Breastfeeding for 4 months or more enhances children's lung volume, cohort study suggests

An infant who is breastfed for 4 months or more may benefit from improved lung volume at age 10 years, a new study concludes. Researchers in the United States and United Kingdom teamed together to study the protective effects of breastfeeding; they specifically evaluated the relationship between breastfeeding duration and later lung volume. The study population was drawn from the Isle of Wight birth cohort (n=1,456), a largely white (99%) group of children recruited between January...

An infant who is breastfed for 4 months or more may benefit from improved lung volume at age 10 years, a new study concludes.

Researchers in the United States and United Kingdom teamed together to study the protective effects of breastfeeding; they specifically evaluated the relationship between breastfeeding duration and later lung volume.

The study population was drawn from the Isle of Wight birth cohort (n=1,456), a largely white (99%) group of children recruited between January 1989 and February 1990. Breastfeeding practices and duration were prospectively assessed at birth and at subsequent follow-up visits (1 and 2 years). The researchers classified children according to how long they were breastfed: not breastfed (n=196), <2 months (n=243), 2 to <4 months (n=142), and >=4 months (n=374). At ages 1, 2, 4, and 10 years, the researchers updated the original questionnaire-based information, and a study physician performed a physical exam and recorded symptoms of asthma and allergic diseases. At age 10 years, lung volume tests were performed on all consenting children (n=1,033); these tests included forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), FEV1/FVC ratio, and peak expiratory flow (PEF). Maternal history of asthma and allergy was assessed at birth.

The researchers evaluated the effect of breastfeeding duration on lung function using 2 statistical models to adjust for variables.

Comparing those who were not breastfed with those who were breastfed 4 months or more, the researchers found a protective benefit of breastfeeding. Specifically, they determined that after adjusting for current height and weight, birth weight, sex, family social status cluster, and maternal education, breastfed children had FVC that was increased by 54.0 mL (P=.001), FEV1 by 39.5 mL (P=.05), and PEF by 180.8 mL/second (P=.006).

In neither model did breastfeeding for a duration <4 months significantly improve children's lung function.

The researchers also tested the association of breastfeeding and lung function on children of mothers with a history of asthma or allergy. In this analysis, neither model showed a significant association, the authors reported, demonstrating that in the study cohort the effect of breastfeeding was not affected by a maternal history of asthma. This finding is contrary to a study published last year (Guilbert TW, et al. Am J Respir Crit Care Med 2007;176:843-848), they noted.

"In conclusion, this paper adds to the evidence supporting the promotion of prolonged breastfeeding for the improvement of lung volume in late childhood," the authors wrote.

These findings were published online Nov. 10 ahead of print in Thorax by Ogbuanu IU, et al.