weight. For non‐participants, the nurses anonymously reported these measurements together with sex and age. Results 90% of participants had been breastfed. In adjusted analyses, BMI z‐scores were not significantly related to whether or not the child had been breastfed (P = .64), or to the duration of exclusive (P = .80) or partial breastfeeding (P = .94). Logistic regression also showed no significant association between breastfeeding measures and overweight or obesity. Conclusion This study on 8‐year‐old Norwegian children did not support a commonly held notion that breastfeeding reduces the risk of overweight or obesity.

The Duration, Frequency, and Volume of Exclusive Human Milk and/or Infant Formula Consumption and Overweight and Obesity: A Systematic Review

“…Thirty articles, published between 2003 and 2019, were identified that met the inclusion criteria and examined ever, compared with never, consuming human milk and overweight and/or obesity. [1][2][3][4][5][6][7][8][9][10][11][14][15][16][17][19][20][21][22]26,27,[30][31][32][35][36][37][39][40][41] They presented evidence from 21 independent studies. Four of the 21 studies were also described in the section about evidence from siblings (i.e., Linked CENTURY Study, Children of NLSY79, Add Health, and CDS).…”

“…Thirty articles presented evidence from 21 independent studies about the relationship between ever, compared with never, consuming human milk and overweight and/or obesity at 2 years of age and older. [1][2][3][4][5][6][7][8][9][10][11][14][15][16][17][19][20][21][22]26,27,[30][31][32][35][36][37][39][40][41] A synthesis and assessment of the evidence follows.…”

“…The remaining 6 studies may have had insufficient statistical power for some of their analyses, which may account for the lack of statistical significance (see Precision, below). 4,7,9,11,15,30 A closer examination of the evidence from 7 studies (which divided participants into more than 1 group of infants ever fed human milk, based on how long infants consumed human milk, and compared these infants with infants never fed human milk) revealed a trend in the data. Five of the 7 articles found that a longer duration of human milk consumption (e.g., >6 months), compared to never consuming human milk, was significantly associated with lower risk of overweight and/or obesity, but that a shorter duration (e.g., <6 months) was not:…”

“…Associations reported by 3 other studies had confidence intervals greater than 1, which suggests insufficient statistical power. 4,9,15 The final 2 studies did not report confidence intervals 7,30 ; however, de Jong et al 7 had fewer participants than many of the samples in the body of evidence (about 250 participants), and Moschonis et al 30 suggested that analyses of their sample from the EuroPrevall cohort (about 300 participants) in their multi-cohort study, in particular, may have been underpowered.…”

Highlights in this issue

“…Bjertnæs et al examined whether breastfeeding was associated with body mass index (BMI) and the risk of overweight or obesity in a regional Norwegian cohort of 8‐year‐old children. They found that 90% had been breastfed, but the adjusted analyses of the BMI scores were not significantly related to breastfeeding.…”