THE LANCET, Volume 336: Page 942,
Oct 13, 1990.

Breastfeeding and urinary-tract infection

SIR,—As a reaction to a Lancet editorial on case-control studies, Pisacane et al presented such a study suggesting a protective effect of breastfeeding against urinary-tract infection (UTI) in infants 1. We have done a prospective study on a more defined patient population of 81 consecutive children aged 2 1/2 to 6 years (median 0.8 years) with their first known attack of acute pyelonephritis2. The 77 controls were matched for age, sex and living area. complete breastfeeding was significantly briefer among the pyelonephritis patients than among the controls, as our questionnaire on medical history (p < 0.01) and the records from child health centres (p < 0.05) showed. The median duration of complete breastfeeding in the two groups was 9 and 16 weeks, respectively. The difference was seen both among those completely and among those partly breast-fed. The difference in duration of breastfeeding was seen not only in the infants but also in the higher age group. This enduring protective effect suggests that the host defence factors of breast milk must act not just via the directly functioning anti-adhesive capacity of secretory IgA antibodies and receptor analogues against bacteria3,4. There must also be a longer lasting effect, which we assume may be mediated by the effects of breastfeeding on the intestinal flora, promoting a more stable flora with fewer potentially pathogenic strains5. Breastfeeding also seems to make the Escherichia coli strains present lose virulence factors, such as resistance to the bactericidal activity of serum6.

Adhesive bacteria are more often causative in first-time and upper UTI than in recurrent infections, where reflux is more common 7. To elucidate the possible role of the anti-adhesive effects of breast milk on the occurrence of UTI a prospective case-control study of a strictly defined group of patients is required.

Staffan Maarild
Ulf Jodal
Lars Aa. Hanson
Departments of Paediatrics and Clinical Immunology,
University of Göteborg,
S 416 85 Göteborg, Sweden


  1. Pisacane A, Graziano L, Zona G. Breastfeeding and urinary tract infection. Lancet 1990; 336: 50.
  2. Maarild S, Jodal U, Mangelus L. Medical histories of children with acute pyelonephritis compared with controls. Pediatr Infect Dis J 1989; 8: 511-515.
  3. Anderson B, Porras O, Hanson L, Lagergaard T, Svanborg Eden C. Inhibition of attachment of Streptococcus pneumoniae and Haemophilus influenzae by human milk and receptor oligosaccharides. J Infect Dis 1986; 153: 232-237. [PubMed]
  4. Coppa G, Gabrielli O, Giorgi P, et al. Preliminary study of breastfeeding and bacterial adhesion to uroepithelial cells. Lancet 1990; 335: 569-571.
  5. Adlerberth I, Carlsson B, DeMan P, et al. Intestinal colonization with Enterobacteriaceae in Pakistani and Swedish hospital-delivered infants. Acta Paediatr Scand (in press).
  6. Gothefors L, Olling S, Winberg J. Breast-feeding and biological properties of faecal E coli strains. Acta Paediatr Scand 1975; 64: 807-812.
  7. Lomberg H, Hellstroem M, Jodal U, Leffler H, Lincoln K, Svanborg Eden C. Virulence-associated traits in Escherichia coli causing first and recurrent episodes of urinary-tract infection in children with and without vesicoureteral reflux. J Infect Dis 1984; 150: 561-569.

(File revised 15 September 2006)

Return to CIRP library