1 From the Departments of Pediatrics and Epidemiology and Public Health, Yale University School of Medicine, New Haven, CT
To determine whether breast-feeding protects infants from infections, a case-control study was conducted. The cases were previously healthy children who were admitted to Yale-New Haven Hospital for an infectious illness at or before 90 days of age. The controls were chosen from the log of births and matched to the cases for five important demographic variables. In addition, logistic regression models were used to adjust the results for other potential confounders. To minimize the potential surveillance bias that might occur if formulafed and breast-fed infants with the same degree of illness have a different probability of being hospitalized, the case-control pairs were stratified by the severity of the medical condition of the case at the time of hospitalization. For the 281 case-control pairs, the matched odds ratio was .50 (95% confidence interval .32, .77; P < .005), which indicates that breast-feeding is protective against infections. However, this apparent protective effect was diminished substantially when the data were stratified according to the severity of illness: the matched odds ratio for the 164 infants with serious illnesses was .79 (.47, 1.32; P < .50), and for the 117 infants with mild illnesses it was .17 (.03, .44; P < .001). These stratified results suggest that breast-feeding protects infants from hospitalization rather than from infections. Failure to consider the problem of surveillance bias may lead to erroneous conclusions about the protective effect of breast-feeding.
Key Words: breast-feeding infection surveillance bias
Submitted on August 1, 1985
Accepted on February 10, 1986
This article has been cited by other articles:
![]() |
J. M. Paricio Talayero, M. Lizan-Garcia, A. O. Puime, M. J. B. Muncharaz, B. B. Soto, M. Sanchez-Palomares, L. S. Serrano, and L. L. Rivera Full Breastfeeding and Hospitalization as a Result of Infections in the First Year of Life Pediatrics, July 1, 2006; 118(1): e92 - e99. [Abstract] [Full Text] [PDF] |
||||
![]() |
V. R. G. Bachrach, E. Schwarz, and L. R. Bachrach Breastfeeding and the Risk of Hospitalization for Respiratory Disease in Infancy: A Meta-analysis Arch Pediatr Adolesc Med, March 1, 2003; 157(3): 237 - 243. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. L. Wright, M. Bauer, A. Naylor, E. Sutcliffe, and L. Clark Increasing Breastfeeding Rates to Reduce Infant Illness at the Community Level Pediatrics, May 1, 1998; 101(5): 837 - 844. [Abstract] [Full Text] [PDF] |
||||
![]() |
P. D. Scariati, L. M. Grummer-Strawn, and S. B. Fein A Longitudinal Analysis of Infant Morbidity and the Extent of Breastfeeding in the United States Pediatrics, June 1, 1997; 99(6): e5 - e5. [Abstract] [Full Text] [PDF] |
||||
![]() |
U.E. MacIntyre and A R P Walker Lactation - How Important is it? The Journal of the Royal Society for the Promotion of Health, February 1, 1994; 114(1): 20 - 28. [Abstract] [PDF] |
||||
![]() |
M. Walker A Fresh Look at the Risks of Artificial Infant Feeding J Hum Lact, June 1, 1993; 9(2): 97 - 107. [Abstract] [PDF] |
||||
![]() |
K. G. Auerbach, M. J. Renfrew, and M. Minchin Infant Feeding Comparisons: A Hazard to Infant Health? J Hum Lact, June 1, 1991; 7(2): 63 - 71. [Abstract] [PDF] |
||||
![]() |
A. S. Cunningham Studies of breastfeeding and infections. How good is the evidence? A critique of the answer from Yale J Hum Lact, June 1, 1988; 4(2): 54 - 56. [PDF] |
||||