Bottle-feeding Linked to Hypertrophic Pyloric Stenosis

Lara C. Pullen, PhD

October 21, 2013

Bottle-feeding is associated with hypertrophic pyloric stenosis (HPS), according to a population-based case-control study. The effect is most pronounced in the children of older and multiparous women.

Jarod P. McAteer, MD, MPH, from the Division of Pediatric General and Thoracic Surgery at Seattle Children's Hospital in Washington, and colleagues published the results of their study online October 21 in JAMA Pediatrics.

To evaluate the effects of early feeding practice on the development of HPS, the researchers enrolled 714 patients in the observational study. The population included births from January 1, 2003, to December 31, 2009, in Washington State.

The researchers based their analysis on feeding status during birth admission and did not document any switches in feeding that may have occurred at home before the development of HPS.

The investigators found that the incidence of HPA decreased over time, going from 14 per 10,000 births in 2003 to 9 per 10,000 births in 2009. During the same period, the prevalence of breast-feeding increased from 80% to 94%.

The authors calculated that bottle-feeding was associated with an increased risk for HPS (odds ratio [OR], 2.31; 95% confidence interval, 1.81 - 2.95) compared with breast feeding, after adjusting for multiple factors, including infant sex, maternal smoking status, and race.

When the investigators performed subgroup analyses, they found that maternal age was associated with increased risk for HPS (<20 years: OR, 0.98; 95% CI, 0.51 - 1.88; ≥35 years: OR, 6.07; 95% CI, 2.81 - 13.10). Similarly, infants born to multiparous women had an increased risk for HPS (nulliparous OR, 1.60; 95% CI, 1.07 - 2.38; multiparous OR, 3.42; 95% CI, 2.23 - 5.24) compared with first-born infants.

"Our understanding of HPS has advanced greatly since the condition was first described by Hirschsprung in 1888, and diagnostic and treatment paradigms are well established," the authors write." In spite of this, the cause of this disease remains an enigma. It is generally accepted that the etiology is multifactorial, but the relative contributions of genetic and environmental factors, and how those factors interact to cause pyloric muscle hypertrophy within a narrow window in early infancy, are unknown.

They propose that formula osmolarity and gastrointestinal protein content may provide mechanisms by which feedings affect the development of HPS. They had more difficulty explaining the effects of maternal age on the development of HPS.

The link between bottle-feeding and HPS is convincing, with these new data confirming the results of smaller studies, writes Douglas C. Barnhart, MD, MSPH, from the Division of Pediatric Surgery, University of Utah in Salt Lake City, in an accompanying editorial.

However, the mechanism behind the association with multiparous, older mothers is less obvious, he says. "This type of observation is hypothesis generating rather than mechanistically conclusive. It is possible that this effect of bottle feeding is simply more easily demonstrated in these overall lower-risk groups but is still equally present in the first-borns of younger mothers."

The authors and editorialist have disclosed no relevant financial relationships.

JAMA Pediatr. Published online October 21, 2013.


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